Time and Sample Site Dependency of the Optimized CO-Rebreathing Method

Abstract

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.

Stability of hemoglobin mass over 100 days in active men

“…The CO bolus was administered via a 100-ml plastic syringe (Omnifix, B Braun, Melsungen, Germany) connected to a glass spirometer with a 3.5-liter anaesthetic bag attached and was rebreathed for 2 min. Arterialized blood samples (200 l) were taken from a prewarmed finger tip and analyzed in quintuplicate for percent carboxyhemoglobin (%HbCO) using a diode array spectrophotometer (OSM3 Hemoximeter Radiometer) before as well as 8 and 10 min after rebreathing was commenced (6). Peak values of %HbCO were similar to those reported by Schmidt and Prommer (18) and Gore et al (7).…”

“…Hb mass for improved oxygen transport is the key variable of interest for an athlete seeking an unfair advantage from transfusion, and it appears that the CO-rebreathing method has sufficient sensitivity to readily detect the removal and reinfusion of 1-2 units of homologous or autologous blood, since this volume would cause changes in Hb mass ϳ5-10% above or below baseline. This magnitude of decrease or increase in Hb mass is Ϫ2 to 5 times more than the measurement error in experienced hands (6,18). Moreover, a measure of Hb mass via CO rebreathing could be readily incorporated into a hematological passport for elite endurance athletes, since it takes only 15 min to complete, uses small samples of blood (ϳ0.6 ml), and is relatively inexpensive.…”

“…Hb mass was measured every 1-6 days for 100 -114 days, (42 Ϯ 3 measurements, mean Ϯ SD) using a modified version of the CO rebreathing technique first reported by Schmidt and Prommer (18). This modified method has been described in detail by Gore and colleagues (6). Briefly, this procedure comprised inhalation of a bolus of 99.5% chemically pure CO (BOC gasses, Sydney, Australia) in a dose of 1 ml/kg of body mass.…”

Blood doping and its detection

“…The CO rebreathing technique for detecting nonphysiologic increases in Hb mass is still investigational, 24,25 and besides practical difficulties related to this method, its potential inclusion in the blood passport may be problematic, 26 because the margin of variation when assessing Hb mass (biologic and measurement errors) would still allow athletes to manipulate with blood volumes that would increase exercise performance considerably. 27 Finally, it should also be considered that, from an athlete's viewpoint, it may not be desirable to breathe CO shortly before a competition as this may limit exercise performance.…”

Short-Term Arrival Strategies for Endurance Exercise Performance at Moderate Altitude

“…A 2-minute CO rebreathing method, as described by Gore 104 was used to determine total hemoglobin mass, which combined with hemoglobin concentration and hematocrit allowed for the calculation of plasma volume. In brief, we measured initial percent of hemoglobin bound to carbon monoxide (%HbCO) by taking a 100 uL capillary blood sample from a fingertip and using a radiometer OSM3 blood gas analyzer (Radiometer Medical A/S, Copenhagen).…”