Application of the medical anti-shock trouser (MAST) increases cardiac output and tissue perfusion in simulated, mild hypovolaemia

1432-1238

Medical anti-shock trouser (MAST) ; Hypovolaemia ; Cardiac output ; Arterial pressure ; Lower body positive pressure

Springer Online Journal Archives 1860-2000

Medicine

Abstract We have studied the haemodynamic effects of the application of the medical anti-shock trouser (MAST) in 10 healthy subjects in the semi-upright position in order to simulate mild hypovolaemia. Left ventricular end diastolic dimension (EDD) was measured by M-mode echocardiography and cardiac output (CO) by the Doppler ultrasound technique. Forearm blood flow (FBF) was measured by plethysmography and blood pressure (BP) by the standard cuff technique. Systematic increases in MAST pressure of up to 80 mm Hg were applied. EDD increased to a maximum of 9.3% (p≤0.01) which was associated with a maximum increase in CO of 31.7% (p≤0.05). FBF increased by a maximum of 54.2% (p≤0.001) whilst BP increased by a maximum of 12% (p≤0.001). These results demonstrate that the application of the MAST is an effective means of transferring blood to the central circulation by compression of the capacitance vessels resulting in significant increases in cardiac output and tissue perfusion. At high pressures there was evidence of compression of resistance vessels, which may be useful in reducing blood loss. The ease and rapidity with which his suit can be applied suggests that it may be useful in the short term treatment of hypovolaemia.

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