Human Pulmonary Tolerance to Dynamic Over-Pressure.

Abstract : The literature was reviewed for animal and human data defining the limits of dynamic pulmonary overpressure. The physiology and basic theory of decompression are discussed. The current understanding of static pressure limits is discussed, and its basis in the literature identified. The maximum pressure that can be safely tolerated by the human pulmonary system in a dynamic over-pressure situation is unknown. This measurement, in general, has not been performed. Evidence is presented which suggests that the unsupported chest wall of the human population can safely support 80 mmHg static and dynamic over-pressure of the lungs. Safe static pressure in the human population wearing chest and abdomen support devices is at least 190 IumHg. It is probable that a pilot without pulmonary pathology, wearing well designed life support equipment, could support higher pressures without permanent injury. The problem lies in the lack of human data, partly due to the fact that humans have never expected to be exposed to decompression in excess of the data presented in this summary.