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Anesthesia for Abdominal Surgery
ANESTHESIA FOR ABDOMINAL SURGERY
B. ORR WITH the introduction in recent years of new agents and methods of anesthesia, the range of choice of anesthesia has widened so that we cannot now say unreservedly that anyone procedure is best for a given operation. There are still certain general principles and criteria, however, which must be considered in the choice of anesthesia for abdominal surgery. ROBERT
FACTORS AFFECTING THE CHOICE OF THE ANESTHETIC
The first and most important principle to be kept in mind is to choose the anesthesia which will offer to the patient the greatest degree of safety and assure him as far as possible an ultimate complete recovery. Factors to be considered in achieving this objective are: (1) the skill and experience of the anesthesiologist, (2) the effect of the anesthesia on the pathologic condition present, (3) the production of ideal operating conditions for the surgeon, and (4) the choosing of a method which is psychologically suited to the individual patient. The Skill and Experience of the Anesthesiologist.-The skill and experience of the anesthesiologist is probably the most important factor in the choice of anesthesia for abdominal surgery. Obviously, it would be better from the standpoint of the patient to have open drop ether administered by one who is familiar with that method than to have the same person administer a spinal anesthetic to that patient and be unaware of the complications of high spinal anesthesia, such as circulatory disturbances, and so forth, and unable to handle these complications should they occur. The modern trained anesthesiologist must have a knowledge of existing pathologic processes, and be familiar with the pharmacologic action of the various anesthetic drugs especially as they relate to diseased tissues of the patient. He must be skilled in the administration of any anesthetic agent he may wish to employ and must also be capable of handling any of the complications which might arise during the administration of that agent.
The Effect of the Anesthetic Agent on the Pathologic Condition Present.-The effect of the anesthetic agent on the pathologic condition present may have an important bearing on the outcome of the operation. All of the anesthetic agents disturb physiologic functions, some to a much greater extent than others. It is wise to choose an agent which will have the least deleterious effect on already damaged tissues. Probably the most common pathologic condition associated with abdominal operations which may affect the choice of anesthesia is disturbed liver function. In patients with marked liver damage, such as that seen following damage to the bile ducts with obstruction, the wise choice of agents both for premedication and for the operation may be a large factor in determining the successful outcome for the patient. The use of an intermediate acting barbiturate, such as nembutal, for premedication 687
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in such a case may be so depressing that it would be unsafe to proceed with the operation and in some cases even resuscitative measures might be necessary . We believe that the use of pentothal during the operative procedure should be avoided if possible although some think that since the liver is not the main site of detoxification of the ultrashort acting barbiturates, the use of pentothal is not contraindicated. We consider spinal anesthesia the method of choice because of the excellent relaxation and lack of toxic effects, with cyclopropane as the agent of choice for supplementary inhalation anesthesia in these patients because of its lack of disturbance of liver physiology and because of the high concentration of oxygen that can be given with it. The use of ether in operations on the biliary tract is considered a poor choice because of its toxic effect on the liver, although lately it is believed that many of the toxic effects previously ascribed to ether per se were actually the result of accompanying anoxia. Another pathologic condition frequently seen in patients who are to have abdominal operations is intestinal obstruction. Here again, a knowledge of the effect of the various anesthetic agents on the function of the intestine is important. Van Liere, Northup, and Stickney4 have reported on the effects of various agents on the motility of the colon in dogs under light barbital anesthesia. They first demonstrated that barbital in the majority of cases did not appreciably affect the activity of the colon. They then showed that chloroform, diethyl ether and divinyl ether produced a decrease in tone and practically abolished colonic contractions. This was presumably owing to stimulation of the sympathico-adrenal system. Cyclopropane, ethyl bromide and ethyl chloride produced spasm of the muscles of the colon. The action of cyclopropane is attributed -to its cholinergic action. With deep cyclopropane anesthesia contractions are inhibited. Nitrous oxide produced spasm of the musculature which was maintained even when the gas was administered in concentrations high enough to produce a severe degree of anoxia. It was, therefore, presumed that the stimulating action of the nitrous oxide predominated over the degree of anoxia which accompanies high concentrations of nitrous oxide. In human beings the administration of spinal anesthesia produces increased intestinal tone as a result of relative increase in vagal effects. Thus, the intestine is contracted and occupies a much smaller space in the abdominal cavity. This effect of spinal anesthesia in producing contraction of the intestine may theoretically be used as an argument against the use of spinal anesthesia for intestinal obstruction in that it might produce a perforation. We have never seen this occur, however, and believe that the advantages of spinal anesthesia in most cases far outweigh the possibility of this complication. The most dangerous complication which may occur in administering anesthesia to patients with intestinal obstruction is that of aspiration of vomitus. These patients have varying degrees of distention and usually the stomach contains moderate to large amounts of fluid. Even though a Miller-Abbott tube has been passed to depress the bowel there may still be fluid in the stomach so that it should be a routine procedure in all cases of intestinal obstruction to pass a Levin tube into the stomach
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and empty the stomach completely. An added precaution is to wash out the stomach with small amounts of normal saline solution or water so that if there is inadvertent aspiration of vomitus, the material will not be highly acid and thus irritative to the respiratory membranes. If spinal anesthesia is definitely contraindicated, as in the presence of cerebrospinal diseases, infection about the vertebral column, anatomical abnormalities making puncture impossible, or a very poor risk patient, the safest procedure is to intubate the patient under topical anesthesia using an endotracheal tube with an inflatable balloon cuff. Then the patient may be anesthetized with either pentothal or cyclopropane without danger of aspirating vomitus. Curare may then be used to produce the required relaxation. Another important point is that at the end of the operation before the endotracheal tube is removed a careful check with the surgeon should be made to be sure that the stomach is empty. The danger of aspiration is just as great at the end of the operation as it is in the early stages. A large number of patients who come to the clinic for abdominal operations have accompanying heart disease, especially in the older age groups. These patients may be roughly divided into three groups: those with cardiac irregularities, those with congestive failure or a history of congestive failure in the past, and those with a history of a myocardial infarct. In the first group the choice of anesthesia is not too much of a problem provided the cardiac irregularity is not also accompanied by a history of congestive failure or myocardial infarct. The main contraindication is against the use of cyclopropane where the increased irritability of the cardiac musculature may lead to ventricular fibrillation. Other forms of anesthesia, such as spinal, pentothal-curare combinations or ether, may be used as indicated, always bearing in mind that adequate amounts of oxygen must be available to the tissues. Many times it has been observed that a cardiac irregularity will disappear under ether anesthesia. The group of patients who have some degree of congestive heart failure or have a history of congestive failure in the past is probably the most difficult to control under anesthesia. A high degree of cooperation between the cardiologist, the anesthesiologist, and the surgeon is necessary in order to give the patient the best chance for survival. Preoperative preparation is most important and should be directed toward reducing pulmonary edema and correcting ventricular imbalance. If indicated, the patient may be dehydrated preoperatively by giving a diuretic and withholding salt and sodium from the diet. No saline solution should be given either before or during the operation. If the hemoglobin is low, washed red cells may be given slowly to build up the hemoglobin to safe levels for anesthesia. Most cardiologists favor digitalizing these patients preoperatively. In emergencies they may be rapidly digitalized by the use of cedilanid intravenously. As to the conduct of the anesthesia itself, spinal anesthesia is considered the anesthesia of choice for abdominal procedures. Sarnoff and Farr 2 have reported a series of patients with pulmonary edema treated by the use of spinal anesthesia in whom marked improvement was
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noted following the spinal. This they attributed to the fact that the pooling of blood in the areas affected by the spinal anesthetic resulted in a decreased return to the right heart and thus allowed the left ventricle to withdraw a larger proportion of blood, and hence extravascular fluid, from the lungs. Also if there is decreased peripheral resistance following spinal anesthesia, the left ventricle would be able to work more efficiently against this lowered resistance. Oxygen should be given continuously during the operation and general anesthesia should be avoided if possible. If a supplementary anesthesia is necessary it is essential that a high concentration of oxygen accompany its administration. Fluid therapy during the operation must be controlled accurately if congestive failure and pulmonary edema are to be avoided. No saline solution should be given. Blood should be given only to replace that which is lost and it may be necessary to weigh sponges in order to estimate blood loss with any degree of accuracy. In these patients it is much better to err on the side of giving not enough fluid than giving too much. There is a small group of patients who because of their pathologic condition are considered bad risks and not suitable for spinal anesthesia. Most of these are in the older age groups, have more or less advanced arteriosclerotic changes and have suffered marked weight losses. Under spinal anesthesia it is difficult to maintain normal blood pressure levels in these patients even with the judicious administration of vasopressor drugs. They seem to run a much smoother course with cyclopropane anesthesia and the intravenous administration of curare for relaxation. Care must be taken in using this combination that the patient has fully recovered the use of his respiratory muscles at the end of the operation before he is taken back to the room. In order to insure a patent airway and to provide a means of artificial respiration if necessary an endotracheal tube with an inflatable cuff should be inserted into the trachea when using the cyclopropane-curare combination. Another even smaller group of patients for abdominal surgery includes those patients who are too poor risks for spinal or general anesthesia but in whom operation is indicated as a life-saving measure. Regional anesthesia consisting of intercostal block and abdominal field block is the anesthesia of choice in such cases and may be supplemented with a splanchnic block by the surgeon as the abdominal cavity is entered. The anesthesiologist should give supportive treatment in the form of inhalation of 100 per cent oxygen and fluid therapy. Some of these patients will improve enough during the operation as the existing pathologic state is corrected so that they will tolerate a light general anesthesia if necessary before the close of the operation. The Production of Ideal Operating Conditions for the Surgeon.-The production of satisfactory operating conditions for the surgeon is an important factor to be considered in anesthesia for abdominal surgical procedures. There is little doubt that spinal anesthesia offers the most ideal conditions from the surgeon's viewpoint. The advantages to the surgeon are the complete relaxation, the contracture of the intestine and the quietness of the abdominal contents which facilitates difficult exposures, and the minimizing of trauma to the intestine by forcible
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retraction and walling off with packs. Spinal anesthesia is nearly always supplemented with some form of general anesthesia, depending on the type and location of the operation. For lower abdominal operations the supplementary anesthesia may consist of pentothal" intravenously combined with nitrous oxide-oxygen inhalation or light cyclopropane anesthesia. Nembutal intravenously may be sufficient. For upper abdominal surgical procedures, and gastric operations in particular, we have found it advantageous to introduce an endotracheal tube with a balloon cuff after inducing anesthesia with pentothal or cyclopropane and thoroughly spraying the pharynx and larynx with 10 per cent cocaine solution. With this method, maintenance of an open airway is assured, the danger of aspiration of vomitus is eliminated, secretions may be easily removed from the respiratory tract if necessary, and the Levin tube may be manipulated without loss of anesthetic concentration as occurs when a face mask has to be removed. Also, a quiet abdomen is assured and a free airway established. A former disadvantage of spinal anesthesia, that of limitation of duration of the single dose injection method, has been overcome by the introduction of the continuous spinal method, using either the malleable needle technic of Lemmon! or the indwelling catheter method of Tuohy.3 With either of these methods the spinal anesthesia may be prolonged for an indefinite period. Since the introduction of curare we now frequently use a dose of curare at the end of the operation for closure rather than give an additional dose of the spinal anesthetic agent. The recent availability of the shorter acting drug, syncurine, has made this technic even more advantageous as the curare-like effect is worn off by the time the patient is returned to his room. Another technic which is now used in many places is that of general anesthesia with either pentothal or cyclopropane combined with the use of curare intravenously for relaxation. This method eliminates the former objection to general-anesthesia for abdominal surgery, namely that patients had to be carried to dangerously low levels of anesthesia in order to provide adequate relaxation and satisfactory working conditions for the surgeon. With curare, however, adequate relaxation is obtained while the patient is in a relatively light stage of anesthesia with minimal depressing action on vital organs. We do not feel that conditions are quite as ideal for the surgeon with this method as with spinal anesthesia because of the lack of constriction of the intestine which is produced with spinal anesthesia. The use of ether for abdominal operations cannot be ignored. While it does not produce conditions to be compared with those produced by spinal anesthesia, still in the average risk patient satisfactory relaxation can be produced, especially if careful attention is paid to maintaining a clear airway. It is probably the best agent for use by the occasional anesthetist. For abdominal operations on small children and infants, ether is considered the anesthetic of choice and is preferably administered through an endotracheal tube using an insufflation or semiclosed technic so that there is a minimum of dead space and resistance to breathing.
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Psychologic Effect of the Anesthesia on the Patient.-Finally, the psychologic effect of the an~sthesia on the patient must be considered. This problem can usually be solved with little difficulty at the time of the preoperative visit to the patient. The confidence of the patient must be obtained. If a little time is spent with the patient in explaining in general, but not in detail, what to expect in the way of anesthesia, very rarely will a patient object to any anesthetic procedure the anesthesiologist may wish to use. If patients who object to spinal anesthesia are carefully questioned, it is usually found that what they object to actually is being awake in the operating room. When it is explained to them that they will be put to sleep after the spinal anesthetic is given they will be perfectly willing to accept that form of anesthesia when convinced that it is to their advantage. Careful premedication with nembutal, morphine and scopolamine will usually obviate the patient's apprehension and fear of the trip to the operating room. There is one instance where a detailed explanation of the anesthetic procedure to the patient will be of invaluable aid and may make the difference between success and failure of the anesthesia. This refers to those patients in whom it is necessary to insert an endotracheal catheter under topical anesthesia before the patient is put to sleep. If the patient is unaware of the object of the procedure he may become uncooperative and unmanageable or even hysterical when he finds he cannot talk after the tube is inserted. If a careful explanation is given beforehand the patient will usually be calm and cooperative. In general, children under 10 years of age are not psychologically suited for spinal anesthesia and some form of general anesthesia is preferable. For children over the age of 10 the decision as to whether spinal anesthesia is suitable or not must be made after a careful estimate of the child's emotional make-up. If spinal anesthesia is administered it is wise to put the child to sleep after the spinal anesthetic is given, using either pentothal or nembutal intravenously. CONCLUSIONS
With the introduction of newer agents and technics of anesthesia, a wider choice of anesthesia for surgical procedures in the abdomen is available. The primary objective of increased safety to the patient must always be kept in mind with whatever agent and technic is used. The skill and judgment of the anesthesiologist are factors which must never be minimized. Some of the problems associated with anesthesia for abdominal surgery have been discussed. REFERENCES 1. Lemmon, W. T.: A method of continuous spinal anesthesia; preliminary report. Ann. Surg. 111 :141-144 (Jan.) 1940.
2. Sarnoff, S. T. and Farr, H. W.: Spinal anesthesia in the therapy of pulmonary edema: A preliminary report. Anesthesiol. 5:69-76 (Jan.) 1944. 3. Tuohy, E. B.: Continuous spinal anesthesia; its usefulness and technic involved. Anesthesiol. 5:142-14S (Mar.) 1944. 4. Van Liere, E. J., Northup, D. W. and Stickney, J. C.: A comparative study of the action of various anesthetic agents on the muscles of the colon in the dog. Anesthesiol. 5:597-604 (Nov.) 1944.
COMPLICATIONS OF SPINAL ANESTHESIA URBAN
H.
EVERSOLE
IT is perhaps unfortunate that the actual induction of spinal anesthesia is usually such a relatively simple procedure. This has too often led to a lack of appreciation of its magnitude as well as the hazards with which it may be accompanied. The management and supervision of the patient under spinal anesthesia is extremely important. No spinal anesthesia is finished upon completion of the spinal puncture and injection of the anesthetic agent. The patient should be under the constant care and observation of a physician acquainted with all the possible complications of spinal anesthesia and who has adequate facilities to prevent or correct any untoward conditions that may arise. For the sake of convenience, complications of spinal anesthesia may be divided into: (1) those occurring at the time of operation and (2) those that do not manifest themselves until the postoperative period. COMPLICATIONS OCCURRING AT THE TIME OF OPERATION
Undoubtedly a very large majority of complications encountered during the course of spinal anesthesia are associatQd either directly or indirectly with improper distribution of the anesthetic agent in the subarachnoid space. The agent may not reach a level sufficiently high in the subarachnoid space or may travel too far cephalad, thus reaching a level too high. Inadequate Anesthesia.-If the level is not high ~nough to provide adequate muscular relaxation and to eliminate painful stimuli, the spinal anesthesia must, of necessity, be considered inad~quate and a supplementary agent used. Pentothal sodium intravenously or cyclopropane gas is usually quite satisfactory as a supplementary agent for the relief of pain. Curare and curare-like drugs, administered intravenously, have proved to be of great value as adjuncts to inadequate spinal anesthesia when muscular relaxation is desired. Wearing Off of Anesthesia before Completion of Operation.-With a single dose of a spinal anesthetic too often the oReration outlasts the anesthesia. This condition, of course, necessitates the use of supplementary anesthesia. As with inadequate spinal anesthesia, pentothal sodium or cyclopropane has proved quite useful as a supplementary agent with the addition of curare for muscular relaxation. The transition is more easily accomplished if the supplementary anesthetic is started before the patient begins to feel pain or there is any loss of muscular relaxation. Warning signs other than the elapse of time or tight abdominal muscles that the anesthesia may be about to wear off are: increased restlessness, sweating, rise in blood pressure or the patient may complain of a vague feeling of discomfort, without any actual pain, at the site of the operation. 693
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Respiratory Depression.-If the spinal anesthetic agent is distributed too far cephalad in the subarachnoid space, serious respiratory depression may result. This complication is more prone to occur when spinal anesthesia is employed for upper abdominal surgery. If the motor divisions of the thoracic nerves are anesthetized as high as the fourth thoracic segment (the height necessary for satisfactory upper abdominal surgery), the intercostal muscles below this level will be inactive and the elevation of the ribs and expansion of the chest with inspiration will be the result of the pull of the four upper intercostal muscles. If the agent continues to progress cephalad until the remaining intercostal nerves become involved, the chest will no longer expand with inspiration. If the patient is asked to take a deep breath at this time, only diaphragmatic breathing can be observed. The chest will remain entirely motionless or the intercostal spaces may even retract on inspiration. This is one of the earliest and most important warning signs that anesthesia is going too high. At this time the patient may complain of numbness or tingling in the hands due to involvement of the roots of the brachial plexus. If the agent continues until it reaches the level of the fourth cervical nerve root, the diaphragm becomes paralyzed and complete respiratory arrest ensues. Usually before respiration becomes completely arrested the conscious patient will attempt to increase the size of the chest cavity on inspiration by greater effort on the part of the accessory muscles of respiration. This can be detected by observing the patient's neck for increased activity of the sternomastoid and platysma muscles. The voice may be lost and the patient become quite apprehensive. It is of utmost importance that respiratory impairment be recognized at once. If unrelieved, this condition will lead to anoxia, circulatory collapse and death. The treatment is obvious. It consists of the administration of oxygen, with some mechanical assistance to inspiration if there is inadequate respiratory exchange. This assistance is absolutely essential if there is complete respiratory arrest. Assistance to respiration is best accomplished by administering oxygen from a gas machine and exerting rhythmic pressure on the breathing bag coincident with each attempt at inspiration on the part of the patient. If there is no attempt at inspiration, the lungs should be inflated by pressure on the breathing bag at a rate of about sixteen times per minute. Obviously, the establishment of a free and unobstructed airway is imperative. This may require the insertion of an endotracheal tube. Respiratory stimulants are not indicated and pressor drugs should be used at this stage only to treat secondary circulatory depression. If immediate and adequate treatment is instituted, this condition need cause no great alarm and usually secondary circulatory depression does not occur. Respiratory depression due to spinal anesthesia rarely lasts longer than twenty or thirty minutes. While this respiratory depression is usually thought of as peripheral in nature, it is quite possible that the anesthetic agent may be present in the fourth ventricle and exert an influence directly on the respiratory center. Circulatory Depression.-Some degree of circulatory depression quite
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commonly accompanies spinal anesthesia. This depression may at times be profound and alarming. Serious falls of blood pressure are much more common with high spinal anesthesia than when the anesthesia is confined to the lower part of the abdomen. It has been suggested that this fall in blood pressure was due to an hematogenous intoxication and that the rapid absorption into the blood stream of the anesthetic drug injected in the subarachnoid space produced the hypotensive effects observed. However, we know that much larger quantities of the agent can be injected directly into the blood stream without producing hypotension comparable to that produced by spinal anesthesia. Smith and his associates3 have suggested that the hypotension is due largely to a stagnation of the blood in the postarteriolar bed. They have postulated that this venous stagnation is accompanied by a lessened stroke volume and a decreased cardiac output. Perhaps the theory at the present time which has the widest acceptance is that of paralysis of the vasoconstrictor fibers in the anterior spinal nerve roots with a resulting loss of tone and stagnation of the blood in the arteriolar bed. The hypotension which so often accompanies spinal anesthesia may be alarming and should always be considered unphysiologic. Surgical manipulation in the abdomen, of course, plays a part in the production of blood pressure falls, and circulatory depression will most surely follow unrelieved respiratory depression. It has been well demonstrated that the routine use of sympathomimetic drugs prior to the administration of a spinal anesthetic is a valuable safeguard against circulatory depression. For many years 50 to 75 mg. of ephedrine has been almost uniformly accepted as the routine preanesthetic drug for the support of blood pressure. Many drugs have been used to treat a falling blood pressure under spinal anesthesia, notably epinephrine, ephedrine and neosynephrine. Epinephrine is evanescent in its action; however, it has the greatest effect of any agent. The systolic rise may be accompanied by a diastolic fall. It does not stimulate the respiratory center as does ephedrine. Occasionally apnea may follow the use of epinephrine due to the sudden increase of pressure in the carotid sinus and the cardio-aortic area. Increased pulse rate frequently accompanies the use of this drug, and it may be followed by bradycardia. The hypertension also may be followed by hypotension. Restlessness and apprehension are often distressing side effects of epinephrine. This drug acts by direct stimulation on the myocardium and the conduction tissue, and, of course, is dangerous in the presence of other factors affecting cardiac irritability. Repeated doses of epinephrine cause equal action. Ephedrine lasts longer but does not produce as marked an effect as epinephrine, and is not usually followed by the hypotension so often observed after administration of epinephrine. However, repeated doses will not produce an equal effect and may cause cardiac depression. Ephedrine is a respiratory stimulant and may increase the minute volume as much as 20 per cent. Bradycardia may be an accompaniment and some central side effects, such as nervousness, may be noted.
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Neosynephrine produces a greater effect than ephedrine and does not last as long. It does, however, last approximately five times as long as epinephrine. Its action is largely that of vasoconstriction but there may be some direct cardiac action. Arrhythmias following the use of neosynephrine are uncommon. However, bradycardia may be an accompaniment. This is probably due to direct action on the sino-auricular node or it may be a compensatory reflex. The heart has a tendency to dilate when neosynephrine is used. There is no central stimulation. Ten to 20 mg. of neosynephrine in 1000 cc. of solution (physiologic salt or 5 per cent dextrose) as an intravenous drip has proved to be of great value in supporting blood pressure during spinal anesthesia. One must always bear in mind, however, that a pressor drug should never be used as a substitute for fluids or blood in cases of hypotension due to blood loss or surgical shock. Nausea, Retching and Vomiting.-Nausea, retching and vomiting are common and annoying complications of spinal anesthesia. With the increasing tendency to give some sort of a complementary agent to render the patient unconscic)Us during the course of spinal anesthesia, we do not see these complications as frequently as formerly. However, when spinal anesthesia is employed without a complementary or supplementary agent, and nausea and retching are more than a temporary disturbance, the patient should be rendered unconscious with some general anesthetic agent such as cyclopropane or pentothal. This enables the surgical procedure to continue uninterruptedly and relieves the patient of an uncomfortable and disturbing experience. The danger of vomitus being aspirated into the trachea and bronchi should always be borne in mind. This danger may be further enhanced if a general anesthetic -is administered after the patient has already vomited. Pyloric or Small Bowel Obstruction.-Another alarming complication may arise with patients who have obstruction of the pylorus or small bowel with proximal dilatation of the intestine. The administration of a spinal anesthetic with its tendency to increase the tone of the bowel followed by manipulations of the bowel by the surgeon may result in pouring out of large quantities of material into the pharynx from where it may be aspirated into the respiratory passages. Unless prompt, adequate treatment is instituted at once this complication may be serious. The patient should immediately be placed in the head-down position and all of the material aspirated from the pharynx. If there is evidence that any of the material has been aspirated into the trachea or bronchi, bronchoscopy should be performed immediately to clear the air passages. As a precautionary measure against this complication, in any patient suffering from pyloric or small bowel obstruction a Levin tube should be placed in the stomach prior to the administration of the anesthetic. The presence of a Miller-Abbott tube in the small bowel is not a sufficient safeguard against the aspiration of vomitus, and if there is any question of an obstruction still persisting at the time of operation, a Levin tube should be placed in the stomach in addition to the Miller-
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Abbott tube. Neglect of this precautionary measure may result in a fatality. Nervousness and Apprehension.-Many patients object to being awake during an operation. There is no reason why any patient who wishes it cannot be asleep and still have the advantage of spinal anesthesia. An additional dose of morphine intravenously after the patient is in the operating room and before the induction of spinal anesthesia often allays apprehension and nervousness. The intravenous administration of 1 to 3 grains of pentobarbital sodium (nembutal) is valuable also for patients who are nervous or apprehensive. Intravenous pentobarbital sodium is less likely to cause nausea than is intravenous morphine. Quite often an intravenous dose of morphine or nembutal is all the supplementary anesthetic needed. Provision of an Intravenous Route for Supplementary Agents.-If an intravenous needle is placed in the great saphenous vein near the medial malleolus and a small drip of fluid maintained throughout an operative procedure, a route is constantly available for the administration of supplementary anesthetic agents or for the administration of supportive drugs and fluids. The use of the saphenous vein has the advantage of removing the intravenous apparatus to a point where it will not interfere with any type of surgery except that on the lower extremities. If the intravenous drip is not started until after the spinal anesthetic is given the insertion of the needle causes no discomfort and the dilatation of the vein which follows spinal anesthesia facilitates the insertion of the needle. In the past this procedure was reserved for poor risk patients or for patients upon whom extensive operative procedures were contemplated. More recently it has become almost a routine with spinal anesthesia and the feeling of security that comes with having an intravenous route always available for the administration of drugs and fluids is well worth the additional effort and expense which this procedure entails. NEUROLOGIC COMPLICATIONS OF SPINAL ANESTHESIA
Since the central nervous system is the site of action of all anesthetic agents whether general or spinal, it is not surprising that complications of the nervous system occur after all types of anesthesia. While no particular type of neurologic complication can be said to be limited entirely to one type of anesthesia, and hemiplegias and various types of peripheral nerve lesions can follow both general and spinal anesthesia, certain complications are much more prone to follow spinal anesthesia and certain others more prone to follow general anesthesia. Convulsions, extrapyramidal rigidity, postoperative psychoses and degenerative changes in the cerebral cortex and lenticular nuclei have been reported most often after general anesthesia. Headache, septic and aseptic meningitis, arachnoiditis, neuritis, myelitis and the so-called cauda equina syndrome comprise the complications most frequently reported following spinal anesthesia.
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Etiology.-It is usually quite difficult to determine the exact etiologic factor responsible for neurologic complications following spinal anesthesia. Certain spinal anesthetic drugs in high enough concentration cause a specific, toxic, destructive effect on nerve tissue when injected into the subarachnoid space in experimental animals. The incidence of these lesions increases as the concentration of the drug is increased. Also, it seems evident that the lesions produced are the result of the spinal anesthetic agent itself since the damage is usually manifested so soon after the administration of the drug. Other possible etiologic factors must, however, be considered. Direct Trauma.- Direct trauma may play a part in some neurologic complications following spinal anesthesia. There does seem to be a definite relationship between a traumatic spinal puncture which causes pain to extend down one leg followed by the injection of a spinal anesthetic drug with a persistent neurologic complication referable to the same leg, yet in view of the large number reported of diagnostic spinal punctures performed without serious neurologic complications, it seems unlikely that trauma can be considered as a major etiologic factor in the production of postspinal neurologic complications. Inflammatory Reaction.-The rapidity of onset of most of these complications of itself seems to preclude inflammatory reaction as an etiologic factor. Furthermore, it is usually impossible to cultivate organisms from the spinal fluid of patients with postspinal neurologic complications, and the predominating cells are generally lymphocytes rather than polymorphonuclear leukocytes. These complications are seldom associated with an elevation in temperature or other signs of an inflammatory process. Toxicity of the Drug.-There is considerable evidence that neurologic complications are due to direct toxic action of the agent itself. Not all of the nerves influenced by the anesthetic agent are affected by the paralysis. The anesthetic may have been sufficient for an upper abdominal operation, yet the ultimate paralysis be limited to the lumbosacral or sacral nerves. These, of course, are the nerves that are exposed to the greatest concentration of the agent. Permanent paralysis seems to occur most frequently in the nerve tissue which comes in contact with the drug in its greatest concentration. Furthermore, it seems unlikely that these complications are of an allergic nature, but that the concentration employed with most anesthetic drugs is only a little· short of that which would produce paralysis in a higher percentage of patients. Neurologic Disease Precipitated by Spinal Anesthesia.-Spinal anesthesia may be a precipitating factor in the exacerbation of certain preexisting neurologic conditions such as pernicious anemia with combined sclerosis, multiple sclerosis and tabes dorsalis. Two patients at the Lahey Clinic received spinal anesthesia for the removal of carcinomas in other parts of the body and, upon examination, because of the fact that the spinal anesthesia failed to wear off, were found to have metastasis to the spine resulting in almost complete cerebrospinal fluid block. In addition to the group of peripheral neuropathies commonly re-
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ferred to as the cauda equina syndrome, such other complications as headaches, septic and aseptic meningitis, arachnoiditis and cranial nerve palsies must be considered as neurologic complications. Headache.-Headache is one of the most distressing postspinal complications from the patient's standpoint. This complication may arise following a diagnostic spinal puncture as well as spinal puncture followed by the injection of a spinal anesthetic agent. Many theories have been advanced to explain this complication. One theory is that there is chemical irritation of the pia mater by the anesthetic agent which in turn causes excessive absorption of spinal fluid with lowering of spinal fluid pressure. Another theory is that headache is the result of slow leakage of spinal fluid through the dural puncture opening into the subdural space which is under negative pressure. This lowering of spinal fluid pressure is supposed to be responsible for removing the watery cushion upon which the brain rests, allowing the brain to sag against the bony framework of the skull, which in turn irritates the dural fibers of the trifacial and the two occipital nerves. This pressure further tends to depress the basilar venous plexus and diminish the outflow of blood, thus increasing the venous tension. Some credence may be lent to'this theory because of the fact that most of these headaches can be relieved by lowering the patient's head. A third theory is that orthostatic hypotension and tachycardia occurring in patients who have received spinal anesthesia for delivery may play a large part in the production of their headaches. The headaches may be frontal, temporal or occipital. Throbbing in the head is produced on sitting or standing. Sometimes the main complaint may be stuffiness in the ears, while other patients may have little headache but complain of stiffness of the nape of the neck or shoulders. The treatment of headache following spinal anesthesia, for the most part, is conservative and not very satisfactory. Patients with the milder types generally respond to rest in bed with the bed level or in the headdown position. Relief is sometimes obtained with mild analgesics, but more stubborn cases require constant medication with salicylates and occasionally an opiate. The more intractable type of postspinal headache should be investigated carefully. A lumbar puncture should be done and spinal fluid dynamics determined along with microscopic and bacteriologic investigations of spinal fluid to rule out meningitis. When the spinal fluid pressure is low, benefit has been obtained by returning it to normal with the injection of physiologic saline or 5 per cent dextrose solution. However, when the spinal fluid is elevated (and it is sometimes with postspinal headache) it should be returned to normal by the withdrawal of spinal fluid. If the spinal fluid pressure is elevated, the patient should be put on a dehydration regimen and given 25 per cent dextrose intravenously. Weintraub and associates,4 in a study of postspinal headaches in 45 patients out of a series of 300 who received spinal anesthesia for delivery, found that 50 per cent of the patients with headache demonstrated orthostatic hypotension or tachycardia or both. The other 50 per cent who had headache did not have orthostatic hypotension or tachycardia or both. However, they were able to relieve the head-
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aches in both groups by the application of abdominal compression by means of tight binders. From these observations they concluded that postspinal headaches in the postpartum patient are due to two factors: (1) the most important, the sudden relief of intra abdominal pressure following delivery superimposed on the action of the anesthetic, and (2) spinal fluid leakage. Cranial Nerve Palsies.-From time to time we read reports of cranial nerve palsies following spinal anesthesia. While the abducens or sixth nerve is the one most frequently affected, there have been reports of palsies of almost all of the cranial nerves. The mechanism by which a cranial nerve is paralyzed is difficult to explain, and this is a very rare complication. There is no treatment of this condition and recovery can be expected in almost every instance. The Cauda Equina Syndrome.-Some manifestation of the so-called cauda equina syndrome is usually thought of when postoperative neurologic complications are mentioned. This complication is brought to the anesthesiologist's attention because the patient fails to regain the use of his lower extremities in the usual time following spinal anesthesia. On examination, a certain amount of loss of both motor and sensory function is generally found to involve some part of the lumbosacral nerve distribution. Associated conditions may be varying degrees of urinary retention and incontinence of feces with loss of tone of the anal sphincter. This loss of sensation may involve only the saddle area, one or both legs or the entire body below the umbilicus. As was pointed out previously, an examination of these patients reveals that the basic lesion is in the region of the cauda equina where the nerves have met the anesthetic agent in its highest concentration. The following case report illustrates this complication: A white man, aged 42, a bartender, complained of cold legs for the past two years and associated cramps in the calf muscles for the last six months. A diagnosis of thromboangiitis obliterans was made and hospitalization for further investigation, with possible lumbar sympathectomy, was advised. He was given 14 mg. of tetracaine (ponto caine) hydrochloride and 2.66 cc. of 10 per cent dextrose for spinal anesthesia for skin temperature readings. The spinal puncture was made in the third lumbar interspace. Anesthesia developed to the eighth thoracic segment. After twenty-four hours the anesthesia was still present and the patient was paralyzed from his waist down. A spinal puncture at that time showed an initial pressure of 50 mm. of water, total protein 347 mg., and sugar 21 mg. per 100 cc., with 57 lymphocytes. Approximately thirty hours after the spinal anesthetic was administered an exploration of the lower thoracic and upper lumbar cord was performed, under endotracheal ether anesthesia, for what was thought to be a spinal fluid block. No block was found and the cord showed only slightly increased vascularity. The patient remained in the hospital for three months and showed but little improvement. There was improvement in the sensation over the area supplied by the second lumbar nerve and a slight return of motor power in the feet. Although he voided voluntarily, a small amount of residual urine with an associated pyuria persisted througout his hospital stay. He was discharged
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from the hospital without ever having regained the use of his lower extremities. During his stay at home over the next fourteen months there was no improvement in his condition. He died seventeen months after the development of the complication. A complete necropsy, including the brain and spinal cord, was obtained. The pertinent pathologic observations were in the spinal cord. The following is a comment by the neuropathologist: "The principal pathologic observation IS the loss of nerve fibers in the root of the cauda equina and the regeneration of fine nerve fibers in the anterior root. The degeneration of the posterior columns of the spinal cord is unquestionably secondary to destruction of the posterior roots. The fibrous thickening and cellular proliferation in the meninges may be viewed as the final stage of an inflammatory process, whether induced by chemical irritation or infection. The pathologic observations are approximately the type one would expect in a lesion one to two years of age. The partial sparing of some roots and the regeneration of others would account for the retention of some bladder function and sensation. There are no vascular lesions suggestive of thromboangiitis obliterans. I believe that the changes in the anterior roots which were first interpreted as neurofibromatosis are regenerative phenomena. The observations are consistent with, although not pathognomonic of, the cauda equina syndrome of spinal anesthesia."
Prevention of Postspinal Neurologic Complications.-The following is a regimen which has been suggested in an attempt to prevent postspinal neurologic complications: 1. Very close attention should be paid to the cleansing and sterilizing of apparatus used in the administration of spinal anesthesia. The routine rinsing of syringes and needles with sterile isotonic solution of sodium chloride immediately before their use is an additional precaution. 2. Drugs should be used from manufacturer's ampules whose labels are legible, whose walls are intact and whose contents on routine inspection before use are clear and free from insoluble particles or crystals. 3. Ampules containing spinal anesthetic drugs should be sterilized by soaking them in a nonirritating, highly colored sterilizing solution. The addition of a strong concentration of dye to these solutions in which the ampules are immersed is of value in detecting the occasional defective ampule into which the sterilizing solution may have leaked. Irritating solutions containing alcohol, phenol or formaldehyde should not be used because of the danger of their entering the ampule through microscopic breaks and in turn being injected into the subarachnoid space. Many of the spinal anesthetic agents now in use can be sterilized by autoclaving and this circumvents the possibility of a sclerosing sterilizing solution entering the ampule. 4. Solutions containing even a faint suggestion of turbidity or cloudiness should be discarded. 5. Spinal puncture should not be made through or near areas of infection. 6. Spinal anesthesia should not be given to patients with known spinal cord disease, such as tabes dorsalis, multiple sclerosis, pernicious anemia with symptoms of combined system disease, and tumors of the spinal cord. Patients who have herniated intervertebral disks with signs of
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peripheral nerve paralysis, loss of bowel or bladder function or with an elevation of the total protein content of the spinal fluid should not be given spinal anesthesia. 7. Patients suffering from known virus infections, such as poliomyelitis or chickenpox, should not be given spinal anesthesia. 8. A history of delayed return of motor function or severe paresthesias following a previous spinal anesthesia should be considered a contraindication to the subsequent use of this type of anesthesia. 9. If the spinal puncture causes a radiating paresthesia, the anesthetic agent should not be injected until adjustment of the needle has freed the patient of this pain. We have seen 2 patients in whom this warning was not heeded and the administration of the spinal anestbetic agent caused a unilateral paralysis of one leg. 10. A persistently bloody spinal tap contraindicates the injection of a spinal anesthetic agent. 11. Routine determination of the spinal fluid dynamics should be carried out on all patients complaining of intractable back pain or pain that seems out of proportion to the pathologic condition for which the surgical procedure is being performed. Experience has shown that spinal cord pathology (metastatic disease or primary carcinoma) can be detected in a certain number of these patients by such a routine. 12. When it has been difficult or impossible to obtain the desired height of anesthesia by the ordinary methods a spinal block should be suspected. It is advisable to terminate such a spinal anesthesia by flushing out the subarachnoid space with isotonic solution of sodium chloride in order to remove any residual anesthetic solution that may have been deposited in the subarachnoid space.
Management of the Cauda Equina Syndrome Following Spinal Anesthesia.-Since the loss of bowel and bladder function from the standpoint of the life of the patient is probably the most serious of all of the symptoms of the cauda equina syndrome, some discussion of the management of tllis complication is warranted. Each step in the sequence of events leading up to the mishap demands careful investigation. A complete history and physical examination in addition to a review of the preanesthetic information should be obtained. The extent of the impairment of the nerve function must be ascertained. It is of paramount importance that the functional state of the bowel and bladder be determined so that treatment, if needed, can be instituted immediately. Tidal irrigation of the bladder, as described by Munro,!· 2 offers a real chance for recovery of function without infection of the urinary tract. It is extremely difficult to give an effective cleansing enema by ordinary methods to a patient whose rectal sphincter is incompetent. However, if a large Foley catheter is inserted into the rectum and the cuff inflated an effective enema can be administered. In order that preexisting pathologic changes in the spinal cord may be detected early, any patient in whom there is evidence of a postspinal cauda equina complication should have an investigation of the spinal fluid dynamics. In conjunction with this maneuver it is advisable to
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irrigate the subarachnoid space with isotonic solution of sodium chloride to insure the removal of any remaining anesthetic agent. This attempt to remove any residual anesthetic agent takes on additional significance when a spinal fluid block is discovered. When the abnormalities of the spinal fluid are limited to an elevation in the total protein and cell count, daily spinal punctures for the withdrawal of fluid should be performed. During the recovery period, the duration of which may be extremely variable, the nursing routine must be a vigorous one if decubitus ulceration, ankylosed joints, malnutrition and muscular atrophy are to be avoided. REFERENCES 1. Munro, D.: The treatment of urinary bladder in cases with injury of spinal cord. Am. J. Surg. 38:120--136 (Oct.) 1937.
2. Munro, D.: Tidal drainage and cystometry in treatment of sepsis associated with spinal-cord injuries; study of 165 cases. New England J. Med. 229: 6-14 (July 1) 1943. 3. Smith, H. W., Rovenstine, E. A., Goldring, W., Chasis, H., and Ranges, H. A.: Effects of spinal anesthesia on circulation in normal, unoperated man with reference to autonomy of arterioles, and especially those of renal circulation. J. Clin. Investigation 18:319-341 (May) 1939. 4. Weintraub, F., Antine, W. and Raphael, A. J.: Postpartum headache after low spinal anethesia in vaginal delivery and its treatment. Am. J. Obst. & Gynec. 54:682-686 (Oct.) 1947.
B. ORR WITH the introduction in recent years of new agents and methods of anesthesia, the range of choice of anesthesia has widened so that we cannot now say unreservedly that anyone procedure is best for a given operation. There are still certain general principles and criteria, however, which must be considered in the choice of anesthesia for abdominal surgery. ROBERT
FACTORS AFFECTING THE CHOICE OF THE ANESTHETIC
The first and most important principle to be kept in mind is to choose the anesthesia which will offer to the patient the greatest degree of safety and assure him as far as possible an ultimate complete recovery. Factors to be considered in achieving this objective are: (1) the skill and experience of the anesthesiologist, (2) the effect of the anesthesia on the pathologic condition present, (3) the production of ideal operating conditions for the surgeon, and (4) the choosing of a method which is psychologically suited to the individual patient. The Skill and Experience of the Anesthesiologist.-The skill and experience of the anesthesiologist is probably the most important factor in the choice of anesthesia for abdominal surgery. Obviously, it would be better from the standpoint of the patient to have open drop ether administered by one who is familiar with that method than to have the same person administer a spinal anesthetic to that patient and be unaware of the complications of high spinal anesthesia, such as circulatory disturbances, and so forth, and unable to handle these complications should they occur. The modern trained anesthesiologist must have a knowledge of existing pathologic processes, and be familiar with the pharmacologic action of the various anesthetic drugs especially as they relate to diseased tissues of the patient. He must be skilled in the administration of any anesthetic agent he may wish to employ and must also be capable of handling any of the complications which might arise during the administration of that agent.
The Effect of the Anesthetic Agent on the Pathologic Condition Present.-The effect of the anesthetic agent on the pathologic condition present may have an important bearing on the outcome of the operation. All of the anesthetic agents disturb physiologic functions, some to a much greater extent than others. It is wise to choose an agent which will have the least deleterious effect on already damaged tissues. Probably the most common pathologic condition associated with abdominal operations which may affect the choice of anesthesia is disturbed liver function. In patients with marked liver damage, such as that seen following damage to the bile ducts with obstruction, the wise choice of agents both for premedication and for the operation may be a large factor in determining the successful outcome for the patient. The use of an intermediate acting barbiturate, such as nembutal, for premedication 687
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in such a case may be so depressing that it would be unsafe to proceed with the operation and in some cases even resuscitative measures might be necessary . We believe that the use of pentothal during the operative procedure should be avoided if possible although some think that since the liver is not the main site of detoxification of the ultrashort acting barbiturates, the use of pentothal is not contraindicated. We consider spinal anesthesia the method of choice because of the excellent relaxation and lack of toxic effects, with cyclopropane as the agent of choice for supplementary inhalation anesthesia in these patients because of its lack of disturbance of liver physiology and because of the high concentration of oxygen that can be given with it. The use of ether in operations on the biliary tract is considered a poor choice because of its toxic effect on the liver, although lately it is believed that many of the toxic effects previously ascribed to ether per se were actually the result of accompanying anoxia. Another pathologic condition frequently seen in patients who are to have abdominal operations is intestinal obstruction. Here again, a knowledge of the effect of the various anesthetic agents on the function of the intestine is important. Van Liere, Northup, and Stickney4 have reported on the effects of various agents on the motility of the colon in dogs under light barbital anesthesia. They first demonstrated that barbital in the majority of cases did not appreciably affect the activity of the colon. They then showed that chloroform, diethyl ether and divinyl ether produced a decrease in tone and practically abolished colonic contractions. This was presumably owing to stimulation of the sympathico-adrenal system. Cyclopropane, ethyl bromide and ethyl chloride produced spasm of the muscles of the colon. The action of cyclopropane is attributed -to its cholinergic action. With deep cyclopropane anesthesia contractions are inhibited. Nitrous oxide produced spasm of the musculature which was maintained even when the gas was administered in concentrations high enough to produce a severe degree of anoxia. It was, therefore, presumed that the stimulating action of the nitrous oxide predominated over the degree of anoxia which accompanies high concentrations of nitrous oxide. In human beings the administration of spinal anesthesia produces increased intestinal tone as a result of relative increase in vagal effects. Thus, the intestine is contracted and occupies a much smaller space in the abdominal cavity. This effect of spinal anesthesia in producing contraction of the intestine may theoretically be used as an argument against the use of spinal anesthesia for intestinal obstruction in that it might produce a perforation. We have never seen this occur, however, and believe that the advantages of spinal anesthesia in most cases far outweigh the possibility of this complication. The most dangerous complication which may occur in administering anesthesia to patients with intestinal obstruction is that of aspiration of vomitus. These patients have varying degrees of distention and usually the stomach contains moderate to large amounts of fluid. Even though a Miller-Abbott tube has been passed to depress the bowel there may still be fluid in the stomach so that it should be a routine procedure in all cases of intestinal obstruction to pass a Levin tube into the stomach
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and empty the stomach completely. An added precaution is to wash out the stomach with small amounts of normal saline solution or water so that if there is inadvertent aspiration of vomitus, the material will not be highly acid and thus irritative to the respiratory membranes. If spinal anesthesia is definitely contraindicated, as in the presence of cerebrospinal diseases, infection about the vertebral column, anatomical abnormalities making puncture impossible, or a very poor risk patient, the safest procedure is to intubate the patient under topical anesthesia using an endotracheal tube with an inflatable balloon cuff. Then the patient may be anesthetized with either pentothal or cyclopropane without danger of aspirating vomitus. Curare may then be used to produce the required relaxation. Another important point is that at the end of the operation before the endotracheal tube is removed a careful check with the surgeon should be made to be sure that the stomach is empty. The danger of aspiration is just as great at the end of the operation as it is in the early stages. A large number of patients who come to the clinic for abdominal operations have accompanying heart disease, especially in the older age groups. These patients may be roughly divided into three groups: those with cardiac irregularities, those with congestive failure or a history of congestive failure in the past, and those with a history of a myocardial infarct. In the first group the choice of anesthesia is not too much of a problem provided the cardiac irregularity is not also accompanied by a history of congestive failure or myocardial infarct. The main contraindication is against the use of cyclopropane where the increased irritability of the cardiac musculature may lead to ventricular fibrillation. Other forms of anesthesia, such as spinal, pentothal-curare combinations or ether, may be used as indicated, always bearing in mind that adequate amounts of oxygen must be available to the tissues. Many times it has been observed that a cardiac irregularity will disappear under ether anesthesia. The group of patients who have some degree of congestive heart failure or have a history of congestive failure in the past is probably the most difficult to control under anesthesia. A high degree of cooperation between the cardiologist, the anesthesiologist, and the surgeon is necessary in order to give the patient the best chance for survival. Preoperative preparation is most important and should be directed toward reducing pulmonary edema and correcting ventricular imbalance. If indicated, the patient may be dehydrated preoperatively by giving a diuretic and withholding salt and sodium from the diet. No saline solution should be given either before or during the operation. If the hemoglobin is low, washed red cells may be given slowly to build up the hemoglobin to safe levels for anesthesia. Most cardiologists favor digitalizing these patients preoperatively. In emergencies they may be rapidly digitalized by the use of cedilanid intravenously. As to the conduct of the anesthesia itself, spinal anesthesia is considered the anesthesia of choice for abdominal procedures. Sarnoff and Farr 2 have reported a series of patients with pulmonary edema treated by the use of spinal anesthesia in whom marked improvement was
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noted following the spinal. This they attributed to the fact that the pooling of blood in the areas affected by the spinal anesthetic resulted in a decreased return to the right heart and thus allowed the left ventricle to withdraw a larger proportion of blood, and hence extravascular fluid, from the lungs. Also if there is decreased peripheral resistance following spinal anesthesia, the left ventricle would be able to work more efficiently against this lowered resistance. Oxygen should be given continuously during the operation and general anesthesia should be avoided if possible. If a supplementary anesthesia is necessary it is essential that a high concentration of oxygen accompany its administration. Fluid therapy during the operation must be controlled accurately if congestive failure and pulmonary edema are to be avoided. No saline solution should be given. Blood should be given only to replace that which is lost and it may be necessary to weigh sponges in order to estimate blood loss with any degree of accuracy. In these patients it is much better to err on the side of giving not enough fluid than giving too much. There is a small group of patients who because of their pathologic condition are considered bad risks and not suitable for spinal anesthesia. Most of these are in the older age groups, have more or less advanced arteriosclerotic changes and have suffered marked weight losses. Under spinal anesthesia it is difficult to maintain normal blood pressure levels in these patients even with the judicious administration of vasopressor drugs. They seem to run a much smoother course with cyclopropane anesthesia and the intravenous administration of curare for relaxation. Care must be taken in using this combination that the patient has fully recovered the use of his respiratory muscles at the end of the operation before he is taken back to the room. In order to insure a patent airway and to provide a means of artificial respiration if necessary an endotracheal tube with an inflatable cuff should be inserted into the trachea when using the cyclopropane-curare combination. Another even smaller group of patients for abdominal surgery includes those patients who are too poor risks for spinal or general anesthesia but in whom operation is indicated as a life-saving measure. Regional anesthesia consisting of intercostal block and abdominal field block is the anesthesia of choice in such cases and may be supplemented with a splanchnic block by the surgeon as the abdominal cavity is entered. The anesthesiologist should give supportive treatment in the form of inhalation of 100 per cent oxygen and fluid therapy. Some of these patients will improve enough during the operation as the existing pathologic state is corrected so that they will tolerate a light general anesthesia if necessary before the close of the operation. The Production of Ideal Operating Conditions for the Surgeon.-The production of satisfactory operating conditions for the surgeon is an important factor to be considered in anesthesia for abdominal surgical procedures. There is little doubt that spinal anesthesia offers the most ideal conditions from the surgeon's viewpoint. The advantages to the surgeon are the complete relaxation, the contracture of the intestine and the quietness of the abdominal contents which facilitates difficult exposures, and the minimizing of trauma to the intestine by forcible
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retraction and walling off with packs. Spinal anesthesia is nearly always supplemented with some form of general anesthesia, depending on the type and location of the operation. For lower abdominal operations the supplementary anesthesia may consist of pentothal" intravenously combined with nitrous oxide-oxygen inhalation or light cyclopropane anesthesia. Nembutal intravenously may be sufficient. For upper abdominal surgical procedures, and gastric operations in particular, we have found it advantageous to introduce an endotracheal tube with a balloon cuff after inducing anesthesia with pentothal or cyclopropane and thoroughly spraying the pharynx and larynx with 10 per cent cocaine solution. With this method, maintenance of an open airway is assured, the danger of aspiration of vomitus is eliminated, secretions may be easily removed from the respiratory tract if necessary, and the Levin tube may be manipulated without loss of anesthetic concentration as occurs when a face mask has to be removed. Also, a quiet abdomen is assured and a free airway established. A former disadvantage of spinal anesthesia, that of limitation of duration of the single dose injection method, has been overcome by the introduction of the continuous spinal method, using either the malleable needle technic of Lemmon! or the indwelling catheter method of Tuohy.3 With either of these methods the spinal anesthesia may be prolonged for an indefinite period. Since the introduction of curare we now frequently use a dose of curare at the end of the operation for closure rather than give an additional dose of the spinal anesthetic agent. The recent availability of the shorter acting drug, syncurine, has made this technic even more advantageous as the curare-like effect is worn off by the time the patient is returned to his room. Another technic which is now used in many places is that of general anesthesia with either pentothal or cyclopropane combined with the use of curare intravenously for relaxation. This method eliminates the former objection to general-anesthesia for abdominal surgery, namely that patients had to be carried to dangerously low levels of anesthesia in order to provide adequate relaxation and satisfactory working conditions for the surgeon. With curare, however, adequate relaxation is obtained while the patient is in a relatively light stage of anesthesia with minimal depressing action on vital organs. We do not feel that conditions are quite as ideal for the surgeon with this method as with spinal anesthesia because of the lack of constriction of the intestine which is produced with spinal anesthesia. The use of ether for abdominal operations cannot be ignored. While it does not produce conditions to be compared with those produced by spinal anesthesia, still in the average risk patient satisfactory relaxation can be produced, especially if careful attention is paid to maintaining a clear airway. It is probably the best agent for use by the occasional anesthetist. For abdominal operations on small children and infants, ether is considered the anesthetic of choice and is preferably administered through an endotracheal tube using an insufflation or semiclosed technic so that there is a minimum of dead space and resistance to breathing.
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Psychologic Effect of the Anesthesia on the Patient.-Finally, the psychologic effect of the an~sthesia on the patient must be considered. This problem can usually be solved with little difficulty at the time of the preoperative visit to the patient. The confidence of the patient must be obtained. If a little time is spent with the patient in explaining in general, but not in detail, what to expect in the way of anesthesia, very rarely will a patient object to any anesthetic procedure the anesthesiologist may wish to use. If patients who object to spinal anesthesia are carefully questioned, it is usually found that what they object to actually is being awake in the operating room. When it is explained to them that they will be put to sleep after the spinal anesthetic is given they will be perfectly willing to accept that form of anesthesia when convinced that it is to their advantage. Careful premedication with nembutal, morphine and scopolamine will usually obviate the patient's apprehension and fear of the trip to the operating room. There is one instance where a detailed explanation of the anesthetic procedure to the patient will be of invaluable aid and may make the difference between success and failure of the anesthesia. This refers to those patients in whom it is necessary to insert an endotracheal catheter under topical anesthesia before the patient is put to sleep. If the patient is unaware of the object of the procedure he may become uncooperative and unmanageable or even hysterical when he finds he cannot talk after the tube is inserted. If a careful explanation is given beforehand the patient will usually be calm and cooperative. In general, children under 10 years of age are not psychologically suited for spinal anesthesia and some form of general anesthesia is preferable. For children over the age of 10 the decision as to whether spinal anesthesia is suitable or not must be made after a careful estimate of the child's emotional make-up. If spinal anesthesia is administered it is wise to put the child to sleep after the spinal anesthetic is given, using either pentothal or nembutal intravenously. CONCLUSIONS
With the introduction of newer agents and technics of anesthesia, a wider choice of anesthesia for surgical procedures in the abdomen is available. The primary objective of increased safety to the patient must always be kept in mind with whatever agent and technic is used. The skill and judgment of the anesthesiologist are factors which must never be minimized. Some of the problems associated with anesthesia for abdominal surgery have been discussed. REFERENCES 1. Lemmon, W. T.: A method of continuous spinal anesthesia; preliminary report. Ann. Surg. 111 :141-144 (Jan.) 1940.
2. Sarnoff, S. T. and Farr, H. W.: Spinal anesthesia in the therapy of pulmonary edema: A preliminary report. Anesthesiol. 5:69-76 (Jan.) 1944. 3. Tuohy, E. B.: Continuous spinal anesthesia; its usefulness and technic involved. Anesthesiol. 5:142-14S (Mar.) 1944. 4. Van Liere, E. J., Northup, D. W. and Stickney, J. C.: A comparative study of the action of various anesthetic agents on the muscles of the colon in the dog. Anesthesiol. 5:597-604 (Nov.) 1944.
COMPLICATIONS OF SPINAL ANESTHESIA URBAN
H.
EVERSOLE
IT is perhaps unfortunate that the actual induction of spinal anesthesia is usually such a relatively simple procedure. This has too often led to a lack of appreciation of its magnitude as well as the hazards with which it may be accompanied. The management and supervision of the patient under spinal anesthesia is extremely important. No spinal anesthesia is finished upon completion of the spinal puncture and injection of the anesthetic agent. The patient should be under the constant care and observation of a physician acquainted with all the possible complications of spinal anesthesia and who has adequate facilities to prevent or correct any untoward conditions that may arise. For the sake of convenience, complications of spinal anesthesia may be divided into: (1) those occurring at the time of operation and (2) those that do not manifest themselves until the postoperative period. COMPLICATIONS OCCURRING AT THE TIME OF OPERATION
Undoubtedly a very large majority of complications encountered during the course of spinal anesthesia are associatQd either directly or indirectly with improper distribution of the anesthetic agent in the subarachnoid space. The agent may not reach a level sufficiently high in the subarachnoid space or may travel too far cephalad, thus reaching a level too high. Inadequate Anesthesia.-If the level is not high ~nough to provide adequate muscular relaxation and to eliminate painful stimuli, the spinal anesthesia must, of necessity, be considered inad~quate and a supplementary agent used. Pentothal sodium intravenously or cyclopropane gas is usually quite satisfactory as a supplementary agent for the relief of pain. Curare and curare-like drugs, administered intravenously, have proved to be of great value as adjuncts to inadequate spinal anesthesia when muscular relaxation is desired. Wearing Off of Anesthesia before Completion of Operation.-With a single dose of a spinal anesthetic too often the oReration outlasts the anesthesia. This condition, of course, necessitates the use of supplementary anesthesia. As with inadequate spinal anesthesia, pentothal sodium or cyclopropane has proved quite useful as a supplementary agent with the addition of curare for muscular relaxation. The transition is more easily accomplished if the supplementary anesthetic is started before the patient begins to feel pain or there is any loss of muscular relaxation. Warning signs other than the elapse of time or tight abdominal muscles that the anesthesia may be about to wear off are: increased restlessness, sweating, rise in blood pressure or the patient may complain of a vague feeling of discomfort, without any actual pain, at the site of the operation. 693
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Respiratory Depression.-If the spinal anesthetic agent is distributed too far cephalad in the subarachnoid space, serious respiratory depression may result. This complication is more prone to occur when spinal anesthesia is employed for upper abdominal surgery. If the motor divisions of the thoracic nerves are anesthetized as high as the fourth thoracic segment (the height necessary for satisfactory upper abdominal surgery), the intercostal muscles below this level will be inactive and the elevation of the ribs and expansion of the chest with inspiration will be the result of the pull of the four upper intercostal muscles. If the agent continues to progress cephalad until the remaining intercostal nerves become involved, the chest will no longer expand with inspiration. If the patient is asked to take a deep breath at this time, only diaphragmatic breathing can be observed. The chest will remain entirely motionless or the intercostal spaces may even retract on inspiration. This is one of the earliest and most important warning signs that anesthesia is going too high. At this time the patient may complain of numbness or tingling in the hands due to involvement of the roots of the brachial plexus. If the agent continues until it reaches the level of the fourth cervical nerve root, the diaphragm becomes paralyzed and complete respiratory arrest ensues. Usually before respiration becomes completely arrested the conscious patient will attempt to increase the size of the chest cavity on inspiration by greater effort on the part of the accessory muscles of respiration. This can be detected by observing the patient's neck for increased activity of the sternomastoid and platysma muscles. The voice may be lost and the patient become quite apprehensive. It is of utmost importance that respiratory impairment be recognized at once. If unrelieved, this condition will lead to anoxia, circulatory collapse and death. The treatment is obvious. It consists of the administration of oxygen, with some mechanical assistance to inspiration if there is inadequate respiratory exchange. This assistance is absolutely essential if there is complete respiratory arrest. Assistance to respiration is best accomplished by administering oxygen from a gas machine and exerting rhythmic pressure on the breathing bag coincident with each attempt at inspiration on the part of the patient. If there is no attempt at inspiration, the lungs should be inflated by pressure on the breathing bag at a rate of about sixteen times per minute. Obviously, the establishment of a free and unobstructed airway is imperative. This may require the insertion of an endotracheal tube. Respiratory stimulants are not indicated and pressor drugs should be used at this stage only to treat secondary circulatory depression. If immediate and adequate treatment is instituted, this condition need cause no great alarm and usually secondary circulatory depression does not occur. Respiratory depression due to spinal anesthesia rarely lasts longer than twenty or thirty minutes. While this respiratory depression is usually thought of as peripheral in nature, it is quite possible that the anesthetic agent may be present in the fourth ventricle and exert an influence directly on the respiratory center. Circulatory Depression.-Some degree of circulatory depression quite
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commonly accompanies spinal anesthesia. This depression may at times be profound and alarming. Serious falls of blood pressure are much more common with high spinal anesthesia than when the anesthesia is confined to the lower part of the abdomen. It has been suggested that this fall in blood pressure was due to an hematogenous intoxication and that the rapid absorption into the blood stream of the anesthetic drug injected in the subarachnoid space produced the hypotensive effects observed. However, we know that much larger quantities of the agent can be injected directly into the blood stream without producing hypotension comparable to that produced by spinal anesthesia. Smith and his associates3 have suggested that the hypotension is due largely to a stagnation of the blood in the postarteriolar bed. They have postulated that this venous stagnation is accompanied by a lessened stroke volume and a decreased cardiac output. Perhaps the theory at the present time which has the widest acceptance is that of paralysis of the vasoconstrictor fibers in the anterior spinal nerve roots with a resulting loss of tone and stagnation of the blood in the arteriolar bed. The hypotension which so often accompanies spinal anesthesia may be alarming and should always be considered unphysiologic. Surgical manipulation in the abdomen, of course, plays a part in the production of blood pressure falls, and circulatory depression will most surely follow unrelieved respiratory depression. It has been well demonstrated that the routine use of sympathomimetic drugs prior to the administration of a spinal anesthetic is a valuable safeguard against circulatory depression. For many years 50 to 75 mg. of ephedrine has been almost uniformly accepted as the routine preanesthetic drug for the support of blood pressure. Many drugs have been used to treat a falling blood pressure under spinal anesthesia, notably epinephrine, ephedrine and neosynephrine. Epinephrine is evanescent in its action; however, it has the greatest effect of any agent. The systolic rise may be accompanied by a diastolic fall. It does not stimulate the respiratory center as does ephedrine. Occasionally apnea may follow the use of epinephrine due to the sudden increase of pressure in the carotid sinus and the cardio-aortic area. Increased pulse rate frequently accompanies the use of this drug, and it may be followed by bradycardia. The hypertension also may be followed by hypotension. Restlessness and apprehension are often distressing side effects of epinephrine. This drug acts by direct stimulation on the myocardium and the conduction tissue, and, of course, is dangerous in the presence of other factors affecting cardiac irritability. Repeated doses of epinephrine cause equal action. Ephedrine lasts longer but does not produce as marked an effect as epinephrine, and is not usually followed by the hypotension so often observed after administration of epinephrine. However, repeated doses will not produce an equal effect and may cause cardiac depression. Ephedrine is a respiratory stimulant and may increase the minute volume as much as 20 per cent. Bradycardia may be an accompaniment and some central side effects, such as nervousness, may be noted.
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Neosynephrine produces a greater effect than ephedrine and does not last as long. It does, however, last approximately five times as long as epinephrine. Its action is largely that of vasoconstriction but there may be some direct cardiac action. Arrhythmias following the use of neosynephrine are uncommon. However, bradycardia may be an accompaniment. This is probably due to direct action on the sino-auricular node or it may be a compensatory reflex. The heart has a tendency to dilate when neosynephrine is used. There is no central stimulation. Ten to 20 mg. of neosynephrine in 1000 cc. of solution (physiologic salt or 5 per cent dextrose) as an intravenous drip has proved to be of great value in supporting blood pressure during spinal anesthesia. One must always bear in mind, however, that a pressor drug should never be used as a substitute for fluids or blood in cases of hypotension due to blood loss or surgical shock. Nausea, Retching and Vomiting.-Nausea, retching and vomiting are common and annoying complications of spinal anesthesia. With the increasing tendency to give some sort of a complementary agent to render the patient unconscic)Us during the course of spinal anesthesia, we do not see these complications as frequently as formerly. However, when spinal anesthesia is employed without a complementary or supplementary agent, and nausea and retching are more than a temporary disturbance, the patient should be rendered unconscious with some general anesthetic agent such as cyclopropane or pentothal. This enables the surgical procedure to continue uninterruptedly and relieves the patient of an uncomfortable and disturbing experience. The danger of vomitus being aspirated into the trachea and bronchi should always be borne in mind. This danger may be further enhanced if a general anesthetic -is administered after the patient has already vomited. Pyloric or Small Bowel Obstruction.-Another alarming complication may arise with patients who have obstruction of the pylorus or small bowel with proximal dilatation of the intestine. The administration of a spinal anesthetic with its tendency to increase the tone of the bowel followed by manipulations of the bowel by the surgeon may result in pouring out of large quantities of material into the pharynx from where it may be aspirated into the respiratory passages. Unless prompt, adequate treatment is instituted at once this complication may be serious. The patient should immediately be placed in the head-down position and all of the material aspirated from the pharynx. If there is evidence that any of the material has been aspirated into the trachea or bronchi, bronchoscopy should be performed immediately to clear the air passages. As a precautionary measure against this complication, in any patient suffering from pyloric or small bowel obstruction a Levin tube should be placed in the stomach prior to the administration of the anesthetic. The presence of a Miller-Abbott tube in the small bowel is not a sufficient safeguard against the aspiration of vomitus, and if there is any question of an obstruction still persisting at the time of operation, a Levin tube should be placed in the stomach in addition to the Miller-
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Abbott tube. Neglect of this precautionary measure may result in a fatality. Nervousness and Apprehension.-Many patients object to being awake during an operation. There is no reason why any patient who wishes it cannot be asleep and still have the advantage of spinal anesthesia. An additional dose of morphine intravenously after the patient is in the operating room and before the induction of spinal anesthesia often allays apprehension and nervousness. The intravenous administration of 1 to 3 grains of pentobarbital sodium (nembutal) is valuable also for patients who are nervous or apprehensive. Intravenous pentobarbital sodium is less likely to cause nausea than is intravenous morphine. Quite often an intravenous dose of morphine or nembutal is all the supplementary anesthetic needed. Provision of an Intravenous Route for Supplementary Agents.-If an intravenous needle is placed in the great saphenous vein near the medial malleolus and a small drip of fluid maintained throughout an operative procedure, a route is constantly available for the administration of supplementary anesthetic agents or for the administration of supportive drugs and fluids. The use of the saphenous vein has the advantage of removing the intravenous apparatus to a point where it will not interfere with any type of surgery except that on the lower extremities. If the intravenous drip is not started until after the spinal anesthetic is given the insertion of the needle causes no discomfort and the dilatation of the vein which follows spinal anesthesia facilitates the insertion of the needle. In the past this procedure was reserved for poor risk patients or for patients upon whom extensive operative procedures were contemplated. More recently it has become almost a routine with spinal anesthesia and the feeling of security that comes with having an intravenous route always available for the administration of drugs and fluids is well worth the additional effort and expense which this procedure entails. NEUROLOGIC COMPLICATIONS OF SPINAL ANESTHESIA
Since the central nervous system is the site of action of all anesthetic agents whether general or spinal, it is not surprising that complications of the nervous system occur after all types of anesthesia. While no particular type of neurologic complication can be said to be limited entirely to one type of anesthesia, and hemiplegias and various types of peripheral nerve lesions can follow both general and spinal anesthesia, certain complications are much more prone to follow spinal anesthesia and certain others more prone to follow general anesthesia. Convulsions, extrapyramidal rigidity, postoperative psychoses and degenerative changes in the cerebral cortex and lenticular nuclei have been reported most often after general anesthesia. Headache, septic and aseptic meningitis, arachnoiditis, neuritis, myelitis and the so-called cauda equina syndrome comprise the complications most frequently reported following spinal anesthesia.
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Etiology.-It is usually quite difficult to determine the exact etiologic factor responsible for neurologic complications following spinal anesthesia. Certain spinal anesthetic drugs in high enough concentration cause a specific, toxic, destructive effect on nerve tissue when injected into the subarachnoid space in experimental animals. The incidence of these lesions increases as the concentration of the drug is increased. Also, it seems evident that the lesions produced are the result of the spinal anesthetic agent itself since the damage is usually manifested so soon after the administration of the drug. Other possible etiologic factors must, however, be considered. Direct Trauma.- Direct trauma may play a part in some neurologic complications following spinal anesthesia. There does seem to be a definite relationship between a traumatic spinal puncture which causes pain to extend down one leg followed by the injection of a spinal anesthetic drug with a persistent neurologic complication referable to the same leg, yet in view of the large number reported of diagnostic spinal punctures performed without serious neurologic complications, it seems unlikely that trauma can be considered as a major etiologic factor in the production of postspinal neurologic complications. Inflammatory Reaction.-The rapidity of onset of most of these complications of itself seems to preclude inflammatory reaction as an etiologic factor. Furthermore, it is usually impossible to cultivate organisms from the spinal fluid of patients with postspinal neurologic complications, and the predominating cells are generally lymphocytes rather than polymorphonuclear leukocytes. These complications are seldom associated with an elevation in temperature or other signs of an inflammatory process. Toxicity of the Drug.-There is considerable evidence that neurologic complications are due to direct toxic action of the agent itself. Not all of the nerves influenced by the anesthetic agent are affected by the paralysis. The anesthetic may have been sufficient for an upper abdominal operation, yet the ultimate paralysis be limited to the lumbosacral or sacral nerves. These, of course, are the nerves that are exposed to the greatest concentration of the agent. Permanent paralysis seems to occur most frequently in the nerve tissue which comes in contact with the drug in its greatest concentration. Furthermore, it seems unlikely that these complications are of an allergic nature, but that the concentration employed with most anesthetic drugs is only a little· short of that which would produce paralysis in a higher percentage of patients. Neurologic Disease Precipitated by Spinal Anesthesia.-Spinal anesthesia may be a precipitating factor in the exacerbation of certain preexisting neurologic conditions such as pernicious anemia with combined sclerosis, multiple sclerosis and tabes dorsalis. Two patients at the Lahey Clinic received spinal anesthesia for the removal of carcinomas in other parts of the body and, upon examination, because of the fact that the spinal anesthesia failed to wear off, were found to have metastasis to the spine resulting in almost complete cerebrospinal fluid block. In addition to the group of peripheral neuropathies commonly re-
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ferred to as the cauda equina syndrome, such other complications as headaches, septic and aseptic meningitis, arachnoiditis and cranial nerve palsies must be considered as neurologic complications. Headache.-Headache is one of the most distressing postspinal complications from the patient's standpoint. This complication may arise following a diagnostic spinal puncture as well as spinal puncture followed by the injection of a spinal anesthetic agent. Many theories have been advanced to explain this complication. One theory is that there is chemical irritation of the pia mater by the anesthetic agent which in turn causes excessive absorption of spinal fluid with lowering of spinal fluid pressure. Another theory is that headache is the result of slow leakage of spinal fluid through the dural puncture opening into the subdural space which is under negative pressure. This lowering of spinal fluid pressure is supposed to be responsible for removing the watery cushion upon which the brain rests, allowing the brain to sag against the bony framework of the skull, which in turn irritates the dural fibers of the trifacial and the two occipital nerves. This pressure further tends to depress the basilar venous plexus and diminish the outflow of blood, thus increasing the venous tension. Some credence may be lent to'this theory because of the fact that most of these headaches can be relieved by lowering the patient's head. A third theory is that orthostatic hypotension and tachycardia occurring in patients who have received spinal anesthesia for delivery may play a large part in the production of their headaches. The headaches may be frontal, temporal or occipital. Throbbing in the head is produced on sitting or standing. Sometimes the main complaint may be stuffiness in the ears, while other patients may have little headache but complain of stiffness of the nape of the neck or shoulders. The treatment of headache following spinal anesthesia, for the most part, is conservative and not very satisfactory. Patients with the milder types generally respond to rest in bed with the bed level or in the headdown position. Relief is sometimes obtained with mild analgesics, but more stubborn cases require constant medication with salicylates and occasionally an opiate. The more intractable type of postspinal headache should be investigated carefully. A lumbar puncture should be done and spinal fluid dynamics determined along with microscopic and bacteriologic investigations of spinal fluid to rule out meningitis. When the spinal fluid pressure is low, benefit has been obtained by returning it to normal with the injection of physiologic saline or 5 per cent dextrose solution. However, when the spinal fluid is elevated (and it is sometimes with postspinal headache) it should be returned to normal by the withdrawal of spinal fluid. If the spinal fluid pressure is elevated, the patient should be put on a dehydration regimen and given 25 per cent dextrose intravenously. Weintraub and associates,4 in a study of postspinal headaches in 45 patients out of a series of 300 who received spinal anesthesia for delivery, found that 50 per cent of the patients with headache demonstrated orthostatic hypotension or tachycardia or both. The other 50 per cent who had headache did not have orthostatic hypotension or tachycardia or both. However, they were able to relieve the head-
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aches in both groups by the application of abdominal compression by means of tight binders. From these observations they concluded that postspinal headaches in the postpartum patient are due to two factors: (1) the most important, the sudden relief of intra abdominal pressure following delivery superimposed on the action of the anesthetic, and (2) spinal fluid leakage. Cranial Nerve Palsies.-From time to time we read reports of cranial nerve palsies following spinal anesthesia. While the abducens or sixth nerve is the one most frequently affected, there have been reports of palsies of almost all of the cranial nerves. The mechanism by which a cranial nerve is paralyzed is difficult to explain, and this is a very rare complication. There is no treatment of this condition and recovery can be expected in almost every instance. The Cauda Equina Syndrome.-Some manifestation of the so-called cauda equina syndrome is usually thought of when postoperative neurologic complications are mentioned. This complication is brought to the anesthesiologist's attention because the patient fails to regain the use of his lower extremities in the usual time following spinal anesthesia. On examination, a certain amount of loss of both motor and sensory function is generally found to involve some part of the lumbosacral nerve distribution. Associated conditions may be varying degrees of urinary retention and incontinence of feces with loss of tone of the anal sphincter. This loss of sensation may involve only the saddle area, one or both legs or the entire body below the umbilicus. As was pointed out previously, an examination of these patients reveals that the basic lesion is in the region of the cauda equina where the nerves have met the anesthetic agent in its highest concentration. The following case report illustrates this complication: A white man, aged 42, a bartender, complained of cold legs for the past two years and associated cramps in the calf muscles for the last six months. A diagnosis of thromboangiitis obliterans was made and hospitalization for further investigation, with possible lumbar sympathectomy, was advised. He was given 14 mg. of tetracaine (ponto caine) hydrochloride and 2.66 cc. of 10 per cent dextrose for spinal anesthesia for skin temperature readings. The spinal puncture was made in the third lumbar interspace. Anesthesia developed to the eighth thoracic segment. After twenty-four hours the anesthesia was still present and the patient was paralyzed from his waist down. A spinal puncture at that time showed an initial pressure of 50 mm. of water, total protein 347 mg., and sugar 21 mg. per 100 cc., with 57 lymphocytes. Approximately thirty hours after the spinal anesthetic was administered an exploration of the lower thoracic and upper lumbar cord was performed, under endotracheal ether anesthesia, for what was thought to be a spinal fluid block. No block was found and the cord showed only slightly increased vascularity. The patient remained in the hospital for three months and showed but little improvement. There was improvement in the sensation over the area supplied by the second lumbar nerve and a slight return of motor power in the feet. Although he voided voluntarily, a small amount of residual urine with an associated pyuria persisted througout his hospital stay. He was discharged
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from the hospital without ever having regained the use of his lower extremities. During his stay at home over the next fourteen months there was no improvement in his condition. He died seventeen months after the development of the complication. A complete necropsy, including the brain and spinal cord, was obtained. The pertinent pathologic observations were in the spinal cord. The following is a comment by the neuropathologist: "The principal pathologic observation IS the loss of nerve fibers in the root of the cauda equina and the regeneration of fine nerve fibers in the anterior root. The degeneration of the posterior columns of the spinal cord is unquestionably secondary to destruction of the posterior roots. The fibrous thickening and cellular proliferation in the meninges may be viewed as the final stage of an inflammatory process, whether induced by chemical irritation or infection. The pathologic observations are approximately the type one would expect in a lesion one to two years of age. The partial sparing of some roots and the regeneration of others would account for the retention of some bladder function and sensation. There are no vascular lesions suggestive of thromboangiitis obliterans. I believe that the changes in the anterior roots which were first interpreted as neurofibromatosis are regenerative phenomena. The observations are consistent with, although not pathognomonic of, the cauda equina syndrome of spinal anesthesia."
Prevention of Postspinal Neurologic Complications.-The following is a regimen which has been suggested in an attempt to prevent postspinal neurologic complications: 1. Very close attention should be paid to the cleansing and sterilizing of apparatus used in the administration of spinal anesthesia. The routine rinsing of syringes and needles with sterile isotonic solution of sodium chloride immediately before their use is an additional precaution. 2. Drugs should be used from manufacturer's ampules whose labels are legible, whose walls are intact and whose contents on routine inspection before use are clear and free from insoluble particles or crystals. 3. Ampules containing spinal anesthetic drugs should be sterilized by soaking them in a nonirritating, highly colored sterilizing solution. The addition of a strong concentration of dye to these solutions in which the ampules are immersed is of value in detecting the occasional defective ampule into which the sterilizing solution may have leaked. Irritating solutions containing alcohol, phenol or formaldehyde should not be used because of the danger of their entering the ampule through microscopic breaks and in turn being injected into the subarachnoid space. Many of the spinal anesthetic agents now in use can be sterilized by autoclaving and this circumvents the possibility of a sclerosing sterilizing solution entering the ampule. 4. Solutions containing even a faint suggestion of turbidity or cloudiness should be discarded. 5. Spinal puncture should not be made through or near areas of infection. 6. Spinal anesthesia should not be given to patients with known spinal cord disease, such as tabes dorsalis, multiple sclerosis, pernicious anemia with symptoms of combined system disease, and tumors of the spinal cord. Patients who have herniated intervertebral disks with signs of
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peripheral nerve paralysis, loss of bowel or bladder function or with an elevation of the total protein content of the spinal fluid should not be given spinal anesthesia. 7. Patients suffering from known virus infections, such as poliomyelitis or chickenpox, should not be given spinal anesthesia. 8. A history of delayed return of motor function or severe paresthesias following a previous spinal anesthesia should be considered a contraindication to the subsequent use of this type of anesthesia. 9. If the spinal puncture causes a radiating paresthesia, the anesthetic agent should not be injected until adjustment of the needle has freed the patient of this pain. We have seen 2 patients in whom this warning was not heeded and the administration of the spinal anestbetic agent caused a unilateral paralysis of one leg. 10. A persistently bloody spinal tap contraindicates the injection of a spinal anesthetic agent. 11. Routine determination of the spinal fluid dynamics should be carried out on all patients complaining of intractable back pain or pain that seems out of proportion to the pathologic condition for which the surgical procedure is being performed. Experience has shown that spinal cord pathology (metastatic disease or primary carcinoma) can be detected in a certain number of these patients by such a routine. 12. When it has been difficult or impossible to obtain the desired height of anesthesia by the ordinary methods a spinal block should be suspected. It is advisable to terminate such a spinal anesthesia by flushing out the subarachnoid space with isotonic solution of sodium chloride in order to remove any residual anesthetic solution that may have been deposited in the subarachnoid space.
Management of the Cauda Equina Syndrome Following Spinal Anesthesia.-Since the loss of bowel and bladder function from the standpoint of the life of the patient is probably the most serious of all of the symptoms of the cauda equina syndrome, some discussion of the management of tllis complication is warranted. Each step in the sequence of events leading up to the mishap demands careful investigation. A complete history and physical examination in addition to a review of the preanesthetic information should be obtained. The extent of the impairment of the nerve function must be ascertained. It is of paramount importance that the functional state of the bowel and bladder be determined so that treatment, if needed, can be instituted immediately. Tidal irrigation of the bladder, as described by Munro,!· 2 offers a real chance for recovery of function without infection of the urinary tract. It is extremely difficult to give an effective cleansing enema by ordinary methods to a patient whose rectal sphincter is incompetent. However, if a large Foley catheter is inserted into the rectum and the cuff inflated an effective enema can be administered. In order that preexisting pathologic changes in the spinal cord may be detected early, any patient in whom there is evidence of a postspinal cauda equina complication should have an investigation of the spinal fluid dynamics. In conjunction with this maneuver it is advisable to
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irrigate the subarachnoid space with isotonic solution of sodium chloride to insure the removal of any remaining anesthetic agent. This attempt to remove any residual anesthetic agent takes on additional significance when a spinal fluid block is discovered. When the abnormalities of the spinal fluid are limited to an elevation in the total protein and cell count, daily spinal punctures for the withdrawal of fluid should be performed. During the recovery period, the duration of which may be extremely variable, the nursing routine must be a vigorous one if decubitus ulceration, ankylosed joints, malnutrition and muscular atrophy are to be avoided. REFERENCES 1. Munro, D.: The treatment of urinary bladder in cases with injury of spinal cord. Am. J. Surg. 38:120--136 (Oct.) 1937.
2. Munro, D.: Tidal drainage and cystometry in treatment of sepsis associated with spinal-cord injuries; study of 165 cases. New England J. Med. 229: 6-14 (July 1) 1943. 3. Smith, H. W., Rovenstine, E. A., Goldring, W., Chasis, H., and Ranges, H. A.: Effects of spinal anesthesia on circulation in normal, unoperated man with reference to autonomy of arterioles, and especially those of renal circulation. J. Clin. Investigation 18:319-341 (May) 1939. 4. Weintraub, F., Antine, W. and Raphael, A. J.: Postpartum headache after low spinal anethesia in vaginal delivery and its treatment. Am. J. Obst. & Gynec. 54:682-686 (Oct.) 1947.