Comparison of Vasopressin versus Norepinephrine in a Pig Model of Refractory Cardiogenic Shock Complicated by Cardiac Arrest and Resuscitated with Veno-arterial ECMO

Background: The choice of the best vasopressor after ExtraCorporeal Membrane Oxygenation (ECMO) implantation after cardiac arrest is not well defined. Circulatory flow recovery with ECMO is associated with vasoplegia and vasopressor need. The present study aimed to compare the effects of norepinephrine and vasopressin in the first 6 h after ECMO initiation. Methods: Cardiac arrest was induced in 20 pigs by coronary surgical ligature and veno-arterial-ECMO was started after a 30-min period of cardio-pulmonary resuscitation. Pigs were randomized into two groups, arginine vasopressin (AVP) or norepinephrine (NE), with the drugs titrated to maintain a mean arterial pressure (MAP) at 65 mm Hg. Macrocirculatory and metabolic parameters were assessed by lactate clearance. Microcirculatory parameters were assessed by sublingual microcirculation with Sidestream Dark Field imaging and peripheral Near InfraRed Spectroscopy. Pulmonary edema was evaluated by measuring lung wet/dry weight ratio. Results: No difference was found between groups regarding ECMO flow and MAP. Fluid resuscitation volume was higher in the NE group (14,000 [11,250-15,250] mL vs. 3,500 [1,750-4,000] mL in the AVP group, P < 0.05). Lung wet/dry weight ratio was higher in the Norepinephrine group. Lactate clearance between H0 and H6 was higher in the AVP group (47.84 [13.42-82.73]% vs. the NE group 25.66 [-7.31 to 35.34)% vs. P < 0.05). No significant difference was observed for sublingual microcirculation values. Baseline tissue oxygen saturation was comparable and higher at both H3 and H6 in the Vasopressin group comparatively to the Norepinephrine group (P < 0.05). Renal and liver function evolution also remained similar in the two groups throughout the study. Conclusions: AVP administration in refractory cardiac arrest resuscitated by veno-arterial-ECMO is associated with a faster lactate clearance, less fluid resuscitation, and less pulmonary edema when compared with NE for similar global and regional hemodynamic effects.