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Mediastinal mass resection: Femorofemoral cardiopulmonary bypass before induction of anesthesia in the management of airway obstruction
Mediastinal Mass Resection: Femorofemoral Cardiopulmonary Bypass Before Induction of Anesthesia in the Management of Airway Obstruction Deepak K. Tempe, MD, Rajesh Arya, MD, Sumir Dubey, MS, Mch, Sangeeta Khanna, MD, A. S. Tomar, MD, Vijay Grover, MS, Mch, M. Nigam, MS, Mch, U. K. Makwane, MD
T
OTAL OCCLUSION OF THE AIRWAY leading to fatal cardiopulmonary arrest is a well-known complication of mediastinal tumors.1,2 The airway occlusion can occur during induction of anesthesia, extubation, surgical resection, or simply by a change of posture. The maintenance of the airway is a challenge to the anesthesiologist, particularly if the obstruction is at the lower tracheal level. In an extreme situation, femorofemoral cardiopulmonary bypass (CPB) can be kept ready before induction of anesthesia so that oxygenation can be maintained by initiation of CPB, if irreversible airway obstruction occurs. A patient with an anterior mediastinal mass and a superior vena cava syndrome in whom femorofemoral CPB was kept on standby before induction of anesthesia is described. The principles of airway management in patients with mediastinal masses are reviewed. CASE REPORT A 22-year-old man weighing 35 kg presented with complaints of pain on the right side of the chest and neck, swelling on the right side of the neck, breathlessness at rest, and cough off and on. He was a short-statured man for his age, which perhaps was attributable to chronic debility and the accompanying scoliosis. The complaints started about 6 months ago with pain on the right side of the chest. Gradually the pain extended to the right side of the face along with the appearance of swelling. His dyspnea was New York Heart Association class I at the beginning and progressed gradually to class IV. He had difficulty in lying supine and could not lie in the left lateral position at all because of respiratory distress. He also had hoarseness of the voice. There was no history of hemoptysis, hematemesis, or dysphagia. On clinical examination, the patient had swelling of the right half of the neck. He was wheezing and showed slight suprasternal and intercostal retractions at rest. He had ptosis of the right eye, and there were dilated veins on the chest and neck. Radiograph of the chest showed severe tracheal compression and deviation in association with a large mediastinal tumor (Fig 1). The tracheal compression was maximal in the distal trachea and carina. The superior vena cavogram showed dilated and tortuous collateral veins. The tracheal compression was obvious in these films (Fig 2). Computed tomography (CT) examination confirmed the findings (Fig 3). Although the larynx appeared normal on clinical examination, indirect laryngoscopy revealed that it was deviated to the left side and the vocal cords were normal. The pulmonary function tests revealed a forced vital capacity of 1360 mL (36% of predicted) and forced expiratory volume in 1 second of 1110 mL (30% of predicted). The facility for measuring the respiratory flow volume loops was not available at the time, and it could not be used for the assessment. Fine-needle aspiration cytology suggested the diagnosis of a neurogenic tumor. A right posterolateral thoracotomy for excision of the tumor was planned. It was believed that total airway obstruction at the carinal level during induction of anesthesia could occur in this patient, and it was reasoned that in such an event, emergency attempts at establishing the airway, including a low tracheostomy, would have little chance of success. It was decided to keep femorofemoral CPB on standby before the induction of anesthesia. No premedication was administered, and the various procedures to be performed under local anesthesia were explained to the patient in detail. It was planned to cannulate the femoral vessels under local anesthesia, then administer general anesthesia in a semiupright position with inhalation anesthetics. It was decided to use succinylcholine as the muscle relaxant to facilitate intubation if ventilation could be assisted
easily by mask. In case of severe airway obstruction occurring at any stage from induction of general anesthesia and positioning of the patient until the completion of surgery, CPB would be initiated quickly to overcome the dangers of hypoxia. A rigid bronchoscope was kept ready for emergency use. An activated coagulation time of ⬎300 seconds was planned during the entire surgical procedure. In the operating room, electrocardiogram monitoring was begun, and radial arterial and venous catheterization were performed under local anesthesia. Heparin, 300 U/kg, was administered to the patient and morphine, 10 mg; pancuronium, 4 mg; and midazolam, 5 mg, were added to the pump prime. The surgeon proceeded with the percutaneous cannulation of the femoral vessels (Shaw kit, CR Bard Inc, Tewksbury, MA) under local anesthesia. During venous cannulation, the blood pressure decreased suddenly to 40 to 50 mmHg and heart rate to 30 to 40 beats/min. CPB was initiated, and flows of 1 to 1.5 L/min were established. Simultaneously, the patient was given morphine, 15 mg; thiopental, 100 mg; and pancuronium, 6 mg, and tracheal intubation with a No. 7.5 cuffed endotracheal tube was accomplished after ventilating the lungs with 100% oxygen. There was no difficulty in delivering positive-pressure ventilation after intubation. The patient was placed in the left lateral position, and when it was confirmed that there was no difficulty in ventilating the patient in this position, the CPB was discontinued with a blood pressure of 90 to 100 mmHg. The CPB time was 6 minutes. Thoracotomy revealed a large firm mass (12 cm ⫻ 10 cm) that had compressed the right upper and middle lobes of the lung. Dilated vessels were present over the capsule of the tumor. The tumor could only be removed piecemeal owing to adhesions to the surrounding structures. A cell saver (Dideco Shiley, Mirandola, Italy) was used to salvage blood lost during surgery. The rest of the operative course was uneventful. Residual heparin was neutralized at the end of the surgery, and femoral cannulae were removed. The patient was ventilated electively for 32 hours. Postoperative chest radiograph showed expansion of the right lung and restoration of the tracheal lumen (Fig 4). The patient was extubated with all due precautions, which included readiness to reintubate if breathing difficulty occurred. A total of 4 U of banked blood (2 fresh warm and 2 cold) and 2 U of platelet-rich plasma were transfused to the patient along with 500 mL of cell saver blood during surgery. Re-exploration was done for excessive bleeding 8 hours later, and an additional 4 U of blood were given during the postoperative period. Histopathology revealed the diagnosis of a well-differentiated liposarcoma. DISCUSSION
Total occlusion of the airway can occur with the induction of general anesthesia in patients with a mediastinal tumor. This occlusion has been ascribed to a decrease in inspiratory muscle tone leading to a decrease in the lung volume that produces loss of the tethering effect of expanded lungs on the airways.3
From the Departments of Anaesthesiology, Cardiothoracic Surgery, and Radiology, G.B. Pant Hospital, New Delhi, India. Address reprint requests to Deepak K. Tempe, MD, Professor of Anaesthesiology, Department of Anaesthesiology, G.B. Pant Hospital, New Delhi-110002 India. E-mail: [email protected] Copyright © 2001 by W.B. Saunders Company 1053-0770/01/1502-0019$35.00/0 doi:10.1053/jcan.2001.21988 Key words: mediastinal mass, airway obstruction, femoro-femoral bypass
Journal of Cardiothoracic and Vascular Anesthesia, Vol 15, No 2 (April), 2001: pp 233-236
233
234
Fig 1. Chest radiograph (posteroanterior view) shows a large mediastinal mass occupying the right side with tracheal deviation and compression of the distal trachea and carina.
Relaxation of airway smooth muscle by anesthetic agents4 makes the airways more compressible. It has been shown that the use of muscle relaxants is followed by inability to ventilate patients with mediastinal tumors.2,5 Occasionally, the mediastinal mass can compress the pulmonary arteries, leading to life-threatening hypoxia.6 General anesthesia for patients with mediastinal tumors can be hazardous and occasionally fatal. It was recognized that administration of general anesthesia to this patient would be extremely hazardous. It was thought that emergency attempts at low tracheostomy in the event of total airway obstruction occurring during induction of anesthesia would be time-consuming and dangerous. The authors chose to cannulate the femoral vessels under local anesthesia and to keep the CPB circuit ready to initiate CPB in the event of airway obstruction. Successful use of femoral CPB has been described in patients with a mediastinal mass6 and tracheal tumors obstructing the carina and trachea.7,8 In the patient with a mediastinal mass,6 administration of general anesthesia had produced severe cyanosis on 2 earlier occasions necessitating cancellation of the procedure. Some authors have used femoral CPB as a standby in patients with tracheal masses but have preferred to keep the femoral vessels exposed under local anesthesia without cannulation.9,10 In both of these reports, no difficulty was encountered during induction of anesthesia; however, in one of them,10 cannulation was performed after opening the chest because moderate difficulty was encountered with adequate inflation of the lungs and CPB was instituted for resection of the tumor. In a more recent report, Riley et al11 used CPB as a standby (without femoral vessel cannulation), but they used helium-oxygen during induction of anesthesia. Although CPB was not required, these investigators encountered extreme difficulty in maintaining airway patency with spontaneous ventilation and severe decreases in oxygen saturation. In a few reports of aortic arch aneurysms causing airway obstruction, cannulation of femoral vessels under local anesthesia was proposed before induction of general anesthesia.12,13 It could not be
TEMPE ET AL
performed successfully, however, because the patients were irritable and uncooperative. In another case of an aneurysm of the descending thoracic aorta, femorofemoral CPB was successfully established before induction of general anesthesia.14 The authors preferred to cannulate the femoral vessels and to keep CPB ready because it was thought that there was a definite danger of the patient developing airway obstruction. The patient’s forced vital capacity was severely deranged, and the possibility of total superior vena cava obstruction was a consideration, the management of which would have required CPB. Because of the chronic nature of the superior vena cava obstruction, the collateral circulation was likely to be well developed in this patient so that drainage through the inferior vena cava cannula was expected to be adequate. It is known that airway problems can occur during surgical resection, and cannulation of the femoral vessels in the lateral position would be difficult and time-consuming. Prior cannulation allows for handling the emergency situation in a safe and unhurried fashion, and CPB is now considered a safe and acceptable everyday clinical tool. The incidence of airway complications with general anesthesia in patients with mediastinal masses has been reported to be 7% to 18%.15 Some of the criteria that are considered to identify patients at risk of airway complications are the presence of preoperative respiratory symptoms, evidence of tracheobronchial compression by CT scan, mediastinal thoracic ratio (size of mediastinal mass compared with the thoracic diameter) of ⬎50%, and plateauing of expiratory flow rate on pulmonary function tests.15 Most of these criteria were present in this patient, making him a high-risk candidate for airway obstruction. The institution of CPB was necessary in this patient for hemodynamic, not respiratory reasons; this was due to excessive insertion of the venous cannula by the surgeon, which was passed beyond the inferior vena cava–right atrium junction. The venous cannula is normally placed in the inferior vena cava just below the inferior vena cava–right atrium junction. Be-
Fig 2. Superior vena cavogram shows dilated and tortuous collateral veins with total obstruction of the superior vena cava; tracheal deviation and compression are also noted.
MEDIASTINAL MASS RESECTION
235
Fig 3. (A and B) Chest CT scans show tracheal compression above the carina. (C and D) Chest CT scans show tracheal compression at the level of the carina and after bifurcation of the trachea.
Fig 4. Postoperative chest radiograph shows expansion of the right lung and restoration of the tracheal lumen.
cause of the scoliosis and short stature of the patient, the length of insertion was misjudged by the surgeon. The cannula was withdrawn a few centimeters, and CPB was discontinued with normal hemodynamics. If overinsertion of the venous cannula had not happened, CPB probably would not have been necessary in this patient. Exposure of the femoral vessels without cannulation may have avoided the need to go on CPB as well as the need to administer heparin to the patient. In the event of cardiopulmonary decompensation (which could have occurred anytime during the entire surgical procedure), however, the duration for which the oxygenation could have been delayed is expected to be 3 to 5 minutes. This may be longer if the cannulation was required after positioning the patient during surgical resection. Such a delay is not desirable because the neurologic outcome may be adversely affected. It has been suggested that a carefully planned anesthetic along with the availability of a rigid bronchoscope may be enough to deal with patients with anterior mediastinal masses.16 Ferrari and Bedford16 used an inhalation technique for induction of anesthesia in pediatric cancer patients. They encountered several episodes of cardiorespiratory compromise in pa-
236
TEMPE ET AL
tients; in 2 of the patients, airway obstruction developed during maintenance of anesthesia with change of posture. Such a technique was possible perhaps because of a short surgical procedure (lymph node biopsy) that could be completed in a position that was not ideal for the surgeon. Such a situation is unacceptable in patients undergoing thoracotomy for a major tumor resection. An alternative method of securing the airway is the use of a rigid bronchoscope as a stylet for a reinforced endotracheal tube.17 This method was not considered in the present case because of the obstruction of the airway at the lower tracheal and carinal level. The possibility of using a left-sided doublelumen tube placed over a fiberoptic bronchoscope was considered. The patient also had bronchial compression, however, so that compression of the right bronchus leading to ventilationperfusion mismatch could have occurred. It has been reported that single-lung ventilation in such a situation results in marked hypoxia because of right-to-left shunting in the underventilated lung.18 The present case highlights that airway problems may not
arise even though they are predicted preoperatively. The converse is also true. The anesthesiologist cannot be complacent and must be fully prepared to deal with a respiratory and hemodynamic catastrophe. Ignoring these precautions can place the patient in a life-threatening situation.19 The authors believe that it is not desirable to struggle with the maintenance of the patient’s airway during induction of anesthesia and to allow life-threatening hypoxia to occur before a decision is made to cannulate the femoral vessels and initiate CPB. The time spent in the initiation of CPB (usually in a hurry) in a hemodynamically compromised patient may be dangerous. It may be a consideration for short procedures, such as a biopsy, but in a patient undergoing a thoracotomy for tumor resection, a catastrophic situation may arise at any point during surgery. What if CPB is not required at all? The complications of cannulating the femoral vessels can be considered minor in a unit where cardiac surgery is routinely performed. The authors believe that cannulation of the femoral vessels and keeping the CPB circuit ready to initiate CPB in such patients is justified.
REFERENCES 1. Northrip DR, Bohman BK, Tsueda K: Total airway occlusion and superior vena cava syndrome in a child with an anterior mediastinal tumor. Anesth Analg 65:1079-1082, 1986 2. Neuman GG, Weingarten AE, Abramowitz RM, et al: The anesthetic management of the patient with an anterior mediastinal mass. Anesthesiology 60:144-147, 1984 3. Bergman NA: Reduction in resting and expiratory position of the respiratory system with induction of anesthesia and neuromuscular paralysis. Anesthesiology 57:14-17, 1982 4. Fletcher SW, Flacke W, Alper MH: The actions of general anesthetic agents on tracheal smooth muscle. Anesthesiology 29:517522, 1968 5. Mackie AM, Watson CB: Anaesthesia and mediastinal masses: A case report and review of the literature. Anaesthesia 39:899-903, 1984 6. Hall KD, Friedman M: Extracorporeal oxygenation for induction of anesthesia in a patient with an intrathoracic tumor. Anesthesiology 42:493-495, 1975 7. Woods FM, Neptune WB, Palatchi A: Resection of the carina and mainstem bronchi with the use of extracorporeal circulation. N Engl J Med 264:492-494, 1961 8. Jensen V, Milne B, Salerno T: Femoral-femoral cardiopulmonary bypass prior to induction of anaesthesia in the management of upper airway obstruction. Can Anaesth Soc J 30:270-272, 1983 9. Dodge TL, Mahaffey JE, Thomas JD: The anesthetic management of a patient with an obstructing intratracheal mass: A case report. Anesth Analg 56:295-298, 1977 10. Adkins PC, Izawa EM: Resection of tracheal cylindroma using cardiopulmonary bypass. Arch Surg 88:405-409, 1964
11. Riley RH, Raper GD, Newman MAJ: Helium-oxygen and cardiopulmonary bypass standby in anaesthesia for tracheal stenosis. Anaesth Intensive Care 22:710-713, 1994 12. Mori M, Chuma R, Kiichi Y, et al: The anesthetic management of a patient with a thoracic aortic aneurysm that caused compression of the left mainstem bronchus and the right pulmonary artery. J Cardiothorac Vasc Anesth 7:579-584, 1993 13. MacGillivray RG: Tracheal compression caused by aneurysm of the aortic arch. Anaesthesia 40:270-277, 1985 14. Charrette EJP, Winton TL, Salerno TA: Acute respiratory insufficiency from an aneurysm of the descending thoracic aorta. J Thorac Cardiovasc Surg 85:467-470, 1983 15. Robie DK, Gursoy MH, Pokorny WJ: Mediastinal tumors— airway obstruction and management. Semin Pediatr Surg 3:259-266, 1994 16. Ferrari LR, Bedford RF: General anesthesia prior to treatment of anterior mediastinal masses in pediatric cancer patients. Anesthesiology 72:991-995, 1990 17. Pelton CJJ, Ratner IA: A technique of airway management in children with obstructed airway due to tumor. Ann Thorac Surg 48: 301-302, 1989 18. Amaha K, Ojutsu Y, Nakamura Y: Major airway obstruction by mediastinal tumour. Br J Anaesth 45:1082-1084, 1973 19. Takeda S, Miyoshi S, Omori K, et al: Surgical rescue for life-threatening hypoxemia caused by a mediastinal tumor. Ann Thorac Surg 68:2324-2326, 1999
T
OTAL OCCLUSION OF THE AIRWAY leading to fatal cardiopulmonary arrest is a well-known complication of mediastinal tumors.1,2 The airway occlusion can occur during induction of anesthesia, extubation, surgical resection, or simply by a change of posture. The maintenance of the airway is a challenge to the anesthesiologist, particularly if the obstruction is at the lower tracheal level. In an extreme situation, femorofemoral cardiopulmonary bypass (CPB) can be kept ready before induction of anesthesia so that oxygenation can be maintained by initiation of CPB, if irreversible airway obstruction occurs. A patient with an anterior mediastinal mass and a superior vena cava syndrome in whom femorofemoral CPB was kept on standby before induction of anesthesia is described. The principles of airway management in patients with mediastinal masses are reviewed. CASE REPORT A 22-year-old man weighing 35 kg presented with complaints of pain on the right side of the chest and neck, swelling on the right side of the neck, breathlessness at rest, and cough off and on. He was a short-statured man for his age, which perhaps was attributable to chronic debility and the accompanying scoliosis. The complaints started about 6 months ago with pain on the right side of the chest. Gradually the pain extended to the right side of the face along with the appearance of swelling. His dyspnea was New York Heart Association class I at the beginning and progressed gradually to class IV. He had difficulty in lying supine and could not lie in the left lateral position at all because of respiratory distress. He also had hoarseness of the voice. There was no history of hemoptysis, hematemesis, or dysphagia. On clinical examination, the patient had swelling of the right half of the neck. He was wheezing and showed slight suprasternal and intercostal retractions at rest. He had ptosis of the right eye, and there were dilated veins on the chest and neck. Radiograph of the chest showed severe tracheal compression and deviation in association with a large mediastinal tumor (Fig 1). The tracheal compression was maximal in the distal trachea and carina. The superior vena cavogram showed dilated and tortuous collateral veins. The tracheal compression was obvious in these films (Fig 2). Computed tomography (CT) examination confirmed the findings (Fig 3). Although the larynx appeared normal on clinical examination, indirect laryngoscopy revealed that it was deviated to the left side and the vocal cords were normal. The pulmonary function tests revealed a forced vital capacity of 1360 mL (36% of predicted) and forced expiratory volume in 1 second of 1110 mL (30% of predicted). The facility for measuring the respiratory flow volume loops was not available at the time, and it could not be used for the assessment. Fine-needle aspiration cytology suggested the diagnosis of a neurogenic tumor. A right posterolateral thoracotomy for excision of the tumor was planned. It was believed that total airway obstruction at the carinal level during induction of anesthesia could occur in this patient, and it was reasoned that in such an event, emergency attempts at establishing the airway, including a low tracheostomy, would have little chance of success. It was decided to keep femorofemoral CPB on standby before the induction of anesthesia. No premedication was administered, and the various procedures to be performed under local anesthesia were explained to the patient in detail. It was planned to cannulate the femoral vessels under local anesthesia, then administer general anesthesia in a semiupright position with inhalation anesthetics. It was decided to use succinylcholine as the muscle relaxant to facilitate intubation if ventilation could be assisted
easily by mask. In case of severe airway obstruction occurring at any stage from induction of general anesthesia and positioning of the patient until the completion of surgery, CPB would be initiated quickly to overcome the dangers of hypoxia. A rigid bronchoscope was kept ready for emergency use. An activated coagulation time of ⬎300 seconds was planned during the entire surgical procedure. In the operating room, electrocardiogram monitoring was begun, and radial arterial and venous catheterization were performed under local anesthesia. Heparin, 300 U/kg, was administered to the patient and morphine, 10 mg; pancuronium, 4 mg; and midazolam, 5 mg, were added to the pump prime. The surgeon proceeded with the percutaneous cannulation of the femoral vessels (Shaw kit, CR Bard Inc, Tewksbury, MA) under local anesthesia. During venous cannulation, the blood pressure decreased suddenly to 40 to 50 mmHg and heart rate to 30 to 40 beats/min. CPB was initiated, and flows of 1 to 1.5 L/min were established. Simultaneously, the patient was given morphine, 15 mg; thiopental, 100 mg; and pancuronium, 6 mg, and tracheal intubation with a No. 7.5 cuffed endotracheal tube was accomplished after ventilating the lungs with 100% oxygen. There was no difficulty in delivering positive-pressure ventilation after intubation. The patient was placed in the left lateral position, and when it was confirmed that there was no difficulty in ventilating the patient in this position, the CPB was discontinued with a blood pressure of 90 to 100 mmHg. The CPB time was 6 minutes. Thoracotomy revealed a large firm mass (12 cm ⫻ 10 cm) that had compressed the right upper and middle lobes of the lung. Dilated vessels were present over the capsule of the tumor. The tumor could only be removed piecemeal owing to adhesions to the surrounding structures. A cell saver (Dideco Shiley, Mirandola, Italy) was used to salvage blood lost during surgery. The rest of the operative course was uneventful. Residual heparin was neutralized at the end of the surgery, and femoral cannulae were removed. The patient was ventilated electively for 32 hours. Postoperative chest radiograph showed expansion of the right lung and restoration of the tracheal lumen (Fig 4). The patient was extubated with all due precautions, which included readiness to reintubate if breathing difficulty occurred. A total of 4 U of banked blood (2 fresh warm and 2 cold) and 2 U of platelet-rich plasma were transfused to the patient along with 500 mL of cell saver blood during surgery. Re-exploration was done for excessive bleeding 8 hours later, and an additional 4 U of blood were given during the postoperative period. Histopathology revealed the diagnosis of a well-differentiated liposarcoma. DISCUSSION
Total occlusion of the airway can occur with the induction of general anesthesia in patients with a mediastinal tumor. This occlusion has been ascribed to a decrease in inspiratory muscle tone leading to a decrease in the lung volume that produces loss of the tethering effect of expanded lungs on the airways.3
From the Departments of Anaesthesiology, Cardiothoracic Surgery, and Radiology, G.B. Pant Hospital, New Delhi, India. Address reprint requests to Deepak K. Tempe, MD, Professor of Anaesthesiology, Department of Anaesthesiology, G.B. Pant Hospital, New Delhi-110002 India. E-mail: [email protected] Copyright © 2001 by W.B. Saunders Company 1053-0770/01/1502-0019$35.00/0 doi:10.1053/jcan.2001.21988 Key words: mediastinal mass, airway obstruction, femoro-femoral bypass
Journal of Cardiothoracic and Vascular Anesthesia, Vol 15, No 2 (April), 2001: pp 233-236
233
234
Fig 1. Chest radiograph (posteroanterior view) shows a large mediastinal mass occupying the right side with tracheal deviation and compression of the distal trachea and carina.
Relaxation of airway smooth muscle by anesthetic agents4 makes the airways more compressible. It has been shown that the use of muscle relaxants is followed by inability to ventilate patients with mediastinal tumors.2,5 Occasionally, the mediastinal mass can compress the pulmonary arteries, leading to life-threatening hypoxia.6 General anesthesia for patients with mediastinal tumors can be hazardous and occasionally fatal. It was recognized that administration of general anesthesia to this patient would be extremely hazardous. It was thought that emergency attempts at low tracheostomy in the event of total airway obstruction occurring during induction of anesthesia would be time-consuming and dangerous. The authors chose to cannulate the femoral vessels under local anesthesia and to keep the CPB circuit ready to initiate CPB in the event of airway obstruction. Successful use of femoral CPB has been described in patients with a mediastinal mass6 and tracheal tumors obstructing the carina and trachea.7,8 In the patient with a mediastinal mass,6 administration of general anesthesia had produced severe cyanosis on 2 earlier occasions necessitating cancellation of the procedure. Some authors have used femoral CPB as a standby in patients with tracheal masses but have preferred to keep the femoral vessels exposed under local anesthesia without cannulation.9,10 In both of these reports, no difficulty was encountered during induction of anesthesia; however, in one of them,10 cannulation was performed after opening the chest because moderate difficulty was encountered with adequate inflation of the lungs and CPB was instituted for resection of the tumor. In a more recent report, Riley et al11 used CPB as a standby (without femoral vessel cannulation), but they used helium-oxygen during induction of anesthesia. Although CPB was not required, these investigators encountered extreme difficulty in maintaining airway patency with spontaneous ventilation and severe decreases in oxygen saturation. In a few reports of aortic arch aneurysms causing airway obstruction, cannulation of femoral vessels under local anesthesia was proposed before induction of general anesthesia.12,13 It could not be
TEMPE ET AL
performed successfully, however, because the patients were irritable and uncooperative. In another case of an aneurysm of the descending thoracic aorta, femorofemoral CPB was successfully established before induction of general anesthesia.14 The authors preferred to cannulate the femoral vessels and to keep CPB ready because it was thought that there was a definite danger of the patient developing airway obstruction. The patient’s forced vital capacity was severely deranged, and the possibility of total superior vena cava obstruction was a consideration, the management of which would have required CPB. Because of the chronic nature of the superior vena cava obstruction, the collateral circulation was likely to be well developed in this patient so that drainage through the inferior vena cava cannula was expected to be adequate. It is known that airway problems can occur during surgical resection, and cannulation of the femoral vessels in the lateral position would be difficult and time-consuming. Prior cannulation allows for handling the emergency situation in a safe and unhurried fashion, and CPB is now considered a safe and acceptable everyday clinical tool. The incidence of airway complications with general anesthesia in patients with mediastinal masses has been reported to be 7% to 18%.15 Some of the criteria that are considered to identify patients at risk of airway complications are the presence of preoperative respiratory symptoms, evidence of tracheobronchial compression by CT scan, mediastinal thoracic ratio (size of mediastinal mass compared with the thoracic diameter) of ⬎50%, and plateauing of expiratory flow rate on pulmonary function tests.15 Most of these criteria were present in this patient, making him a high-risk candidate for airway obstruction. The institution of CPB was necessary in this patient for hemodynamic, not respiratory reasons; this was due to excessive insertion of the venous cannula by the surgeon, which was passed beyond the inferior vena cava–right atrium junction. The venous cannula is normally placed in the inferior vena cava just below the inferior vena cava–right atrium junction. Be-
Fig 2. Superior vena cavogram shows dilated and tortuous collateral veins with total obstruction of the superior vena cava; tracheal deviation and compression are also noted.
MEDIASTINAL MASS RESECTION
235
Fig 3. (A and B) Chest CT scans show tracheal compression above the carina. (C and D) Chest CT scans show tracheal compression at the level of the carina and after bifurcation of the trachea.
Fig 4. Postoperative chest radiograph shows expansion of the right lung and restoration of the tracheal lumen.
cause of the scoliosis and short stature of the patient, the length of insertion was misjudged by the surgeon. The cannula was withdrawn a few centimeters, and CPB was discontinued with normal hemodynamics. If overinsertion of the venous cannula had not happened, CPB probably would not have been necessary in this patient. Exposure of the femoral vessels without cannulation may have avoided the need to go on CPB as well as the need to administer heparin to the patient. In the event of cardiopulmonary decompensation (which could have occurred anytime during the entire surgical procedure), however, the duration for which the oxygenation could have been delayed is expected to be 3 to 5 minutes. This may be longer if the cannulation was required after positioning the patient during surgical resection. Such a delay is not desirable because the neurologic outcome may be adversely affected. It has been suggested that a carefully planned anesthetic along with the availability of a rigid bronchoscope may be enough to deal with patients with anterior mediastinal masses.16 Ferrari and Bedford16 used an inhalation technique for induction of anesthesia in pediatric cancer patients. They encountered several episodes of cardiorespiratory compromise in pa-
236
TEMPE ET AL
tients; in 2 of the patients, airway obstruction developed during maintenance of anesthesia with change of posture. Such a technique was possible perhaps because of a short surgical procedure (lymph node biopsy) that could be completed in a position that was not ideal for the surgeon. Such a situation is unacceptable in patients undergoing thoracotomy for a major tumor resection. An alternative method of securing the airway is the use of a rigid bronchoscope as a stylet for a reinforced endotracheal tube.17 This method was not considered in the present case because of the obstruction of the airway at the lower tracheal and carinal level. The possibility of using a left-sided doublelumen tube placed over a fiberoptic bronchoscope was considered. The patient also had bronchial compression, however, so that compression of the right bronchus leading to ventilationperfusion mismatch could have occurred. It has been reported that single-lung ventilation in such a situation results in marked hypoxia because of right-to-left shunting in the underventilated lung.18 The present case highlights that airway problems may not
arise even though they are predicted preoperatively. The converse is also true. The anesthesiologist cannot be complacent and must be fully prepared to deal with a respiratory and hemodynamic catastrophe. Ignoring these precautions can place the patient in a life-threatening situation.19 The authors believe that it is not desirable to struggle with the maintenance of the patient’s airway during induction of anesthesia and to allow life-threatening hypoxia to occur before a decision is made to cannulate the femoral vessels and initiate CPB. The time spent in the initiation of CPB (usually in a hurry) in a hemodynamically compromised patient may be dangerous. It may be a consideration for short procedures, such as a biopsy, but in a patient undergoing a thoracotomy for tumor resection, a catastrophic situation may arise at any point during surgery. What if CPB is not required at all? The complications of cannulating the femoral vessels can be considered minor in a unit where cardiac surgery is routinely performed. The authors believe that cannulation of the femoral vessels and keeping the CPB circuit ready to initiate CPB in such patients is justified.
REFERENCES 1. Northrip DR, Bohman BK, Tsueda K: Total airway occlusion and superior vena cava syndrome in a child with an anterior mediastinal tumor. Anesth Analg 65:1079-1082, 1986 2. Neuman GG, Weingarten AE, Abramowitz RM, et al: The anesthetic management of the patient with an anterior mediastinal mass. Anesthesiology 60:144-147, 1984 3. Bergman NA: Reduction in resting and expiratory position of the respiratory system with induction of anesthesia and neuromuscular paralysis. Anesthesiology 57:14-17, 1982 4. Fletcher SW, Flacke W, Alper MH: The actions of general anesthetic agents on tracheal smooth muscle. Anesthesiology 29:517522, 1968 5. Mackie AM, Watson CB: Anaesthesia and mediastinal masses: A case report and review of the literature. Anaesthesia 39:899-903, 1984 6. Hall KD, Friedman M: Extracorporeal oxygenation for induction of anesthesia in a patient with an intrathoracic tumor. Anesthesiology 42:493-495, 1975 7. Woods FM, Neptune WB, Palatchi A: Resection of the carina and mainstem bronchi with the use of extracorporeal circulation. N Engl J Med 264:492-494, 1961 8. Jensen V, Milne B, Salerno T: Femoral-femoral cardiopulmonary bypass prior to induction of anaesthesia in the management of upper airway obstruction. Can Anaesth Soc J 30:270-272, 1983 9. Dodge TL, Mahaffey JE, Thomas JD: The anesthetic management of a patient with an obstructing intratracheal mass: A case report. Anesth Analg 56:295-298, 1977 10. Adkins PC, Izawa EM: Resection of tracheal cylindroma using cardiopulmonary bypass. Arch Surg 88:405-409, 1964
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