Difference in end-tidal carbon dioxide changes during cardiopulmonary resuscitation between cardiac arrest due to asphyxia and VF/VT cardiac arrest
© BioMed Central Ltd 2003
Published: 3 March 2003
In recent years there has been an increased interest in the use of capnometry, the noninvasive continuous measurement of partial pressure of end-tidal carbon dioxide (petCO2) in expired air. petCO2 monitoring has been useful in determining the effectiveness of cardiopulmonary resuscitation. During cardiopulmonary reanimation (CPR) the petCO2 correlates with cardiac output and efficacy of cardiac compressions and as such has been shown to have prognostic value in CPR. This study was undertaken to compare initial petCO2 and petCO2 after 1 min during CPR in cardiac arrest due to asphyxia versus cardiac arrest due to ventricular fibrillation (VF).
This prospective study was conducted at the Center of Emergency Medicine – Pre-hospital Unit Maribor, Slovenia. The study included two groups of patients. The first group represented patients who suffered from heart arrest due to asphyxia. The causes of asphyxia included foreign body in the airway, aspiration, suicide with hanging, drowning, edema or tumor of airway and acute asthma attack. The initial rhythm was either asystole or pulse-less electrical activity. We compared this group of patients with those whose cause of heart arrest was AMI or malignant arrhythmias (VF or pulseless VT). petCO2 measurements were made by infrared side stream capnometer (BCI Capnocheck Model 20600A1; BCI international, Waukesha, WI, USA). petCO2 was measured for both groups immediately after intubation (first measurement) and then repeatedly every minute. Thus the initial, average and end petCO2 was detected for both groups. We performed the same procedure for the patients with return of spontaneous circulation (ROSC) and for those without ROSC. Statistics used: Student's t test, χ2 test, P < 0.05 was considered significant.
The value of initial, average, final and petCO2 after 1 min of CPR for arrest due to asphyxia and VT/VF cardiac arrest
Initial petCO2 (mean)
petCO2 after 1 min of CPR (mean)
Average petCO2 (mean)
Final petCO2 (mean)
64.2 ± 15.2
28.4 ± 5.3
43.2 ± 10.2
28.4 ± 10.6
VF/VT cardiac arrest
12.5 ± 5.1
23.6 ± 4.3
16.4 ± 6.3
22.4 ± 8.3
In cardiac arrest caused by asphyxia, the initial petCO2 is much higher than in cardiac arrest due to VF and does not correlate with ROSC.
After 1 min of CPR, petCO2 correlates with ROSC and it is an important method for noninvasive monitoring of the effectiveness of CPR.