Purpose of the study
Hemoglobin, pO2 and lactate are part of routine laboratory tests in survivors of cardiac arrest. They represent possible treatment targets, however, optimum levels are not known. The purpose of our study was to determine the differences in survivors and non-survivors after cardiac arrest in post-resuscitation hemoglobin, pO2 and lactate levels in our patient population. 
Materials and methods
We retrospectively included patients >18 years old with non-traumatic out-of-hospital or in-hospital cardiac arrest who were admitted from 1st January 2015 to 31st December 2016. We analysed the lowest hemoglobin, the highest pO2 and the highest lactate in the first 24 hours after admission in survivors and non-survivors to hospital discharge. 
Results 
We included 153 patients, 109 (71.2%) were males, mean age was 63.8±13.1 years, and 62 (40.5%) survived to hospital discharge. There were no differences between survivors and non-survivors in age (70±12 years vs. 66±13, p=0.06) and gender (70.9% vs. 71.4%, p=1.00). Rate of ventricular fibrillation (51.6% vs. 24.2%, p=0.006) and bystander CPR (54.8% vs. 31.9%, p=0.007) were significantly higher in survivors. The lowest hemoglobin was significantly higher in survivors (132.5±21.4 g/l vs. 112.9±26, p<0.0001), while the highest pO2 and lactate were significantly higher in non-survivors (16.2±6.4 kPa vs. 19±9.7 kPa, p=0.04, and 4.9±3.1 mmol/l vs. 8.5±5.5 mmol/l, p<0.0001, respectively).  
Conclusions
The results of our study are in concordance with other studies, where higher hemoglobin, lower pO2 and lower lactate were associated with better survival. Prospective, randomized studies are required to determine the target levels of these parameters.

1 - Higher post-resuscitation hemoglobin, lower pO2 and lower lactate are associated with survival after cardiac arrest