Survey of the Relationship Between End Tidal CO2 and Return of Spontaneous Circulation During Cardiopulmonary Resuscitation

Return of spontaneous circulation is the first purpose of cardiopulmonary resuscitation, and quality of cardiopulmonary resuscitation is an important factor for return of spontaneous circulation in cardiopulmonary arrest patients. Therefore, survey of end tidal CO2 can be a feedback for quality of CPR. This study was conducted with the aim of determining the relationship end tidal CO2 and return of spontaneous circulation.
In this descriptive cross-sectional study, 80 cases of CPR based on inclusion and exclusion criteria were selected by convenience sampling at Ghaem hospital of Mashhad (2014). The instruments used included patients demographic data and information about the progress of cardiopulmonary resuscitation including end-tidal carbon dioxide levels and the results CPR. At the beginning of cardiopulmonary resuscitation, Capnograph was connected to endotracheal tube and the patient’s end-tidal CO2 was recorded and it was related to the Return of Spontaneous Circulation (ROSC was defined as the presence of a palpable femoral arterial pulse and a systolic blood pressure above 80 mmHg for longer than three minutes). Data were collected and analyzed using the SPSS software version 16 and descriptive (frequency, mean and standard deviation) and inferential statistics (Chi-square, Fisher's exact, t-test, correlation and linear regression).
Mean and standard deviation of age of patients was 67.3 ± 1.5 years; 47.5% were male and 98.8% of patient’s cardiac rhythm in the start of CPR was asystole. The End Tidal CO2 (ETCO2) in patients with successful CPR was 21.6 ± 13.7 mmhg and in others was 17.7 ± 10.2 mmHg (P=0.16). The results showed that in patients that end-tidal CO2 during resuscitation was less than 1 mm Hg, the rate of return of spontaneous circulation was 41.2% and in patients that end-tidal CO2 during resuscitation was 30-41 mmHg, the rate of return of spontaneous circulation was 75%.
The results showed that high levels of ETCO2 during cardiopulmonary resuscitation increased potential of return of spontaneous circulation. The ETCO2 can be a feedback for quality of CPR. Therefore, the use of end-tidal carbon dioxide monitoring during cardiopulmonary resuscitation to CPR members is recommended.