Variability in mechanisms associated with tolerance to progressive reductions in central blood volume (1157.3)
Abstract
High tolerance to reductions in central blood volume has been associated with higher heart rate (HR), sympathetic nerve activity (SNA), and cardiac baroreflex sensitivity (BRS). Using subjects classified as high tolerance to lower body negative pressure (LBNP), we tested the hypothesis that subjects with BRS > 1.0 would demonstrate greater LBNPtolerance associated with higher HR, PVR, and SNA than subjects with BRS 1.0, N = 49, and Group 2 = BRS 1.0) had lower HR (107 ± 19 vs. 131 ± 20 beats/min), higher SV (45 ± 15 vs. 36 ± 15 ml), less SNA (45 ± 13 vs. 53 ± 7 bursts/min), and less increase in PVR (4.1 ± 1.3 vs. 4.5 ± 2.6) compared to Group 2 (BRS < 1.0). Conclusions: Contrary to our hypothesis, higher HR, SNA and BRS were not associated with greater tolerance to reduced central blood volume. In a cohort of high tolerant subjects, some individuals rely on cardiac filling and vagal withdrawal to defend AP while others rely on sympathoexcitation.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Apr 01, 2014
- Source ID
- 10.1096/fasebj.28.1_supplement.1157.3
Entities
People
- Carmen Hinojosa‐laborde
- Robert Carter Iii.
- Víctor A. Convertino
Organizations
- United States Army Institute of Surgical Research
- United States Department of Defense