Increase of LBNP tolerance using elastic compression stockings.
BACKGROUND
Astronauts returning from spaceflight are affected by reduced orthostatic tolerance resulting from exposure to weightlessness. There are some countermeasures currently in use to improve cardiovascular performance of returning astronauts, while there are others that are being tested in flight and in ground-based investigations. This paper presents a study on the use of elastic compression stockings to reduce leg blood capacity (LBC) which is believed to be one of the determinants of orthostatic tolerance.


METHODS
The data are from 6 healthy men with a mean age of 36 +/- 5 (SE) yr. Assessment of the effectiveness of stockings in improving orthostatic tolerance is based on a presyncopal-limited lower body negative pressure (LBNP) test, consisting of successive 3 min exposures to negative pressures of -20 hPa (-15 mmHg), -40 hPa (-30 mmHg), and decrements in steps of 10 hPa (7.5 mmHg) from then on until termination of the test.


RESULTS
Results show an increase in the maximal level of LBNP tolerated (88 hPa or 66 mmHg for control vs. 108 hPa or 81 mmHg for stockings; p = 0.018) as well as in the cumulative stress index (CSI) (1122 hPa-min or 842 mmHg-min for control vs. 1734 hPa-min or 1300 mmHg-min for stockings; p = 0.029).


CONCLUSIONS
The improvement of LBNP tolerance with elastic compression stockings coupled with their ease of use support the need for further experimental studies for evaluating their potential as a countermeasure for astronauts after return from spaceflight.
Melçhior
F M
FM
Laboratoire de Médecine Aérospatiale, Centre d'Essais en Vol, Brétigny S/Orge, France.
Thullier
P H
PH
Lejeune
D
D
Kerguélen
M
M
Srinivasan
R S
RS
D000328:Adult; D018480:Astronauts; D001458:Bandages; D006801:Humans; D008150:Lower Body Negative Pressure; D008297:Male; D014893:Weightlessness / Q000009:adverse effects*