Pediatric Extracorporeal Cardiopulmonary Resuscitation: Development of a Porcine Model and the Influence of Cardiopulmonary Resuscitation Duration on Brain Injury

Abstract

BACKGROUND: The primary objective was to develop a porcine model of prolonged (30 or 60 minutes) pediatric cardiopulmonary resuscitation (CPR) followed by 22-to 24-hour survival with extracorporeal life support, and secondarily to evaluate differences in neurologic injury. METHODS AND RESULTS: Ten-kilogram, 4-week-old female piglets were used. First, model development established the tech-nique (n=8). Then, a pilot study was conducted (n=15). After 80% survival was achieved in the final 5 pilot animals, a proof-of-concept randomized study was completed (n=11). Shams (n=6) underwent anesthesia only. Severe neurological injury was determined by a composite score of mitochondrial function, neuropathology, and cerebral metabolism: scale of 0– 6 (severe: >3). Among 15 piglets in the pilot study, overall survival was 10 (67%); of the final 5, overall survival was 4 (80%). Eleven piglets were then randomized to 60 (CPR60, n=5) or 30 minutes of CPR (CPR30, n=5); 1 animal was excluded from prerandomization for intra-abdominal hemorrhage (10/11, 91% survival). Three of 5 animals in the CPR60 group had severe neurological injury scores versus 1 of 5 in the CPR30 group (P=0.52). During ECMO, CPR60 animals had lower pH (CPR60: 7.4 [IQR 7.4–7.4] versus CPR30: 7.5 [IQR 7.4–7.5], P=0.022), higher lactate (CPR60: 6.8 [IQR 6.8–11] versus CPR30: 4.2 [IQR 4.1– 4.3] mmol/L; P=0.012), and higher ICP (CPR60: 19.3 [IQR 11.7– 29.3] versus CPR30: 7.9 [IQR 6.7– 9.3] mm Hg; P=0.037). Both groups had greater mitochondrial injury than shams (CPR60: P<0.001; CPR30: P<0.001). CPR60 did not differ from CPR30 in mitochon-drial respiration, neuropathology, or cerebral metabolism. CONCLUSIONS: A pediatric porcine model of extracorporeal cardiopulmonary resuscitation after 60 and 30 minutes of CPR consistently resulted in 24-hour survival with more severe lactic acidosis in the 60-minute cohort.