Air-Flow Patterns and Pulmonary Ventilation During Manual Artificial Respiration on Apneic Normal Adults. II

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Abstract
The use of a carefully balanced spirometer and the clinical pneumotachograph together, in series, provides a method for simultaneously recording the tidal volume measurement and the air-flow pattern during manual artificial respiration. Subjects who are totally apneic are required for such studies in order that the air-flow pattern reflect only the respiratory movements produced by the manipulations of the operator. Totally apneic curarized-anesthetized normal adult males have been used for these detns. since their worth has been proven in previous studies on artificial respiration in this laboratory. Ten normal healthy adult male students were used as subjects upon whom the Schafer Prone Pressure method and several of the newer "push-pull" manual methods were applied. It was reaffirmed that the Arm-Lift Back-Pressure, Hip-Lift Back-Pressure and Hip-Roll Back-Pressure methods are uniformly at least twice as effective, as regards pulmonary ventilation, as the Schafer (push only) method. The Hip-Lift Back-Pressure method is the most effective, but the Arm-Lift Back-Pressure method is significantly easier to perform. A number of variations of these methods were evaluated. Back-pressure over the mid-back (just at the lower tips of the scapulae) gave significantly greater ventilation than scapular pressure. This back-pressure was significantly superior to the standard Schafer Prone Pressure over the floating ribs. The Hip-Roll Back-Pressure method was found to be twice as good in ventilating the lungs as Schafer backpressure, but somewhat less effective than the hip-lift backpressure method. In the arm-lift back-pressure method there was no difference in the accomplished ventilation by lifting near the elbows or at the axillae, although the former proved easier to do. Lifting the arms until the chest was raised from the floor significantly increased the tidal volume with the arm-lift back-pressure method. When the arm-lift back-pressure, hip-roll back-pressure and hip-lift back-pressure methods were repeated on a wheeled litter, it was found that the ventilation for all methods was slightly reduced, although still approx. double the Schafer method. Each of the manual "push-pull" methods has 4 phases: (1) active inspiration[long dash]lift or roll; (2) passive expiration[long dash]release; (3) active expiration[long dash]press; and (4) passive inspiration[long dash]release. Each of the passive phases is followed by an active phase in the same direction and the end-inspiratory and end- expiratory volumes are detd. by these active maneuvers. Measurement of the pneumotachograms showed that each of the active phases (arm-lift, hip-lift, hip-roll and back-pressure) required approx. 1.5 sec. for movement of 95% of the total ventilatory volume of that phase. Since practical considerations dictate that the release phase requires approx. the same time for completion, it can be shown that the ideal rate of performance of these methods is a 5- to 6-sec. cycle with 10-12 complete cycles/min.