In the past, comprehensive pulmonary function studies have required the facilities of a specially-equipped laboratory, which are not available at most medical institutions. The evaluation of pulmonary function by computer-analysis as described in this paper is useful in determining any underlying physiologic problem such as small airway disease, maldistribution of airflow, lung volume abnormalities, large airway disease, etc. These evaluations can be done at any hospital to enable individualized planning of the pre-operative, intra-operative and postoperative management of patients with a high risk of pulmonary complications, such as morbidly obese patients.