PRODUCTION OF GAS IN HUMAN TISSUES AT LOW PRESSURES

Abstract : The development of a gas phase in human tissues was studied by exposing the left hand of each of 6 volunteer subjects to a total pressure of 49 mm. Hg or less. A gas pocket which developed in the hands of 4 of the subjects was clearly discernible by visual inspection and an appropriate roentgenographic technic. The gas pocket developed at chamber pressures less than 26 mm. Hg (23. 2 km.) on initial exposure and disappeared at a chamber pressure greater than 226 MM. Hg (9.2 km.). The swelling was never painful, always disappeared promptly on repressurization of the chamber, and has never caused any apparent temporary or permanent injury to the hand. Subsequent exposure of the hand to a low total pressure caused swelling at 70 mm. Hg or more. Carbon dioxide and water vapor are believed to be the main gases involved in the phenomenon. A satisfactory plethysmograph was developed and used in this research project in studying the change in volume of the human hand at extreme chamber pressures.