Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark.
Department of Public Health, Section of Sport Science, Aarhus University, Aarhus C, Denmark.
J Clin Monit Comput. 2023 Apr;37(2):437-447. doi: 10.1007/s10877-022-00921-2. Epub 2022 Oct 6.
We examined whether a semi-automated carbon monoxide (CO) rebreathing method accurately detect changes in blood volume (BV) and total hemoglobin mass (tHb). Furthermore, we investigated whether a supine position with legs raised reduced systemic CO dilution time, potentially allowing a shorter rebreathing period. Nineteen young healthy males participated. BV and tHb was quantified by a 10-min CO-rebreathing period in a supine position with legs raised before and immediately after a 900 ml phlebotomy and before and after a 900 ml autologous blood reinfusion on the same day in 16 subjects. During the first CO-rebreathing, arterial and venous blood samples were drawn every 2 min during the procedure to determine systemic CO equilibrium in all subjects. Phlebotomy decreased (P < 0.001) tHb and BV by 166 ± 24 g and 931 ± 247 ml, respectively, while reinfusion increased (P < 0.001) tHb and BV by 143 ± 21 g and 862 ± 250 ml compared to before reinfusion. After reinfusion BV did not differ from baseline levels while tHb was decreased (P < 0.001) by 36 ± 21 g. Complete CO mixing was achieved within 6 min in venous and arterial blood, respectively, when compared to the 10-min sample. On an individual level, the relative accuracy after donation for tHb and BV was 102-169% and 55-165%, respectively. The applied CO-rebreathing procedure precisely detect acute BV changes with a clinically insignificant margin of error. The 10-min CO-procedure may be reduced to 6 min with no clinical effects on BV and tHb calculation. Notwithstanding, individual differences may be of concern and should be investigated further.
我们研究了半自动化一氧化碳（CO）重呼吸法是否能准确检测血容量（BV）和总血红蛋白质量（tHb）的变化。此外，我们还研究了抬高腿部的仰卧位是否会缩短全身 CO 稀释时间，从而可能缩短重呼吸周期。19 名年轻健康男性参与了研究。在 16 名参与者中，在同一天内，在腿部抬高的仰卧位下进行 10 分钟的 CO 重呼吸，在采血前、采血后即刻、采血后 900ml 自体血回输前和采血后 900ml 自体血回输后进行 BV 和 tHb 的定量分析。在第一次 CO 重呼吸期间，在所有受试者中，在程序的每 2 分钟抽取动脉和静脉血样，以确定全身 CO 平衡。采血使 tHb 和 BV 分别降低（P<0.001）166±24g 和 931±247ml，而回输使 tHb 和 BV 分别增加（P<0.001）143±21g 和 862±250ml，与回输前相比。回输后，BV 与基线水平无差异，而 tHb 降低（P<0.001）36±21g。与 10 分钟的样本相比，在静脉和动脉血中分别在 6 分钟内达到 CO 完全混合。在个体水平上，tHb 和 BV 的捐赠后相对准确性分别为 102-169%和 55-165%。应用的 CO 重呼吸程序可以精确检测急性 BV 变化，误差幅度临床可忽略不计。10 分钟的 CO 程序可以缩短至 6 分钟，对 BV 和 tHb 的计算无临床影响。尽管如此，个体差异可能值得关注，需要进一步研究。
