Intermittent Positive Pressure Breathing

Intermittent positive pressure breathing produced by artificial means, is brought about by actively raising the pressure in the lungs during inspiration, the expiratory phase being either passive or mediated through an active mechanism creating negative pressure in the lungs (table 1). Effective ventilation may thus be maintained in apneic subjects, and at the same time the Hering-Breuer reflex is stimulated by distention of pulmonary alveoli. According to Drinker.¹this is the best line of attack for the promptest possible restoration of normal respiratory movements. Intermittent positive pressure breathing may be given by mouth to mouth insufflation, a simple effective method seldom used. A more commonly employed method consists in applying intermittent positive pressure through an anesthesia breathing bag which may be equipped with a safety valve set at 14 mm. of mercury as advocated by Waters.²A manual bellows respirator³with a safety valve that prevents excessive