The decision to proceed with any surgical procedure involves a careful consideration of the anticipated benefits of surgery and an assessment of the risks associated with the operation. An important component of estimating the benefit of surgery is knowledge of the natural history of the condition in question. It is a popular, though inaccurate, conception of the preoperative evaluation that the evaluating physician “clears” the patient for surgery. This implies a binary clinical scenario: Either the patient is at low risk and is “cleared” or the risk is excessive and the patient is “turned down” for surgery. The reality, of course, is more complex and often more gray than black and white. A more accurate view of preoperative evaluation fulfills two goals: first, to accurately define the morbidity and risks of surgery, both short and long term, and second, to identify specific factors or conditions that can be addressed preoperatively to modify the patient’s risk of morbidity. The formulation of an approach to accomplish these goals requires knowledge of both the specific characteristics of the patient population and the general effects of thoracic surgery on patients.

Many patients undergoing a noncardiac thoracic surgical procedure do so as a consequence of known or suspected lung or esophageal cancer. These diseases share the common risk factor of a significant and prolonged exposure to cigarette smoking and commonly include older individuals. The combination of age and prolonged cigarette smoking yields a population with a significant incidence of comorbid factors beyond the primary diagnosis. A major source of comorbidity in the population of patients with lung cancer is the presence of chronic obstructive pulmonary disease (COPD). The diagnosis of COPD is an independent risk factor for the development of lung cancer, after controlling cigarette smoke exposure.^1,2 The combination of these factors, plus the magnitude of the surgical procedures, presents a challenge to the clinicians evaluating such patients. The potential for perioperative morbidity and mortality is substantial, but at the same time, the lack of effective alternative therapy for the patient’s malignancy means that the consequence of not being a surgical candidate is almost certain death. This quandary led Gass and Olsen to ask, “What is an acceptable surgical mortality in a disease with 100% mortality?”³

The Charlson Comorbidity Index (CCI),⁴ which generates a score based on the presence of comorbid conditions, was originally designed as a measure of the risk of 1-year mortality attributable to comorbidity of hospitalized patients. This index has been demonstrated to stratify the risk of postoperative complications in thoracic surgery patients.^4,5 In nonsmall cell lung cancer patients, the CCI is a better predictor of survival than individual comorbid conditions and has been recommended for use in the selection of patients for NSCLC surgery.⁶ A recent study, compared the CCI to another comorbidity index, the Kaplan–Feinstein index (KFI), and demonstrated the CCI performed better at predicting perioperative mortality and death from noncancer causes after surgery.⁷

Surgical procedures and the anesthesia administered to permit such procedures have significant impact on respiratory physiology that contributes to the development of postoperative pulmonary complications. Because the incidence of pulmonary complications is directly related to the proximity of the planned procedure to the diaphragms, patients undergoing pulmonary, esophageal, or other thoracic surgical procedures fall into the category of patients at high risk for postoperative respiratory complications.⁸

Intraoperatively, the use of inhaled volatile agents can affect gas exchange by altering diaphragmatic and chest wall function. These changes occur without corresponding alterations in blood flow and give rise to areas of low ventilation/perfusion and cause the gradient for alveolar–arterial oxygen to widen.

In the postoperative period, a number of factors contribute to the development of complications. These include an alteration in breathing pattern to one of rapid shallow breaths with the absence of periodic deep breaths (sighs) and abnormal diaphragmatic function. These breathing derangements are caused by pain and diaphragmatic dysfunction secondary to splanchnic efferent neural impulses arising from the manipulation of abdominal contents. This has the effect of reducing the functional residual capacity (FRC), that is, the resting volume of the respiratory system. The FRC declines by an average of 35% after thoracotomy and lung resection and by approximately 30% after upper abdominal operations.⁹ If the FRC declines sufficiently to approach closing volume—the volume at which small airways closure begins to occur—patients may develop atelectasis and are predisposed to impairment in gas exchange and infectious complications.¹⁰ The closing volume is elevated in patients with underlying lung disease, narrowing the distinction between the FRC and the closing volume.

The alterations in lung volume that occur as a result of reduction in both the inspiratory capacity (the maximal inhalation volume attained starting from a given lung volume) and the expiratory reserve volume (the maximal exhalation volume from a given lung volume) contribute to a decline in the effectiveness of cough and cause increased difficulty in clearing pulmonary secretions.

The complications associated with thoracic procedures are reviewed in Chapter 8 and are discussed with greater specificity in the many surgical technique chapters of this book. In general, however, the most common complications after major thoracic procedures are respiratory and cardiovascular. Although the exact frequency varies from series to series, pneumonia, atelectasis, arrhythmias (particularly atrial fibrillation), and congestive heart failure are the most common. Myocardial infarction, prolonged air leak, empyema, and bronchopleural fistula, although less common, also occur with significant frequency.¹¹ It follows, therefore, that particular attention to pulmonary and cardiac reserve and risk factors should be a major component of the preoperative evaluation.

The clinicians evaluating a patient for a major thoracic surgical procedure have several goals for the evaluation process. The foremost objective is to provide an accurate assessment of the short- and long-term risks of morbidity and mortality for a given procedure in a given patient while identifying factors that can be addressed preoperatively to reduce the possibility of adverse events. Less obvious benefits of the comprehensive evaluation include identification of risk factors and other health issues that may facilitate institution of interventions regardless of the plans for surgery.

History

Although the field of thoracic surgery has been dramatically altered by the development of new technologies, both in imaging and in therapeutics, the history and physical examination remain the most important components of the preoperative evaluation. There is no substitute for a careful history and physical examination when it is performed by an experienced clinician. Table 4-1 highlights the important components of the patient history. Although age is a risk factor for perioperative morbidity and often a factor used by both patient and physician to assess the risk and potential benefit of surgery,^12–15 much of this added risk is a consequence of the accompanying comorbidities. Recent publications suggest age alone is not an independent factor predicting mortality. Chambers et al.¹⁶ showed that 30-day mortality rates, hospital length of stay, and global quality of life (QoL) were not influenced by age (age <70 years vs. age ≥70 years). Similar findings were found by Okami et al.,¹⁷ who reported that octogenarian patients with stage I lung cancer had reasonable long-term outcomes.

Although many of the elements of the history are self-explanatory, several bear further exposition.

Patients who are current smokers should be advised to quit. Importantly, there is a better chance of achieving smoking cessation in COPD patients after a lung cancer diagnosis (over 50%)¹⁸ compared with smokers without this diagnosis, and better survival has been reported for those who quit after a diagnosis of early-stage lung cancer versus those who continue to smoke.¹⁹ In addition, smokers compared with nonsmokers are at greater risk of postoperative complications including delayed wound healing, pulmonary and cardiovascular complications, and mortality as shown in randomized trials.²⁰ A meta-analysis found a relative risk reduction of 41% for prevention of postoperative complications with trials of 4 weeks smoking cessation having the largest treatment effect.²⁰ The ideal time for quitting is still controversial. A small number of observational studies have described a paradoxical increase in the risk of postoperative complications in patients who quit within 2 months of surgery,²¹ which may be related to a selection bias (sicker subjects at increased risk of complications were more likely to quit).²⁰ A large retrospective study of in-hospital outcomes for 7990 primary lung cancer resections found an increased mortality for current smokers with adjusted odd ratio (AOR) 3.5 and confidence intervals (CIs) 1.1 to 11 and for those who quit for less than a month prior to surgery (AOR: 4.6, CI: 1.2–18).²² However, there was no difference in mortality between current smokers and those who quit within a month. Therefore, it is recommended that patients be advised to quit smoking before surgery regardless of the time and, if possible, allow for a month of smoking abstinence to reduce the risk of postoperative complications to the level of a nonsmoker.²³

Pharmacotherapy improves the likelihood of successful abstinence. Combining the use of nicotine replacement therapy and counseling has a higher rate of success.²⁴ Currently available pharmacotherapies include nicotine replacement therapy, bupropion, and nicotine agonist, varenicline.²⁴

A critical component of the preoperative evaluation is the assessment of the patient’s functional status. It is well established that there is a broad range of symptoms and functional impairments in patients with similar pulmonary function test results.²⁵ As described below, functional capacity is a major determinant of operative candidacy and an important component of the decision algorithm for both the pulmonary and cardiac elements of the preoperative evaluation. A number of approaches have been taken to determine functional capacity. These include questionnaires, tests of locomotion (e.g., the 6-minute walk or stair climbing tests), and cardiopulmonary exercise testing (CPET) (discussed below).

Physical Examination

Although most patients being evaluated for thoracic surgery have a normal or near-normal physical examination, it is an important component of the evaluation. The examination of the patient should include an assessment of general overall appearance, including signs of wasting. Respiratory rate and the use of accessory muscles of respiration should be noted. Careful observation of the patient as he or she moves around the examining room, climbs onto the examination table, lies down, and sits up can provide important information about functional status. Examination of the head and neck should include assessment of adenopathy and focal neurologic deficits or signs, particularly Horner syndrome in patients with a Pancoast tumor. The pulmonary examination should include an assessment of diaphragmatic motion (by percussion) and note of any paradoxical respiratory pattern in the recumbent position. The presence of rales should raise the possibility of pneumonia, heart failure, or pulmonary fibrosis. The cardiac examination should include assessment of a third heart sound to suggest left ventricular failure, murmurs to suggest valvular lesions, and an accentuated pulmonic component of the second heart sound to suggest pulmonary hypertension. The heart rhythm and the absence or presence of any irregular heartbeats should be noted. The abdominal examination should note liver size, presence or absence of palpable masses or adenopathy, and any tenderness. The examination of the extremities should note any edema, cyanosis, or clubbing. The presence of clubbing should not be attributed to COPD and raises the possibility of intrathoracic malignancy or congenital heart disease. The patient’s gait should be observed both as an assessment of neurologic function and to confirm the patient’s ability to participate in postoperative mobilization.

Pulmonary rehabilitation improves exercise capacity in patients with moderate and severe COPD. This intervention can improve the exercise performance in patients with severely reduced exercise capacity (<10 mL/kg/min or nonsurgical candidates) to a potentially resectable level (mean improvement 2.8 mL/kg/min).²⁶ However, the recommended duration of these programs (6–8 weeks) restricts the implementation of this intervention in the great majority of cases. Although there is evidence that the length of hospital stay could be shortened by 3 days with this intervention,²⁷ there is scarce information of other beneficial effects. Therefore, the use of pulmonary rehabilitation before surgical treatment for lung cancer may have a role limited to those patients with much reduced exercise capacity and early-stage lung cancer.