(1040) Implementing a Cardiopulmonary Bypass Vasoplegia Protocol: A Step-Wise Approach With Angiotensin II

Introduction: Vasoplegia occurs peri-operatively in the setting of cardiopulmonary bypass (CPB) and is characterized extreme hypotension. In a subset of patients, hypotension persists despite the use conventional vasopressor agents. The use of rescue agents such as hydroxocobalamin (B12), methylene blue (MB) and angiotensin II (ATII) has gained popularity; however, there is a lack of a standardized definition of refractory vasoplegia and treatment pathways. The aim of this study was to create and implement a protocolized approach to the management of refractory vasoplegia.

Methods: This was a retrospective, pre/post study of patients undergoing CPB between 7/2023 and 7/2024 with protocol implementation occurring in 1/2024. All patients prior to this were considered to be the Pre-Group with those after being the Post-Group. A multidisciplinary team developed a standardized, step-wise protocol (MB -> ATII -> B12) to treat refractory vasoplegia that was initiated when vasopressor doses exceeded 0.25 ug/kg/min norepinephrine equivalents. The primary outcome was the reduction of refractory vasoplegia drug expenditures per CPB case between the two groups. Secondary outcomes included percentage of cases requiring therapy, efficacy of each treatment modality and exploring dose-response to ATII.

Results: A total of 1,134 CPB cases were reviewed with 175 patients receiving at least one dose of B12, MB or ATII, with 113 in the Pre-group and 62 in the Post-Group. The most commonly administered medication in the Pre-group was B12 (90%) and MB in the Post-group (64%). The median refractory vasoplegia medication expenditure per CPB case decreased from $150 to $70 in the Post-Group, p < 0.05, which represented a total cost savings of $44,182. The percent of CPB cases utilizing a refractory vasoplegia medication decreased from 20% to 11% in the Post-Group, p < 0.05. ATII was used after MB failure in 17 patients and was administered an average of 42 minutes after MB dosing. The median duration and dose of ATII infusion were 136 minutes and 23.6 ng/kg/min, respectively. Three patients (18%) failed ATII therapy and required B12.

Conclusions: A standardized approach to refractory vasoplegia after CPB led to a reduction in patients requiring treatment and decrease in drug expenditures with most patients responding to MB.