Effects of pneumatic antishock garment inflation in normovolemic subjects

Abstract

This study examines the effects of inflation of pneumatic antishock garments (PASG) in 10 normovolemic men (mean age 44 +/- 6 yr) undergoing diagnostic catheterization. Seven subjects had normal heart function and no evidence of coronary artery disease (CAD); three patients had CAD. High-fidelity multisensor catheters were employed to simultaneously record right and left heart pressures before PASG inflation and after inflation to 40, 70, and 100 mmHg. A thermal dilution catheter was used to obtain pulmonary capillary wedge pressure and cardiac output. Counterpressure increases greater than or equal to 40 mmHg were associated with significant changes in left and right heart pressures. Right and left ventricular end-diastolic pressures increased 100% (P less than 0.01); mean pulmonary arterial and aortic pressures increased 77 and 25%, respectively (P less than 0.01); systemic vascular resistance increased 22% (P less than 0.05) and pulmonary vascular resistance did not change in normal subjects at maximum PASG inflation. Heart rate, cardiac output, and aortic and pulmonary arterial pulse pressures did not change during inflation in either group. Right and left ventricular end-diastolic pressures and pulmonary capillary wedge pressure were greater (P less than 0.05) in the CAD group compared with the normal subjects during PASG inflation. The data suggest that the primary mechanism whereby PASG inflation induces changes in central hemodynamics in normovolemic subjects is through an acute increase in left ventricular afterload. PASG changes in afterload and pulmonary capillary wedge pressure imply that these devices should be used with caution in patients with compromised cardiac function.

Cardiovascular effects of anti-G suit inflation at 1 and 2 G

“…At 100 mmHg of inflation, ð _ QÞ was still unchanged but SV increased. Rubal et al (1989) made similar findings in supine subjects.…”

R Egional B Lood F Low After P Neumatic a Nti-Shock G Arment I Nflation

“…Our results are compatible with the literature regarding the regional hemodynamic effects of the PASG. [31][32][33][34][35][36][37][38][39][40][41] Subjects with exsanguinating hemorrhage below the distal aorta have shown improved outcomes with the PASG in both animal models 2-6 and human cases. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] The major side effects of the PASG are also caused by lack of distal perfusion.…”

Impact of Afterload on the Assessment of Severity of Aortic Stenosis

“…However, Pcom possibly increases the venous return from lower extremities, which could explain, to some extent, increased E velocity, and slightly increased LV end-diastolic dimension. However, a previous study clearly demonstrated that the primary mechanism whereby Pcom induced changes in hemodynamics is through an acute increase in LV afterload 13). In addition, a change in LV CO was minimal, highlighting the impression that hemodynamic effect by venous return for cardiac performance was, if any, negligible.…”