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General Anesthesia for Mouth Surgery
The Journal o f the American Dental Association
12
Soc., 1894, pp. 33-43, 42-45; D. Cosmos, 36: 542-55«» July 189425. Seat of Green Stain. Odontog. ] ., 15: 1894-1895, p. 90. 26. C l a u d e , G. H .: Union Convention of the Washington City Dental Society and the Maryland State Dental Association. Disc., D. Cosmos, 37:716, August 1895. 27. G r a m m , C. T .: Etiology of Green Stain. D. Cosmos, 37:759-764, September 1895. 28. B a r r e t t , W. C.: Classification of SoCalled Green Stain. D. Cosmos, 37:764-767, September 1895. 29. P a l m e r , S. B.: Therapeutics of Green Stain. D. Cosmos, 37:767-774, September
>895.
30. Green Stain. D. Digest, 1:618-628, October 1895. 31. G o a d b y , K. W .: Mycology of Mouth. New York: Longmans, Green and Co., 1903, p. 24. 32. C o l y e r , J. F.: Dental Surgery and Pathology. Ed. 3. New York: Longmans, Green and C o ., 1910, pp. 681-682.
33. T o m e s , C. S.: Manual of Dental An atomy. Ed. 7. (Nasmyth’s Membrane.) Phil adelphia: P. Blakiston’s Son and Co., 1914, pp. 120-125. 34. K e n d a l l , A. I.: Bacteriology. General, Pathological, Intestinal. Philadelphia: Lea and Febiger, 1916, p. 547. 35. W il l ia m s , J. L.: Disputed Points and Unsolved Problems in Normal and Patho logical Histology of Enamel. / . D. Res., 5 : 27-116, September 1923. 36. J o r d a n , E. O.: Textbook of General Bacteriology. Philadelphia: W. B. Saunders Company, 1933, p. 216. 37. B a d a n e s , B . B . : Role of Fungi in De posits upon Teeth. D. Cosmos, 75:1154-1160, December 1933. 38. B e r k e , J. D .: Etiology and Histology of Dental Tartars. D. Cosmos, 77:134-139, Feb ruary 1935. 39. T h o m a , K. H .: Oral Diagnosis and Treatment Planning. Philadelphia: W. B. Saunders Company, 1936, p. 144.
GENERAL ANESTHESIA FOR MOUTH SURGERY By G e o r g e W . C h r is tia n s e n , A.B., M.S., D.D.S., Detroit, Mich.
ITROUS oxide-oxygen as a gen eral anesthetic for mouth surgery is well established as the safest and most flexible and useful agent of its kind. The necessity for this satisfactory general anesthetic is emphasized by the host of patients whose operative needs or individual makeup demand with drawal from consciousness not possible by any other means. Opposition to it arises chiefly from three sources: (1) en thusiastic advocates of local anesthesia; (2) those who have not learned to use it and so remain unaware of its blessings; (3) those practitioners who, because of unpleasant experiences, attempt to dis credit the use of nitrous oxide-oxygen as unsafe and impracticable. The truth de serves repeating that if any other agent were employed with the same disregard
N
Jour. A.D.A., Vol. 26, January 1939
for experience in and knowledge of its employment, the consequences would not be as they are. Nitrous oxide-oxygen meets the needs of the patient who requires a short gen eral anesthesia without unpleasant or prolonged after-effect, as well as of pa tients requiring longer narcosis. Its ap plicability is surprisingly general, but obviously there are limitations, some of which will be recalled by the following “don’ts” : 1. Don’t attempt the removal of deeply impacted mandibular teeth or similar difficult tasks in unfavorable cases, be cause you will not succeed and the an esthetic will not be the cause. 2. Don’t begin the use of nitrous ox ide-oxygen armed only with a few in structions about percentage mixtures and
Christiansen— General Anesthesia for Mouth Surgery some vague ideas about the signs of anesthesia. 3 . D on’ t neglect to have the face mask within easy reach, ready for immediate use. 4 . D on’t have the patient’ s relatives in the operating room, because you may not be at leisure to explain to them the signs o f anesthesia, and without an ex planation the appearance o f the patient may be somewhat disconcerting to them. 5 . D on’ t depend on the physician who
Fig. 1 .— R igh t prop, properly placed, a f fordin g adequate vision.
Fig. 2 .— L on g prop placed between incisor teeth. This procedure is less effective and may cause posterior displacement o f the mandible.
occupies the adjoining suite to administer the anesthetics. The odds are that he knows no more about keeping the patient asleep with the mouth open than you do, and the results may be disappointing and perhaps injurious to your practice.
13
6 . D on’ t fail to learn something about premedication and to use it when neces sary. 7 . Don’ t expect smooth anesthesia if the stomach is full, and don’t forget to have the patient empty the bladder. Em barrassment is unnecessary and we should prevent it. EQUIPMENT
For uniformly good results, the arma-
Fig. 3 .— Long prop placed between incisor teeth, permitting retrusion o f mandible to de crease airway.
Fig. 4 .— Displacem ent o f mandible by short prop between incisor teeth, causing for ward m ovem ent with heavy pressure loosening or displacing teeth.
mentarium must contain a modern ma chine whose operation is thoroughly understood, connected with an adequate supply o f both nitrous oxide and oxygen, with attachments which can be depended
14
T h e Journal o f the A m erica n D en ta l Association
on not to fail. You will also need sat isfactory mouth gags for opening the mouth, if necessary with force, gauze packs of various sizes, restraining straps and an effective aspirator to remove blood and saliva. The assistant, although not necessarily a qualified anesthetist, should know how to operate the machine, be familiar with the appearance and conduct of a patient under general anesthesia and realize what is expected of her. INDUCTION
The patient is seated well back in the chair the back rest of which is at right angles to the seat, and then the chair is
Fig. 5 .— Lateral swing o f m andible with de creased vision o f operative field, w hich occurs if prop is placed between anterior teeth.
tipped backward so that, with relaxa tion, the body will slide backward and not forward, out of the chair. The head rest is adjusted so that the airway is straight, and the hands are clasped by interlocking the fingers. After careful study, a mouth-prop is chosen, and this is placed as far back as possible, where it will be most effective, and the patient is cautioned not to push the prop for ward with the tongue. Time and effort spent on this seemingly trivial matter of determining the right prop and locating it correctly will be well repaid. Poor working conditions caused by failure to
keep the mouth open wide enough com plicate the operation needlessly and make breathing difficult by malposition of the mouth-pack. Because of lack of vision, teeth are broken off, soft tissues are lac erated, lips are cut and bruised and the anesthetic level is disturbed. The oper ator should decide in the beginning how to keep the mouth open, make provision for it and see that it is done. (Figs. 1-5.) The valve starting the flow of gas is now opened and the nose piece adjusted. If no gas is coming through the tube, there is a sensation of smothering, and since the patient has probably feared this, a bad beginning is made. After a few breaths, tfye mouth is covered and the
Fig. 6 .— Intratracheal (M a gill’ s) tube, made from com m ercial rubber tubing, 9 -12 mm. outside diameter, 25 cm. long, one end beveled at 30 degree angle.
mandible is supported, and the patient is assured that all is well. One hundred per cent nitrous oxide is used since the ul timate object is to put the patient to sleep, and long inductions often cause delay and disturbance. When conscious ness is partially lost, restraint which will be effective without injury or interfer ence with breathing is applied. MAINTENANCE
Next, signs of anesthesia are looked for, and when the eyeballs are fixed lat
Christiansen— G eneral A n esthesia fo r M o u th Surgery
15
erally or downward and breathing is rhythmic, a gauze pack is inserted and tucked well back against the velum with the ends pushed laterally, effectively closing the oropharynx. Judgment must be used as to the size o f this first pack because if the space is small, forcing the tongue out o f position with a large pack will cause trouble, and, conversely, a small amount o f gauze will be useless if the tongue is flat and the tissues are re laxed. In other words, the right pack should be used and blood and mouth fluids should be taken care o f with other
invaluable since it saves both carbon di oxide and nitrous oxide. However, smooth efficient rebreathing and careless mouth packing do not coexist; hence, the latter must not be neglected.
Fig. 7 .— Endotracheal tube in position shown extending through naris, oropharynx and nasopharynx past epiglottis (E ) into trachea ( T ) .
Fig. 8 .— L on g m outh prop between anterior teeth forcin g mandible posteriorly to reduce airway. T h e presence o f the tube preyents obstruction.
packs and an aspirator, so that the throat will remain dry. During the stage o f maintenance o f anesthesia, the exhaling valve in the nasal inhaler is closed and gases are de livered with enough force to discourage mouth breathing. By adjustment o f the bellows pressure, rebreathing is estab lished, and, for any but a short case, is
loosened. The patient is not allowed to exert unnecessary effort in arising to ex pectorate. Instead, he should be allowed to use a towel or an emesis dish in the semisupine position. Since, in this twi light o f half-consciousness, the patient may be dizzy or terribly frightened, per haps from a horrible, realistic dream, he should be spoken to softly and assured
RECOVERY
When the operation is completed, the mouth-prop is removed and the mouth slightly closed, the mixture is enriched to 100 per cent oxygen for a few breaths, the nose piece is lifted off and, when the reflexes return, the mouth pack is taken out to avoid gagging, and the restraint
The Journal of the American Dental Association
i6
that the unpleasant feeling will pass soon ; and if there is sobbing, we should explain to him that the cause was just a dream and that all is well again. I f the patient screams, both the mouth and nostrils are closed during exhalation and he is asked not to be noisy. Except in young children, unnecessary disturb ance is usually avoided in this way. We should be sure too that the teeth can be brought into occlusion, which will rule out the possibility o f dislocation at the mandibular joint. CYANOSIS
Probably the most frequent cause o f an uneven, unbalanced maintenance or working stage o f surgical anesthesia, not caused by faulty application o f the mouth prop or pack, is uncertainty as to when the patient is all right; in other words, failure to accept a degree of cy anosis as normal for some cases and to distinguish it from oxygen want, a rare condition if the airway is clear. As long as the surgeon demands that the thick necked muscular patient be brought back to a pretty pink when the anesthetic level is satisfactory, as revealed by respiratory, muscle and pupillary findings, poor an esthesia will continue, as will needless explanations to the patient that he is a poor risk and in the future should de mand a local anesthetic. Cyanosis is a natural concomitant o f anesthesia for many persons, and must be accepted as such. T o illustrate this: I f an attempt is made to divide a fixed number o f units among too many persons, the supply will become exhausted and some will go without any. Likewise, in producing anesthesia with nitrous oxide, there may be insufficient oxygen to combine with all t h e , available hemoglobin and the blood becomes darker, but in no sense is an oxygen deficiency produced when plenty o f oxygen is being transported to the tissues. Under the circumstances, there is no cause for w orry: such a pa
tient may be anesthetized with perfect safety as long as the signs o f anesthesia are observed carefully. ANOXEMIA
In contrast, the anemic have a lesser amount o f hemoglobin, all o f which must function abundantly to supply the metabolic needs, but which a much smaller amount o f oxygen satisfies, and cyanosis does not appear even if enough oxygen is not available. Waiting in this case for color change to warn o f danger ously deep necrosis might be fatal. Thus, the presence or absence of cyanosis can not be used as a measure o f the depth of anesthesia. True, oversaturation with nitrous oxide produces a dark blue or grayish shade, but accompanying this is other evidence which tells the story more vividly than does this color. These prin ciples must be acknowledged and under stood before rational management of anesthesia is possible. ENDOTRACHEAL ANESTHESIA
After surgical anesthesia is produced, the problem remains to maintain it. The most frequent causes o f non-performance are nasal obstruction; mechanical inter ference from misshapen mandibles; strug gling, more or less violent, o f the patient when the anesthetic level is changed by even a slight dilution with air, and as a result o f antral surgery, hemorrhage which pours into the airway unless trau matizing packs are placed in the posterior nares. In such cases, the gases may be transmitted undiluted to their destina tion by means o f so-called endotracheal intubation (Fig. 6 ), which is accom plished by passing a well-lubricated tube through the more open naris, past the nasopharynx and oropharynx, between the cords and into the trachea. (Fig. 7 .) T o accomplish this, surgical anesthesia is first produced and insertion o f the tube is attempted by the indirect or blind
Christiansen— General Anesthesia for Mouth Surgery method, which frequently is almost im mediately successful. Occasionally diffi culty is met, and sometimes direct ex posure with the laryngoscope is neces sary. Lundy 1 says : When there seems to be any respiratory obstruction, dyspnea or heaving abdominal movements, quiet respiration and adequate and easy control of administration of the anesthetic can be brought about by the use of a large bore, soft rubber intratracheal (McGill’s) tube.2 In more than 50 per cent of cases, this tube can be inserted through the nostril and into the trachea without the necessity of opening the patient’s mouth or, by use of the laryngoscope, the tube can be placed under direct vision. When the tube is in place, it can be attached to the gas machine and anesthesia can be carried out smoothly, on an even plane, for an indefinite period. These trials consume time, during which the patient wakens. The former level must be restored before continuing. Office practice seldom demands this ar rangement, but as a means o f sustaining anesthesia under circumstances which offer otherwise insurmountable difficul ties, intubation has a particular place. (Fig. 8 .) CONCLUSIONS
If, in deep anesthesia, breathing is not ample, we must investigate to find out why before respiration stops, but if it does, the mouth prop and pack are re moved, the mandible is elevated, and the face mask is used to inflate the chest with oxygen. This is timed so that an inter val exists for exhalation and the pro cedure is then repeated. Resuscitation by this means is extremely successful even when circulation as well as respira tion apparently has ceased. The rule “ Be sure you are right, then
17
go ahead” is definitely applicable in this work. Confidence appends a carefully evolved plan which one knows will work. Therefore these issues should be deter mined on each application for general anesthesia: 1 . Are there any marked contra-indications such as advanced car diac disease or respiratory obstruction? 2 . Is the mandible short and misshapen so as to predispose the patient to re stricted breathing? 3 . Is trismus present and, if so, what is the cause? 4 . Is there pterygomaxillary or parapharyngeal edema which may indicate localized ab scesses ready to rupture if the mouth is opened? 5 . Is the operation one which the operator can do well ? I f the findings are not satisfactory, an other method should be chosen, because, generally speaking, more skill is needed than with local anesthesia to assure the same result; therefore, the surgeon who, through inexpertness and fumbling, re quires thirty minutes for ten minutes’ work, will not have his task simplified. Clumsy manipulation o f the mandible and inattention to the mouth packs change the anesthetic level and needlessly prolong narcosis. One’ s judgment o f nitrous oxideoxygen anesthesia must be fa ir; it is possible that other methods may not have been found infallible. Time spent in learning to administer nitrous oxideoxygen will be richly repaid in appre ciative patients and by increased personal satisfaction at having enlisted another valuable aid in the battle against pain. BIBLIOGRAPHY
1. L u n d y , J. S.: Recent Advances in Anes thesia. J.A.M.A., 1x0:434, February 5, 1938. 2. T u o h y , E. B.: Intratracheal Anesthesia. Proc. Staff M eet. M ayo Clinic, 11:91-95, February 1936. 1649 David Whitney Building.
12
Soc., 1894, pp. 33-43, 42-45; D. Cosmos, 36: 542-55«» July 189425. Seat of Green Stain. Odontog. ] ., 15: 1894-1895, p. 90. 26. C l a u d e , G. H .: Union Convention of the Washington City Dental Society and the Maryland State Dental Association. Disc., D. Cosmos, 37:716, August 1895. 27. G r a m m , C. T .: Etiology of Green Stain. D. Cosmos, 37:759-764, September 1895. 28. B a r r e t t , W. C.: Classification of SoCalled Green Stain. D. Cosmos, 37:764-767, September 1895. 29. P a l m e r , S. B.: Therapeutics of Green Stain. D. Cosmos, 37:767-774, September
>895.
30. Green Stain. D. Digest, 1:618-628, October 1895. 31. G o a d b y , K. W .: Mycology of Mouth. New York: Longmans, Green and Co., 1903, p. 24. 32. C o l y e r , J. F.: Dental Surgery and Pathology. Ed. 3. New York: Longmans, Green and C o ., 1910, pp. 681-682.
33. T o m e s , C. S.: Manual of Dental An atomy. Ed. 7. (Nasmyth’s Membrane.) Phil adelphia: P. Blakiston’s Son and Co., 1914, pp. 120-125. 34. K e n d a l l , A. I.: Bacteriology. General, Pathological, Intestinal. Philadelphia: Lea and Febiger, 1916, p. 547. 35. W il l ia m s , J. L.: Disputed Points and Unsolved Problems in Normal and Patho logical Histology of Enamel. / . D. Res., 5 : 27-116, September 1923. 36. J o r d a n , E. O.: Textbook of General Bacteriology. Philadelphia: W. B. Saunders Company, 1933, p. 216. 37. B a d a n e s , B . B . : Role of Fungi in De posits upon Teeth. D. Cosmos, 75:1154-1160, December 1933. 38. B e r k e , J. D .: Etiology and Histology of Dental Tartars. D. Cosmos, 77:134-139, Feb ruary 1935. 39. T h o m a , K. H .: Oral Diagnosis and Treatment Planning. Philadelphia: W. B. Saunders Company, 1936, p. 144.
GENERAL ANESTHESIA FOR MOUTH SURGERY By G e o r g e W . C h r is tia n s e n , A.B., M.S., D.D.S., Detroit, Mich.
ITROUS oxide-oxygen as a gen eral anesthetic for mouth surgery is well established as the safest and most flexible and useful agent of its kind. The necessity for this satisfactory general anesthetic is emphasized by the host of patients whose operative needs or individual makeup demand with drawal from consciousness not possible by any other means. Opposition to it arises chiefly from three sources: (1) en thusiastic advocates of local anesthesia; (2) those who have not learned to use it and so remain unaware of its blessings; (3) those practitioners who, because of unpleasant experiences, attempt to dis credit the use of nitrous oxide-oxygen as unsafe and impracticable. The truth de serves repeating that if any other agent were employed with the same disregard
N
Jour. A.D.A., Vol. 26, January 1939
for experience in and knowledge of its employment, the consequences would not be as they are. Nitrous oxide-oxygen meets the needs of the patient who requires a short gen eral anesthesia without unpleasant or prolonged after-effect, as well as of pa tients requiring longer narcosis. Its ap plicability is surprisingly general, but obviously there are limitations, some of which will be recalled by the following “don’ts” : 1. Don’t attempt the removal of deeply impacted mandibular teeth or similar difficult tasks in unfavorable cases, be cause you will not succeed and the an esthetic will not be the cause. 2. Don’t begin the use of nitrous ox ide-oxygen armed only with a few in structions about percentage mixtures and
Christiansen— General Anesthesia for Mouth Surgery some vague ideas about the signs of anesthesia. 3 . D on’ t neglect to have the face mask within easy reach, ready for immediate use. 4 . D on’t have the patient’ s relatives in the operating room, because you may not be at leisure to explain to them the signs o f anesthesia, and without an ex planation the appearance o f the patient may be somewhat disconcerting to them. 5 . D on’ t depend on the physician who
Fig. 1 .— R igh t prop, properly placed, a f fordin g adequate vision.
Fig. 2 .— L on g prop placed between incisor teeth. This procedure is less effective and may cause posterior displacement o f the mandible.
occupies the adjoining suite to administer the anesthetics. The odds are that he knows no more about keeping the patient asleep with the mouth open than you do, and the results may be disappointing and perhaps injurious to your practice.
13
6 . D on’ t fail to learn something about premedication and to use it when neces sary. 7 . Don’ t expect smooth anesthesia if the stomach is full, and don’t forget to have the patient empty the bladder. Em barrassment is unnecessary and we should prevent it. EQUIPMENT
For uniformly good results, the arma-
Fig. 3 .— Long prop placed between incisor teeth, permitting retrusion o f mandible to de crease airway.
Fig. 4 .— Displacem ent o f mandible by short prop between incisor teeth, causing for ward m ovem ent with heavy pressure loosening or displacing teeth.
mentarium must contain a modern ma chine whose operation is thoroughly understood, connected with an adequate supply o f both nitrous oxide and oxygen, with attachments which can be depended
14
T h e Journal o f the A m erica n D en ta l Association
on not to fail. You will also need sat isfactory mouth gags for opening the mouth, if necessary with force, gauze packs of various sizes, restraining straps and an effective aspirator to remove blood and saliva. The assistant, although not necessarily a qualified anesthetist, should know how to operate the machine, be familiar with the appearance and conduct of a patient under general anesthesia and realize what is expected of her. INDUCTION
The patient is seated well back in the chair the back rest of which is at right angles to the seat, and then the chair is
Fig. 5 .— Lateral swing o f m andible with de creased vision o f operative field, w hich occurs if prop is placed between anterior teeth.
tipped backward so that, with relaxa tion, the body will slide backward and not forward, out of the chair. The head rest is adjusted so that the airway is straight, and the hands are clasped by interlocking the fingers. After careful study, a mouth-prop is chosen, and this is placed as far back as possible, where it will be most effective, and the patient is cautioned not to push the prop for ward with the tongue. Time and effort spent on this seemingly trivial matter of determining the right prop and locating it correctly will be well repaid. Poor working conditions caused by failure to
keep the mouth open wide enough com plicate the operation needlessly and make breathing difficult by malposition of the mouth-pack. Because of lack of vision, teeth are broken off, soft tissues are lac erated, lips are cut and bruised and the anesthetic level is disturbed. The oper ator should decide in the beginning how to keep the mouth open, make provision for it and see that it is done. (Figs. 1-5.) The valve starting the flow of gas is now opened and the nose piece adjusted. If no gas is coming through the tube, there is a sensation of smothering, and since the patient has probably feared this, a bad beginning is made. After a few breaths, tfye mouth is covered and the
Fig. 6 .— Intratracheal (M a gill’ s) tube, made from com m ercial rubber tubing, 9 -12 mm. outside diameter, 25 cm. long, one end beveled at 30 degree angle.
mandible is supported, and the patient is assured that all is well. One hundred per cent nitrous oxide is used since the ul timate object is to put the patient to sleep, and long inductions often cause delay and disturbance. When conscious ness is partially lost, restraint which will be effective without injury or interfer ence with breathing is applied. MAINTENANCE
Next, signs of anesthesia are looked for, and when the eyeballs are fixed lat
Christiansen— G eneral A n esthesia fo r M o u th Surgery
15
erally or downward and breathing is rhythmic, a gauze pack is inserted and tucked well back against the velum with the ends pushed laterally, effectively closing the oropharynx. Judgment must be used as to the size o f this first pack because if the space is small, forcing the tongue out o f position with a large pack will cause trouble, and, conversely, a small amount o f gauze will be useless if the tongue is flat and the tissues are re laxed. In other words, the right pack should be used and blood and mouth fluids should be taken care o f with other
invaluable since it saves both carbon di oxide and nitrous oxide. However, smooth efficient rebreathing and careless mouth packing do not coexist; hence, the latter must not be neglected.
Fig. 7 .— Endotracheal tube in position shown extending through naris, oropharynx and nasopharynx past epiglottis (E ) into trachea ( T ) .
Fig. 8 .— L on g m outh prop between anterior teeth forcin g mandible posteriorly to reduce airway. T h e presence o f the tube preyents obstruction.
packs and an aspirator, so that the throat will remain dry. During the stage o f maintenance o f anesthesia, the exhaling valve in the nasal inhaler is closed and gases are de livered with enough force to discourage mouth breathing. By adjustment o f the bellows pressure, rebreathing is estab lished, and, for any but a short case, is
loosened. The patient is not allowed to exert unnecessary effort in arising to ex pectorate. Instead, he should be allowed to use a towel or an emesis dish in the semisupine position. Since, in this twi light o f half-consciousness, the patient may be dizzy or terribly frightened, per haps from a horrible, realistic dream, he should be spoken to softly and assured
RECOVERY
When the operation is completed, the mouth-prop is removed and the mouth slightly closed, the mixture is enriched to 100 per cent oxygen for a few breaths, the nose piece is lifted off and, when the reflexes return, the mouth pack is taken out to avoid gagging, and the restraint
The Journal of the American Dental Association
i6
that the unpleasant feeling will pass soon ; and if there is sobbing, we should explain to him that the cause was just a dream and that all is well again. I f the patient screams, both the mouth and nostrils are closed during exhalation and he is asked not to be noisy. Except in young children, unnecessary disturb ance is usually avoided in this way. We should be sure too that the teeth can be brought into occlusion, which will rule out the possibility o f dislocation at the mandibular joint. CYANOSIS
Probably the most frequent cause o f an uneven, unbalanced maintenance or working stage o f surgical anesthesia, not caused by faulty application o f the mouth prop or pack, is uncertainty as to when the patient is all right; in other words, failure to accept a degree of cy anosis as normal for some cases and to distinguish it from oxygen want, a rare condition if the airway is clear. As long as the surgeon demands that the thick necked muscular patient be brought back to a pretty pink when the anesthetic level is satisfactory, as revealed by respiratory, muscle and pupillary findings, poor an esthesia will continue, as will needless explanations to the patient that he is a poor risk and in the future should de mand a local anesthetic. Cyanosis is a natural concomitant o f anesthesia for many persons, and must be accepted as such. T o illustrate this: I f an attempt is made to divide a fixed number o f units among too many persons, the supply will become exhausted and some will go without any. Likewise, in producing anesthesia with nitrous oxide, there may be insufficient oxygen to combine with all t h e , available hemoglobin and the blood becomes darker, but in no sense is an oxygen deficiency produced when plenty o f oxygen is being transported to the tissues. Under the circumstances, there is no cause for w orry: such a pa
tient may be anesthetized with perfect safety as long as the signs o f anesthesia are observed carefully. ANOXEMIA
In contrast, the anemic have a lesser amount o f hemoglobin, all o f which must function abundantly to supply the metabolic needs, but which a much smaller amount o f oxygen satisfies, and cyanosis does not appear even if enough oxygen is not available. Waiting in this case for color change to warn o f danger ously deep necrosis might be fatal. Thus, the presence or absence of cyanosis can not be used as a measure o f the depth of anesthesia. True, oversaturation with nitrous oxide produces a dark blue or grayish shade, but accompanying this is other evidence which tells the story more vividly than does this color. These prin ciples must be acknowledged and under stood before rational management of anesthesia is possible. ENDOTRACHEAL ANESTHESIA
After surgical anesthesia is produced, the problem remains to maintain it. The most frequent causes o f non-performance are nasal obstruction; mechanical inter ference from misshapen mandibles; strug gling, more or less violent, o f the patient when the anesthetic level is changed by even a slight dilution with air, and as a result o f antral surgery, hemorrhage which pours into the airway unless trau matizing packs are placed in the posterior nares. In such cases, the gases may be transmitted undiluted to their destina tion by means o f so-called endotracheal intubation (Fig. 6 ), which is accom plished by passing a well-lubricated tube through the more open naris, past the nasopharynx and oropharynx, between the cords and into the trachea. (Fig. 7 .) T o accomplish this, surgical anesthesia is first produced and insertion o f the tube is attempted by the indirect or blind
Christiansen— General Anesthesia for Mouth Surgery method, which frequently is almost im mediately successful. Occasionally diffi culty is met, and sometimes direct ex posure with the laryngoscope is neces sary. Lundy 1 says : When there seems to be any respiratory obstruction, dyspnea or heaving abdominal movements, quiet respiration and adequate and easy control of administration of the anesthetic can be brought about by the use of a large bore, soft rubber intratracheal (McGill’s) tube.2 In more than 50 per cent of cases, this tube can be inserted through the nostril and into the trachea without the necessity of opening the patient’s mouth or, by use of the laryngoscope, the tube can be placed under direct vision. When the tube is in place, it can be attached to the gas machine and anesthesia can be carried out smoothly, on an even plane, for an indefinite period. These trials consume time, during which the patient wakens. The former level must be restored before continuing. Office practice seldom demands this ar rangement, but as a means o f sustaining anesthesia under circumstances which offer otherwise insurmountable difficul ties, intubation has a particular place. (Fig. 8 .) CONCLUSIONS
If, in deep anesthesia, breathing is not ample, we must investigate to find out why before respiration stops, but if it does, the mouth prop and pack are re moved, the mandible is elevated, and the face mask is used to inflate the chest with oxygen. This is timed so that an inter val exists for exhalation and the pro cedure is then repeated. Resuscitation by this means is extremely successful even when circulation as well as respira tion apparently has ceased. The rule “ Be sure you are right, then
17
go ahead” is definitely applicable in this work. Confidence appends a carefully evolved plan which one knows will work. Therefore these issues should be deter mined on each application for general anesthesia: 1 . Are there any marked contra-indications such as advanced car diac disease or respiratory obstruction? 2 . Is the mandible short and misshapen so as to predispose the patient to re stricted breathing? 3 . Is trismus present and, if so, what is the cause? 4 . Is there pterygomaxillary or parapharyngeal edema which may indicate localized ab scesses ready to rupture if the mouth is opened? 5 . Is the operation one which the operator can do well ? I f the findings are not satisfactory, an other method should be chosen, because, generally speaking, more skill is needed than with local anesthesia to assure the same result; therefore, the surgeon who, through inexpertness and fumbling, re quires thirty minutes for ten minutes’ work, will not have his task simplified. Clumsy manipulation o f the mandible and inattention to the mouth packs change the anesthetic level and needlessly prolong narcosis. One’ s judgment o f nitrous oxideoxygen anesthesia must be fa ir; it is possible that other methods may not have been found infallible. Time spent in learning to administer nitrous oxideoxygen will be richly repaid in appre ciative patients and by increased personal satisfaction at having enlisted another valuable aid in the battle against pain. BIBLIOGRAPHY
1. L u n d y , J. S.: Recent Advances in Anes thesia. J.A.M.A., 1x0:434, February 5, 1938. 2. T u o h y , E. B.: Intratracheal Anesthesia. Proc. Staff M eet. M ayo Clinic, 11:91-95, February 1936. 1649 David Whitney Building.