Effect of different durations of post-resuscitation oxygen ventilation on neurological function in rats after cardiac arrest

Abstract

Objective To investigate the effect of pure oxygen ventilation under normothermia for different durations on the neurological outcome inarat model of asphyxia cardiac arrest. Methods Atotal of 32 male SD rats were treated with cardiopulmonary resuscitation 6 min after cardiac arrest induced by asphyxia. After return of spontaneous circulation (ROSC), the rats were randomly divided into 4 groups according to the duration of ventilation of pure oxygen (8 in each group), that is, 0 min group (O2-0 min), 20 min group (O2-20 min), 60 min group (O2-60 min) and 180 min group (O2-180 min). Physiological parameters, continuous electroencephalography (EEG) waveforms, and EEG power of each band during post-resuscitation were recorded and compared among the groups. The serum contents of cardiac troponinT(cTnT) and S100 β protein were measured by enzyme-linked immunosorbent assay (ELISA) at the basic state and 6hafter resuscitation. The neurological deficit score (NDS), 96-hour survival rate and histological changes of hippocampus were compared in the groups. Results After resuscitation, the mean arterial pressure (MAP) was decreased significantly, and the left ventricular ejection fraction (LVEF) was decreased first and then increased in the 4 groups. The 2 indicators were significantly higher in the O2-180 min group than the O2-0 min group (P < 0.05). With the increase of oxygen ventilation, shorter EEG recovery time and gradually stronger EEG power spectrum energy were observed in all the groups. The O2-180 min group had significantly shorter time and stronger energy than the O2-0 min group (P < 0.05). At 6hafter resuscitation, cerebral and myocardial injuries were obviously milder in the O2-180 min group than the O2-0 min group (S100β, P < 0.01; cTnT, P < 0.05). NDS, survival rate and hippocampal injury were significantly improved in the O2-180 min group when compared with the O2-0 min group. Conclusions In this rat model of asphyxia cardiac arrest, prolonged pure oxygen inhalation under normothermia can alleviate cerebral injury, improve neurological outcome and increase the survival rate.

Keywords

• cardiopulmonary resuscitation
• oxygen inhalation time
• brain injury
• ischemia-reperfusion