Surgical problems in space: an overview.

Terrestrial experience indicates that surgical emergencies may cause significant morbidity in space, and may present unique problems. Microgravity physiologic changes that may increase susceptibility to, and complications from, injury include fluid redistribution and diuresis, bone demineralization, and immune system alterations. Conventional diagnostic tests may be unavailable or unreliable--e.g. the radiologic finding of "air under the diaphragm", which conventionally indicates perforation of an air-containing hollow viscus, such as the stomach, with a gravity-dependent rising of gas in the abdominal cavity to collect under the diaphragm. Microgravity surgical experience is limited, but studies conducted in the U.S.S.R. and on KC-135 aircraft indicate that, although surgical procedures are possible, weight and volume constraints, lack of gravity, altered fluid mechanics, and risk of environmental contamination mandate considerable modifications of conventional equipment and technique.