The incidence of postoperative pulmonary morbidity was studied in 910 surgical patients who had received preoperative screening by routine history-physical exami- nation, chest x-ray, and spirometry. Retrospective data were correlated with results of the preoperative screening procedures to calculate accuracy and efficiency of each test and test-combination. Use of the data to predict total cost of therapy, and cost per patient benefited, is described for a protocol of perioperative respiratory therapy when it is administered to all patients with positive screening tests. The optimum screening procedure is identified by comparison. It was shown that when an op- timum screening procedure is used, with therapy administered only to patients with positive screening tests, about 80% of at-risk patients can be identified preoperatively and the cost of therapy can be reduced by up to 50%, or, in a selected population, by up to 75%. A screening procedure using all three of the tests studied, in combination, was shown to provide maximum economy of therapy with minimum loss of effi- ciency. The routine history-physical examination alone, for identification of at-risk patients, was shown to be inaccurate and inefficient. Spirometry was shown to be equally as useful as chest x-ray in improving the accuracy and efficiency of screening procedures.
