(139) Vasopressin Timing in Vasoplegic Shock and the Effect on Postoperative Atrial Fibrillation

Introduction: Vasoplegic shock is a form of distributive shock seen after exposure to cardiopulmonary bypass. Use of catecholamines increase the risk of developing post-operative atrial fibrillation (POAF), suggesting a role for non-catecholamine vasopressors. Prior literature in vasoplegic shock noted a reduction in POAF when utilizing vasopressin as the primary vasopressor. No literature exists regarding the timing of adjunctive vasopressin and its impact on POAF.

Methods: This was a retrospective, single-center cohort study evaluating patients admitted to the cardiothoracic intensive care unit (ICU). Patients were eligible if they underwent cardiothoracic surgery, were diagnosed with vasoplegic shock and treated with norepinephrine and vasopressin within 24 hours of ICU admission. Early vasopressin use was defined as receipt within six hours of ICU admission. The primary outcome was the incidence of POAF during ICU admission. Secondary outcomes included time to atrial fibrillation development, duration of vasoplegic shock, in-hospital mortality and ICU and hospital length of stay (LOS).

Results: 126 patients were included, with 101 patients in the early group and 25 patients in the delayed group. Patients were primarily male, Caucasian and had a median POAF score of 2. Coronary artery bypass grafting occurred in 78.6% of patients. Hemodynamics at ICU admission were similar between groups, as were initial vasopressor and inotrope requirements. POAF occurred in 21.8% of patients in the early vasopressin group compared to 28% of patients in the delayed vasopressin group (p = 0.508). Of those who developed POAF, 72.4% occurred while on vasopressors. Time to POAF development was not significantly different between groups (41.9 vs 49 hours, p = 0.647). Patients in the early vasopressin group had a significantly shorter duration of vasoplegia (39 vs 60 hours, p < 0.001) in addition to shorter ICU (2.2 vs 3 days, p = 0.009) and hospital (7.1 vs 9.8 days, p = 0.005) LOS. No differences were seen with in-hospital mortality or acute kidney injury at 48 hours.

Conclusions: Early initiation of vasopressin was not associated with decreased rates of POAF but may impact duration of vasoplegia and may decrease ICU and hospital LOS.