Reflex responses to regional venous pooling during lower body negative pressure in humans

J. R. Halliwill, L. A. Lawler, T. J. Eickhoff, M. J. Joyner, S. L. Mulvagh

Research output: Contribution to journalArticlepeer-review

49 Scopus citations

Abstract

Lower body negative pressure is frequently used to simulate orthostasis. Prior data suggest that venous pooling in abdominal or pelvic regions may have major hemodynamic consequences. Therefore, we developed a simple paradigm for assessing regional contributions to venous pooling during lower body negative pressure. Sixteen healthy men and women underwent graded lower body negative pressure protocols to 60 mmHg while wearing medical anti-shock trousers to prevent venous pooling under three randomized conditions: 1) no trouser inflation (control), 2) only the trouser legs inflated, and 3) the trouser legs and abdominopelvic region inflated. Without trouser inflation, heart rate increased 28 ± 4 beats/min, mean arterial pressure fell -3 ± 2 mmHg, and forearm vascular resistance increased 51 ± 9 units at 60 mmHg lower body negative pressure. With inflation of either the trouser legs or the trouser legs and abdominopelvic region, heart rate and mean arterial pressure did not change during lower body negative pressure. By contrast, although the forearm vasoconstrictor response to lower body negative pressure was attenuated by inflation of the trouser legs (Δforearm vascular resistance 33 ± 10 units, P < 0.05 vs. control), attenuation was greater with the inflation of the trouser legs and abdominopelvic region (Δforearm vascular resistance 16 ± 5 units, P < 0.05 vs. control and trouser legs- only inflation). Thus the hemodynamic consequences of pooling in the abdominal and pelvic regions during lower body negative pressure appear to be less than in the legs in healthy individuals.

Original languageEnglish (US)
Pages (from-to)454-458
Number of pages5
JournalJournal of applied physiology
Volume84
Issue number2
DOIs
StatePublished - 1998

Keywords

  • Arterial baroreflex
  • Blood pooling
  • Cardiopulmonary reflex
  • Orthostasis

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Fingerprint Dive into the research topics of 'Reflex responses to regional venous pooling during lower body negative pressure in humans'. Together they form a unique fingerprint.

Cite this