Time and sample site dependency of the optimized CO-rebreathing method
Date
2006
Authors
Gore, Christopher J.
Bourdon, Pitre C.
Woolford, Sarah M.
Ostler, Laura M.
Eastwood, Annette
Scroop, Garry Campbell
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
Medicine and Science in Sports and Exercise, 2006; 38(6):1187-1193
Statement of Responsibility
Gore CJ, Bourdon PC, Woolford SM, Ostler LM, Eastwood A and Scroop GC.
Conference Name
Abstract
Purpose: A new method to estimate hemoglobin mass (Hbmass) requires capillary blood and rebreathing a carbon-monoxide (CO) bolus for 2 min. We hypothesized that incomplete circulatory mixing of CO could confound this method, so we compared capillary with venous blood to determine whether sampling site altered the percentage of carboxyhemoglobin (%HbCO) and the reliability and accuracy of the "2-min Hbmass." The conventional 20-min CO-rebreathing procedure was used as the Hbmass criterion.
Methods: In the first experiment (N = 12), both fingertip capillary and antecubital venous blood were sampled 4 and 6 min after commencing 2 min of CO-rebreathing. Within 8 d, these subjects completed two 2-min and one 20-min CO-rebreathing periods. For the latter, capillary and venous blood were collected simultaneously after two 10-min periods of rebreathing. In a second experiment (N = 6), both capillary and venous blood were sampled 4, 6, 8, 10, and 12 min after commencing 2 min of CO-rebreathing. A third experiment (N = 6) evaluated the reliability of a modified 2-min CO-rebreathing test with capillary blood sampled at minutes 8 and 10.
Results: Typical error (TE) for the first two 2-min tests was 1.1% (90% confidence limits 0.9-1.8%), but the average Hbmass from 2-min capillary blood was 4.8% lower than from venous blood for the 20-min procedure. In the second experiment, peak venous %HbCO occurred at minute 6, and the difference between capillary and venous values was minimal (mean ± SD; 0.08 ± 0.07, 0.01 ± 0.09) at minutes 8 and 10. TE for the third experiment was 1.2% (0.8-2.5%).
Conclusion: A modified 2-min CO-rebreathing procedure using capillary or venous blood sampled 8 and 10 min after starting CO-rebreathing allows complete circulatory mixing and provides an accurate and reliable estimate of Hbmass.
School/Discipline
School of Medical Sciences : Pharmacology