Hyperoxia, hypocapnia and hypercapnia as outcome factors after cardiac arrest in children.
PURPOSE
Arterial hyperoxia after resuscitation has been associated with increased mortality in adults. The aim of this study was to test the hypothesis that post-resuscitation hyperoxia and hypocapnia are associated with increased mortality after resuscitation in pediatric patients.


METHODS
We performed a prospective observational multicenter hospital-based study including 223 children aged between 1 month and 18 years who achieved return of spontaneous circulation after in-hospital cardiac arrest and for whom arterial blood gas analysis data were available.


RESULTS
After return of spontaneous circulation, 8.5% of patients had hyperoxia (defined as PaO(2)>300 mm Hg) and 26.5% hypoxia (defined as PaO(2)<60 mm Hg). No statistical differences in mortality were observed when patients with hyperoxia (52.6%), hypoxia (42.4%), or normoxia (40.7%) (p=0.61). Hypocapnia (defined as PaCO(2)<30 mm Hg) was observed in 13.5% of patients and hypercapnia (defined as PaCO(2)>50 mm Hg) in 27.6%. Patients with hypercapnia or hypocapnia had significantly higher mortality (59.0% and 50.0%, respectively) than patients with normocapnia (33.1%) (p=0.002). At 24h after return of spontaneous circulation, neither PaO(2) nor PaCO(2) values were associated with mortality. Multiple logistic regression analysis showed that hypercapnia (OR, 3.27; 95% CI, 1.62-6.61; p=0.001) and hypocapnia (OR, 2.71; 95% CI, 1.04-7.05; p=0.04) after return of spontaneous circulation were significant mortality factors.


CONCLUSIONS
In children resuscitated from cardiac arrest, hyperoxemia after return of spontaneous circulation or 24h later was not associated with mortality. On the other hand, hypercapnia and hypocapnia were associated with higher mortality than normocapnia.