'Live' Dynamic Testing of the F 2400-6 and the Type 19325 Oxygen Pressure Regulators.

The performance of two oxygen pressure regulators used in hypobaric experimentation was evaluated with live dynamic testing technique. Human subjects imposed various levels of respiratory demands on the regulator systems by performing a variety of activities. Use of the Type 19325 regulator resulted in inspiratory and expiratory mask cavity pressures which were, in most instances, within acceptable limits. The F 2400-6 regulator tended to induce, to a greater extent, mask cavity pressures in excess of recommended limits. Consistently higher P less than 0.01 peak and total respiratory flow rates were obtained when the Type 19325 regulator was used compared to those obtained when the F 2400-6 regulator was used. Based on these results of mask cavity pressures and respiratory flow rates, it was apparent that the F 2400-6 oxygen regulator imposed a greater impedance to breathing than the Type 19325 oxygen regulator.