Neurologic Outcome after Asphyxial Cardiac Arrest in a Juvenile Porcine Model: Comparison of Epinephrine and Vasopressin, Alone or Combined with Nitroglycerin

Abstract

Aims: Hypoxemic encephalopathy is a devastating complication of asphyxial cardiac arrest in children, commonly occurring despite prompt resuscitation. Epinephrine, incorporated in present algorithms, may contribute to unfavorable outcome by causing excessive vasoconstriction, but the effects of alternative agents are unclear. Here, we compared the neurologic outcome after epinephrine with that after vasopressin (alone or combined with nitroglycerin) in a juvenile porcine model of asphyxia. Study Design: Randomized experimental animal study. Place and Duration of Study: Experimental surgery and surgical research department, of the Medical School, Athens University, from January 2013 to February 2016. Methodology: Asphyxia was induced in 30 Landrace piglets (12-15 weeks of age) by occlusion of the endotracheal tube, leading to cardiac arrest. Four minutes thereafter, resuscitation was commenced with mechanical ventilation and chest compressions. The animals were randomized into three treatment groups, namely into epinephrine (E, n=10) vasopressin (VP, n=10) or vasopressin plus nitroglycerin (VP+NTG, n=10). Hemodynamic variables were measured at baseline and for 30 minutes after the onset of resuscitation. Neurological deficit and brain histological damage scores were assessed in survivors at 24 hours.   Results: At baseline, hemodynamic variables did not differ between groups. The rates of restoration of spontaneous circulation (ROSC), followed by successful extubation, were comparable in the three groups, as were 24-hour survival rates. Mean aortic pressure and coronary perfusion pressure were higher in the VP and VP+NTG groups at the 5th minute of resuscitation, but lower than in the E group at the 30th minute. Neurological deficit and brain histological damage were improved after VP or VP+NTG, compared to that after E. Conclusion: In this juvenile porcine model of asphyxial cardiac arrest, vasopressin (with or without nitroglycerin) yielded improved neurologic outcome, when compared to epinephrine, albeit similar ROSC and survival rates.