Abstract 107: Comparison Between Cerebral Microcirculatory Blood Flow Following Epinephrine and Vasopressin During CPR
Introduction. Both epinephrine and vasopressin increase cerebral cortical large vessel pressure when administered during CPR. However, we recently demonstrated that epinephrine reduces cerebral cortical microcirculatory blood flow (MBF). Accordingly, we explored the effects of non-adrenergic vasopressin on cerebral cortical perfusion.
Methods. Ten domestic male pigs weighing 40 ± 2 kg were intubated and mechanically ventilated. A fronto-parietal bilateral craniotomy was created. MBF was measured with the Orthogonal Polarization Spectral imaging method using the CYTOSCAN A/R (Cytometrics Inc., Philadelphia, PA). Tissue carbon dioxide tension (PbCO2) was measured with a miniature carbon dioxide tissue electrode (CO2-O2-PH ABG Module, Optical Sensors Inc, MN). Blood flow velocity in pial and penetrating vessels < 20 μm was graded from 0 (no flow) to 3 (normal). Ventricular fibrillation (VF) was induced by an AC current delivered to the right ventricular endocardium. VF was untreated for 3 min. Animals were randomized to receive either epinephrine (30 μg/kg) or vasopressin (0.4 U/kg) at one minute after the start of CPR. After 4 minutes of CPR including precordial compression and ventilation with oxygen, defibrillation was attempted.
Results. All animals were successfully resuscitated. Significantly lower PbCO2 and greater MBF were observed after vasopressin (Figure⇓).
Conclusion. Cortical microcirculatory blood flow was markedly reduced after epinephrine, but not after vasopressin.