Abstract
To evaluate mechanisms of late orthostatic intolerance, slow fluid shifts along the body axis were studied during deconditioning by 24-h bed-rest and during 13-min upright tilts before and after this manoeuvre. In 11 healthy male subjects the fluid volumes of a thorax and a calf segment (impedance plethysmography) as well as tissue thickness at the forehead and the tibia (miniature ultrasonic plethysmograph) were recorded. Cardiovascular performance was monitored by recording heart rate (electrocardiogram), brachial and finger arterial pressure (by the Riva Rocci method and by the Finapres technique) as well as stroke volume (by impedance cardiography). Bed-rest led to a cephalad fluid shift with a mean interstitial leg dehydration of 2.2 ml·-100 ml−1 with no changes in body mass and plasma volume. No syncope during the tilt occurred before bed-rest, while after bed-rest 8 subjects fainted between min 2.1 and 9.0 of the tilt. Bed-rest resulted in an augmented initial heart rate response to tilting which was similar in all subjects. In later orthostasis, bed-rest caused two- to threefold faster caudad fluid shifts with higher calf filtration rates in fainters (prior to hypotension) than in nonfainters. Through bed-rest the estimated extravasation within 10 min into general lower body tissue spaces increased by 192 ml in (late) fainters as opposed to only 23 ml in nonfainters. It was concluded that contributing factors to orthostatic intolerance may be slow transcapillary fluid shifts which are easily underestimated and whose quantity and time course call for further investigation after various deconditioning manoeuvres. In particular, the postflight fluid shifts in astronauts who will have markedly dehydrated legs, may impose a circulatory stress which needs to be evaluated. In general, the filtration rate in relevant areas appears to be an integrative and easily determined parameter, reflecting hormonal and neurogenic vascular as well as local interstitial control of the Starling forces.
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References
Aratow M, Fortney SM, Watenpaugh DE, Crenshaw AG, Hargens AR (1993) Transcapillary fluid response to lower body negative pressure. J Appl Physiol 74:2763–2770
Beetham WP, Buskirk ER (1958) Effects of dehydration, physical conditioning and heat acclimatization on the response to passive tilting. J Appl Physiol 13:465–468
Berg HE, Tedner B, Tesch PA (1993) Changes in the lower limb muscle cross-sectional area after transition from standing to supine. Acta Physiol Scand 148:379–385
Blamick CA, Goldwater DJ, Convertino VA (1988) Leg vascular responsiveness during acute orthostasis following simulated weightlessness. Aviat Space Environ Med 59:40–43
Breithaupt K, Erb KA, Neumann B, Wolf GK, Belz GG (1990) Comparison of four noninvasive techniques to measure stroke volume: dual-beam doppler echoaortography, electrical impedance cardiography, mechanosphygmography and M-mode echocardiography of left ventricle. Am J Noninvas Cardiol 4:203–209
Butler GC, Xing H, Northey DR, Hughson RL (1991) Reduced orthostatic tolerance following 4 h head-down tilt. Eur J Appl Physiol 62:26–30
Convertino VA, Doerr DF, Flores JF, Hoffler GW, Buchanan P (1988) Leg size and muscle functions associated with leg compliance. J Appl Physiol 64:1017–1021
Convertino VA, Mathes KL, Lasley ML, Tomaselli CM, Frey MAB, Hoffler GW (1993) Hemodynamic and hormonal responses to lower body negative pressure in men with varying profites of strength and aerobic power. Eur J Appl Physiol 67:492–498
Ebert TJ, Smith JJ, Barney JA, Merrill DC, Smith GK (1986) The use of thoracic impedance for determining thoracic blood volume changes in man. Aviat Space Environ Med 57:49–53
Greenleaf JE, Leftheriotis G (1989) Orthostatic responses following 30-day bed rest deconditioning with isotonic and isokinetic exercise training. Aviat Space Environ Med 60:537–542
Hagan RD, Diaz FJ, Horvath SM (1978) Plasma volume changes with movement to supine and standing position. J Appl Physiol Respir Environ Exerc Physiol 45:414–418
Hargens AR (1983) Fluid shifts in vascular and extravascular spaces during and after simulated weightlessness. Med Sci Sports Exerc 15:421
Harrison MH (1986) Athletes, astronauts and orthostatic tolerance. Sports Med 3:428–435
Hildebrandt W, Schütze H, Stegemann J (1991) On the reliability of the Penaz cuff during systemic and local fingertip vasodilatation ar rest and in exercise. Eur J Appl Physiol 62:175–179
Hildebrandt W, Schiltze H, Stegemann J (1993) Higher capillary filtration rate in the calves of endurance trained subjects during orthostatic stress. Aviat Space Environ Med 64:380–385
Hinghofer-Szalkay H, Moser M (1986) Fluid and protein shifts after postural changes in humans. Am J Physiol 250 (Heart Circ Physiol 19): H68-H75
Hyatt KH, West DA (1977) Reversal of bedrest-induced orthostatic intolerance by lower body negative pressure and saline. Aviat Space Environ Med 48:120–124
Hyatt KH, Kamenetsky LG, Smith WM (1969) Extravascular dehydration as an etiologic factor in post-recumbency orthostatism. Aerosp Med 40:644–650
Imholz BP, Settels JJ, van der Meiracker AH, Wesseling KH, Wieling W (1990) Non-invasive continuous finger blood pressure measurement during orthostatic stress compared to intraarterial pressure. Cardiovasc Res 24:214–221
Kirsch KA, Merke J, Hinghofer-Szalkay H, Barnkow M, Wicke HJ (1980a) A new miniature plethysmograph to measure volume changes in small circumscribed tissue areas. Pfltigers Arch 383:189–194
Kirsch KA, Merke J, Hinghofer-Szalkay H (1980b) Fluid volume distribution within superficial shell tissues along body axis during changes of body posture in man. The application of a new miniature plethysmographic method. Pflügers Arch 383:195–201
Kirsch KA, Baartz F-J, Gunga H-C, Röcker L, Wicke HJ, Bünsch B (1993) Fluid shifts into and out of superficial tissues under microgravity and terrestrial conditions. Clin Invest 71:687–689
Länne T, Lundvall J (1989) Very rapid net transcapillary fluid absorption from skeletal muscle and skin in man during pronounced hypovolaemic circulatory stress. Acta Physiol Scand 136:1–6
Levine BD, Buckey JC, Fritsch JM, Yancy CW, Watenpaugh DE, Snell PG, Lane LD, Eckberg DL (1991) Physical fitness and cardiovascular regulation: mechanisms of orthostatic intolerance. J Appl Physiol 70:112–120
Lockette W, Brennaman B (1990) Atrial natriuretio factor increases vascular permeability. Aviat Space Environ Med 61:1121–1124
Löllgen H, Klein KE, Gebhardt U, Beier J, Hordinsky J, Sarrasch V, Borger H, Just H (1986) Hemodynamic response to LBNP following 2 hours of HDT (−6°). Aviat Space Environ Med 57:406–412
Louisy F, Gaudin C, Oppert JM, Güell A, Guezennec CY (1990) Haemodynamics of leg veins during a 30-days-6° head-down bedrest with and without lower body negative pressure. Eur J Appl Physiol 61:349–355
Mayerson HS, Burch GE (1939) Relationship of tissue (subcutaneous and intramuscular) and venous pressures to syncope induced in man by gravity. Am J Physiol 128:258–269
Mellander S, Öberg B, Odelram H (1964) Vascular adjustment to increased transmural pressure in cat and man with special reference to shifts in capillary fluid transfer. Acta Physiol Scand 61:34–48
Moore TP, Thornton WE (1987) Space shuttle inflight and postflight fluid shifts measured by leg volume changes. Aviat Space Environ Med 58 [Suppl 9]:A91–96
Melchior FM, Fortney SM (1993) Orthostatic intolerance during a 13-day bed rest does not result from increased leg compliance. J Appl Physiol 74:286–292
Müller EW, Hohlweck H, Plath H, Baisch F (1984) Leg volume changes. Responses to LBNP during 7 days of 0-G simulation (6∧ HDT). 2nd European Symposium of Life Science Research in Space, Porz Wahn, Germany, June 4–6, ESA SP-212 (August 1984). F. Baisch, DLR, postbox 906058, 51126 Cologne, Germany, pp 159–162
Musgrave FS, Zechmann VW, Mains RC (1969) Changes in total leg volume during lower body negative pressure. Aerosp Med 40:602–606
Nixon JV, Murray RG, Bryant C, Johnson RL, Mitchell JH, Holland OB, Gomez-Sanchez C, Vergne-Marini P, Blomqvist CG (1979) Early cardiovascular adaptation to simulated zero gravity. J Appl Physiol 46:541–548
Sather TM, Goldwater DJ, Montgomery LD, Convertino VA (1986) Cardiovascular dynamics associated with tolerance to lower body negative pressure. Aviat Space Environ Med 57:413–419
Sekiguchi C, Yumikura S, Murai T, Miyamoto A, Yajima K (1993) Hemodynamic and hormonal correlates with exposure to lower body negative pressure after 12 hours head-downtilt. Aviat Space Environ Med 64:599–605
Sherwood A, Carter LS, Morphy CA (1991) Cardiac output by impedance cardiography: two alternative methodologies compared with thermodilution. Aviat Space Environ Med 62:116–122
Smith J (1990) Circulatory response to the upright posture. CRC Press, Boca Raton, Fla.
Stegemann J, Meier U, Skipka W, Hartlieb W, Hemmer B, Tibes U (1975) Effects of a multi-hour immersion with intermittent exercise on the urinary excretion and tilt table tolerance in athletes and nonathletes. Aviat Space Environ Med 46:26–29
Stick C (1981) Impedance plethysmography: measurements of volume changes of human limbs caused by capillary filtration. Eur J Appl Physiol 47:405–418
Strauss MB, Davis RK, Rosenbaum JD, Rossmeisl EC (1951) Water diuresis produced during recumbency by the intravenous infusion of isotonic saline solution. J Clin Invest 30:862–868
Vogt FB (1967)Tift table and plasma volume changes with short term deconditioning experiments. Aerosp Med 38:564–568
Volicer L, Jean-Charles R, Chobanian AV (1976) Effects of head-down tilt on fluid and electrolyte balance. Aviat Space Environ Med 47:1065–1068
Williamson JW, Shi X, Chen JJ, Crandall CG, Squires WG, Krock LP, Raven PB (1992) Aerobic fitness, II. Orthostasis andVO2max following head down tilt. Med Sci Sports Exerc 24:999–1006
Williamson JW, Crandall CG, Shi X, Squires WG, Raven PB (1993) Hormonal response during orthostasis following 4 hours of head-down-tilt. Aviat Space Environ Med 64:604–611
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Hildebrandt, W., Gunga, H.C., Herrmann, J. et al. Enhanced slow caudad fluid shifts in orthostatic intolerance after 24-h bed-rest. Europ. J. Appl. Physiol. 69, 61–70 (1994). https://doi.org/10.1007/BF00867929
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DOI: https://doi.org/10.1007/BF00867929