Heines Serge J H, Strauch Ulrich, Roekaerts Paul M H J, Winkens Bjorn, Bergmans Dennis C J J
Department of Intensive Care, Maastricht University Medical Centre, Maastricht, The Netherlands.
J Emerg Med. 2013 Jul;45(1):130-5. doi: 10.1016/j.jemermed.2012.11.019. Epub 2013 Jan 30.
The determination of end-tidal carbon dioxide (etCO2) is very helpful in cardiac resuscitation for confirmation and monitoring of endotracheal tube placement and as an indicator of return of circulation and effectiveness of chest compressions. There is now also widespread use of capnometry on-site at emergency and trauma fields.
We studied the accuracy and correlation of three capnometers (EMMA, Medtronic, and Evita) with partial pressure of arterial CO2 (PaCO2) measurements.
The three capnometers were placed in-line in the ventilator tubing of the patient. Forty sedated and mechanically ventilated post-cardiac surgery patients were studied. Twenty consecutive etCO2 values were collected simultaneously from all three monitors while drawing an arterial blood sample. Paired sample t-test and Pearson correlation were used to compare the capnometers and their correlation with PaCO2.
The correlation of etCO2 measurements between all three capnometers was good (Emma vs. Evita: 0.874, Emma vs. Medtronic: 0.949, Evita vs. Medtronic: 0.878). The correlation of PaCO2 with the Evita is the lowest (0.671) as compared to the EMMA (0.693) and the Medtronic (0.727). The lowest dispersion of the difference between etCO2 and PaCO2 was seen in EMMA (3.30), the highest in Evita (3.98).
A good correlation between etCO2 and PaCO2 was shown with the three capnometers in the present study. However, etCO2 measurements were not valid to estimate PaCO2 in these patients. Therefore, capnometry cannot be used to replace serial blood gas analyses completely, but may be a good cardiopulmonary trend monitor and alerting system in catastrophic events.
呼气末二氧化碳（etCO2）的测定在心脏复苏中对于确认和监测气管插管位置非常有帮助，并且可作为循环恢复和胸外按压效果的指标。目前，在急诊和创伤现场也广泛使用二氧化碳监测仪。
我们研究了三种二氧化碳监测仪（EMMA、美敦力和Evita）与动脉血二氧化碳分压（PaCO2）测量值的准确性和相关性。
将这三种二氧化碳监测仪串联放置在患者的呼吸机管道中。对40例心脏手术后接受镇静和机械通气的患者进行了研究。在采集动脉血样本时，同时从所有三台监测仪上连续收集20个etCO2值。采用配对样本t检验和Pearson相关性分析来比较这些二氧化碳监测仪及其与PaCO2的相关性。
所有三台二氧化碳监测仪之间的etCO2测量值相关性良好（Emma与Evita：0.874，Emma与美敦力：0.949，Evita与美敦力：0.878）。与EMMA（0.693）和美敦力（0.727）相比，Evita与PaCO2的相关性最低（0.671）。etCO2与PaCO2之间差异的离散度在EMMA中最低（3.30），在Evita中最高（3.98）。
本研究中三种二氧化碳监测仪显示etCO2与PaCO2之间具有良好的相关性。然而，在这些患者中，etCO2测量值不能有效估计PaCO2。因此，二氧化碳监测法不能完全替代系列血气分析，但在灾难性事件中可能是一种良好的心肺趋势监测和警报系统。
