Exercise tolerance test in lung cancer patients: The relationship between exercise capacity and postthoracotomy hospital mortality

To evaluate the significance of the blood lactate threshold as a predictor of postthoracotomy hospital mortality resulting from pulmonary complications, a 3-minute incremental exercise test was administered to 33 lung cancer patients who underwent thoracotomy between October, 1981, and May, 1984. The oxygen consumption/body surface area at an arterial lactate level of 20 mg/dl (V̇O₂/BSA at La-20) was adopted as the blood lactate threshold. Age and pulmonary function parameters such as forced expiratory volume in one second (FEV₁)/body surface area (BSA), FEV₁/forced vital capacity, diffusing capacity for the carbon monoxide/lung volume, and maximum ventilatory volume/BSA revealed significant differences between patients with postthoracotomy pulmonary complications and those without such complications. However, there was no difference in pulmonary function test results between the surviving and decreased patients. In contrast, although V̇O₂/BSA at La-20 did not differ between the patients with and without pulmonary complications, it differed significantly between the surviving and deceased patients. We concluded that postthoracotomy pulmonary complications depended on the severity of preoperatively associated pulmonary function disorders and that the blood lactate threshold expressed by V̇O₂/BSA at La-20 was an important indicator of the risk of hospital mortality.