A national survey of hospitals was conducted to evaluate the usage of lung expansion maneuvers in the prevention and management of postoperative atelectasis associated with abdominal and thoracic surgery. Equal numbers of hospitals were randomly selected from the nine American Hospital Association regions and from bed-size groups of 50 to 200 beds, 201 to 400 beds, and greater than 400 beds. Preoperative and postoperative prophylactic therapy was found to be similar in all groups except for a lower usage of intermittent positive-pressure breathing (IPPB) in the western third of the United States compared with the central third. In the treatment of postoperative atelectasis there are significant differences in the use of chest physical therapy, IPPB, and intermittent continuous positive airway pressure based on hospital size. Objective measurements of tidal volume or inspiratory capacity as a guide to therapeutic decisions are performed more frequently in the western regions. Surgical statistics relative to the number of abdominal and surgical procedures done and the incidence of postoperative atelectasis are also presented.