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Virginia Tech

Reliability of a semi-automated CO₂ rebreathing system for cardiac output measures during exercise

Abstract

dc:description.abstract

Computer-assisted technology for noninvasive determination of cardiac output (Q̇, Lmin⁻¹) offers potential to re-examine measurement stability with established methods involving CO₂ rebreathing. Reproducibility of Q̇ was examined at rest and during steady-state cycle ergometer exercise (x̄ = 51% of V̇O₂pk; SD = ± 7%) using Defares’ exponential method (MedGraphics™ CPX/D system). Characteristics of the 19 female subjects were: (Mean and SD) age = 34.6 yr and 6.6 and V̇O₂pk= 32.8 mlkg⁻¹min⁻¹ and 9.5. The Q̇ trial consisted of 15 min of seated rest and 15 min of exercise. Values were determined in triplicate at each of minutes, 6, 10, 14. Stability of subjects responses before each rebreathing maneuver was verified by inspection of V̇O₂, Two-way ANOVA’s were performed on the Q̇ data for differences; means (Lmin⁻¹), SD’s, and reliability coefficients were: Rest Q̇-6 min Q̇-10 min Q̇-14 min R Day 1 5.1 ± 0.8 5.0 ± 1.1 4.8 ± 0.9 0.81 Day 2 4.7 ± 0.8 4.6 ± 0.8 4.6 ± 0.8 0.82 Exercise Q̇-6 min Q̇-10 min Q̇-14 min R Day 1 9.14 ± 1.2 9.3 ± 1.4 9.2 ± 1.1 0.93 Day 2 8.6 ± 1.5 8.7 ± 1.4 8.7 ± 1.3 0.97 Day 1 Day 2 R Rest 5.0 ± 0.8 4.7 ± 0.7 0.05 Exercise 9.2 ± 1.2 8.7 ± 1.4 0.84 Although these findings demonstrated within-test and between-test reproducibility of Q̇ to be comparable to that described in the published literature (Kirby TE. J Cardiac Rehabil 5:97-101, 1985) the new semi-automated computerized system (MedGraphics CPX/D) offers a quick, easy, and efficient assessment of cardiac output.

Degree

thesis:*
Name thesis:degree_name
Master of Science
Level thesis:degree_level
masters
Discipline thesis:degree_discipline
Health and Physical Education
Department dc:contributor.department
Health and Physical Education
Grantor dc:publisher
Virginia Tech
Year dc:date.issued
1996

Author and committee

dc:creator, dc:contributor.*
Author dc:creator
  • Davis, Richard Alan
Chair dc:contributor.committeechair
  • Herbert, William G.
Committee members dc:contributor.committeemember
  • Davis, Shala E.
  • Sebolt, Don R.

Subjects

dc:subject × 4

Rights

dc:rights
Statement dc:rights
  • In Copyright
Language dc:language.iso
en

Identifiers

dc:identifier.*
Dc Identifier Other
etd-11182008-063156
OAI identifier oai:identifier
oai:vtechworks.lib.vt.edu:10919/45843

Chain of custody

source
Harvested from
Virginia Tech
Base URL
vtechworks.lib.vt.edu/oai/request
Last updated
2026-07-22
Source record
OAI-PMH GetRecord
citation

Davis, Richard Alan. Reliability of a semi-automated CO₂ rebreathing system for cardiac output measures during exercise. masters thesis, Virginia Tech, 1996. http://hdl.handle.net/10919/45843