Elective Initial Blood Testing for the Neurological Outcomes of Pediatric Out-of-Hospital Cardiac Arrests

Introduction: Predictive blood testing for outcomes of out-of-hospital cardiac arrest (OHCA) remains unclear in childhood. Methods: We retrospectively analyzed < 15 years old patients with OHCA who entered Kyushu University Hospital between 2006 and 2021. Pediatric Cerebral Performance Category Scale (PCPC) and ΔPCPC score (post-arrest PCPC 30 days minus pre-arrest value) classified them into intact survival (ΔPCPC = 0) or poor survival (ΔPCPC = 1–4), and death or brain-death (PCPC = 6). Initial laboratory data on admission were studied focusing on outcomes and time from detection of CA to emergency room (ED). Results: Eligible 115 patients included 38 (15 intact-, 23 poor-) survivors and 77 deaths. Serum transaminase, lactate dehydrogenase, and potassium levels were higher in death cases than survivors, but did not differentiate poor from intact survivors. Blood gas data showed better levels in intact survivors than others, but did not differentiate poor survivors from deaths. In 41 witnessed cases including 16 (8 intact-, 8 poor-) survivors, no one survived with > 40 min of time from detection of CA to ED. In 28 witnessed cases with < 40 min of time from CA to ED, no biochemical variables discriminated the three groups of patients, but three blood gas parameters (pH, HCO₃⁻, and BE) differentiated intact survivors from the other two groups. Furthermore, pH and BE were correlated with the duration of CA before hospital arrival in the analysis of witnessed OHCA patients. Conclusions: Initial blood gas data on admission provide valuable information for estimating the duration of CA before hospital arrival and reflect survivors' outcomes in pediatric OHCA patients.