CASE CONFERENCE

CASE 6-5-1992 Anesthetic Considerations

for Thoracoscopic

Procedures

Jawad IJ. Hasnain, MD, Mark J. Krasna, MD, Steven J. Barker, PhD, MD, Darryl S. Weiman, MD, and Glenn J.R. Whitman, MD

Cm! 1 A 77-year-old white man was admitted with a left-sided pleura1 effusion. His past history included prolonged asbestos exposure and heavy smoking. He presented with dyspnea and wcight 10s~. Physical examination revealed a thin individual with a large barrel-shaped chest. Preoperative pulmonary function tests showed an FEVt of 1.2 L. A computerized tomography scan showed multiple pleura1 plaques and areas of thickening, especially along the mediastinal pleura. Because of the patient’s poor pulmonary status, flexible bronchoscopy and thoracoscopy were scheduled. The planned perioperative monitoring included indwelling arterial pressure, end-tidal CO1 (ETCO& and peripheral oxygen saturation (SpO$ Anesthesia was induced with thiamylal, fentanyl, and vecuronium. The trachea was intubated initially with a single-lumen endotracheal tube for flexible fiberoptic bronchoscopy. Following this, a double-lumen right-sided endobronchial tube was inserted. After confirmatory chest auscultation and flexible bronchoscopy, the patient was positioned in the right lateral decubitus position. Anesthetic maintenance included fentanyl, vecuronium, and isoflurane/air/oxygen. One-lung ventilation (OLV) was maintained during the thoracoscopic procedure. During diagnostic thoracoscopy, the stopcock of the cannula was left open to room air to maintain an open pneumothorax. Air insufflation pressures of 10 to 11 mmHg were used to attain better visibility. Hemodynamic monitoring and management included special attention to changes in blood pressure, heart rate and rhythm, end-tidal CO2 because of the potential for arrhythmias, fa11 in venous return and cardiac output, gas embolism, and direct compression of cardiac structures. The surgical procedure involved multiple pleura1 biopsies and

instillation of tetracycline into the pleura1 cavity. The patient did wel1 during and following surgery and was discharged 2 days after chest tube removal. Case 2

A 4%year-old white man was referred from the oncology service for a thoracoscopic pericardiectomy. His history included Hodgkin’s lymphoma, which was treated in the past with chemotherapy and radiation. The pericardial effusion was believed to be secondary to recurrent Hodgkin’s disease. The effusion was drained percutaneously to relievc the tamponade. After induction of genera1 anesthesia with fentanyl, midazolam, and vecuronium, a double-lumen endobronchial tube was placed and its position confirmed with a fiberoptic bronchoscope. Hemodynamic monitoring included indwelling arterial and central venous pressure catheters, and a pulse oximetcr. An 11 .O-mm laparoscopic cannula was inserted through the fifth left intercostal spacc in the posterior axillary line. The trocar was removed and the valve was held open to collapse the left lung. The oxygen saturation was wel1 maintained during OLV. On inspection through the videoscope, the pericardium was markedly thickened. Two additional incisions were made along the anterior axillary line to place additional cannulae. The pericardium was lifted with a biopsy grasper and an opening made with thc cautery probe. Once an adequate area of pericardium had been freed from the underlying epicardium, the pericardiectomy was performed with ENDO-GIA stapler applications. The staple lines were checked for hemostasis. The patient tolerated the procedure well. The trachea was extubated in the operating room and thc patient was discharged home on the second postoperative day. Case 3

Jawad Li. Hasnain, MD, Mark J. Krasna, MD, Depatiment of Anesthesiology, University of Matyland Hospital, Baltimore, MD; Steven J. Barker, PhD, MD, Depattment ofAnesthesiology, University of Califomia, Irvine, CA; Dar@ S. Weirnan, MD, Glenn JR. Whitman, MD, Division of Cardiothoracic Surgety, Medical College of Pennsylvania, Philadelphia, PA. Address reprint requests to Jawad Li. Hasnain, MD, Assistant Professor, Department of Anesthesiology, University of Matyland Hospital, Baltimore, MD 21201. Copyright 8 1992 hy W.B. Saunders Company 1053-0770/92/0605-0018$03.00/0 Key words: unesthesia. thoracoscopic procedures 624

A 2%year-old black woman with a history of spontaneous pneumothorax and interstitial pulmonary parenchymal changes was referred for lung biopsy. Her history and physical examination were negative for any significant cardiopulmonary disease. Thoracoscopy and lung biopsy were planned. Anesthetic management involved continuous arterial pressure, ETC02, and SpOZ monitoring, and a double-lumen endobronchial tube with deflation of the left (operative) lung. After induction with fentanyl, thiamylal, and vecuronium, anesthesia was maintained with alfentanil, vecuronium, and isofluranelairioxygen. After deflation of

Journalof Cardiothoracic and Vascular Anesthesia,

Vol

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the left hmg, the thoracoscope was inserted via the fifth intercostal space. The insufflation pressures were maintained at 10 to 11 mmHg during thoracoscopy. An area at the apex of the lung suspicious for microblebs was noted. A biopsy forceps and a 12-mm ENDO-GIA stapling device were inserted via two additional trocar incisions and a wedge biopsy was obtained. The staple line was examined under saline at 20 cmHp0 pressure and no leaks were noted. The intraoperative course remained stable and the recovery was unremarkable. DISCUSSION

Conventional thoracotomy is associated with a clinically significant incidence of postoperative morbidity and mortality, especially in high-risk patients who have significant cardiopulmonary disease. Immunocompromised and cancer patients undergoing chemotherapy are also at high risk. In patients with chronic lung disease, compared with normal healthy patients, there is a 20-fold increase in the incidence of postoperative pulmonary complications.’ Patients with a vita1 capacity or FEV1 less than 50% are at a very high risk. In a series of 1,500 patients with a wide variety of respiratory diseases treated over a 30-year period, the incidence of respiratory complications was 63% following intrathoracic procedures.2 In a group of 464 patients with chronic pulmonary disease, the highest incidence of pulmonary complications occurred in patients undergoing thoracotomy.3 In another study, patients with chronic obstructive pulmonary disease undergoing thoracic surgery were found to have twice the mortality compared with those with similar respiratory impairment but undergoing nonthoracic surgery.4 Postoperative pain due to a thoracotomy incision causes splinting of the chest wall, prevents coughing and deep breathing, leading to retention of secretions, and decreases functional residual capacity. This causes either low ventilationlperfusion regions or atelectasis and resultant hypoxemia. This hypoexemia can result in congestive heart failure (CHF). Other predisposing factors for CHF include recent myocardial infarction, preexisting pulmonary hypertension, old age, and an immunocompromised state. Videothoracoscopy is being used at many institutions for various diagnostic as wel1 as therapeutic procedures, including lung resection and decortication.5,6 Laparoscopic cholecystectomy has resulted in the widespread use of endoscopic techniques for a wide variety of procedures. Availability of improved imaging equipment and suitable surgical instruments has led to the advancement of this modality. The thoracoscopic approach has the potential for reduction of intraoperative and postoperative morbidity and mortality, compared with conventional thoracotomy. Thoracoscopy, however, entails certain risks, which can be minimized with appropriate perioperative management. Thoracoscopy essentially obviates the need for the chest incision and decreases the postoperative morbidity related to hypoxemia and its consequences as described above. This procedure is better tolerated by high-risk groups of patients. However, like laparoscopy, thoracoscopy is associated with certain risks. The pathophysiologic changes and

their management associated with laparoscopy were recently reviewed.’ Cardiovascular compromise related to compression by insufflated gas can result in decreased venous return and reduced cardiac output. Gas embolism can result from high insufflation pressures and open venous channels. The insufflation pressure should be kept to a maximum of 10 to 11 mmHg and meticulous surgical hemostasis is required. Continuous monitoring of end-tidal CO2 is an early indicator of gas embolism. Additionally, continuous monitoring of arterial pressure via an indwelling radial artery catheter permits detection of early changes related to cardiovascular compression an.d/or effects of gas embolism. ETCO? monitoring and appropriate regulation of ventilation prevent endogenous catecholamine stimulation and arrhythmias. Genera1 anesthesia allows better control of the cardiorespiratory status. Centra1 venous pressure or pulmonary artery pressure should be monitored if indicated. Double-lumen endobronchial intubation offers optimal protection of the airway from aspiration of gastric contents, as wel1 as isolation of the ventilated lung.* Appropriate depth of genera1 anesthesia and use of muscle relaxants minimize motion at the operative site and facilitate the surgical procedure. Genera1 anesthesia, combined with continuous epidural or intrathecal anesthesia, offers additional advantages of decreased need for intravenous anesthetics as wel1 as postoperative pain control. However, the thoracoscopic technique has decreased the need for postoperative analgesia, and there is less need to supplement genera1 anesthesia with regional blocks. Intercostal nerve blocks have been used for postoperative pain control. However, cautions include inadvertent intrathecal injection resulting in total spinal black and systemic toxic reactions related to increased absorption of local anesthetic due to the highly vascular intercostal space. The thoracoscopic technique does not usually require intercostal blocks because mild analgesics are sufficient in the postoperative period. Thoracoscopy may also minimize the exposure of health care personnel to communicable diseases such as acquired immunodeficiency syndrome and hepatitis. Discussion of perioperative considerations and rapport among team members is extremely helpful, especially in high-risk patients. Compared with conventional thoracotomy, videothoracoscopy has the potential for reduction of intraoperative and postoperative morbidity and mortality. Careful monitoring and management of cardiorespiratory hemodynamics can prevent complications such as pneumothorax and gas embolism. Anesthetic Considerations for Thoracoscopic Procedures*

Thoracoscopy is not a new surgical technique, its use in the treatment of tuberculosis was reported by Jacobeus in 1921.g However, advances in both surgical and anesthetic management have led to the application of this technique in progressively sicker patients. The recent introduction of laser surgery via thoracoscopy has created a new treatment modality for several chronic lung diseases.lOall *Steven J. Barker, PhD, MD

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CASE 6.5- ---199r

Drs Hasnain and Krasna describe three cases of anesthesia for thoracoscopic procedures: two cases of lung or pleura1 biopsy and one pericardiectomy. One-lung ventilation was used in al1 cases to facilitate the surgical procedure. Although the authors do not comment on the required duration of OLV for these cases, the nature of the procedures implies that it would be relatively short. Our own experience with thoracoscopy involves a relatively long surgical procedure performed on patients whose preoperative pulmonary status is extremely poor.r2 To date, we have anesthetized more than 40 patients for thoracoscopic laser ablation of emphysematous bullae. In this procedure, a CO2 laser is used through the thoracoscope to shrink large bullae, thus allowing the remaining normal lung to further expand in the chest cavity. These patients were elderly (mean age = 63 years) smokers who had a high incidence of coexisting cardiovascular disease. They were al1 pulmonaty cripples with little or no exercise tolerante. Most of them used supplemental oxygen 24 hours a day. Among the first 22 patients, the mean preoperative FEV, was 0.58 L. In view of their poor preoperative status, they were not considered good candidates for open thoracotomy and resection of lung bullae. However, the laser ablation procedures required a long period of OLV, the average being 170 Of- 53 minutes. Six of the first 22 patients underwent 4 hours of OLV. It was not expected that these long periods of OLV would be tolerated wel1 in this group of ASA physical status 1V patients. Yet, their oxygenation and ventilation during and after OLV were much better than expected, as shown in Fig 1. Their mean PaOz after anesthetic induction and intubation, but before thoracoscopy, was 492 t 124 mmHg, which was far higher than these patients could achieve when spontaneously brcathing 100% oxygen. Apparently the institution of positive-pressure controlled ventilation expands their normal lung regions better than spontaneous breathing. The lowest PaO during OLV was 43 mmHg, which obviously required intervention by the anesthesiologist.

TLV

Bafora

TLV

Afier

Fig 1. Mean values of PaOz (front) and PaCO* (raar) dwing three phases of laser thoracoscopy: (1) after intubation, before deflation of operative lung (TLV Before). (2) during one-lung ventilation (OLV Dwing), and (3) after reinflation of operative lung (TLV After). Standard deviations shown as error bars.

Al1 episodes of hypoxemia ( PaO less than hO mmHg «ISpOz less than 90%) were treatcd by using the alternating CPAP/PEEP search protocol described by Benumof.‘? We first added 5 cmHzO of continuous positive airway pressure (CPAP) to the nondependent, nonvcntilated lung. If this failed to correct hypoxemia, 5 cmHZO of positive endexpiratory pressure (PEEP) was given to the dependent lung. This process was continued incrementally until hypoxemia resolved. In this series, it has never required more than 5 cmHzO of CPAP and PEEP. Hemodynamic variables were also remarkably sta& during these long thoracoscopy procedures. Mean cardiac index (CI) and mean arterial pressure (MAP) showed no statistically significant changes either during or after OLV. There were two exceptions to this behavior, who both became hypotensive immediately after the initiation of OLV. It was found by experience that these patients, who presumably had a limited cardiac reserve, could be made more tolerant of OLV by carefully increasing their lcft ventricular preload. This was guided by a pulmonary artery catheter, which became a standard part of the anesthetic protocol for this patient group. Some patients also required mild inotropic support during the OLV phase of the procedure. The laser ablation procedure produces one complication not often seen in thoracoscopic biopsy or pleurodesis operations, such as those described by Hasnain and Krasna. In every case, a large bronchopleural air leak was encountered at the end of the OLV period. In the early cases, this leak sometimes amounted to 80% of inspired tidal volume. It was found by experience that leaks of less than 50% of tidal volume would usually resolve spontaneously during the early postoperative period. Larger leaks required further surgical intervention, usually through the thoracoscope. The presence of these bronchopleural leaks led to a change from volume-controlled to pressure-controlled ventilation early in the case scrics. The volume-controlled ventilator cannot adequately ventilate or oxygenate these patients during the post-OLV period, whereas the pressurecontrolled ventilator increases flow rate in response to the air leak and thus maintains the preset peak inspiratory pressure. The Seimens 900-C Servo ventilator (Siemens, Elmford, NY) was used for al1 laser thoracoscopies for this reason. This ventilator is also equipped with anesthetic vaporizers. Postoperatively, it was found that the emphysematous patients were not good candidates for early weaning and extubation. In fact, the mean duration of postoperative mechanica1 ventilation was 9 t 14 days. This being the case, high-dose narcotic or “cardiac” anesthesia is used for the laser ablations, which has resulted in a more stable intraoperative course. For thoracoscopies on healthier patients (eg, pleurodesis), a combination intravenous/inhalation anesthetic is used and we have often discharged these patients home on the day of surgery. A DLT is required for al1 thoracoscopies, but 1 see no reason to use a right endobronchial tube. As noted by Benumof,13 right-sided tubes are much harder to place properly and are far more likely to move to an improper location intraoperatively. This is the result of the high bifurcation of the right upper lobe bronchus. which is often

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occluded by an improperly located endobronchial tube. Proper location of the left-sided DLT is verified by fiberoptic bronchoscopy at the time of insertion, after turning to the decubitus position, and at the occurrence of any unexplained fa11in PaO*. The DLT is removed at the end of the procedure and replaced with a conventional singlelumen tube. Thoracoscopy is a diagnostic and therapeutic procedure that is being “rediscovered” as a useful modality for a number of diseases. As anesthesiologists, we wil1 encounter an increasing number of these procedures in both relatively healthy patients (pleurodesis) and extremely ill patients (laser ablation of bullae). The anesthetic management wil1 vary a great deal with the patient’s status. Some patients can be treated in the surgical day-care setting, whereas others wil1 require pulmonary artery catheterization, highdose narcotic anesthesia, and prolonged pressure-controlled mechanica1 ventilation. Videothoracoscopy:

The Surgeon’s

Viewt

“Minima1 access surgery” seems to be the marketing code words for the early 1990s. In the cases reported by Hasnain and Krasna, videothoracoscopy is advocated as an approach to the thoracic cavity, which “. . . has the potential for reduction of intraoperative and postoperative morbidity and mortality.” It is wel1 to keep in mind that the first description of thoracoscopy dates back to the early 19OOs, but the procedure did not become widespread until the 1970s. Since that time, numerous articles have appeared in the world’s literature detailing experiences of up to 250 cases by individual surgeons. Video-assisted thoracoscopy is now such a hot item that no less than five papers presented at the Society of Thoracic Surgeons in February 1992 dealt with this procedure. Hasnain and Krasna make three sweeping generalizations based on their experience. These are (1) Thoracoscopy has the potential to reduce intraoperative and postoperative morbidity and mortality compared to standard tDarry1 S. Weiman, MD, Glenn J.R. Whitman, MD

thoracotomy; (2) Thoracoscopy decreases the need for intravenous anesthetics and postoperative pain control; and (3) Thoracoscopy “. . obviates the need for the chest incision . . .“. From a literature review, along with experience in both thoracoscopy and thoracotomy, it is difficult to figure from where they draw their conclusions. NO prospective randomized trials have been done comparing the morbidity and mortality of these two procedures. Also, no assessment of the differente in postoperative pain, pulmonary function, or exercise tolerante has been done to our knowledge. In fact, the factors that predispose a patient to risk of postoperative complications from a thoracotomy are stil1 being sought and remain an area of ongoing debate.14,15 The total incision size used for a video-assisted thoracoscopy (which actually may be two or three separate incisions) is probably not much different from the incision of a standard muscle-sparing thoracotomy. For example, if a lung resection is being done, the stapling device stil1 needs to be inserted and this may require an incision of 8 cm or longer (if a TA-55 stapling device is used). The main differente appears to be that the ribs are not spread in the thoracoscopy patients, which, theoretically at least, would cut down on the postoperative pain of these patients. However, it also cuts down on the surgeon’s ability to get control if surgical bleeding occurs. It appears that a resurgence of this old surgical procedure is upon US. Pleura1 biopsy, lung biopsy and resection, closure of bronchopleural fistulae, closure of an open thoracic duet, pericardial biopsy, pleurodesis, and sympathectomy are al1 being done via thoracoscopy. Before we can conclude that this procedure is as good or better than a standard thoracotomy, prospective randomized studies wil1 need to be done with thorough and standard preoperative and postoperative assessments. Only through these studies can we begin to draw the types of conclusions that Hasnain and Krasna draw from their three patients. It is time for these studies to be done so that the marketing tool of thoracoscopy can either be justified or laid to rest.

REFERENCES

Stein M, Koota GM, Simon M, et al: Pulmonary evaluation of surgical patients. JAMA 181:765-770,1962 2. Anderson WH, Dossett BE, Hamilton GE: Prevention of 1.

postoperative pulmonary complications. JAMA 186:763-766, 1963 3. Tarhan S, Moffitt EA, Sessler AD, et al: Risk of anesthesia and surgery in patients with chronic bronchitis and chronic obstructive pulmonary disease. Surgery 74:720-726,1973 4. Harmon E, Lillington G: Pulmonary risk factors in surgery. Med Clin North Am 63:1289-1298,1979 5. Krasna MJ, Flowers JL: Diagnostic thoracoscopy in a patient with a pleura1 mass. Surg Lap Endo 1:94-97, 1991 6. Nazem A, Krasna MJ: Thoracoscopic lung resection: Use of a new endoscopic linear stapler. Surg Lap Endo 1:248-250,199l 7. Hasnain JU, Matjasko MJ: Practica1 anesthesia for laparoscopic procedures. In Zucker C (ed): Laparoscopic Procedures for the Surgeon. Quality Medical Publishing, Inc., St. Louis, 1991, pp 77-86 8. Benumof JL: Separation of the two lungs (double-lumen tube intubation). In Benumof JL (ed): Anesthesia for Thoracic Surgery. W.B. Saunders Co., Philadelphia, 1983, pp 223-259

9. Jacobeus HC: The practica1 surgery of the chest. Surg Gynecol

importante of thoracoscopy Obstet 32:493,1921

10. Wakabayashi A: Thoracoscopic ablation treatment of recurrent or persistent spontaneous Ann Thorac Surg 48:651-653,1989

in

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ll. Torre M, Belloni P: Nd:YAG Laser pleurodesis through thoracoscopy: New curative therapy in spontaneous penumothorax. Ann Thorac Surg 47:887-889,1989 12. Barker SJ, Clarke C, Hyatt J, Le N, Bhakta C: Thoracoscopic laser ablation of bullous emphysema: An anesthetic case study. Anesth Analg 72:Sll, 1991 13. Benumof JL: Anesthesia for Thoracic PA, Saunders, 1987, pp 284-285

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14. Olsen GN, Weiman DS, Bolton JWR, et al: Submaximal invasive exercise testing and quantitative lung scanning in the evaluation for tolerante of lung resection. Chest 95:267-273,1989 15. Olsen GN, Bolton JWR, Weiman DS, Hornung climbing as an exercise test to predict the postoperative tions of lung resection. Chest 99:587-590, 1991

CA: Stair complica-