Effect of body inversion on hemodynamics determined by two-dimensional echocardiography

The purpose of this study was to determine if head-down inversion of normal men from a supine position would increase blood return to the heart. Eight healthy, normovolemic men were placed into 10 degrees, 30 degrees, 60 degrees, and 90 degrees head-down tilt positions. BP and two-dimensional echocardiograms were recorded at the supine baseline and immediately after inversion. There was no significant change in left ventricular end-diastolic volume, stroke volume, cardiac output, or BP with inversion, except for a significant increase in diastolic pressure at the 60 degree position. The efficacy of placing hypotensive shock patients in the head-down tilt position is discussed.