Arterial blood gas parameters during cardiopulmonary resuscitation and sustained return of spontaneous circulation in out-of-hospital cardiac arrest: a preplanned secondary analysis of the AMCPR trial.
June-Sung Kim, Youn-Jung Kim, Won Young Kim
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In 30 seconds
This preplanned secondary analysis of the AMCPR trial examined arterial blood gas parameters during emergency-department resuscitation in adults with out-of-hospital cardiac arrest. Among 135 patients with a sample at the protocol-defined 10-minute time point, higher PaO₂ was independently associated with sustained return of spontaneous circulation (adjusted odds ratio 1.02; 95% CI 1.01-1.02). Exploratory analyses identified PaO₂ >60 mmHg and PaCO₂ <70 mmHg as optimal cut-offs; pH and lactate showed no consistent pattern. The PaO₂ association was only partly separable from resuscitation duration.
Key findings
- Of 251 patients, 93 (37.1%) achieved sustained ROSC; 135 had a 10-minute arterial blood gas sample.
- In the primary analysis, 10-minute PaO₂ was associated with sustained ROSC (adjusted odds ratio 1.02; 95% CI 1.01-1.02).
- Exploratory analyses identified PaO₂ >60 mmHg and PaCO₂ <70 mmHg as optimal cut-offs; pH and lactate showed no consistent pattern.
- Twenty patients (8.0%) survived to discharge and 2 (0.8%) had a favorable neurological outcome.
Why it matters
Arterial blood gas measurements during monitored resuscitation may offer physiologic information relevant to sustained ROSC beyond hemodynamic monitoring. The observed association between higher PaO₂ and ROSC is clinically informative, but its partial relationship with resuscitation duration means it should not be interpreted as evidence that changing PaO₂ improves outcomes.
What to keep in mind
This was a secondary analysis, and the primary analysis included only the 135 patients with a 10-minute sample. The PaO₂ association was only partly separable from resuscitation duration.