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Physicians routinely discuss pulmonary function and its impact on prognosis or operative risk. Although many studies have related various measures of pulmonary function to postoperative outcome, there has been no study designed to determine which of the spirometric measures of pulmonary function tests reflects the actual abstract idea of pure pulmonary function. A homogeneous population of 70 male patients was subjected to pulmonary function tests and a simple stair climb. Measures of pulmonary function (including FEV1, FEV1%, FVC, FVC%, and MVV%) were factor analyzed in a measurement model of pulmonary function to obtain reliability and validity estimates in predicting performance on a simple stair-climb test. The analysis revealed several interesting aspects concerning the relative importance of the various spirometric measures of pulmonary function tests. The validity estimates of the pulmonary function measures were as follows: FEV1% = 0.917; FEV1 = 0.886; MVV% = 0.769; FVC% = 0.715; FVC = 0.694. Analysis indicates that the FEV1% was the single best spirometric indicator of pulmonary function when predicting the physiologic outcome (followed closely by the FEV1). In addition, the various spirometric measures of pulmonary function were not equally valid nor interchangeable in such analysis. Although the number of stairs climbed correlates well with pulmonary function (r = 0.626), the coefficient of non-determination (i.e., 1-r2) suggests that about 61% of the performance on the stair climb may be explained by other parameters (i.e., cardiac function, determination, altitude, etc.).

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The results of routinely performed multigated blood pool studies (MUGA) were compared with the presence of postthoracotomy complications in 46 adult men in a retrospective chart review. Pulmonary function measurements were also examined in relation to the presence of complications experienced. There was only one death, but survivable complications were not predicted by the MUGA results. The addition of MUGA as a routine preoperative cardiac screening technique did not result in increased ability to predict postoperative cardiopulmonary complications.

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The evaluation of patients with lung cancer should include an assessment of physiologic risk. This assessment begins with simple pulmonary function studies such as spirometry and diffusing capacity. Abnormalities of these test results should stimulate further assessment with quantitative lung scanning and noninvasive exercise testing. Resection should not be recommended in patients with extremely high risk; however, because of the poor prognosis, patients must be integrally involved in the decision to not resect the lung cancer.

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A reduction in lung volume is used to diagnose physiologic restriction in the pulmonary function tests of patients with lung disease. Airflow obstruction is commonly associated with hyperinflation of static lung volume. Because restriction and obstruction exert opposite effects on lung volumes, we questioned whether the lack of hyperinflation of static lung volumes could indicate the presence of concomitant restriction in patients with airflow obstructive ventilatory defects. To assess this, we evaluated by pulmonary function tests and chest roentgenograms of 58 patients with airflow obstruction (group 1), 18 of whom then sustained various types of resection for lung cancer (group 2) as a type of superimposed restriction. We selected 80 percent of predicted as the lower limit of "normal" frequently used by clinical pulmonary function laboratories. Despite a statistically significant decrease in total lung capacity (p less than 0.05) for the postpneumonectomy patients, when the static lung volume measurements of the patients with resection were evaluated, no one lung volume showed a consistent reduction sufficient to detect the superimposed restriction in all these patients. Using 80 percent of predicted as "normal," 61 percent of our patients with airflow obstruction and superimposed restriction would have been missed. We conclude that it is clinically difficult, based on only static lung volume measurements alone, to detect restriction superimposed on the hyperinflation of airflow obstruction unless these lung volumes are reduced to below accepted "normal" limits.

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The results of a clinically performed preoperative stair climb was compared to the presence of postthoracotomy complications in the retrospective hospital record review of 54 adult men. The stair climb was a maximum of five flights (125 steps) performed at the patient's rate and terminated at his request. Pulmonary function measurements and facets of the stair climb physiology were also examined in reference to the presence, type, and severity of complications experienced. Most minor complications such as transient arrhythmias, atelectasis, and pneumonia were clearly not predicted by the stair climb performance. The ability to climb three flights preoperatively most clearly separated those patients having the longer postoperative intubation and hospital stay, greater frequency of complications, and cumulative complication score (p less than 0.005). This retrospective study did not have sufficient numbers of fatal cardiopulmonary complications to exclude the possibility that these may be predicted by the results of this simple test.

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Despite extensive preoperative staging, unresectability of a bronchogenic carcinoma may not be known until an exploratory thoracotomy is done. Failures in anatomic staging occur because of inability to detect local extent of hilar lesions and inability to detect small deposits of metastatic disease. At the University of South Carolina, nine of 75 patients who underwent thoracotomies were found to be unresectable. Using an extensive staging protocol, the "back out" thoracotomy rate can be reduced to a minimum whereas no patient is denied a chance for surgical cure.

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Lung resection in patients with cardiopulmonary dysfunction is associated with increased risk. We studied 52 elderly male patients with airflow obstruction and a lung mass. Studies were performed at rest with routine ventilatory tests and lung scan quantitation of right-left lung function. Cycle ergometry exercise was then performed at 2 submaximal work loads (25 and 40 watts). Data were obtained using systemic and pulmonary artery catheterization for blood pressures, thermal dilution cardiac output, and blood gases. Twenty-nine patients underwent lung resection and seven failed to tolerate the procedure (death within 60 days or prolonged ventilator dependence). Those parameters most clearly separating the group tolerating surgery (n = 22) from the intolerant group (n = 7) were obtained during exercise and included: cardiac index (tolerant 5.5 +/- 1.3 vs intolerant 3.9 +/- 0.3 L/min/m2, p less than .01), O2 delivery (p less than .01) and calculated VO2 ml/kg/min (tolerant 11.3 +/- 2.1 vs intolerant 7.8 +/- 1.5 ml/kg/min, p less than .001). Pulmonary vascular pressures and calculated resistance did not predict intolerance. Calculated VO2 at 40 watts did not separate those patients who had survivable complications from those who did not (p much greater than .05). Multivariate analysis suggests that exercise VO2 is an important predictor of tolerance of lung resection because it reflects the effects of cardiac function and O2 transport. In our patients with COPD, submaximal exercise testing predicted intolerance of lung resection better than calculation using quantitative lung scanning. Exercise testing may accomplish this goal by uncovering deficits in O2 transport.

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Exercise testing prior to lung resection has long and honored tradition. It began as a test of tolerance using simple techniques such as stair climbing. This was followed by aggressive and invasive protocols using right cardiac catheterization in the search for pulmonary hypertension. More recently, measurement of VO2 with exercise has been reported to predict both postoperative mortality and survivable morbidity. Exercise testing holds promise as a noninvasive test to predict the physiologic outcome from lung resection. Significant questions remain concerning the pathophysiologic mechanisms responsible for an abnormal result and who should be denied thoracotomy based on these results.

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Seventy male patients with a mean age of 56.8 years scheduled for pulmonary function testing were subjected to a stair climb in order to determine the relationship, if any, between the number of steps climbed and the results of pulmonary function testing. The number of steps completed was plotted against the different parameters which may be used as predictors of post-thoracotomy outcome. The stair climb acts as a stress test and, although there is a strong relationship to pulmonary function tests, it also is an indicator of many other parameters including cardiovascular status, cooperation, and determination. Based on results of this study, the stair climb can be used as a reliable screening test of pulmonary function. Also, preoperative patients who are unable to perform pulmonary function tests can be evaluated accurately for lung resection by use of the stair climb test.

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