Accession Number : ADA262335


Title :   The Effect of Various Straining Maneuvers on Cardiac Volumes at 1G and During +Gz Acceleration


Descriptive Note : Final rept. Jan 84-Aug 85


Corporate Author : HARRY G ARMSTRONG AEROSPACE MEDICAL RESEARCH LAB WRIGHT-PATTERSON AFB OH


Personal Author(s) : Goodyear, Chuck ; Jennings, Tom ; Tripp, Lloyd ; Howell, Lora ; Seaworth, John ; Ratino, David


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a262335.pdf


Report Date : 23 Jan 1989


Pagination or Media Count : 20


Abstract : The purpose of this study was to evaluate the effect of Valsalva (Val), isometric contraction (Iso) and the L-1 maneuvers (L-1) on cardiac volumes at IG and during 4G. Two-dimensional echocardiography was used to measure volumes. IG Phase: Eight seated male subjects performed the three maneuvers. The end-diastolic volume (EDV) decreased during Val and L-1 (p 0.05) . EDV decreased initially but then returned to baseline with Iso. 4G Phase: Seven male subjects experienced three 30 second 4G epochs while performing the three maneuvers. During 4G, 3 of 7 performing Val, 2 of 7 performing Iso, and none performing L-1, experienced peripheral light loss. EDV decreased and stabilized below baseline during the 4Gz epoch (p 0.05). Heart rate and cardiac output increased for all maneuvers. Differences between the effects of Val, Tso, and L-1 on G-tolerance do not appear to be related to a differential ability to maintain cardiac volumes. L-1 must provide more C protection due to the isometric contraction component of the maneuver and its ability to increase blood pressure.... Echocardiography, Straining maneuver.


Descriptors :   *BLOOD PRESSURE , *ECHOCARDIOGRAPHY , *ACCELERATION TOLERANCE , *PULMONARY BLOOD CIRCULATION , STABILIZATION , OUTPUT , VOLUME , TWO DIMENSIONAL , LIGHT , PHASE , BASE LINES , PRESSURE , TOLERANCE , PROTECTION , MALES , MANEUVERS , LOSSES , HEART RATE , CONTRACTION


Subject Categories : Medicine and Medical Research


Distribution Statement : APPROVED FOR PUBLIC RELEASE