Abstract 13458: Survival After Out-of-hospital Cardiac Arrests and Arterial Oxygen Partial Pressure During Cardiopulmonary Resuscitation: The CRITICAL Study in Osaka, Japan

Introduction: The current resuscitation guidelines recommend the use of the highest possible inspired oxygen concentration during cardiopulmonary resuscitation (CPR). On the other hand, there are conflicting results that PaO 2 after return of spontaneous circulation might be harmful to better outcome. Hypothesis: The objective of this study is to investigate the association between PaO 2 during CPR and survival after out-of-hospital cardiac arrests (OHCA). Methods: Study design: Multicenter cohort study. In Osaka Prefecture, Japan, we registered all consecutive OHCA patients who were transported to institutions participating in our CRITICAL registry since July 1, 2012. From this registry, we included non-traumatic adult OHCA patients with arterial blood gas sampled at the hospitals during CPR. The main exposure was PaO 2 in arterial blood gas analysis during CPR. We classified PaO 2 values as three categories (hypoxemia: 0-60 mmHg; normoxemia: 60-300 mmHg; and hyperoxemia: ≥300 mmHg), referring to previous studies. The primary outcome was survival at one-month after OHCA. Multivariable logistic regression analysis was used to adjust confounders. Results: We analyzed 710 patients. Among them, 4.5% (N = 32) survived at one month and 1.5% (N = 11) had a neurologically favorable outcome. As PaO 2 categories during CPR became higher, one-month survival increased (3.0% [16/528] in hypoxemia, 6.6% [11/166] in normoxemia, and 31.2% [5/16] in hyperoxemia). The adjusted odds ratio (AOR) for one-month survival, controlling for first documented rhythm and bystander witness, reffered to the hypoxemia group was 1.98 (95%CI 0.83-4.69, P=0.120 ) in normoxemia and 8.03 (95%CI 2.16-29.80, P=0.002) in hyperoxemia group. Conclusions: Higher PaO 2 categories during CPR were associated with better survival at one-month in non-traumatic adult OHCA patients. During CPR, maintaining high PaO 2 might be useful for improving outcomes of OHCA patients.