CASE REPORTS
Anesthesia
for Bilateral
Single-Lung
B.S. Lee, MD, F.H. Sarnquist,
P
ATIENTS WITH end-stage lung disease have been successfully treated with lung transplantation. Singlelung transplantation has been used for patients with endstage pulmonary fibrosis,‘-3 and double-lung transplantation has been used for patients with end-stage emphysema, cystic fibrosis, and bilateral pulmonary sepsis.4.5 Doublelung transplantation has been performed as an en-bloc the anesthetic considerations of which transplantation4.5; have been reviewed recently by Gayes et al.6 Bilateral single-lung transplantation is an evolving technique, that avoids some of the potential complications of the en-bloc method, including cardiopulmonary bypass (CPB), tracheal anastomosis, and cardiac surgery.’ A report of the anesthetic management of the first patient at the Stanford University Hospital to have bilateral single-lung transplantations is presented. CASE
REPORT
A 39-year-old white man with cY-1-antitrypsin deficiency, resultant severe COPD, dyspnea at rest, and requiring nasal cannula oxygen at 2 L/min was admitted to the Stanford University Hospital when donor lungs became available. He had progressive dyspnea for 6 years. Pulmonary function tests before admission showed a forced vital capacity (FVC) of 1.32 L (24% of predicted), forced expiratory volume in 1 second (FEV,) of 0.52 Lisec (12% of predicted), maximum midexpiratory flow rate (FEF,,.,,) of 0.24 Lisec (5% of predicted), maximum minute ventilation (MMV) of 28 L/min (15% of predicted), diffusing capacity for carbon monoxide (DLCO) of 7 mliminlmm Hg (20% of predicted), and the analysis of his arterial blood gases (ABG) showed a pH of 7.42, PaCO, of 42 mm Hg, and PaO, of 59 mm Hg (F,O, = 0.21). An echocardiogram demonstrated left ventricular (LV) wall thickening and normal contractility, abnormal septal motion consistent with increased right ventricular (RV) pressure or RV hypertrophy, and normal left and right atria. The chest radiograph showed marked hyperinflation of both lungs with emphysematous changes consistent with severe chronic obstructive pulmonary disease (COPD). There was no evidence of hepatic, gastric, or renal manifestations of the cu-1-antitrypsin deficiency. Generalized cachexia (height = 185 cm, weight = 51 kg) was attributed to his chronic disease state. The patient had neck pain with neck extension, a small mandible, and a decreased range of motion at the temporomandibular joint, suggesting that the patient’s trachea might be difficult to intubate. The patient’s medications included albuterol, cromolyn, mucomyst, theophylline, and saturated solution potassium iodide. The patient was taken to the operating room, breathing supplemental oxygen supplied by nasal cannula, where monitors were placed (5-lead ECG, digital pulse oximeter, precordial stethoscope, and blood pressure cuff). While the patient was sitting in the 45” upright position necessitated by his dyspnea, a radial arterial and two large-bore intravenous catheters were inserted using
Transplantation
MD, and V.A. Starnes, MD sterile technique. This patient had not received premeditation because of his compromised respiratory status. The oxygen saturation was greater than 95% during this period. Sterilized anesthesia equipment was used. The patient was preoxygenated and anesthesia was slowly induced. Fentanyl and midazolam were administered while maintaining cricoid pressure. When the patient lost consciousness, he was placed in the supine position and manual ventilation was begun. Care was taken to minimize peak airway pressures. After muscle relaxation with pancuronium was achieved, direct laryngoscopy was performed with visualization of the vocal cords; however, intubating the trachea with the double-lumen endotracheal tube (DLT) was impossible. The airway was secured with a single-lumen 8.0-mm endotracheal tube, which was then changed to a left-sided 41F DLT using a Bougie device as a guide. Fiberoptic bronchoscopy confirmed the correct endotracheal tube position. Bilateral ventilation was initiated. The ventilator was adjusted to maintain low to normal peak inspiratory pressures (low tidal volumes) and to emphasize increased expiratory time (decreased inspiratoryi expiratory ratio). The arterial blood gas (ABG) analysis showed a mild respiratory acidosis (Table 1). A pulmonary artery (PA) catheter introducer was inserted using sterile technique in the right internal jugular vein; however, repeated attempts at passing the balloon-tipped catheter into the PA resulted in ventricular ectopy with hypotension. The catheter balloon was inflated and the catheter tip was left positioned in the RV. The surgeons prepared the right femoral site for arterial and venous cannulation. CPB was to be instituted when ventilation of the native or donor lung was inadequate or when the RV was unduly loaded by PA clamping. It was anticipated that CPB would be needed because of the severity of the COPD. Through an epigastric incision, the surgeons prepared omental flaps on pedicles for the bronchial omentopexies. Then, they commenced the bilateral anterior fourth intercostal “clam shell” thoracotomy. The right thorax was operated on first. Single-lung ventilation of the left native lung was initiated, and the right lung was allowed to collapse to atmospheric pressure. The surgeons clamped the right PA, resulting in the expected increase of RV pressure. Nitroglycerin (1 pg/kg/min) was administered to reduce the pulmonary vascular resistance. The ABG analysis showed a worsening respiratory acidosis, and the ventilator was adjusted to increase the minute ventilation. When the clamps were removed from the right donor lung, the RV pressures decreased. End-tidal carbon dioxide (P&O,) initially increased and then decreased.
From the Departments of Anesthesiology and Cardiothoracic Surgev, Stanford UniversityMedical Center, Stanford, CA. Address reprint requests to F.H. Samquist, Department of Anesthesiology, Stanford University Medical Center, 300 Pasteur Dr, Stanford, CA 94305. Copyright o I992 b_yW.B. Saunders Company 1053-0770192/060.?-0016$03.0010
Journalof Cardiothoracic and VascularAnesthesia, Vol6, No 2 (April), 1992: pp 201-203
201
202
LEE, SARNQUIST,
AND STARNES
Table 1. Perioperative Data A
B
C
D
E
_._____..
F
G
4
Ventilation
Peak inspiratory pressure (cm H,O) Fractional inspired oxygen ABG analysis
0.21 7.42
PH
8.6
6.6
14
11
12
12
5
6
25
32
13
23
18
38
6.3
Minute volume (L/min) Frequency (per min)
1.0 7.34
3.8
1.0 7.22
7.0
0.6 7.28
8.0
0.6 7.35
0.4
0.3 7.53
7.40
0.21 7.44
PaO, (mm Hg)
59
516
494
148
80
160
133
92
PaCO, (mm Hg)
42
54
62
47
41
35
27
39
37
28
29
24
35 47
59
P&D,
(mm Hg)
PaCO,-P&O,
gradient (mm Hg)
A-a gradient (mm Hg) Hemodynamics Blood pressure (S/D) (mm Hg) Heart rate (per minute) Right ventricular pressure (S/D) (mm Hg) Thermoregulation Bladder temperature (C)
76
17
26
18
17
8
130
142
221
297
81
100/70
80145
90
80
80145
85145
100/50
90150
110
110
120
126
32121
40120
26113
24/l
32110
36.7
35.3
34.0
32.6
36.6
NOTE. A, preoperative clinic; B, bilateral ventilation and perfusion, left and right native lungs; C, single ventilation and perfusion, left native lung; 13, lung; F, bilateral ventilation and perfusion. left and right donor lungs: G, intensive care unit, first admission; and H, postoperative clinic, 3 months posttransplantation. bilateral ventilation and perfusion, left native lung and right donor lung; E, single-lung ventilation and perfusion, right donor
The ABG analysis showed a decrease of the respiratory acidosis. The left lung was allowed to collapse to atmospheric pressure and the left PA was clamped. The RV pressure, heart rate, and systemic blood pressure remained stable. Once the left donor lung was implanted, ventilation and perfusion of both donor lungs were instituted. The ABG analysis showed a resolution of the respiratory acidosis and adequate oxygenation with minimal oxygen supplementation (Table 1). Despite the use of intravenous fluid warmers, an inspired gas humidifier, a warming pad, and a warm room, rapid loss of body heat occurred, causing a problem of severe hypothermia. The patient’s bladder temperature decreased steadily to 326°C during the procedure. Partial CPB via the right femoral site was instituted for 18 minutes to rewarm the patient. The bladder temperature increased to 36.9”C. He was brought back to the operating room 2 hours later for bleeding. Exploration of the chest showed bleeding from a vessel on the left mainstem bronchus. During this procedure, the right lung was not expanding as well as the left lung. Fiberoptic bronchoscopy showed tenacious secretions at the right middle lobe and right lower lobe bronchi, which were removed through the bronchoscope. Ventilation of these lobes improved. The patient
returned to the intensive care unit with stable hemodynamics and oxygenation. This patient was weaned from the ventilator on the second postoperative day and extubated without incident. By the third postoperative day, the patient had an oxygen saturation of 97% while breathing room air. A right middle lobe pneumonia, which complicated his postoperative course, was treated with antibiotics. By 1 week postoperatively, he was able to walk 50 yards, which was further than he had in years. The patient was discharged on the 44th postoperative day. Pulmonary function tests from 3 months posttransplantation showed a FVC of 3.00 L (55% of predicted), FEV, of 2.69 L/set (65% of predicted), and FEF,.,, of 2.81 L/set (67% of predicted), and analysis of ABG showed pH 7.44, PaCO,, 39 mm Hg, and PaO,, 92 mm Hg, (SO, = 0.21). He continues to progress well with increasing body weight (60 kg) and exercise endurance.
DISCUSSION
Bilateral single-lung transplantation seems to be the best operation for the patient with preserved cardiac function and emphysema, cystic fibrosis, or bilateral pulmonary sepsis. This procedure enables transplantation of the lungs and heart into different recipients and avoids the risks associated with cardiac transplantation (denetvated heart, accelerated atherosclerotic coronary artery disease, and acute and chronic cardiac rejection). Bilateral single-lung transplantation may avoid the need for CPB, which is always needed for the en-bloc method. In addition, the bronchial anastomoses of the bilateral single-lung transplantation seem to have a lower incidence of dehiscence than the tracheal anastomosis of the en-bloc method. For these reasons, this patient underwent bilateral single-lung transplantation for end-stage emphysema. During the procedure, several difficulties were encountered. On the basis of physical examination, it was predicted that the patient’s trachea would be difficult to intubate. The intubation by direct laryngoscopy with a 41F DLT was impossible because of the awkward shape, stiffness, and size of this endotracheal tube and the decreased range of motion of the neck and temporomandibular joint. Only after securing the airway with a single-lumen endotracheal tube by direct laryngoscopy and the use of a Bougie device were the authors able to intubate the trachea with the DLT. After intubation, the problem of ventilating severely emphysematous lungs was encountered. Ventilation of the single native lung for the first side of the bilateral procedure proved difficult, resulting in moderate respiratory acidosis. Much of the difficulty arose from the inability to increase minute ventilation. An increase in frequency or tidal volume would have compromised the expiratory time and
BILATERAL
SINGLE LUNG TRANSPLANTATION
203
resulted in “breath stacking,” increased peak inspiratory pressures, and further hyperinflation. The respiratory acidosis was a transient, moderate physiological insult that the patient tolerated well; therefore, it was elected to avoid the use of CPB. End-tidal carbon dioxide values and tracings could not be used to assess ventilation because P&O, did not accurately predict PaCO,. The P&O, tracing demonstrated considerable slope to the phase-three “plateau.” A large and inconsistent PaCO,-P&O, gradient was present throughout the anesthetic (Table 1). This probably reflects the relatively short expiratory time contrasted to the expiratory time needed to reach a true P&O, in such emphysematous lungs, and the combinations of native and donor lungs being ventilated in the different phases of the surgery. Therefore, during the anesthetic, intermittent ABG analyses were used to optimize ventilation. The A-a gradients varied during the different stages of surgery. The A-a gradient increased progressively during the middle stages of the surgery. This was related to the low tidal volumes used during these stages, resulting in atelectasis and ventilation/perfusion mismatch. These small tidal volumes and the resultant low peak inspiratory pressures were used to prevent trauma to the bronchial anastomoses. At the conclusion of the surgery, carefully increasing tidal volumes and increasing peak inspiratory pressures showed bronchial anastomotic site integrity during bilateral ventilation of the left and right donor lungs. These larger tidal volumes led to a decrease in atelectasis and ventilation/ perfusion mismatch, resulting in an improved A-a gradient that permitted use of a lower F,O, and reduced the chance of oxygen toxicity in the donor lungs. More hemodynamic instability with single-lung ventilation/perfusion was anticipated than was observed. Preoperatively, the echocardiogram, ECG, and chest radiograph suggested RV hypertrophy or RV hypertension. However, RV pressure measurements from the intracardiac catheter were normal with bilateral native lung perfusion. Native single-lung perfusion demonstrated a mild increase in RV pressures with a decrease in systemic blood pressure. The nitroglycerin infusion reduced the pulmonary vascular resis-
tance. The blood pressure was stable during this phase of surgery and did not warrant instituting CPB. On beginning perfusion of the donor lung, RV pressures decreased acutely, reflecting the change in the pulmonary vasculature (Table 1). There was an increase in the cross-sectional area of the pulmonary vasculature and the volume of the pulmonary vasculature of the donor lung to be filled with blood, which necessitated intravenous fluid administration. At the beginning of the case, it was anticipated that CPB woufd be needed for at least part of the procedure, probably during the transplantation of the second lung. Although ordinary measures were used to maintain body temperature, this cachetic patient with a high body surface area-to-weight ratio and extensive incisions and exposure was unable to maintain his body temperature during the skin preparation or when his chest was wide open. The expectation was to’rewarm the patient using the CPB heat exchanger during the bypass period. However, as the procedure progressed swiftly without the anticipated physiological problems, it became apparent that CPB would not be necessary. However, by then the most vigorous efforts to maintain body temperature were inadequate and his core body temperature dropped to 32.6”C. Concern for possible dysrhythmias or coagulation problems at this temperature led to use of a short period of CPB via the femoral artery and vein solely to rewarm the patient to normal levels. This was accomplished without difficulty. Whether this was strictly necessary is unclear because the effect of patient temperature at the end of bypass on outcome has not been studied in this setting. This new surgical procedure provides challenging issues for the anesthesiologist. For each patient a plan needs to be formulated for each of the various courses that a patient may follow during the case. There is the possibility that single native lung ventilation will be inadequate for the patient, and the possibility that the heart will be unable to tolerate the PA clamping. There is also the possibility that CPB might be avoided completely, as was almost the case in this patient. The anesthetic plan needs to be flexible and complete to cover any of these possibilities.
REFERENCES 1. Toronto Lung Transplant Group: Experience with single lung transplantation for pulmonary fibrosis. JAMA 259:2258-2262,1988 2. Toronto Lung Transplant Group: Lung transplantation for pulmonary fibrosis. N Engl J Med 314:1140-11451986 3. Cooper JD, Pearson FG, Patterson GA, et al: Technique of successful lung transplantation in humans. J Thorac Cardiovasc Surg 93:173-181,1987 4. Patterson GA, Cooper JD, Dark JH, et al: Experimental and clinical double-lung transplantation. J Thorac Cardiovasc Surg 95:70-74,1988
5. Cooper JD, Patterson GA, Grossman R, transplantation for advanced chronic obstructive Rev Respir Dis 139::303-307,1989
et al: Double-lung lung disease.
Am
6. Gayes JM, Giron L, Nissen MD, et al: Anesthetic considerations for patients undergoing double-lung transplantation. J Cardiothorac Anesth 4:486-498,199O 7. Kaiser LR, Pasque MK, Trulock EP, et al: Bilateral sequential lung transplantation: The procedure of choice for double-lung replacement. Ann Thorac Surg 52:438446,1991
Anesthesia
for Bilateral
Single-Lung
B.S. Lee, MD, F.H. Sarnquist,
P
ATIENTS WITH end-stage lung disease have been successfully treated with lung transplantation. Singlelung transplantation has been used for patients with endstage pulmonary fibrosis,‘-3 and double-lung transplantation has been used for patients with end-stage emphysema, cystic fibrosis, and bilateral pulmonary sepsis.4.5 Doublelung transplantation has been performed as an en-bloc the anesthetic considerations of which transplantation4.5; have been reviewed recently by Gayes et al.6 Bilateral single-lung transplantation is an evolving technique, that avoids some of the potential complications of the en-bloc method, including cardiopulmonary bypass (CPB), tracheal anastomosis, and cardiac surgery.’ A report of the anesthetic management of the first patient at the Stanford University Hospital to have bilateral single-lung transplantations is presented. CASE
REPORT
A 39-year-old white man with cY-1-antitrypsin deficiency, resultant severe COPD, dyspnea at rest, and requiring nasal cannula oxygen at 2 L/min was admitted to the Stanford University Hospital when donor lungs became available. He had progressive dyspnea for 6 years. Pulmonary function tests before admission showed a forced vital capacity (FVC) of 1.32 L (24% of predicted), forced expiratory volume in 1 second (FEV,) of 0.52 Lisec (12% of predicted), maximum midexpiratory flow rate (FEF,,.,,) of 0.24 Lisec (5% of predicted), maximum minute ventilation (MMV) of 28 L/min (15% of predicted), diffusing capacity for carbon monoxide (DLCO) of 7 mliminlmm Hg (20% of predicted), and the analysis of his arterial blood gases (ABG) showed a pH of 7.42, PaCO, of 42 mm Hg, and PaO, of 59 mm Hg (F,O, = 0.21). An echocardiogram demonstrated left ventricular (LV) wall thickening and normal contractility, abnormal septal motion consistent with increased right ventricular (RV) pressure or RV hypertrophy, and normal left and right atria. The chest radiograph showed marked hyperinflation of both lungs with emphysematous changes consistent with severe chronic obstructive pulmonary disease (COPD). There was no evidence of hepatic, gastric, or renal manifestations of the cu-1-antitrypsin deficiency. Generalized cachexia (height = 185 cm, weight = 51 kg) was attributed to his chronic disease state. The patient had neck pain with neck extension, a small mandible, and a decreased range of motion at the temporomandibular joint, suggesting that the patient’s trachea might be difficult to intubate. The patient’s medications included albuterol, cromolyn, mucomyst, theophylline, and saturated solution potassium iodide. The patient was taken to the operating room, breathing supplemental oxygen supplied by nasal cannula, where monitors were placed (5-lead ECG, digital pulse oximeter, precordial stethoscope, and blood pressure cuff). While the patient was sitting in the 45” upright position necessitated by his dyspnea, a radial arterial and two large-bore intravenous catheters were inserted using
Transplantation
MD, and V.A. Starnes, MD sterile technique. This patient had not received premeditation because of his compromised respiratory status. The oxygen saturation was greater than 95% during this period. Sterilized anesthesia equipment was used. The patient was preoxygenated and anesthesia was slowly induced. Fentanyl and midazolam were administered while maintaining cricoid pressure. When the patient lost consciousness, he was placed in the supine position and manual ventilation was begun. Care was taken to minimize peak airway pressures. After muscle relaxation with pancuronium was achieved, direct laryngoscopy was performed with visualization of the vocal cords; however, intubating the trachea with the double-lumen endotracheal tube (DLT) was impossible. The airway was secured with a single-lumen 8.0-mm endotracheal tube, which was then changed to a left-sided 41F DLT using a Bougie device as a guide. Fiberoptic bronchoscopy confirmed the correct endotracheal tube position. Bilateral ventilation was initiated. The ventilator was adjusted to maintain low to normal peak inspiratory pressures (low tidal volumes) and to emphasize increased expiratory time (decreased inspiratoryi expiratory ratio). The arterial blood gas (ABG) analysis showed a mild respiratory acidosis (Table 1). A pulmonary artery (PA) catheter introducer was inserted using sterile technique in the right internal jugular vein; however, repeated attempts at passing the balloon-tipped catheter into the PA resulted in ventricular ectopy with hypotension. The catheter balloon was inflated and the catheter tip was left positioned in the RV. The surgeons prepared the right femoral site for arterial and venous cannulation. CPB was to be instituted when ventilation of the native or donor lung was inadequate or when the RV was unduly loaded by PA clamping. It was anticipated that CPB would be needed because of the severity of the COPD. Through an epigastric incision, the surgeons prepared omental flaps on pedicles for the bronchial omentopexies. Then, they commenced the bilateral anterior fourth intercostal “clam shell” thoracotomy. The right thorax was operated on first. Single-lung ventilation of the left native lung was initiated, and the right lung was allowed to collapse to atmospheric pressure. The surgeons clamped the right PA, resulting in the expected increase of RV pressure. Nitroglycerin (1 pg/kg/min) was administered to reduce the pulmonary vascular resistance. The ABG analysis showed a worsening respiratory acidosis, and the ventilator was adjusted to increase the minute ventilation. When the clamps were removed from the right donor lung, the RV pressures decreased. End-tidal carbon dioxide (P&O,) initially increased and then decreased.
From the Departments of Anesthesiology and Cardiothoracic Surgev, Stanford UniversityMedical Center, Stanford, CA. Address reprint requests to F.H. Samquist, Department of Anesthesiology, Stanford University Medical Center, 300 Pasteur Dr, Stanford, CA 94305. Copyright o I992 b_yW.B. Saunders Company 1053-0770192/060.?-0016$03.0010
Journalof Cardiothoracic and VascularAnesthesia, Vol6, No 2 (April), 1992: pp 201-203
201
202
LEE, SARNQUIST,
AND STARNES
Table 1. Perioperative Data A
B
C
D
E
_._____..
F
G
4
Ventilation
Peak inspiratory pressure (cm H,O) Fractional inspired oxygen ABG analysis
0.21 7.42
PH
8.6
6.6
14
11
12
12
5
6
25
32
13
23
18
38
6.3
Minute volume (L/min) Frequency (per min)
1.0 7.34
3.8
1.0 7.22
7.0
0.6 7.28
8.0
0.6 7.35
0.4
0.3 7.53
7.40
0.21 7.44
PaO, (mm Hg)
59
516
494
148
80
160
133
92
PaCO, (mm Hg)
42
54
62
47
41
35
27
39
37
28
29
24
35 47
59
P&D,
(mm Hg)
PaCO,-P&O,
gradient (mm Hg)
A-a gradient (mm Hg) Hemodynamics Blood pressure (S/D) (mm Hg) Heart rate (per minute) Right ventricular pressure (S/D) (mm Hg) Thermoregulation Bladder temperature (C)
76
17
26
18
17
8
130
142
221
297
81
100/70
80145
90
80
80145
85145
100/50
90150
110
110
120
126
32121
40120
26113
24/l
32110
36.7
35.3
34.0
32.6
36.6
NOTE. A, preoperative clinic; B, bilateral ventilation and perfusion, left and right native lungs; C, single ventilation and perfusion, left native lung; 13, lung; F, bilateral ventilation and perfusion. left and right donor lungs: G, intensive care unit, first admission; and H, postoperative clinic, 3 months posttransplantation. bilateral ventilation and perfusion, left native lung and right donor lung; E, single-lung ventilation and perfusion, right donor
The ABG analysis showed a decrease of the respiratory acidosis. The left lung was allowed to collapse to atmospheric pressure and the left PA was clamped. The RV pressure, heart rate, and systemic blood pressure remained stable. Once the left donor lung was implanted, ventilation and perfusion of both donor lungs were instituted. The ABG analysis showed a resolution of the respiratory acidosis and adequate oxygenation with minimal oxygen supplementation (Table 1). Despite the use of intravenous fluid warmers, an inspired gas humidifier, a warming pad, and a warm room, rapid loss of body heat occurred, causing a problem of severe hypothermia. The patient’s bladder temperature decreased steadily to 326°C during the procedure. Partial CPB via the right femoral site was instituted for 18 minutes to rewarm the patient. The bladder temperature increased to 36.9”C. He was brought back to the operating room 2 hours later for bleeding. Exploration of the chest showed bleeding from a vessel on the left mainstem bronchus. During this procedure, the right lung was not expanding as well as the left lung. Fiberoptic bronchoscopy showed tenacious secretions at the right middle lobe and right lower lobe bronchi, which were removed through the bronchoscope. Ventilation of these lobes improved. The patient
returned to the intensive care unit with stable hemodynamics and oxygenation. This patient was weaned from the ventilator on the second postoperative day and extubated without incident. By the third postoperative day, the patient had an oxygen saturation of 97% while breathing room air. A right middle lobe pneumonia, which complicated his postoperative course, was treated with antibiotics. By 1 week postoperatively, he was able to walk 50 yards, which was further than he had in years. The patient was discharged on the 44th postoperative day. Pulmonary function tests from 3 months posttransplantation showed a FVC of 3.00 L (55% of predicted), FEV, of 2.69 L/set (65% of predicted), and FEF,.,, of 2.81 L/set (67% of predicted), and analysis of ABG showed pH 7.44, PaCO,, 39 mm Hg, and PaO,, 92 mm Hg, (SO, = 0.21). He continues to progress well with increasing body weight (60 kg) and exercise endurance.
DISCUSSION
Bilateral single-lung transplantation seems to be the best operation for the patient with preserved cardiac function and emphysema, cystic fibrosis, or bilateral pulmonary sepsis. This procedure enables transplantation of the lungs and heart into different recipients and avoids the risks associated with cardiac transplantation (denetvated heart, accelerated atherosclerotic coronary artery disease, and acute and chronic cardiac rejection). Bilateral single-lung transplantation may avoid the need for CPB, which is always needed for the en-bloc method. In addition, the bronchial anastomoses of the bilateral single-lung transplantation seem to have a lower incidence of dehiscence than the tracheal anastomosis of the en-bloc method. For these reasons, this patient underwent bilateral single-lung transplantation for end-stage emphysema. During the procedure, several difficulties were encountered. On the basis of physical examination, it was predicted that the patient’s trachea would be difficult to intubate. The intubation by direct laryngoscopy with a 41F DLT was impossible because of the awkward shape, stiffness, and size of this endotracheal tube and the decreased range of motion of the neck and temporomandibular joint. Only after securing the airway with a single-lumen endotracheal tube by direct laryngoscopy and the use of a Bougie device were the authors able to intubate the trachea with the DLT. After intubation, the problem of ventilating severely emphysematous lungs was encountered. Ventilation of the single native lung for the first side of the bilateral procedure proved difficult, resulting in moderate respiratory acidosis. Much of the difficulty arose from the inability to increase minute ventilation. An increase in frequency or tidal volume would have compromised the expiratory time and
BILATERAL
SINGLE LUNG TRANSPLANTATION
203
resulted in “breath stacking,” increased peak inspiratory pressures, and further hyperinflation. The respiratory acidosis was a transient, moderate physiological insult that the patient tolerated well; therefore, it was elected to avoid the use of CPB. End-tidal carbon dioxide values and tracings could not be used to assess ventilation because P&O, did not accurately predict PaCO,. The P&O, tracing demonstrated considerable slope to the phase-three “plateau.” A large and inconsistent PaCO,-P&O, gradient was present throughout the anesthetic (Table 1). This probably reflects the relatively short expiratory time contrasted to the expiratory time needed to reach a true P&O, in such emphysematous lungs, and the combinations of native and donor lungs being ventilated in the different phases of the surgery. Therefore, during the anesthetic, intermittent ABG analyses were used to optimize ventilation. The A-a gradients varied during the different stages of surgery. The A-a gradient increased progressively during the middle stages of the surgery. This was related to the low tidal volumes used during these stages, resulting in atelectasis and ventilation/perfusion mismatch. These small tidal volumes and the resultant low peak inspiratory pressures were used to prevent trauma to the bronchial anastomoses. At the conclusion of the surgery, carefully increasing tidal volumes and increasing peak inspiratory pressures showed bronchial anastomotic site integrity during bilateral ventilation of the left and right donor lungs. These larger tidal volumes led to a decrease in atelectasis and ventilation/ perfusion mismatch, resulting in an improved A-a gradient that permitted use of a lower F,O, and reduced the chance of oxygen toxicity in the donor lungs. More hemodynamic instability with single-lung ventilation/perfusion was anticipated than was observed. Preoperatively, the echocardiogram, ECG, and chest radiograph suggested RV hypertrophy or RV hypertension. However, RV pressure measurements from the intracardiac catheter were normal with bilateral native lung perfusion. Native single-lung perfusion demonstrated a mild increase in RV pressures with a decrease in systemic blood pressure. The nitroglycerin infusion reduced the pulmonary vascular resis-
tance. The blood pressure was stable during this phase of surgery and did not warrant instituting CPB. On beginning perfusion of the donor lung, RV pressures decreased acutely, reflecting the change in the pulmonary vasculature (Table 1). There was an increase in the cross-sectional area of the pulmonary vasculature and the volume of the pulmonary vasculature of the donor lung to be filled with blood, which necessitated intravenous fluid administration. At the beginning of the case, it was anticipated that CPB woufd be needed for at least part of the procedure, probably during the transplantation of the second lung. Although ordinary measures were used to maintain body temperature, this cachetic patient with a high body surface area-to-weight ratio and extensive incisions and exposure was unable to maintain his body temperature during the skin preparation or when his chest was wide open. The expectation was to’rewarm the patient using the CPB heat exchanger during the bypass period. However, as the procedure progressed swiftly without the anticipated physiological problems, it became apparent that CPB would not be necessary. However, by then the most vigorous efforts to maintain body temperature were inadequate and his core body temperature dropped to 32.6”C. Concern for possible dysrhythmias or coagulation problems at this temperature led to use of a short period of CPB via the femoral artery and vein solely to rewarm the patient to normal levels. This was accomplished without difficulty. Whether this was strictly necessary is unclear because the effect of patient temperature at the end of bypass on outcome has not been studied in this setting. This new surgical procedure provides challenging issues for the anesthesiologist. For each patient a plan needs to be formulated for each of the various courses that a patient may follow during the case. There is the possibility that single native lung ventilation will be inadequate for the patient, and the possibility that the heart will be unable to tolerate the PA clamping. There is also the possibility that CPB might be avoided completely, as was almost the case in this patient. The anesthetic plan needs to be flexible and complete to cover any of these possibilities.
REFERENCES 1. Toronto Lung Transplant Group: Experience with single lung transplantation for pulmonary fibrosis. JAMA 259:2258-2262,1988 2. Toronto Lung Transplant Group: Lung transplantation for pulmonary fibrosis. N Engl J Med 314:1140-11451986 3. Cooper JD, Pearson FG, Patterson GA, et al: Technique of successful lung transplantation in humans. J Thorac Cardiovasc Surg 93:173-181,1987 4. Patterson GA, Cooper JD, Dark JH, et al: Experimental and clinical double-lung transplantation. J Thorac Cardiovasc Surg 95:70-74,1988
5. Cooper JD, Patterson GA, Grossman R, transplantation for advanced chronic obstructive Rev Respir Dis 139::303-307,1989
et al: Double-lung lung disease.
Am
6. Gayes JM, Giron L, Nissen MD, et al: Anesthetic considerations for patients undergoing double-lung transplantation. J Cardiothorac Anesth 4:486-498,199O 7. Kaiser LR, Pasque MK, Trulock EP, et al: Bilateral sequential lung transplantation: The procedure of choice for double-lung replacement. Ann Thorac Surg 52:438446,1991
