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Management of Patients with Pulmonary Insufficiency Undergoing Surgery
Management of Patients with Pulmonary Insufficiency Undergoing Surgery ARTHUR M. OLSEN, M.D.
w.
SPENCER PAYNE, M.D.
JOHN T. MARTIN, M.D.
While the application of current knowledge and techniques has greatly reduced the risks of surgical procedures in patients with respiratory insufficiency, these patients remain a major challenge to the surgeon and the anesthesiologist and to the internist who participates in the preoperative and postoperative care. Whether a patient is to undergo surgery primarily for lung disease or for some other condition complicated by pulmonary insufficiency, problems of management fall into four phases. Obviously, the recognition of the nature of the disorder and the assessment of the pulmonary problem constitute an essential first step. From such knowledge the need for and type of preoperative preparation follow naturally, and then the selection of agents and procedures for anesthesia. Finally, postoperative re-evaluation of the patient and specific treatment-newly instituted or continuingmust be carried on through surgical convalescence and often beyond. We shall attempt to outline the respiratory problems that may confront the candidate for surgery and to discuss the methods and techniques that have been developed to prepare the patient for his operation, to carry him through the actual procedure, and to help him throughlthe postoperative period. Respiratory insufficiency implies an inability of the lungs to exchange gases adequately to meet the needs of the body during effort. Respiratory failure denotes inadequate ventilation at rest. While respiratory insufficiency may be compensated for by reduced activity, increase of either stress or the restrictions on ventilation can produce respiratory failure and death. Major improvements in preoperative and postoperative care and in techniques of surgical procedures and anesthesia have decreased the risk of surgery for the respiratory cripple. However, pulmonary insuffi-
877
878
ARTHUR M. OLSEN,
W.
SPENCER PAYNE, JOHN
T.
MARTIN
ciency remains a threat to survival and must be carefully managed before, during, and following any operative procedure. PREOPERATIVE ASSESSMENT
Evaluation of the nature and extent of the pulmonary problem requires clinical judgment in addition to objective evidence. Dyspnea upon exertion, the commonest sign of respiratory distress, often has nonpulmonary causes. Heart disease such as valvular abnormalities, myocardial ischemia, or cardiac decompensation either improves with appropriate treatment or permits reasonably accurate estimation of risk. Anemias causing dyspnea can be corrected preoperatively by transfusions of whole blood or packed red blood cells. Similarly, dyspnea associated with metabolic disturbances such as hyperthyroidism, diabetes mellitus, and so on must be recognized and met with appropriate measures. Dyspnea results from numerous ventilatory abnormalities. Muscular defects of the thorax, including poliomyelitis, myasthenia gravis, and traumatic quadriplegia, often require mechanical support of ventilation during and after surgery plus drug therapy as applicable. Restrictive conditions such as obesity, rheumatoid spondylitis, kyphoscoliosis, pleural thickening, pulmonary fibrosis, and emphysema pose mechanical limitations of ventilation which surgical dressings or restrictive body positions may accentuate postoperatively. Dyspnea due to diffuse obstruction of the airway, resulting from bronchiolar spasm of asthma or emphysema or from the presence of widespread, tenacious secretions of chronic bronchitis or bronchiectasis, is usually amenable to therapy prior to surgery. Estimation of tolerance for exercise is an important preoperative procedure. Stair climbing or simple movements during examination often quantitate ventilatory impairment well. Attention to the degree and symmetry of chest expansion, the volume of breath sounds, the presence of wheezing or stridor, and distention in the veins of the neck adds valuable information. Recognition of respiratory distress in the horizontal positionwhether supine, prone, or lateral-helps to modify posture on the operating table to the benefit of the patient. Thoracic roentgenograms should be made routinely of all candidates for surgical procedures. Fluoroscopy may help further in evaluating pulmonary disability. Objective measurements of pulmonary function clarify the type and degree of insufficiency. The vital capacity, maximal breathing capacity, residual volume and its relation to total volume, arterial oxygen saturation, and carbon-monoxide diffusion all are helpful parameters; and sometimes the electrocardiogram serves likewise. Bronchospirometry may be helpful if resection of pulmonary tissue is contemplated. Although the data obtained are only guides, a maximal breathing capacity of less than 50 per
MANAGEMENT OF' SURGERY PATIENTS WITH PULMONARY INSUFFICIENCY
879
cent foretells a difficult postoperative course and argues against pulmonary resection. It is imperative that the patient himself have a clear understanding of his pulmonary problem and that he cooperate fully in preoperative preparation and postoperative care. If tracheotomy is likely, its advantages should be discussed. PREOPERATIVE CARE
In the presence of pre-existing respiratory insufficiency, acute infections of the respiratory tract are potentially fatal; their presence contraindicates elective surgery and demands aggressive treatment. Weight reduction is indicated in obesity and metabolic disorders should be corrected as well as possible before operation. While mechanical conditions such as spondylitis or neuromuscular disease of the chest wall or diaphragm may improve only minimally with preoperative efforts, training the patient in the use of ventilatory assisters will aid in postoperative care. Chronic cough merits preoperative preparation. Use of tobacco should be stopped completely. Respiratory irritants and known offending allergens should be avoided. Dust-control measures are beneficial. The unnecessary cough should be suppressed; but when tracheobronchial secretions are present, they should be liquefied. Iodides, ammonium chloride, and guaiacol derivatives plus copious fluid intake aid in loosening secretions so that cough will be effective. Aerosols of water or saline or heated-mist inhalations are useful; the addition of detergents or enzymes is seldom needed for liquefying sputum. Patients with asthmatic bronchitis or pulmonary emphysema often benefit from hospitalization to facilitate preparation for surgery. Control of cough, liquefaction of sputum, knowledge of inhalation teChniques, and familiarity with intermittent positive-pressure devices (such as flowsensitive valves) for administration can be attained more effectively by hospitalized patients than by outpatients. When bronchopulmonary suppuration is present, preoperative use of antibiotics may be indicated. Cultures and sensitivity tests can identify the offending organism and indicate proper treatment. Often the use of a broadly effective antibiotic such as tetracycline for five or six days before operation will be adequate. As a rule, penicillin should be used only if the principal organism is a streptococcus or Diplococcus pneumoniae. The type of organism may indicate other drugs such as erythromycin, streptomycin, chlortetracycline, chloramphenicol, polymyxin, or colistimethate (Colymycin). Administration of antibiotics by inhalation may be helpful: for example, streptomycin or neomycin may be given by aerosol in doses of 200 mg./ml. four times daily. Polymyxin in doses of 10 to 20 mg./ml. may
880
ARTHUR M. OLSEN,
W.
SPENCER PAYNE, JOHN
T.
MAR1'IN
be administered by aerosol inhalation if pseudomonas organisms are present in respiratory-tract secretions. Steroid compounds are often beneficial in preparing the pulmonary cripple for operation. In patients who have taken steroids continuously or intermittently during some period before surgery, extra medication may be indicated to support adrenal function during and after the operation. Additionally, in patients with severe asthmatic bronchitis steroid therapy often eases the bronchospasm and controls secretions sufficiently to permit surgery. Likewise, some patients who have pulmonary fibrosis or interstitial pneumonitis associated with diseases such as the Hamman-Rich syndrome or sarcoidosis may have pulmonary function improved by steroid therapy. The location for the contemplated surgical procedure is important in assessing the significance of ventilatory insufficiency. Operations on the head, neck, extremities, and perineum have little effect upon ventilation. However, abdominal operations, flank procedures, and operations involving the rib cage often restrict ventilation by visceral packs, abdominal distention, tight dressings, or inspiratory pain; and they may limit or prevent coughing. Operations on the heart and esophagus which interfere minimally with the movements of the chest wall and diaphragm are usually well tolerated. When pulmonary resection is intended, consideration must be given to the adequacy of the remaining lung tissue and to the temporary crippling of the respiratory effort in the ipsilateral lung. Although the lung tissue remaining after lobectomy expands to provide the best prosthesis for the thoracic space, its function often is seriously impaired. ANESTHETIC MANAGEMENT
After careful preoperative evaluation and preparation, the anesthetic must be managed so as to produce adequate operating conditions with the least possible drug impairment of the vital functions of the patient. Following administration of the anesthetic, the patient should resume vigorous spontaneous control of his vital functions at the earliest possible moment. Premedication should be selected for each patient individually. In the absence of pain, opiates are of little value, since their side effects include circulatory instability and impaired ventilatory response to increased tensions of carbon dioxide. Tranquillity can be produced in a high percentage of patients by judicious doses of barbiturates or related compounds. Atropine or scopolamine can be of use in controlling bronchial secretions. Scopolamine has less effect on reflex parasympathetic phenomena affecting the heart and lungs, but also has less tendency to produce tachycardia than does atropine. The location and duration of intended surgical procedure usually dictates the method of administering anesthesia. Conduction anesthesia is
MANAGEMENT OF SURGERY PATIENTS WITH PULMONARY INSUFFICIENCY
881
effective for surgery on the extremities and perineum as well as certain areas of the surface of the trunk and head. The respiratory cripple, however, often requires active expiration using abdominal muscles to assist; thus relaxation of the abdominal wall is detrimental to his ventilation. Consequently, spinal anesthesia for an abdominal procedure may be just as hazardous as carefully administered general anesthesia-and without the added comfort of sleep for the patient. Most general anesthetic agents are acceptable for the pulmonary cripple. An exception might be cyclopropane, a flammable bronchoconstrictor which could be detrimental to the asthmatic or hazardous in the presence of cautery. Halothane, a newer agent, is potent, rapid-acting, nonirritating to the respiratory mucosa, and nonflammable. It tends to increase pulmonary compliance-probably in part by relaxing respiratory smooth muscle. The analgesic potency of ether, its minimal cardiovascular depressant effect in light levels of anesthesia, its tendency to combat bronchospasm in the asthmatic, the high percentage of oxygen with which it can be used, and its ease of administration make it still a useful agent for intrathoracic surgery. Flammability, of course, is its drawback. Thiopental (Pentothal), given in small doses intravenously, is a useful agent for induction. Ventilatory support must be maintained throughout anesthesia and into the postanesthetic period until the patient can resume adequate spontaneous ventilation. Ordinarily an endotracheal tube is useful in patients with prior ventilatory deficiency, though occasionally one with a marked tendency toward bronchospasm may react adversely to this foreign body. The tube supports the upper part of the airway and decreases anatomic dead space. Control or assistance of ventilation, either by manual techniques or by a carefully supervised automatic ventilator, overcomes the depressant effect of anesthetic agents and premedicant drugs. Though inflation of the lungs can be augmented thus, deflation under anesthesia is usually a passive phenomenon of the recoil of the lung tissue and chest wall. Thoracic fixation and air trapping impair deflation and are difficult to manage. High residual volume, poor mixing of pulmonary gases, and slow induction and emergence from anesthesia result. Application of subatmospheric pressure ("negative pressure") to the airway may decrease intrathoracic pressure centrally prior to alveolar emptying and increase the degree of air trapping. Sometimes operating positions needed for surgical exposure further upset already impaired ventilation. This is most likely to occur in the lateral position with the kidney rest elevated, in the prone position, in the lithotomy position, and in the steep Trendelenburg position. When pulmonary embarrassment is evident, these positions may have to be modified to permit effective ventilation during anesthesia. For enabling the pulmonary cripple to regain control of vital functions at the earliest possible moment after operation, the manner in which
882
ARTHUR
M.
OLSEN,
W.
SPENCER PAYNE, JOHN
T.
MARTIN
anesthesia is maintained has great importance. To assure uncomplicated recovery from anesthesia, the amounts of anesthetic agents and muscle relaxants must not be excessive and observation of the patient must be constant. Airway secretions must be aspirated carefully, coughing must be encouraged, and muscle tone to support adequate spontaneous ventilation must be restored. Routine postoperative chest roentgenography provides information about unsuspected chest pathology incidental to surgery or anesthesia such as pneumothorax, hemothorax, or atelectasis. High oxygen tensions in humidified air should be provided. Removal of the endotracheal tube requires careful consideration, since its absence increases the anatomic dead space, withdraws support of the upper airway, and makes aspiration of intratracheal secretions more difficult. A tracheotomy may be necessary to permit effective ventilation and should be performed at the first indication of its need. Cuffed tracheostomy tubes are available so that mechanical ventilators may be used if necessary. Bronchodilators are helpful if expiratory slowing is a factor and may be given either intravenously or by nebulization. Heated-mist units can provide adequate airway humidification for tracheotomized patients and should be employed. POSTOPERATIVE MANAGEMENT
The most critical period in the management of patients with pulmonary insufficiency comes immediately following operation, when the patient must depend upon recovery of his own capabilities for continued ventilation and airway patency. Obviously, all the preceding phases of assessment, treatment, and management have been directed to restoration of these natural resources to the maximum feasible. The anticipation of the specific needs of a given patient is an essential factor in the success of this transition. Equally important, however, is the hour-to-hour and day-to-day reassessment of the patient in this early period. It is during this time too that not only the respiratory cripple, but even the patient with normal pulmonary reserve, may suddenly experience decompensation. It is senseless, of course, to sharply divorce observations of the respiratory system from observations of the patient as a whole. Skin color and temperature, state of consciousness, quality of peripheral pulses, pulse rate, blood pressure, and even urinary output are valid indices of pulmonary function, as they are of cardiovascular, central nervous system, and urinary function. Although radiographic examination of the thorax is of inestimable value in assessing the thorax and its contents, simple bedside examination is indispensable. Tidal exchange of gases by the lung can be assessed effectively by auscultation of the lungs and by observation of the force and volume of expiration and of the degree and effort of thoracic excursions. Poor respiratory exchange has many causes; and if not correctable by
MANAGEMENT OF SURGERY PATIENTS WITH PULMONARY INSUFFICIENCY
883
simple or expedient means, it is the major indication for use of a mechanical ventilator in the postoperative period. Anticipation of the need for assistance in eliminating tracheobronchial secretions is essential in avoiding potentially lethal episodes of pulmonary atelectasis and anoxia among patients with already compromised pulmonary reserve. On occasion, bronchoscopy will be required to remove thick, tenacious secretions or coagulated blood from the tracheobronchial tree. Frequent or ineffective nasotracheal aspiration is often a valid indication of the need for tracheostomy. Problems with airway patency and poor ventilation are so often associated that the cuffed tracheostomy tube should be inserted even though there may be no immediate or anticipated need other than to decrease the respiratory dead space and create a convenient stoma for tracheobronchial aspiration. Later, if needed, the balloon cuff of the tracheostomy tube can be inflated for use with an intermittent positive-pressure apparatus. The ultimate effectiveness of respiration in terms of tissue oxygenation and elimination of carbon dioxide depends, of course, on adequate perfusion of the lung and the other organs and tissues of the body. The maintenance of nutrition, blood volume, hemoglobin, and fluid and electrolyte balances is mundane but essential in the care of any surgical patient; but it assumes critical proportions in the management of the patient with an already compromised respiratory reserve. Bronchodilators, agents that liquefy tracheobronchial secretions, humidification, high oxygen tensions in inspired gas mixtures, and the intermittent positive-pressure respirator all are important factors in postoperative management of the patient with respiratory insufficiency, in addition to whatever measures may have been initiated preoperatively. A high-oxygen environment, though desirable in many situations, may precipitate carbon-dioxide narcosis in the patient with pulmonary insufficiency and respiratory acidosis. Often postoperative analysis of the partial pressure of carbon dioxide, pH, and buffer base is essential for the recognition and treatment of respiratory and metabolic aberrations in acid-base balance. The use of analgesics in the patient with respiratory insufficiency is also a critical postoperative problem. Although age, sex, weight, and vigor influence the usual dosage of these agents, their specific depressant effects on the cough reflex and respiratory center may be hazardous to the respiratory cripple. However, even such a potent agent as morphine, if given in a minimal dose of 1 mg. (1/65 grain), will often effect worthwhile prolonged analgesia and tranquillity without undue depression. In cases of respiratory insufficiency, it is probably not wise to have any narcotic agent administered at regular intervals by the nursing staff: re-evaluation with each administration is best. Occasionally, regional nerve block can be used as an effective means to control incisional pain and thereby improve ventilation and decrease the need for narcotics. Surgical dressings may restrict ventilatory motion
884
ARTHUR M. OLSEN,
W.
SPENCER PAYNE, JOHN
T.
MARTIN
and should be applied with the avoidance of this effect in mind. The prevention or correction of abdominal distention in the postoperative period has a similar desirable influence on pulmonary ventilation. Maintenance of pulmonary expansion following operations within the thorax is essential. Intercostal drainage tubes placed in the thorax at the time of surgery to evacuate air and fluid require continued maintenance in the postoperative period to assure their continued function. This maintenance and the eventual removal of the tubes should not allow the introduction of infection into the pleural space nor the accidental introduction of air. Repeated radiographic examination of the thorax is needed to assess the adequacy of pleural-space drainage. Pulmonary edema, congestive heart failure, and cardiac arrhythmia are not uncommon as postoperative complications of older patients and those with pulmonary insufficiency. Cardiac arrhythmias occur more frequently in patients undergoing intrathoracic procedures than in those undergoing surgery on the abdomen, head and neck, or extremities. Since such problems cannot always be anticipated by preoperative assessments, careful observation is essential in the postoperative period. COMMENT
It is obviously beyond the scope of this presentation to give in detail the management of all complications or even to list all the means currently available for assessing and treating the complications peculiar to management of patients with pulmonary insufficiency. The essential features of good management, however, are awareness of potential difficulties and diligence in seeking, assessing, and treating these problems. At the completion of a succe_ssful postoperative hospital convalescence, the need for continuation and supervision of treatment must be assessed. Finally, the patient and his relatives must be informed of both the necessity for these measures and the need for their cooperation and understanding of the proposed long-term program. SUMMARY
Patients with asthma, emphysema, pulmonary fibrosis, bronchopulmonary infections, and various other disorders which interfere with the normal function of. the lungs may be candidates for surgical treatment. It is important that the cause of the pulmonary disorder be identified and that risks attributable to the respiratory deficiency be properly assessed. Preoperative preparation depends, of course, upon the nature of the pulmonary disturbance. Appropriate antibiotic therapy should be given for bronchopulmonary infection. Aerosol techniques are available for the
MANAGEMENT OF SURGERY PATIENTS WITH PULMONARY INSUFFICIENCY
885
management of bronchospasm and for the liquefaction and elimination of tracheobronchial secretions. Even steroids have their place in the preparation of some patients. The anesthesiologist must be thoroughly familiar with the nature of the pulmonary problem. He should choose the optimal premedication for the individual patient. The selection of the anesthetic and the method of its administration will be determined not only by the needs of the surgeon, but also by the ventilatory problems of the patient, and especially by the desirability of early recovery of his ability to carryon his own breathing. Many of the measures instituted in the preoperative preparation should be continued in the postoperative period. Because of the need for analgesics and sedatives, the problem of retention of secretions deserves special attention. If the patient is unable to cough up his secretions, mechanical aids such as the intratracheal catheter or even bronchoscopic aspiration must be employed. Tracheostomy is often advantageous, not only for elimination of secretions but also to cut down on the dead space. Mechanical assistance, usually employing flow-sensitive pressure valves, may help the patient with ventilatory problems. Oxygen, heated mist, and bronchodilators may be administered by positive pressure as well as by simpler techniques. Through the cooperative efforts of the surgeon, anesthesiologist, and internist, many respiratory cripples can undergo major as well as minor surgical procedures.
w.
SPENCER PAYNE, M.D.
JOHN T. MARTIN, M.D.
While the application of current knowledge and techniques has greatly reduced the risks of surgical procedures in patients with respiratory insufficiency, these patients remain a major challenge to the surgeon and the anesthesiologist and to the internist who participates in the preoperative and postoperative care. Whether a patient is to undergo surgery primarily for lung disease or for some other condition complicated by pulmonary insufficiency, problems of management fall into four phases. Obviously, the recognition of the nature of the disorder and the assessment of the pulmonary problem constitute an essential first step. From such knowledge the need for and type of preoperative preparation follow naturally, and then the selection of agents and procedures for anesthesia. Finally, postoperative re-evaluation of the patient and specific treatment-newly instituted or continuingmust be carried on through surgical convalescence and often beyond. We shall attempt to outline the respiratory problems that may confront the candidate for surgery and to discuss the methods and techniques that have been developed to prepare the patient for his operation, to carry him through the actual procedure, and to help him throughlthe postoperative period. Respiratory insufficiency implies an inability of the lungs to exchange gases adequately to meet the needs of the body during effort. Respiratory failure denotes inadequate ventilation at rest. While respiratory insufficiency may be compensated for by reduced activity, increase of either stress or the restrictions on ventilation can produce respiratory failure and death. Major improvements in preoperative and postoperative care and in techniques of surgical procedures and anesthesia have decreased the risk of surgery for the respiratory cripple. However, pulmonary insuffi-
877
878
ARTHUR M. OLSEN,
W.
SPENCER PAYNE, JOHN
T.
MARTIN
ciency remains a threat to survival and must be carefully managed before, during, and following any operative procedure. PREOPERATIVE ASSESSMENT
Evaluation of the nature and extent of the pulmonary problem requires clinical judgment in addition to objective evidence. Dyspnea upon exertion, the commonest sign of respiratory distress, often has nonpulmonary causes. Heart disease such as valvular abnormalities, myocardial ischemia, or cardiac decompensation either improves with appropriate treatment or permits reasonably accurate estimation of risk. Anemias causing dyspnea can be corrected preoperatively by transfusions of whole blood or packed red blood cells. Similarly, dyspnea associated with metabolic disturbances such as hyperthyroidism, diabetes mellitus, and so on must be recognized and met with appropriate measures. Dyspnea results from numerous ventilatory abnormalities. Muscular defects of the thorax, including poliomyelitis, myasthenia gravis, and traumatic quadriplegia, often require mechanical support of ventilation during and after surgery plus drug therapy as applicable. Restrictive conditions such as obesity, rheumatoid spondylitis, kyphoscoliosis, pleural thickening, pulmonary fibrosis, and emphysema pose mechanical limitations of ventilation which surgical dressings or restrictive body positions may accentuate postoperatively. Dyspnea due to diffuse obstruction of the airway, resulting from bronchiolar spasm of asthma or emphysema or from the presence of widespread, tenacious secretions of chronic bronchitis or bronchiectasis, is usually amenable to therapy prior to surgery. Estimation of tolerance for exercise is an important preoperative procedure. Stair climbing or simple movements during examination often quantitate ventilatory impairment well. Attention to the degree and symmetry of chest expansion, the volume of breath sounds, the presence of wheezing or stridor, and distention in the veins of the neck adds valuable information. Recognition of respiratory distress in the horizontal positionwhether supine, prone, or lateral-helps to modify posture on the operating table to the benefit of the patient. Thoracic roentgenograms should be made routinely of all candidates for surgical procedures. Fluoroscopy may help further in evaluating pulmonary disability. Objective measurements of pulmonary function clarify the type and degree of insufficiency. The vital capacity, maximal breathing capacity, residual volume and its relation to total volume, arterial oxygen saturation, and carbon-monoxide diffusion all are helpful parameters; and sometimes the electrocardiogram serves likewise. Bronchospirometry may be helpful if resection of pulmonary tissue is contemplated. Although the data obtained are only guides, a maximal breathing capacity of less than 50 per
MANAGEMENT OF' SURGERY PATIENTS WITH PULMONARY INSUFFICIENCY
879
cent foretells a difficult postoperative course and argues against pulmonary resection. It is imperative that the patient himself have a clear understanding of his pulmonary problem and that he cooperate fully in preoperative preparation and postoperative care. If tracheotomy is likely, its advantages should be discussed. PREOPERATIVE CARE
In the presence of pre-existing respiratory insufficiency, acute infections of the respiratory tract are potentially fatal; their presence contraindicates elective surgery and demands aggressive treatment. Weight reduction is indicated in obesity and metabolic disorders should be corrected as well as possible before operation. While mechanical conditions such as spondylitis or neuromuscular disease of the chest wall or diaphragm may improve only minimally with preoperative efforts, training the patient in the use of ventilatory assisters will aid in postoperative care. Chronic cough merits preoperative preparation. Use of tobacco should be stopped completely. Respiratory irritants and known offending allergens should be avoided. Dust-control measures are beneficial. The unnecessary cough should be suppressed; but when tracheobronchial secretions are present, they should be liquefied. Iodides, ammonium chloride, and guaiacol derivatives plus copious fluid intake aid in loosening secretions so that cough will be effective. Aerosols of water or saline or heated-mist inhalations are useful; the addition of detergents or enzymes is seldom needed for liquefying sputum. Patients with asthmatic bronchitis or pulmonary emphysema often benefit from hospitalization to facilitate preparation for surgery. Control of cough, liquefaction of sputum, knowledge of inhalation teChniques, and familiarity with intermittent positive-pressure devices (such as flowsensitive valves) for administration can be attained more effectively by hospitalized patients than by outpatients. When bronchopulmonary suppuration is present, preoperative use of antibiotics may be indicated. Cultures and sensitivity tests can identify the offending organism and indicate proper treatment. Often the use of a broadly effective antibiotic such as tetracycline for five or six days before operation will be adequate. As a rule, penicillin should be used only if the principal organism is a streptococcus or Diplococcus pneumoniae. The type of organism may indicate other drugs such as erythromycin, streptomycin, chlortetracycline, chloramphenicol, polymyxin, or colistimethate (Colymycin). Administration of antibiotics by inhalation may be helpful: for example, streptomycin or neomycin may be given by aerosol in doses of 200 mg./ml. four times daily. Polymyxin in doses of 10 to 20 mg./ml. may
880
ARTHUR M. OLSEN,
W.
SPENCER PAYNE, JOHN
T.
MAR1'IN
be administered by aerosol inhalation if pseudomonas organisms are present in respiratory-tract secretions. Steroid compounds are often beneficial in preparing the pulmonary cripple for operation. In patients who have taken steroids continuously or intermittently during some period before surgery, extra medication may be indicated to support adrenal function during and after the operation. Additionally, in patients with severe asthmatic bronchitis steroid therapy often eases the bronchospasm and controls secretions sufficiently to permit surgery. Likewise, some patients who have pulmonary fibrosis or interstitial pneumonitis associated with diseases such as the Hamman-Rich syndrome or sarcoidosis may have pulmonary function improved by steroid therapy. The location for the contemplated surgical procedure is important in assessing the significance of ventilatory insufficiency. Operations on the head, neck, extremities, and perineum have little effect upon ventilation. However, abdominal operations, flank procedures, and operations involving the rib cage often restrict ventilation by visceral packs, abdominal distention, tight dressings, or inspiratory pain; and they may limit or prevent coughing. Operations on the heart and esophagus which interfere minimally with the movements of the chest wall and diaphragm are usually well tolerated. When pulmonary resection is intended, consideration must be given to the adequacy of the remaining lung tissue and to the temporary crippling of the respiratory effort in the ipsilateral lung. Although the lung tissue remaining after lobectomy expands to provide the best prosthesis for the thoracic space, its function often is seriously impaired. ANESTHETIC MANAGEMENT
After careful preoperative evaluation and preparation, the anesthetic must be managed so as to produce adequate operating conditions with the least possible drug impairment of the vital functions of the patient. Following administration of the anesthetic, the patient should resume vigorous spontaneous control of his vital functions at the earliest possible moment. Premedication should be selected for each patient individually. In the absence of pain, opiates are of little value, since their side effects include circulatory instability and impaired ventilatory response to increased tensions of carbon dioxide. Tranquillity can be produced in a high percentage of patients by judicious doses of barbiturates or related compounds. Atropine or scopolamine can be of use in controlling bronchial secretions. Scopolamine has less effect on reflex parasympathetic phenomena affecting the heart and lungs, but also has less tendency to produce tachycardia than does atropine. The location and duration of intended surgical procedure usually dictates the method of administering anesthesia. Conduction anesthesia is
MANAGEMENT OF SURGERY PATIENTS WITH PULMONARY INSUFFICIENCY
881
effective for surgery on the extremities and perineum as well as certain areas of the surface of the trunk and head. The respiratory cripple, however, often requires active expiration using abdominal muscles to assist; thus relaxation of the abdominal wall is detrimental to his ventilation. Consequently, spinal anesthesia for an abdominal procedure may be just as hazardous as carefully administered general anesthesia-and without the added comfort of sleep for the patient. Most general anesthetic agents are acceptable for the pulmonary cripple. An exception might be cyclopropane, a flammable bronchoconstrictor which could be detrimental to the asthmatic or hazardous in the presence of cautery. Halothane, a newer agent, is potent, rapid-acting, nonirritating to the respiratory mucosa, and nonflammable. It tends to increase pulmonary compliance-probably in part by relaxing respiratory smooth muscle. The analgesic potency of ether, its minimal cardiovascular depressant effect in light levels of anesthesia, its tendency to combat bronchospasm in the asthmatic, the high percentage of oxygen with which it can be used, and its ease of administration make it still a useful agent for intrathoracic surgery. Flammability, of course, is its drawback. Thiopental (Pentothal), given in small doses intravenously, is a useful agent for induction. Ventilatory support must be maintained throughout anesthesia and into the postanesthetic period until the patient can resume adequate spontaneous ventilation. Ordinarily an endotracheal tube is useful in patients with prior ventilatory deficiency, though occasionally one with a marked tendency toward bronchospasm may react adversely to this foreign body. The tube supports the upper part of the airway and decreases anatomic dead space. Control or assistance of ventilation, either by manual techniques or by a carefully supervised automatic ventilator, overcomes the depressant effect of anesthetic agents and premedicant drugs. Though inflation of the lungs can be augmented thus, deflation under anesthesia is usually a passive phenomenon of the recoil of the lung tissue and chest wall. Thoracic fixation and air trapping impair deflation and are difficult to manage. High residual volume, poor mixing of pulmonary gases, and slow induction and emergence from anesthesia result. Application of subatmospheric pressure ("negative pressure") to the airway may decrease intrathoracic pressure centrally prior to alveolar emptying and increase the degree of air trapping. Sometimes operating positions needed for surgical exposure further upset already impaired ventilation. This is most likely to occur in the lateral position with the kidney rest elevated, in the prone position, in the lithotomy position, and in the steep Trendelenburg position. When pulmonary embarrassment is evident, these positions may have to be modified to permit effective ventilation during anesthesia. For enabling the pulmonary cripple to regain control of vital functions at the earliest possible moment after operation, the manner in which
882
ARTHUR
M.
OLSEN,
W.
SPENCER PAYNE, JOHN
T.
MARTIN
anesthesia is maintained has great importance. To assure uncomplicated recovery from anesthesia, the amounts of anesthetic agents and muscle relaxants must not be excessive and observation of the patient must be constant. Airway secretions must be aspirated carefully, coughing must be encouraged, and muscle tone to support adequate spontaneous ventilation must be restored. Routine postoperative chest roentgenography provides information about unsuspected chest pathology incidental to surgery or anesthesia such as pneumothorax, hemothorax, or atelectasis. High oxygen tensions in humidified air should be provided. Removal of the endotracheal tube requires careful consideration, since its absence increases the anatomic dead space, withdraws support of the upper airway, and makes aspiration of intratracheal secretions more difficult. A tracheotomy may be necessary to permit effective ventilation and should be performed at the first indication of its need. Cuffed tracheostomy tubes are available so that mechanical ventilators may be used if necessary. Bronchodilators are helpful if expiratory slowing is a factor and may be given either intravenously or by nebulization. Heated-mist units can provide adequate airway humidification for tracheotomized patients and should be employed. POSTOPERATIVE MANAGEMENT
The most critical period in the management of patients with pulmonary insufficiency comes immediately following operation, when the patient must depend upon recovery of his own capabilities for continued ventilation and airway patency. Obviously, all the preceding phases of assessment, treatment, and management have been directed to restoration of these natural resources to the maximum feasible. The anticipation of the specific needs of a given patient is an essential factor in the success of this transition. Equally important, however, is the hour-to-hour and day-to-day reassessment of the patient in this early period. It is during this time too that not only the respiratory cripple, but even the patient with normal pulmonary reserve, may suddenly experience decompensation. It is senseless, of course, to sharply divorce observations of the respiratory system from observations of the patient as a whole. Skin color and temperature, state of consciousness, quality of peripheral pulses, pulse rate, blood pressure, and even urinary output are valid indices of pulmonary function, as they are of cardiovascular, central nervous system, and urinary function. Although radiographic examination of the thorax is of inestimable value in assessing the thorax and its contents, simple bedside examination is indispensable. Tidal exchange of gases by the lung can be assessed effectively by auscultation of the lungs and by observation of the force and volume of expiration and of the degree and effort of thoracic excursions. Poor respiratory exchange has many causes; and if not correctable by
MANAGEMENT OF SURGERY PATIENTS WITH PULMONARY INSUFFICIENCY
883
simple or expedient means, it is the major indication for use of a mechanical ventilator in the postoperative period. Anticipation of the need for assistance in eliminating tracheobronchial secretions is essential in avoiding potentially lethal episodes of pulmonary atelectasis and anoxia among patients with already compromised pulmonary reserve. On occasion, bronchoscopy will be required to remove thick, tenacious secretions or coagulated blood from the tracheobronchial tree. Frequent or ineffective nasotracheal aspiration is often a valid indication of the need for tracheostomy. Problems with airway patency and poor ventilation are so often associated that the cuffed tracheostomy tube should be inserted even though there may be no immediate or anticipated need other than to decrease the respiratory dead space and create a convenient stoma for tracheobronchial aspiration. Later, if needed, the balloon cuff of the tracheostomy tube can be inflated for use with an intermittent positive-pressure apparatus. The ultimate effectiveness of respiration in terms of tissue oxygenation and elimination of carbon dioxide depends, of course, on adequate perfusion of the lung and the other organs and tissues of the body. The maintenance of nutrition, blood volume, hemoglobin, and fluid and electrolyte balances is mundane but essential in the care of any surgical patient; but it assumes critical proportions in the management of the patient with an already compromised respiratory reserve. Bronchodilators, agents that liquefy tracheobronchial secretions, humidification, high oxygen tensions in inspired gas mixtures, and the intermittent positive-pressure respirator all are important factors in postoperative management of the patient with respiratory insufficiency, in addition to whatever measures may have been initiated preoperatively. A high-oxygen environment, though desirable in many situations, may precipitate carbon-dioxide narcosis in the patient with pulmonary insufficiency and respiratory acidosis. Often postoperative analysis of the partial pressure of carbon dioxide, pH, and buffer base is essential for the recognition and treatment of respiratory and metabolic aberrations in acid-base balance. The use of analgesics in the patient with respiratory insufficiency is also a critical postoperative problem. Although age, sex, weight, and vigor influence the usual dosage of these agents, their specific depressant effects on the cough reflex and respiratory center may be hazardous to the respiratory cripple. However, even such a potent agent as morphine, if given in a minimal dose of 1 mg. (1/65 grain), will often effect worthwhile prolonged analgesia and tranquillity without undue depression. In cases of respiratory insufficiency, it is probably not wise to have any narcotic agent administered at regular intervals by the nursing staff: re-evaluation with each administration is best. Occasionally, regional nerve block can be used as an effective means to control incisional pain and thereby improve ventilation and decrease the need for narcotics. Surgical dressings may restrict ventilatory motion
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ARTHUR M. OLSEN,
W.
SPENCER PAYNE, JOHN
T.
MARTIN
and should be applied with the avoidance of this effect in mind. The prevention or correction of abdominal distention in the postoperative period has a similar desirable influence on pulmonary ventilation. Maintenance of pulmonary expansion following operations within the thorax is essential. Intercostal drainage tubes placed in the thorax at the time of surgery to evacuate air and fluid require continued maintenance in the postoperative period to assure their continued function. This maintenance and the eventual removal of the tubes should not allow the introduction of infection into the pleural space nor the accidental introduction of air. Repeated radiographic examination of the thorax is needed to assess the adequacy of pleural-space drainage. Pulmonary edema, congestive heart failure, and cardiac arrhythmia are not uncommon as postoperative complications of older patients and those with pulmonary insufficiency. Cardiac arrhythmias occur more frequently in patients undergoing intrathoracic procedures than in those undergoing surgery on the abdomen, head and neck, or extremities. Since such problems cannot always be anticipated by preoperative assessments, careful observation is essential in the postoperative period. COMMENT
It is obviously beyond the scope of this presentation to give in detail the management of all complications or even to list all the means currently available for assessing and treating the complications peculiar to management of patients with pulmonary insufficiency. The essential features of good management, however, are awareness of potential difficulties and diligence in seeking, assessing, and treating these problems. At the completion of a succe_ssful postoperative hospital convalescence, the need for continuation and supervision of treatment must be assessed. Finally, the patient and his relatives must be informed of both the necessity for these measures and the need for their cooperation and understanding of the proposed long-term program. SUMMARY
Patients with asthma, emphysema, pulmonary fibrosis, bronchopulmonary infections, and various other disorders which interfere with the normal function of. the lungs may be candidates for surgical treatment. It is important that the cause of the pulmonary disorder be identified and that risks attributable to the respiratory deficiency be properly assessed. Preoperative preparation depends, of course, upon the nature of the pulmonary disturbance. Appropriate antibiotic therapy should be given for bronchopulmonary infection. Aerosol techniques are available for the
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management of bronchospasm and for the liquefaction and elimination of tracheobronchial secretions. Even steroids have their place in the preparation of some patients. The anesthesiologist must be thoroughly familiar with the nature of the pulmonary problem. He should choose the optimal premedication for the individual patient. The selection of the anesthetic and the method of its administration will be determined not only by the needs of the surgeon, but also by the ventilatory problems of the patient, and especially by the desirability of early recovery of his ability to carryon his own breathing. Many of the measures instituted in the preoperative preparation should be continued in the postoperative period. Because of the need for analgesics and sedatives, the problem of retention of secretions deserves special attention. If the patient is unable to cough up his secretions, mechanical aids such as the intratracheal catheter or even bronchoscopic aspiration must be employed. Tracheostomy is often advantageous, not only for elimination of secretions but also to cut down on the dead space. Mechanical assistance, usually employing flow-sensitive pressure valves, may help the patient with ventilatory problems. Oxygen, heated mist, and bronchodilators may be administered by positive pressure as well as by simpler techniques. Through the cooperative efforts of the surgeon, anesthesiologist, and internist, many respiratory cripples can undergo major as well as minor surgical procedures.