Comparison of Early Versus Delayed Initiation of Vasopressin in Post-Cardiothoracic Surgery Vasoplegic Shock and the Effect on Post-Operative Atrial Fibrillation

Post-operative complications of cardiothoracic surgery include vasoplegic shock and post-operative atrial fibrillation (POAF). Use of catecholamines for vasoplegic shock may enhance the risk of POAF; thus, use of non-catecholamine vasopressors is reasonable. This retrospective, single-center cohort study compared early to delayed initiation of vasopressin in vasoplegic shock and assessed the association with POAF. Patients were included if they were ≥ 18 years of age, underwent cardiothoracic surgery, and were diagnosed with vasoplegic shock requiring norepinephrine and vasopressin post-operatively. Early vasopressin use was defined as vasopressin initiated within six hours of ICU admission and delayed vasopressin use was defined as vasopressin initiated greater than six hours and up to 24 hafter ICU admission. In total, 126 patients were included. Patients were primarily male (83.3%) and Caucasian (80.1%). Most patients received coronary artery bypass grafting (77.8%). Post-operative hemodynamics were similar between groups, although patients in the early vasopressin group were more likely to receive earlier initiation of norepinephrine (17 vs 62 min, <i>P</i> < .001). Post-operative atrial fibrillation occurred in 21.8% of patients in the early vasopressin group compared to 28% of patients in the late vasopressin group during ICU admission (<i>P</i> = .508), with most patients on vasopressors at time of POAF onset (72.4%). Observations in patients who received early vasopressin were shorter duration of vasoplegic shock (39 vs 60 h, <i>P</i> < .001), shorter ICU length of stay (2.2 vs 3 days, <i>P</i> = .009) and shorter hospital length of stay (7.1 vs 9.8 days, <i>P</i> = .005). Multivariate logistic regression with variables including intraoperative vasopressin use and the POAF score did not impact the primary outcome. Early initiation of vasopressin was not significantly associated with a decreased rate of POAF in the management of vasoplegic shock after cardiothoracic surgery. Further investigation into early vasopressin use in this patient population is warranted.