The belief is widely held that a nasogastric tube adversely affects pulmonary ventilation, interferes with coughing, and predisposes to postoperative atelectasis. This impression is undoubtedly in part responsible for the present tendency to avoid nasogastric suction after major abdominal operations.
Bevan (1961) measured the forced expiratory volume in one second before and after withdrawal of a nasogastric tube in eight patients after operation and found an improvement of 4% to 24% in seven. On these grounds, he claimed that removal of the tube benefited both breathing and coughing and helped to prevent postoperative pulmonary complications. Although these views may be justified, they are based on insufficient evidence; therefore, it seemed desirable to extend Bevan's (1961) investigation and to interpret the eventual results more rigorously. Accordingly, the effect of a nasogastric tube on pulmonary ventilation was assessed in a larger number of patients, both before and after operation.
Sequential analysis enables