The Value of Arterial Blood Gas Parameters for Prediction of Mortality in Survivors of Out-of-hospital Cardiac Arrest

CONTEXT Sudden cardiac death is one of the leading causes of death in Europe, and early prognostication remains challenging. There is a lack of valid parameters for the prediction of survival after cardiac arrest. AIMS This study aims to investigate if arterial blood gas parameters correlate with mortality of patients after out-of-hospital cardiac arrest. MATERIALS AND METHODS All patients who were admitted to our hospital after resuscitation following out-of-hospital cardiac arrest between January 1, 2008, and December 31, 2013, were included in this retrospective study. The patient's survival 5 days after resuscitation defined the study end-point. For the statistical analysis, the mean, standard deviation, Student's t-test, Chi-square test, and logistic regression analyses were used (level of significance P < 0.05). RESULTS Arterial blood gas samples were taken from 170 patients. In particular, pH < 7.0 (odds ratio [OR]: 7.20; 95% confidence interval [CI]: 3.11-16.69; P < 0.001) and lactate ≥ 5.0 mmol/L (OR: 6.79; 95% CI: 2.77-16.66; P < 0.001) showed strong and independent correlations with mortality within the first 5 days after hospital admission. CONCLUSION Our study results indicate that several arterial blood gas parameters correlate with mortality of patients after out-of-hospital resuscitation. The most relevant parameters are pH and lactate because they are strongly and independently associated with mortality within the first 5 days after resuscitation. Despite this correlation, none of these parameters by oneself is strong enough to allow an early prognostication. Still, these parameters can contribute as part of a multimodal approach to assessing the patients' prognosis.