The effects of intermittent positive pressure breathing (IPPB/I) with compressed air in patients with severe chronic nonspecific obstructive pulmonary disease.

Abstract

The advent of mechanical respirators supplied a useful tool for assisting inadequate respiration (1-4). Segal and Dulfano suggested a practical abbreviated terminology for the various forms of pressure breathing therapy (5). Intermittent positive pressure breathing (IPPB II), producing a gradual increase of positive pressure during inspiration with a rapid fall of expiratory pressure to ambient levels, is considered most effective in producing hyperventilation (6-8). The application of a negative expiratory phase, although considered beneficial in patients with respiratory muscular paralysis (9, 10), has not found favor in the management of patients with b:onchospa~m and chronic diffuse pulmonary dIsease; mamly because the negative expiratory phase mcreases the hazards of bronchiolar collapse and consequent increase in air trapping (11, 12). . The effects of IPPB II in chronic pulmonary dIseases have been studied extensively and found useful by most investigators (13-23). Many of the reports are based on the clinical response without critical attempts to separate the bronchodilator and the oxygen effects from the effect of t~e IPPB/I alone. Moreover, the groups studIed were not clinically homogeneous and the findings not necessarily applicable to all the pulmonary patients. Cullen (16) thought that patients with severe bronchopulmonary obstruction and marked pulmonary failure might not respond as well to IPPB II, but Fraimow disputed this (24). Clinically, the writers have frequently noted that the effects of IPPB II are unsatisfactory in seriously ill patients with chronic diffuse obstructive emphysema. The patient would struggle, resist the machine, and tire easily,