Respiratory function following application of MAST trousers.

To determine whether counterpressure suits such as the medical anti-shock trousers (MAST) reduce functional ventilation, 25 consecutive patients who received MAST support were reviewed retrospectively. The indications for use of MAST were systolic pressure below 80 mm Hg or clinical signs and pressure below 100 mm Hg. In the five patients with head injuries severe acidosis developed, with a mean pH of 7.19. The other groups had only mild acidosis. Although counterpressure suits have been shown to affect mechanical pulmonary function, alveolar ventilation is not significantly impaired.