PREOPERATIVE AND POSTOPERATIVE CARE OF STANDARD AND HIGH RISK SURGICAL PATIENTS

MULTIDISCIPLINARY CARE OF LUNG CANCER PATIENTS, PART I1

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PREOPERATIVE AND POSTOPERATIVE CARE OF STANDARD AND HIGH RISK SURGICAL PATIENTS John J. Reilly, Jr, MD

Many new approaches to the treatment of lung cancer are discussed in this issue. There have been significant advances in the areas of chemotherapy, radiotherapy, and combined modality treatment. At this time, surgical resection remains the central component of curative therapy for lung cancer. The success of perioperative management lies in the attainment of several desirable outcomes. These include minimizing postoperative morbidity and mortality, expansion of the patient population who can safely receive potentially curative therapy, and the resultant reduction in hospital length of stay and costs. This discussion of perioperative management includes patient selection, preoperative interventions, and management in the immediate postoperative period. Intraoperative anesthetic management is not discussed in this review.

RISK STRATIFICATION A number of recent articles review the principles of patient evaluation prior to planned resectional ~urgery.~, 19, 23, 24, 33, 41 A variety of factors

From the Division of Pulmonary and Critical Care Medicine, Brigham and Women’s Hospital, and Harvard Medical School, Boston, Massachusetts

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have been examined to assess “operability” in patients, including pulmonary function, exercise capacity, gender, age, and extent of planned resection. Clinical experience and published reports document that patients with significant obstructive lung disease, as identified by preoperative testing, are at increased risk for perioperative morbidity and mortality. Identification of both “high” and “low” risk populations is an important component of preoperative evaluation. In addition to providing the appropriate perspective from which to discuss treatment options with patients, this process identifies a subset of patients who may benefit from more extensive preoperative evaluation and targeted interventions. The initial test used to assess pulmonary function in this patient population should be spirometry. This testing, performed by a series of forced exhalations into a calibrated instrument, has several characteristics that make it the appropriate screening test. It is relatively inexpensive and is highly reproducible. This is due to the relative effort independence of maximal expiratory flow rates. It is simple to administer and widely available. Important parameters measured with spirometry include the forced expiratory volume in 2 second (FEV,), the forced vital capacity (FVC), and the ratio of these two values. Values obtained during testing are compared with predicted values to generate a percent predicted result for each of these parameters. The major determinants of predicted pulmonary function are age, sex, and height. Ethnic background and weight are less important parameters. Values of FEV, and FVC between 80% and 120% predicted are considered normal. Patients with a reduction in FEV, (percent predicted) and the FEV,/FVC have an obstructive deficit, which is classified as mild, moderate, or severe. Patients with a low FEV,, low FVC, and preserved FEV,/FVC have a restrictive deficit, which is similarly classified as to severity. Given the role of cigarette smoking in the pathogenesis of obstructive lung disease and the established fact that airflow obstruction is an additional independent risk factor for the development of lung cancer, the most common abnormality detected on preoperative spirometry in this population is airflow obstruction. Unfortunately, preoperative spirometry does not accurately identify the minority of patients in this “high risk” population who will develop problems.42Attempts to further stratify these patients at risk have been made utilizing a variety of techniques, including right heart catheterization, balloon occlusion of pulmonary arteries, and exercise testing. PREDICTING POSTOPERATIVE PULMONARY FUNCTION

The medical literature, including a recent study from our institution, documents that the predicted postoperative FEV, (PPO FEV,) is related

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to postoperative morbidity and m0rta1ity.l~For patients ,with peripheral abnormalities on the chest roentgenogram and normal to mildly obsh-ucted spirometry, a simple calculation (a loss of 5.26% per resected segment) accurately predicts postoperative function.20This patient population can be considered to be at relatively low risk for complications. Simple calculation is not an accurate predictor of postoperative function in those individuals not meeting the criteria mentioned previously. Over the past 50 years, a number of approaches have been used to attempt to provide an accurate measure of postoperative function. In patients with central masses, documented or suspected endobronchial obstruction, pleural disease, or moderate to severe obstructive lung disease, further testing is indicated to accurately estimate postoperative function. Among the tests used for this purpose have been bronchospirometry, lateral position testing, and lobar occlusion. In bronchospirometry, an assessment of each lung’s contribution to overall pulmonary function is made by intubating the mainstem bronchus and performing pulmonary function tests of the individual lung. These results are then used to predict postoperative function. Lateral position testing involves performing pulmonary function tests with the patient in both right and left lateral positions, taking advantage of the gravitational dependence of lung function. As the name suggests, lobar occlusion involves placing a balloon catheter in the bronchus of the lobe being considered for resection. The catheter is inflated, occluding the lobe of interest, and pulmonary function is measured to approximate postoperative function. In recent years, these invasive approaches to assessment have been replaced by radionuclide lung scanning. This test involves examination of both ventilation and perfusion of the lung utilizing radioactive tracers. Perfusion is assessed using labeled macroaggregated albumin, which lodges in the pulmonary capillary bed. A gamma camera is used to image the distribution of emitted radiation and the intensity of the radiation is quantitated, providing information concerning the regional distribution of perfusion. These data can then be used to calculate postoperative function by multiplying the preoperative measured function by 100% minus the percent total perfusion to the area of resection. It has been demonstrated that this accurately predicts postoperative function. The studies documenting this fact are listed in Table 1. Traditional teaching has been that patients with a PPO FEV, of less than 800 cc are at high risk and are often considered unresectable. This practice is based upon data obtained in patients undergoing thoracotomy (often for tuberculosis) in the 1940s and 1950s. Significant advances have occurred in surgical technique, anesthetic management, and the medical management of lung disease since that time. It is logical to expect that these advances would translate into improved results in such

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Table 1. USE OF RADIONUCLIDE SCANNING TO PREDICT POSTOPERATIVE PULMONARY FUNCTION

No. Patients

Conclusions

Kristerssonzl

19

DeMeester’O

20

0lsen3O Ah’ Corris8 Kristerssonzo Tonnesen40 SchoonoverJ7

13 27 28 27 25 24

Scanning and PFTs accurate predictor of postoperative VC (r = .73) Scanning and PFTs as good as bronchospirornetry (r= .95), better than lateral position test (r= .86) Good prediction: r = .70 for VC, r = .72 for FEV, Good correlation Good correlation with spirometty, VE,, Vo, Good correlation (VC r = .87; FEV,, r = .90) Good correlation (r =0.89) All patients with severe COPD; scanning superior to lateral position test

Author

PFT = pulmonary function test; COPD = chronic obstructive pulmonary disease. From Reilly JJ Jr, Mentzer SJ, Sugarbaker DJ: Preoperative assessment of patients undergoing pulmonary resection. Chest 103 (suppl): 342S-345S, 1993;with permission.

high-risk patients. This is in fact the case, as documented by the experience at several centers. These reports document that resectional surgery on patients with PPO FEV, of less than 800 cc is feasible, although these patients are clearly at higher risk for development of postoperative complications and death.19,27, 29, 32

STRATIFICATION OF RISK WITHIN THE “HIGH RISK” GROUP

Although a low PPO FEV, denotes a high-risk group, the majority of patients in this group can tolerate surgery with acceptable morbidity and without mortality. A minority, however, suffer severe complications and/or do not survive the hospitalization associated with resection. Understandably, a variety of efforts have been made to further stratify risk within this group. These efforts have included assessment of pulmonary hemodynamics (with or without pulmonary vascular occlusion), exercise testing, and the use of preoperative blood testing and demographic factors. The data concerning invasive hemodynamic assessment of postoperative risk are conflicting and summarized in Table 2. Overall, these data do not support the routine use of invasive hemodynamic measurements as a preoperative assessment tool. The data concerning exercise testing, also summarized in Table 2, suggest that some form of exercise testing helps to identify a subset of patients who are able to tolerate parenchymal resection despite a low PPO FEV,. Patients with an MVo, exceeding 15 mL/kg/min or who can climb three flights of stairs have acceptably

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Table 2. HEMODYNAMIC AND EXERCISE TESTING PRIOR TO THORACOTOMY Author Feel3 LarosZ2 BrundleP 0Isen3O

No. Patients

Conclusion

45

PVR better predictor of postoperative complications than PFTs, ABGs PA pressures not predictive of complications Developed algorithm of FEV,, DL, Po, to predict patients with pulmonary hypertension; no prognostic data PVR not predictive. Cardiac index, 0,, and Vo, more predictive of complications than lung scanning and PFTs VoJBSA at La-20 predictive of mortality, not complications; PFTs not predictive of mortality but predictive of complications MVo,>20 mL/kg/min: 0% mortality and morbidity. MVo,20: 1/10 had complications Retrospective review; stair climbing; increased complications in patients with inability to climb > 3 flights of stairs Clinical stage patients; high-risk patients; 13/34 with MVO, > 15 mL/kg/min 84 patients who passed Reichel ETT went to pneumonectomy with 5% mortality Increased complications in patients unable to perform supine cycle ergometry

142 637 52; 29 patients operated upon

MiyoshiZ8

33

Bechard3

50

22 54 MoriceZ9

37

Millerz6

217 (2340 total)

Gerson15

16 (177 total)

PFT = pulmonary function test; ABG = arterial blood gases; PA = pulmonary artety; BSA = body surface area; ElT = exercise tolerance test; PVR = pulmonary vascular resistance From Reilly JJ Jr, Mentzer SJ, Sugarbaker DJ: Preoperative assessment of patients undergoing pulmonary resection. Chest 103 (suppl): 342S-345S, 1993; with permission.

low morbidity and mortality after potentially curative thoracotomy. These data support the use of some form of exercise testing in the evaluation of patients otherwise considered at "high risk" by virtue of underlying obstructive lung disease or other comorbid conditions. Less formal exercise testing has been common practice for years, in the form of having patients ambulate and climb stairs. An assessment of exercise capability is a more formal means of identifying patients who have a better functional status than do others with similar levels of airflow obstruction. OTHER RISK FACTORS Among the demographic and clinical factors considered as potential indicators of risk are gender, age, and hypercarbia. Some have suggested

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that men are at increased risk after thoracotomy as compared with women.1sAge as a contraindication to thoracotomy has been extensively examined in the literat~re.~, 12,14* 16, l8 Taken as a group, these data suggest that age may play an additive role with other comorbid factors, but alone it is not a contraindication to surgery. Hypercarbia has often been cited as a contraindication to thoracotomy, but two recent publications demonstrate that it is possible to safely operate on patients with Pco2 exceeding 45 mm Hg.19,29

PREOPERATIVE MANAGEMENT

Despite the logic of such an approach, there are only limited data available concerning the utility of aggressive preoperative intervention in improving perioperative outcome. One study examined this question directly and found that smoking cessation, bronchodilators, and pulmonary toilet reduced the incidence of postoperative complication^.^^ In patients with reactive airways disease, whether asthma or chronic bronchitis, a short course of corticosteroids may prove helpful. All patients should be encouraged to cease smoking. This should include counseling and the use of pharmacologic assistance in the form of oral (gum) or transdermal nicotine where appropriate. The airway inflammation associated with cigarette smoking takes several weeks to resolve, so ideally patients should quit a month prior to surgery. The cardiovascular effects dissipate more quickly, within 24 to 48 hours. Clinical practice concerning the willingness to operate on patients unable to quit varies from surgeon to surgeon. Less clear is the utility of preoperative pulmonary rehabilitation-that is, a course of intensive education and supervised exercise undertaken to improve cardiovascular fitness, pulmonary hygeine, and medication compliance and utilization techniques. Such a multidisciplinary approach has been documented to improve well-being and daily function and to reduce hospitalizations. It has not been formally studied in the preoperative setting, but we believe that selected patients benefit from a short (3-4 week) course of intensive therapy prior to surgery. This time interval coincides with the recovery from cigarette smoke-induced airway inflammation in current smokers, a significant benefit in this population. All patients should be re-evaluated after preoperative preparation. It is not uncommon for the institution of bronchodilators and smoking cessation to result in significant improvement in measured pulmonary function. This should be documented, because it may affect the extent of parenchymal resection undertaken by the surgeon.

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POSTOPERATIVE ANALGESIA

There is universal agreement that deep breathing and early mobilization in the immediate postoperative period minimizes respiratory and other (such as deep venous thrombosis/pulmonary embolism) complications and contributes to rapid recovery. A variety of approaches have been used to provide adequate postoperative analgesia. A number of studies have examined different postoperative analgesic regimens, using pain relief, pulmonary function, sedation, nausea, and itching as study variables. Although one study35 suggests that the mode of action of epidural narcotics is via systemic absorption, most conclude that there is less sedation and superior analgesia with regional analgesia rather than with parenteral narcotic^.^, 11, ~ 5 ,M, 36 Studies of local intercostal analgesia compared with epidural analgesia show little difference between the two approaches.'l, 34 The studies do not show any significant measurable difference in pulmonary function in the immediate postoperative period. Another aspect of perioperative analgesia under active investigation is the timing of the initiation of analgesic therapy, based on the observation that analgesic treatment begun prior to surgical incision may result in superior pain control as compared with therapy begun later during the pera at ion.'^ At the present time, the data suggest that a postoperative regimen that uses one of the patient-controlled or local/regional analgesic techniques discussed previously is preferable to the past practice of physician-scheduled analgesic medication. Adequate analgesia is essential to facilitate early patient mobility and to allow patients to take deep breaths. POSTOPERATIVE PULMONARY TOILET

Adequate pulmonary toilet is essential for uncomplicated recovery after thoracotomy. Pneumonia, atelectasis, and respiratory failure represent a substantial number of the morbid events after thoracotomy and contribute to prolonged hospitalization. Published studies have clearly demonstrated that deep breathing after any type of surgery minimizes pulmonary complications. The important factor in postoperative care is to achieve this goal, not any specific approach used to attain the goal. Coaching by the care team, incentive spirometry, and IPPB have been demonstrated to have equivalent efficacy in reducing pulmonary complications (the benefit of incentive spirometry being the deep breath the patient takes to forcibly e ~ h a l e )Many .~ clinicians believe that bronchoscopy performed for removal of secretions benefits selected patients in the postoperative period. Although conservative measures such as bron-

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chodilators and chest physical therapy have been demonstrated to be as efficacious as bronchoscopy in a general ICU population in correcting atelectasis or retained secretions, no such study exists that examines patients after thoracotomy. It is logical to conclude that some patients with impaired pulmonary reserve who have undergone a significant pulmonary resection may benefit from "toilet bronchoscopy" in the postoperative period. This is particularly true for patients who have undergone pneumonectomy. EFFICACY OF COMBINED APPROACH

No randomized controlled studies exist to document the efficacy of careful preoperative evaluation, intensive preoperative intervention, and a multidisciplinary approach to postoperative management utilizing local/regional analgesia and early mobilization. Our institutional experience, however, documents acceptably low morbidity and mortality in patients treated in such a fashion.I9 The mortality in this group of patients, 1% in the low-risk group and 2% in the high-risk group, compares favorably to that in earlier reports for similar surgery. Concomitant with reduced morbidity and mortality is a reduced length of stay, with most patients being discharged 1 week or less after thoracotomy. SUMMARY Much of the clinical teaching concerning preoperative evaluation is based upon clinical observations made several decades ago in patients undergoing thoracotomy for both benign and malignant diseases. More recent experience suggests that many "high risk" patients will tolerate pulmonary parenchymal resection. All patients being considered for surgery should have a complete history and physical examination, chest roentgenogram, and screening spirometry. If this initial evaluation reveals normal or mildly obstructed spirometry and absence of comorbid conditions, then the patient is at low risk and postoperative function may be accurately estimated by simple calculation. For patients with moderate or severe obstruction on spirometry (FEV, less than 50% to 65% predicted), hilar disease, pleural disease, or prior surgery, quantitative radionuclide lung 'scanning is indicated to allow accurate calculation of postoperative function. For patients with a PPO FEV, less than 0.8-1.0 L, additional risk stratification should be done after any preoperative interventions. Typically, this includes a formal or informal assessment of exercise capacity. Patients with se-

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verely impaired exercise capabilities are at very high risk for postoperative morbidity and mortality, and nonsurgical therapy should be considered. All active smokers at the time of evaluation should quit 3 to 4 weeks prior to planned surgery. Patients with purulent sputum should be treated with appropriate antibiotics. All patients with obstruction demonstrated on spirometry should be started on inhaled beta agonists, with or without inhaled corticosteroids. Postoperative management should focus on early mobilization. This requires adequate analgesia without excessive sedation. This is most easily achieved with local or regional analgesia techniques. The use of this approach, as well as patient-controlled analgesia, allows early mobilization and results in a short length of hospital stay. It should be recognized that if patients have an uncomplicated recovery and leave the hospital quickly (less than 6 days), postoperative pain will be a significant issue at home. Patients should be discharged with an adequate analgesia plan and an adequate supply of analgesic medications.

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