Identification of the human electrical impedance indifferent point

A surrogate for the volume indifferent point?

Sara S Jarvis, James A. Pawelczyk

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Head-up tilt (HUT) redistributes ∼700 mL of blood to the dependent regions. In a gravitational field, hydrostatic pressure is balanced against vascular compliance, resulting in a hydrostatic indifferent point (HIP) whose location should be coincident with an indifferent point for volume (VIP). Cardiac filling is determined by the hydrostatic gradient between the HIP/VIP and right atrium. We employed segmental impedance to examine blood volume redistribution during HUT and estimate the location of the VIP. During HUT, impedance increased in the chest and decreased in the lower abdomen, presumably due to blood volume shifts. Using a non-linear model to relate blood volume shifts to the hydrostatic gradient, we estimated the location of the electrical impedance indifferent point between the xyphoid process and iliac crest, at 64.5 ± 2.6% of an individual's height. This method may provide a quantitative framework to assess the effects of blood volume distribution on tilt tolerance.

Original languageEnglish (US)
Pages (from-to)473-480
Number of pages8
JournalEuropean Journal of Applied Physiology
Volume107
Issue number4
DOIs
StatePublished - 2009
Externally publishedYes

Fingerprint

Forensic Anthropology
Blood Volume
Electric Impedance
Head
Hydrostatic Pressure
Nonlinear Dynamics
Heart Atria
Abdomen
Compliance
Blood Vessels
Thorax

Keywords

  • Blood volume distribution
  • Head-up tilt
  • Segmental bioelectrical impedance
  • Volume indifferent point

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Orthopedics and Sports Medicine
  • Physiology (medical)

Cite this

Identification of the human electrical impedance indifferent point : A surrogate for the volume indifferent point? / Jarvis, Sara S; Pawelczyk, James A.

In: European Journal of Applied Physiology, Vol. 107, No. 4, 2009, p. 473-480.

Research output: Contribution to journalArticle

@article{fd90d1bb801447f8844217eaa924c8b0,
title = "Identification of the human electrical impedance indifferent point: A surrogate for the volume indifferent point?",
abstract = "Head-up tilt (HUT) redistributes ∼700 mL of blood to the dependent regions. In a gravitational field, hydrostatic pressure is balanced against vascular compliance, resulting in a hydrostatic indifferent point (HIP) whose location should be coincident with an indifferent point for volume (VIP). Cardiac filling is determined by the hydrostatic gradient between the HIP/VIP and right atrium. We employed segmental impedance to examine blood volume redistribution during HUT and estimate the location of the VIP. During HUT, impedance increased in the chest and decreased in the lower abdomen, presumably due to blood volume shifts. Using a non-linear model to relate blood volume shifts to the hydrostatic gradient, we estimated the location of the electrical impedance indifferent point between the xyphoid process and iliac crest, at 64.5 ± 2.6{\%} of an individual's height. This method may provide a quantitative framework to assess the effects of blood volume distribution on tilt tolerance.",
keywords = "Blood volume distribution, Head-up tilt, Segmental bioelectrical impedance, Volume indifferent point",
author = "Jarvis, {Sara S} and Pawelczyk, {James A.}",
year = "2009",
doi = "10.1007/s00421-009-1148-9",
language = "English (US)",
volume = "107",
pages = "473--480",
journal = "European Journal of Applied Physiology",
issn = "1439-6319",
publisher = "Springer Verlag",
number = "4",

}

TY - JOUR

T1 - Identification of the human electrical impedance indifferent point

T2 - A surrogate for the volume indifferent point?

AU - Jarvis, Sara S

AU - Pawelczyk, James A.

PY - 2009

Y1 - 2009

N2 - Head-up tilt (HUT) redistributes ∼700 mL of blood to the dependent regions. In a gravitational field, hydrostatic pressure is balanced against vascular compliance, resulting in a hydrostatic indifferent point (HIP) whose location should be coincident with an indifferent point for volume (VIP). Cardiac filling is determined by the hydrostatic gradient between the HIP/VIP and right atrium. We employed segmental impedance to examine blood volume redistribution during HUT and estimate the location of the VIP. During HUT, impedance increased in the chest and decreased in the lower abdomen, presumably due to blood volume shifts. Using a non-linear model to relate blood volume shifts to the hydrostatic gradient, we estimated the location of the electrical impedance indifferent point between the xyphoid process and iliac crest, at 64.5 ± 2.6% of an individual's height. This method may provide a quantitative framework to assess the effects of blood volume distribution on tilt tolerance.

AB - Head-up tilt (HUT) redistributes ∼700 mL of blood to the dependent regions. In a gravitational field, hydrostatic pressure is balanced against vascular compliance, resulting in a hydrostatic indifferent point (HIP) whose location should be coincident with an indifferent point for volume (VIP). Cardiac filling is determined by the hydrostatic gradient between the HIP/VIP and right atrium. We employed segmental impedance to examine blood volume redistribution during HUT and estimate the location of the VIP. During HUT, impedance increased in the chest and decreased in the lower abdomen, presumably due to blood volume shifts. Using a non-linear model to relate blood volume shifts to the hydrostatic gradient, we estimated the location of the electrical impedance indifferent point between the xyphoid process and iliac crest, at 64.5 ± 2.6% of an individual's height. This method may provide a quantitative framework to assess the effects of blood volume distribution on tilt tolerance.

KW - Blood volume distribution

KW - Head-up tilt

KW - Segmental bioelectrical impedance

KW - Volume indifferent point

UR - http://www.scopus.com/inward/record.url?scp=70350274102&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=70350274102&partnerID=8YFLogxK

U2 - 10.1007/s00421-009-1148-9

DO - 10.1007/s00421-009-1148-9

M3 - Article

VL - 107

SP - 473

EP - 480

JO - European Journal of Applied Physiology

JF - European Journal of Applied Physiology

SN - 1439-6319

IS - 4

ER -