Zegdi R, Caïd R, Van De Louw A, Perrin D, Burdin M, Boiteau R, Tenaillon A
Department of Intensive Care, Louise Michel Hospital, Courcouronnes, France.
Intensive Care Med. 2000 Sep;26(9):1228-31. doi: 10.1007/s001340000590.
To assess the feasibility of exhaled carbon monoxide (CO) measurements in mechanically ventilated critically ill adult patients and to determine the influence of inspired oxygen fraction on this measurement.
Prospective physiologic study.
Medical ICU in a community hospital.
The study was performed on nine mechanically ventilated patients with varying diagnoses.
Carbon monoxide concentration was determined with an infrared CO analyzer on exhaled breath collected at the outlet of the ventilator. We assessed the stability of exhaled carbon monoxide concentration over a 4-hour period and determined its course during a 7-hour period after inspired oxygen fraction had been abruptly increased from baseline to 1. Carbon monoxide was detected in exhaled breath in each patient at a higher concentration than in inspired gas (0.64 +/- 0.1 ppm vs 0.25 ppm, approximately). Exhaled carbon monoxide did not vary during a 4-hour period in five hemodynamically stable patients. When inspired oxygen fraction was increased from baseline (0.52 +/- 0.04) to 1, exhaled carbon monoxide concentration increased abruptly from baseline (0.63 +/- 0.13 ppm) to a peak value of 1.54 +/- 0.16 ppm within 15 min and returned slowly to baseline values within 7 h.
CO was easily detected in the exhaled breath of mechanically ventilated patients and CO lung excretion was markedly but transiently dependent on inspired oxygen fraction. Other studies are warranted in order to determine the different factors that might influence CO lung excretion in critically ill patients.
评估对机械通气的成年危重症患者进行呼出气一氧化碳（CO）测量的可行性，并确定吸入氧分数对该测量的影响。
前瞻性生理学研究。
社区医院的医学重症监护病房。
对9例诊断各异的机械通气患者进行了研究。
使用红外CO分析仪测定在呼吸机出口收集的呼出气中的一氧化碳浓度。我们评估了4小时内呼出气一氧化碳浓度 的稳定性，并在吸入氧分数从基线突然增加到1后7小时内确定其变化过程。在每位患者的呼出气中均检测到一氧化碳，其浓度高于吸入气体中的浓度（分别约为0.64±0.1 ppm和0.25 ppm）。在5例血流动力学稳定的患者中，4小时内呼出气一氧化碳浓度没有变化。当吸入氧分数从基线（0.52±0.04）增加到1时，呼出气一氧化碳浓度在15分钟内从基线（0.63±0.13 ppm）突然增加到峰值1.54±0.16 ppm，并在7小时内缓慢恢复到基线值。
在机械通气患者的呼出气中很容易检测到CO，并且CO的肺排泄明显但短暂地依赖于吸入氧分数。有必要进行其他研究以确定可能影响危重症患者CO肺排泄的不同因素。
