Application of multivariate statistical analysis to estimate +Gz tolerance based on the changes of hemodynamic parameters during lower body negative pressure (LBNP).
The application of lower body negative pressure (LBNP) is very useful method for simulation of +Gz stress and for evaluation of orthostatic reaction.  The different physiological changes that occur during LBNP test and +Gz acceleration test are similar.  Lategola and Trent found that supine LBNP exposure at the level of -50 mmHg may be equivalent to +2Gz in producing the changes of heart rate (HR).  Polese and coworkers compared hemodynamic changes occurring during upright and supine LBNP at the levels to -70 mmHg with identical measurements made during accelerations to +2Gz, +3Gz, and +4Gz in the same subjects.  They noted for example that HR changes during upright LBNP exceeded HR supine levels.  Peak values of HR during +3Gz and +4Gz significantly exceeded HR levels during both kinds of LBNP, but HR values at +2Gz were equivalent to those at -40 mmHg of upright and -70 mmHg of supine LBNP.  So, the present study was undertaken to evaluate adaptating responses to LBNP stimulus at the level of -60 mmHg, regulatory mechanisms of the circulatory system (central and peripheral) and to look for the possibility of +Gz tolerance prediction based on the changes of some hemodynamic parameters during LBNP.
Turski
B K
BK
Polish Air Force Institute of Aviation Medicine, Warsaw, Poland.
Kuzak
W
W
Debinski
W B
WB
Gembicka-Kuzak
D M
DM
Dabrowski
O B
OB
D000222:Adaptation, Physiological; D000293:Adolescent; D000328:Adult; D000337:Aerospace Medicine; D002498:Centrifugation; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D018471:Hypergravity / Q000009:adverse effects*; D008150:Lower Body Negative Pressure; D008297:Male; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D013997:Time Factors