Alfred I DuPont Hospital for Children, Delaware, USA
Introduction: The incidence of hyperoxemia during post-cardiac arrest care and its effect on neurologic outcomes are not well defined. Tissue level hyperoxia can lead to cell injury and apoptosis, especially following ischemic brain injury. This study was undertaken to determine the incidence of hyperoxemia and to test the hypothesis that it is associated with worse neurologic outcomes as defined by functional status score (FSS).
Methods: This was a retrospective cohort study conducted at a tertiary care hospital including children age < 18 years admitted to the Pediatric Intensive Care Unit (PICU) after cardiac arrest who required mechanical ventilation and survived to hospital discharge or 30 days post cardiac arrest. Hyperoxemia was defined by PaO2 (partial pressure of arterial O2) of >200 mmHg for >50% of all available PaO2 values or by oxygen saturation > 97% while receiving 35% FiO2 or more for >50% of time during the 24 hours post cardiac arrest. Data were also collected regarding confounding factors including in vs out of hospital cardiac arrest, duration of arrest and CPR, and peak lactate, glucose, and sodium levels. The primary outcome was the FSS post-cardiac arrest at 30 days or at discharge.
Results: A total of 84 patients over a period of 10 years who met the inclusion criteria were analyzed. 25 (30%) of the patients had hyperoxemia, and 59 (70%) patients were classified as normoxemic. In the hyperoxemia group 9/27(33.3%) children had in-hospital arrest. In the normoxemia group 40/57(70%) had out of hospital arrest. Average duration of CPR was 4.74 minutes in the hyperoxemia group and 5.08 minutes in the normoxemia group. The average lactate, glucose and sodium levels were 3.98, 188 and 140.6 in the hyperoxemia group and 3.97, 189.9 and 139.1 in the normoxemia group. The average post cardiac arrest FSS was 10.52 in the hyperoxemia group and 9.92 in the normoxemia group. There was no statistical difference in FSS between the two groups.
Conclusions: We are the first to report the incidence of hyperoxemia during post-cardiac arrest care based on duration. We did not find a statistical difference in FSS between the hyperoxemia and normoxemia groups. Retrospective analysis and sample size were important limitations.
