Steedman D J, Robertson C E
Department of Emergency Medicine, Royal Infirmary, Edinburgh.
Arch Emerg Med. 1990 Sep;7(3):129-34. doi: 10.1136/emj.7.3.129.
End-tidal carbon dioxide concentrations were measured prospectively in 12 cardiac arrest patients undergoing cardiopulmonary resuscitation (CPR) in an accident and emergency department. The end-tidal carbon dioxide (CO2) concentration decreased from a mean (+/- SD) of 4.55 +/- 0.88% 1 min after chest compression and ventilation was established, to values ranging from 2.29 +/- 0.84% at 2 min to 1.56 +/- 0.66% following 8 min of CPR. Spontaneous circulation was restored in five patients. This was accompanied by a rapid rise in end-tidal CO2 which peaked at 2 min (3.7 +/- 1.08%). Changes in end-tidal CO2 values were often the first indication of return of spontaneous cardiac output. There was a significant difference in the end-tidal CO2 in patients undergoing CPR before return of spontaneous circulation (2.63 +/- 0.32%) and patients who failed to develop spontaneous output (1.64 +/- 0.89%) (p < 0.001). We conclude that measurement of end-tidal CO2 concentration provides a simple and non-invasive method of measuring blood flow during CPR and can indicate return of spontaneous circulation.
前瞻性地测量了12例在急诊部门接受心肺复苏（CPR）的心脏骤停患者的呼气末二氧化碳浓度。在建立胸外按压和通气后1分钟，呼气末二氧化碳（CO2）浓度从平均（±标准差）4.55±0.88%下降，至CPR 2分钟时为2.29±0.84%，8分钟后为1.56±0.66%。5例患者恢复了自主循环。这伴随着呼气末CO2的迅速上升，在2分钟时达到峰值（3.7±1.08%）。呼气末CO2值的变化往往是自主心输出量恢复的首个迹象。在恢复自主循环前接受CPR的患者（2.63±0.32%）与未产生自主心输出量的患者（1.64±0.89%）的呼气末CO2存在显著差异（p<0.001）。我们得出结论，测量呼气末CO2浓度提供了一种在CPR期间测量血流的简单且非侵入性的方法，并且可以指示自主循环的恢复。
