Cerebral effects of hyperglycemia in experimental cardiac arrest

Objective: To investigate the effects of cardiac arrest on cerebral perfusion and oxidative stress during hyperglycemia and normoglycemia. Design: Experimental animal model. Setting: University laboratory. Subjects: Triple-breed pigs (weight, 22-27 kg). Interventions: Thirty-three pigs were randomized and clamped at blood glucose levels of 8.5-10 mM (high) or 4-5.5 mM (normal) and thereafter subjected to alternating current-induced 12-min cardiac arrest followed by 8 mins of cardiopulmonary resuscitation and direct-current shock to restore spontaneous circulation. Measurements and Main Results: Hemodynamics, regional near-infrared light spectroscopy, regional venous HbO(2), and biochemical markers (Protein S100 beta, troponin I, F-2-isoprostanes reflecting oxidative stress and inflammation) were monitored and/or sampled throughout an observation period of 4 hrs. No significant differences were seen in hemodynamics or biochemical profile. The cerebral oxygenation by means of regional near-infrared light spectroscopy was higher in the hyperglycemic (H) than in the normal (N) group after restoration of spontaneous circulation (p < .05). However, tendencies toward increased protein S100 beta and 15-keto-dihydro-prostaglandin F-2 alpha were observed in the H group but were not statistically significant. Conclusions: The responses to 12-min cardiac arrest and cardiopulmonary resuscitation share large similarities during hyperglycemia and normoglycemia. The higher cerebral tissue oxygenation observed in the hyperglycemia needs to be confirmed and the phenomenon needs to be addressed in future studies. (Crit Care Med 2010; 38: 1726-1732)