J Emerg Med. 2025 Sep 24;80:266-275. doi: 10.1016/j.jemermed.2025.09.024. Online ahead of print.

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) is associated with high mortality. Point of care (POC) blood gas analysis can aid in early risk stratification of OHCA patients by providing insights on metabolic derangements during resuscitation and post-arrest care.

OBJECTIVE: To assess the role of blood gas analysis in predicting OHCA outcomes.

METHODS: Four electronic databases (i.e., ProQuest, PubMed/MEDLINE, ScienceDirect, and Web of Science) were searched in this systematic review (PROSPERO: CRD42024552025). Eligible studies were those that included patients who had experienced OHCA, reported blood gas values, and reported any of the following outcomes: return of spontaneous circulation [ROSC], survival to hospital discharge, or good neurological outcomes.

RESULTS: Thirteen studies were included in the review, with a pooled sample of 14,584 patients; 57% were male. Sampling time differed between studies: either at the beginning of or after 2 cycles of resuscitation, upon arrival, or 10 minutes after arrival to the emergency department. Blood gas values (i.e., pH, pO₂ and pCO₂) varied across studies for patients with ROSC. Some studies reported higher values in ROSC patients compared to non-ROSC patients, and vice versa. Blood gas values were generally higher among patients who survived or had favorable neurological outcomes; however, their mean values varied and were often contradictory across studies, which constrained the pooling of these estimates into a meta-analysis.

CONCLUSION: At present, POC blood gas analysis cannot reliably be used for prognosis among OHCA patients. Future studies should improve the methodology by considering factors like sampling time and source (i.e., venous or arterial).

PubMed:41364951 | DOI:10.1016/j.jemermed.2025.09.024