Abstract：
Duplicate measure of hemoglobin mass by carbon monoxide (CO)-rebreathing is a logistical challenge as recommendations prompt several hours between measures to minimize CO-accumulation. This study investigated the feasibility and reliability of performing duplicate CO-rebreathing procedures immediately following one another. Additionally, it was evaluated whether the obtained hemoglobin mass from three different CO-rebreathing devices is comparable. Fifty-five healthy participants (22 males, 23 females) performed 222 duplicate CO-rebreathing procedures in total. Additionally, in a randomized cross-over design 10 participants completed three experimental trials, each including three CO-rebreathing procedures, with the first and second separated by 24 h and the second and third separated by 5-10 min. Each trial was separated by >48 h and conducted using either a glass-spirometer, a semi-automated electromechanical device, or a standard three-way plastic valve designed for pulmonary measurements. Hemoglobin mass was 3 ± 22 g lower (p < 0.05) at the second measure when performed immediately after the first with a typical error of 1.1%. Carboxyhemoglobin levels reached 10.9 ± 1.3%. In the randomized trial, hemoglobin mass was similar between the glass-spirometer and three-way valve, but ∼6% (∼50 g) higher for the semi-automated device. Notably, differences in hemoglobin mass were up to ∼13% (∼100 g) when device-specific recommendations for correction of CO loss to myoglobin and exhalation was followed. In conclusion, it is feasible and reliable to perform two immediate CO-rebreathing procedures. Hemoglobin mass is comparable between the glass-spirometer and the three-way plastic valve, but higher for the semi-automated device. The differences are amplified if the device-specific recommendations of CO-loss corrections are followed.
摘要：
通过一氧化碳（CO）再呼吸重复测量血红蛋白质量是一项后勤挑战，因为建议在措施之间提示数小时以最大程度地减少CO积累。这项研究调查了立即执行重复的CO再呼吸程序的可行性和可靠性。此外,评估了从三种不同CO再呼吸装置获得的血红蛋白质量是否具有可比性.55名健康参与者(22名男性，23名女性）总共进行了222次重复的CO再呼吸程序。此外,在随机交叉设计中，10名参与者完成了三项实验试验，每个包括三个CO再呼吸程序，第一个和第二个分开24小时，第二个和第三个分开5-10分钟。每个试验间隔>48小时，并使用玻璃肺活量计进行，半自动机电装置，或设计用于肺部测量的标准三通塑料阀。当在第一次测量之后立即进行时,在第二次测量时血红蛋白质量降低3±22g(p<0.05),典型误差为1.1%。羧基血红蛋白水平达到10.9±1.3%。在随机试验中,血红蛋白质量在玻璃肺活量计和三通阀之间相似，但半自动设备要高出6%(50克)。值得注意的是,血红蛋白质量的差异高达13%（~100克），当设备特定的建议校正CO损失为肌红蛋白和呼气时。总之,执行两个即时CO再呼吸程序是可行和可靠的。血红蛋白质量在玻璃肺活量计和三向塑料阀门之间相当，但对于半自动设备来说更高。如果遵循CO损失校正的设备特定建议，则差异会放大。
