A New Statistic for the Evaluation of Respiratory Changes

Abstract

THE design of oxygen facemasks for high-altitude service flying and for emergency use during the recovery phase of space flight presents special problems related to the pressure differences at the intra : extra-somatic boundary. Recent designs, such as the S.P.4 and the M.Mk.2 service masks (Airmed, Ltd.), show the first steps towards solving the basic problem by the provision of adjustable valve pressures operated manually by the crew member. Changes of expiratory valve function, however, produce concomitant changes in the respiratory system as a whole, and these in turn have been shown to affect both the physiological balance and the psychological processes of the wearer¹.