Positive pressure respirations and pneumatic antishock garment application--hemodynamic response

Pneumatic antishock garment (PASG) application has been recommended for treatment of hypovolemic hypotension and intraperitoneal or retroperitoneal hemorrhage. Often these patients require positive pressure respiration (PPR). This study measured the hemodynamic response of low pressure PASG application, with and without PPR, in normovolemic man and the effects of PASG application on serum lactate. Ten patients after coronary artery bypass surgery were studied with PPR and PASG application (3 to 20 hours post-surgery), and PASG alone (24 to 30 hours post-surgery). PASG pressures of 0,5,10,20, and 0 mm Hg were applied for 10 minutes each after which LAP, PCWP, CVP, mean arterial pressure, heart rate, cardiac index, and serum lactate level were measured. PASG application produced significant elevations in right and left ventricular filling pressures. The left ventricular filling pressure response was significantly less with positive pressure respiration. The CVP and LAP increase did not result in a greater cardiac index. Serum lactate levels rose slightly during PASG application. Low-pressure PASG application results in an 'autotransfusion' effect which is greater without PPR.