Abstract 19939: Prolonged Hyperoxic Ventilation After Cardiopulmonary Resuscitation Aggravates Striatal Brain Damage
Purpose: Current guidelines encourage the use of 100% O2 during resuscitation and for an undefined period thereafter even though previous data indicate that pure oxygen ventilation during early reperfusion after cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) increases neuronal death. Retrospectively we analyzed data from a porcine CA model and hypothesized that prolonged hyperoxic reperfusion increases neurohistopathological damage and impairs neurological recovery.
Methods: 15 male pigs underwent 8 mins of CA before 5mins of CPR was performed and defibrillation was attempted. Resuscitated animals were ventilated with either 100 % oxygen for 10 minutes (normoxia; n=7) or 60 minutes (hyperoxia; n=8). At baseline and 10, 60 and 240 minutes after resuscitation physiological variables were obtained. Using an established neurocognitive test in parallel to a neurologic deficit score (NDS) daily functional performance was assessed. On day 5, brains of the re-anaesthetized pigs were harvested for neurohistopathological analyses.
Results: At baseline no differences in hemodynamics and neurological status between groups were observed. Post-resuscitation only PaO2, as a result of the different inspired oxygen fractions, was significantly higher in the hyperoxia group. Hyperoxic animals showed a significantly greater degree of necrotic neurons and perivascular inflammation in the striatum in comparison to normoxic animals. However, for animals exposed to 10 minutes of 100 % oxygen a trend towards improved clinical recovery was observed in both the NDS and the neurocognitive testing.
Conclusion: Prolonged hyperoxic ventilation after CA aggravated necrotic brain damage and perivascular inflammation in the striatum of pigs in this retrospective analysis. FIGURE: Histopathological evaluation of all regions of interest in pigs ventilated with 100% O2 for 1 h (hyperoxia) or 10 min. (normoxia) following successful CPR from CA. *p < 0.05 vs normoxia.
- © 2010 by American Heart Association, Inc.