The Effect of Passive Heat Stress and Exercise-Induced Dehydration on the Compensatory Reserve during Simulated Hemorrhage

Daniel Gagnon, Zachary J. Schlader, Amy Adams, Eric Rivas, Jane Mulligan, Gregory Z. Grudic, Victor A. Convertino, Jeffrey T. Howard, Craig G. Crandall

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Compensatory reserve represents the proportion of physiological responses engaged to compensate for reductions in central blood volume before the onset of decompensation. We hypothesized that compensatory reserve would be reduced by hyperthermia and exercise-induced dehydration, conditions often encountered on the battlefield. Twenty healthy males volunteered for two separate protocols during which they underwent lower-body negative pressure (LBNP) to hemodynamic decompensation (systolic blood pressure <80 mm Hg). During protocol #1, LBNP was performed following a passive increase in core temperature of ∼1.2°C (HT) or a normothermic time-control period (NT). During protocol #2, LBNP was performed following exercise during which: fluid losses were replaced (hydrated), fluid intake was restricted and exercise ended at the same increase in core temperature as hydrated (isothermic dehydrated), or fluid intake was restricted and exercise duration was the same as hydrated (time-match dehydrated). Compensatory reserve was estimated with the compensatory reserve index (CRI), a machine-learning algorithm that extracts features from continuous photoplethysmograph signals. Prior to LBNP, CRI was reduced by passive heating [NT: 0.87 (SD 0.09) vs. HT: 0.42 (SD 0.19) units, P <0.01] and exercise-induced dehydration [hydrated: 0.67 (SD 0.19) vs. isothermic dehydrated: 0.52 (SD 0.21) vs. time-match dehydrated: 0.47 (SD 0.25) units; P <0.01 vs. hydrated]. During subsequent LBNP, CRI decreased further and its rate of change was similar between conditions. CRI values at decompensation did not differ between conditions. These results suggest that passive heating and exercise-induced dehydration limit the body's physiological reserve to compensate for further reductions in central blood volume.

Original languageEnglish (US)
Pages (from-to)74-82
Number of pages9
JournalShock
Volume46
Issue number3S
DOIs
StatePublished - Sep 1 2016
Externally publishedYes

Fingerprint

Lower Body Negative Pressure
Dehydration
Hot Temperature
Hemorrhage
Blood Volume
Heating
Blood Pressure
Induced Hyperthermia
Temperature
Hemodynamics

Keywords

  • Compensatory reserve
  • dehydration
  • exercise
  • heat
  • hemorrhage

ASJC Scopus subject areas

  • Emergency Medicine
  • Critical Care and Intensive Care Medicine

Cite this

Gagnon, D., Schlader, Z. J., Adams, A., Rivas, E., Mulligan, J., Grudic, G. Z., ... Crandall, C. G. (2016). The Effect of Passive Heat Stress and Exercise-Induced Dehydration on the Compensatory Reserve during Simulated Hemorrhage. Shock, 46(3S), 74-82. https://doi.org/10.1097/SHK.0000000000000653

The Effect of Passive Heat Stress and Exercise-Induced Dehydration on the Compensatory Reserve during Simulated Hemorrhage. / Gagnon, Daniel; Schlader, Zachary J.; Adams, Amy; Rivas, Eric; Mulligan, Jane; Grudic, Gregory Z.; Convertino, Victor A.; Howard, Jeffrey T.; Crandall, Craig G.

In: Shock, Vol. 46, No. 3S, 01.09.2016, p. 74-82.

Research output: Contribution to journalArticle

Gagnon, D, Schlader, ZJ, Adams, A, Rivas, E, Mulligan, J, Grudic, GZ, Convertino, VA, Howard, JT & Crandall, CG 2016, 'The Effect of Passive Heat Stress and Exercise-Induced Dehydration on the Compensatory Reserve during Simulated Hemorrhage', Shock, vol. 46, no. 3S, pp. 74-82. https://doi.org/10.1097/SHK.0000000000000653
Gagnon, Daniel ; Schlader, Zachary J. ; Adams, Amy ; Rivas, Eric ; Mulligan, Jane ; Grudic, Gregory Z. ; Convertino, Victor A. ; Howard, Jeffrey T. ; Crandall, Craig G. / The Effect of Passive Heat Stress and Exercise-Induced Dehydration on the Compensatory Reserve during Simulated Hemorrhage. In: Shock. 2016 ; Vol. 46, No. 3S. pp. 74-82.
@article{47bbe6f26f2d416ab4ed790ddcb05dba,
title = "The Effect of Passive Heat Stress and Exercise-Induced Dehydration on the Compensatory Reserve during Simulated Hemorrhage",
abstract = "Compensatory reserve represents the proportion of physiological responses engaged to compensate for reductions in central blood volume before the onset of decompensation. We hypothesized that compensatory reserve would be reduced by hyperthermia and exercise-induced dehydration, conditions often encountered on the battlefield. Twenty healthy males volunteered for two separate protocols during which they underwent lower-body negative pressure (LBNP) to hemodynamic decompensation (systolic blood pressure <80 mm Hg). During protocol #1, LBNP was performed following a passive increase in core temperature of ∼1.2°C (HT) or a normothermic time-control period (NT). During protocol #2, LBNP was performed following exercise during which: fluid losses were replaced (hydrated), fluid intake was restricted and exercise ended at the same increase in core temperature as hydrated (isothermic dehydrated), or fluid intake was restricted and exercise duration was the same as hydrated (time-match dehydrated). Compensatory reserve was estimated with the compensatory reserve index (CRI), a machine-learning algorithm that extracts features from continuous photoplethysmograph signals. Prior to LBNP, CRI was reduced by passive heating [NT: 0.87 (SD 0.09) vs. HT: 0.42 (SD 0.19) units, P <0.01] and exercise-induced dehydration [hydrated: 0.67 (SD 0.19) vs. isothermic dehydrated: 0.52 (SD 0.21) vs. time-match dehydrated: 0.47 (SD 0.25) units; P <0.01 vs. hydrated]. During subsequent LBNP, CRI decreased further and its rate of change was similar between conditions. CRI values at decompensation did not differ between conditions. These results suggest that passive heating and exercise-induced dehydration limit the body's physiological reserve to compensate for further reductions in central blood volume.",
keywords = "Compensatory reserve, dehydration, exercise, heat, hemorrhage",
author = "Daniel Gagnon and Schlader, {Zachary J.} and Amy Adams and Eric Rivas and Jane Mulligan and Grudic, {Gregory Z.} and Convertino, {Victor A.} and Howard, {Jeffrey T.} and Crandall, {Craig G.}",
year = "2016",
month = "9",
day = "1",
doi = "10.1097/SHK.0000000000000653",
language = "English (US)",
volume = "46",
pages = "74--82",
journal = "Shock",
issn = "1073-2322",
publisher = "Lippincott Williams and Wilkins",
number = "3S",

}

TY - JOUR

T1 - The Effect of Passive Heat Stress and Exercise-Induced Dehydration on the Compensatory Reserve during Simulated Hemorrhage

AU - Gagnon, Daniel

AU - Schlader, Zachary J.

AU - Adams, Amy

AU - Rivas, Eric

AU - Mulligan, Jane

AU - Grudic, Gregory Z.

AU - Convertino, Victor A.

AU - Howard, Jeffrey T.

AU - Crandall, Craig G.

PY - 2016/9/1

Y1 - 2016/9/1

N2 - Compensatory reserve represents the proportion of physiological responses engaged to compensate for reductions in central blood volume before the onset of decompensation. We hypothesized that compensatory reserve would be reduced by hyperthermia and exercise-induced dehydration, conditions often encountered on the battlefield. Twenty healthy males volunteered for two separate protocols during which they underwent lower-body negative pressure (LBNP) to hemodynamic decompensation (systolic blood pressure <80 mm Hg). During protocol #1, LBNP was performed following a passive increase in core temperature of ∼1.2°C (HT) or a normothermic time-control period (NT). During protocol #2, LBNP was performed following exercise during which: fluid losses were replaced (hydrated), fluid intake was restricted and exercise ended at the same increase in core temperature as hydrated (isothermic dehydrated), or fluid intake was restricted and exercise duration was the same as hydrated (time-match dehydrated). Compensatory reserve was estimated with the compensatory reserve index (CRI), a machine-learning algorithm that extracts features from continuous photoplethysmograph signals. Prior to LBNP, CRI was reduced by passive heating [NT: 0.87 (SD 0.09) vs. HT: 0.42 (SD 0.19) units, P <0.01] and exercise-induced dehydration [hydrated: 0.67 (SD 0.19) vs. isothermic dehydrated: 0.52 (SD 0.21) vs. time-match dehydrated: 0.47 (SD 0.25) units; P <0.01 vs. hydrated]. During subsequent LBNP, CRI decreased further and its rate of change was similar between conditions. CRI values at decompensation did not differ between conditions. These results suggest that passive heating and exercise-induced dehydration limit the body's physiological reserve to compensate for further reductions in central blood volume.

AB - Compensatory reserve represents the proportion of physiological responses engaged to compensate for reductions in central blood volume before the onset of decompensation. We hypothesized that compensatory reserve would be reduced by hyperthermia and exercise-induced dehydration, conditions often encountered on the battlefield. Twenty healthy males volunteered for two separate protocols during which they underwent lower-body negative pressure (LBNP) to hemodynamic decompensation (systolic blood pressure <80 mm Hg). During protocol #1, LBNP was performed following a passive increase in core temperature of ∼1.2°C (HT) or a normothermic time-control period (NT). During protocol #2, LBNP was performed following exercise during which: fluid losses were replaced (hydrated), fluid intake was restricted and exercise ended at the same increase in core temperature as hydrated (isothermic dehydrated), or fluid intake was restricted and exercise duration was the same as hydrated (time-match dehydrated). Compensatory reserve was estimated with the compensatory reserve index (CRI), a machine-learning algorithm that extracts features from continuous photoplethysmograph signals. Prior to LBNP, CRI was reduced by passive heating [NT: 0.87 (SD 0.09) vs. HT: 0.42 (SD 0.19) units, P <0.01] and exercise-induced dehydration [hydrated: 0.67 (SD 0.19) vs. isothermic dehydrated: 0.52 (SD 0.21) vs. time-match dehydrated: 0.47 (SD 0.25) units; P <0.01 vs. hydrated]. During subsequent LBNP, CRI decreased further and its rate of change was similar between conditions. CRI values at decompensation did not differ between conditions. These results suggest that passive heating and exercise-induced dehydration limit the body's physiological reserve to compensate for further reductions in central blood volume.

KW - Compensatory reserve

KW - dehydration

KW - exercise

KW - heat

KW - hemorrhage

UR - http://www.scopus.com/inward/record.url?scp=84966783496&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84966783496&partnerID=8YFLogxK

U2 - 10.1097/SHK.0000000000000653

DO - 10.1097/SHK.0000000000000653

M3 - Article

VL - 46

SP - 74

EP - 82

JO - Shock

JF - Shock

SN - 1073-2322

IS - 3S

ER -