Venoconstrictive thigh cuffs impede fluid shifts during simulated microgravity
Lindgren, K.N.; Kraft, D.; Ballard, R.E.; Tucker, A.; Hargens, A.R.; Hargens, A.R.
Aviation Space and Environmental Medicine 69(11): 1052-1058
1998
ISSN/ISBN: 0095-6562 PMID: 9819160 Document Number: 496006
Background: This study determined the efficacy of venoconstrictive thigh cuffs, inflated to 50 mmHg, on impeding fluid redistributions during simulated microgravity. Methods: There were 10 healthy male subjects who were exposed to a 2-h tilt protocol which started in the standing position, and was followed by 30 min supine, 30 min standing, 30 min supine, 30 min of -12degree head down tilt (HDT, to simulate microgravity), 15 min of HDT with venoconstrictive thigh cuffs inflated, a further 10 min of HDT, 5 min supine, and 10 min-standing. To increase the sensitivity of the techniques in an Earth-based model, 12degree HDT was used to simulate microgravity effects on body fluid shifts. Volume changes were measured with anthropometric sleeve plethysmography. Results: Transition to the various tilt positions resulted in concomitant decrements in leg volume (Stand (STD) to Supine (SUP), -3.0%; SUP to HDT, -2.0%). Inflation of the venoconstrictive thigh cuffs to 50 mmHg, during simulated microgravity, resulted in a significant 3.0% increase in leg volume from that seen in HDT (p < 0.01). No significant changes in systemic cardiovascular parameters were noted during cuff inflation. Conclusions: We conclude that venoconstrictive thigh cuffs, inflated to 50 mmHg for 15 min during 12degree HDT, can create a more Earth-like fluid distribution. Cuffs could potentially be used to ameliorate the symptoms of cephalad edema seen with space adaptation syndrome and to potentiate existing fluid volume countermeasure protocols.