Medical (military) anti-shock trousers--a short review.

The first recorded use of pneumatic compression as a method to maintain blood pressure in hypovolaemic and hypotensive surgical patients was described by Crile in 1903.He used a pressurized rubber suit with good effect but acknowledged that the suits were prone to perish and leak.In 1909 he described its use in a patient with a cut throat and an unrecordable blood pressure where application of the suit maintained the blood pressure at 110 mm hg for 12 h.With the advent of safe methods of fluid replacement and later of blood transfusion pneumatic compression fell into disuse.It was the use of the G-suit by fighter pilots in the 1940s and 1950s and its value in preventing retinal haemorrhage at altitude that reawoke medical interest in pneumatic compression.Gardner and Dohn (1956) reported the use of a G-suit in combating postural hypotension during surgery performed with the patient in the sitting position.Soon after this the use of a G-suit at a pressure of 20 mm Hg was described in a patient with post-partum intra-abdominal bleeding which had required 57 units of blood and two unsuccessful laparotomies (Gardner et al., 1958).With the G-suit inflated for 24 h only one more unit of blood was required.Later it was shown that in anaesthetized dogs with arterial or venous lacerations the G-suit reduced bleeding dramatically when applied at pressures of 20-40 mm Hg and also elevated and maintained the blood pressure as long as the suit was inflated (Gardner & Storer, 1966; Wangensteen et al., 1968b; Gardner, 1969; Ludewig & Wangensteen, 1969a,b).The control of bleeding by suit pressures well below mean arterial pressure was explained by the fact that the major determinant of tension in a vessel wall is the radius of that vessel (Law of Laplace, vide infra).The maintenance and elevation of blood pressure was thought to be due to redistribution of blood to areas above the suit.Gardner (1969) concluded that the suit should not be applied at pressures greater than 30 mm Hg in man or used to control bleeding above the diaphragm although no reasons for these statements were given.