Abstract Introduction Vasoplegic syndrome is characterized by low systemic vascular resistance (SVR), which results in hypotension, and increased or normal cardiac output. It is a frequent complication following coronary artery bypass grafting (CABG). This condition is primarily mediated by excessive production of nitric oxide, and CABG surgery is directly related to increased nitric oxide synthesis. Postoperative vasoplegic shock is typically managed with vasopressors, with norepinephrine being the first-line agent. Methylene blue has been studied as a potential adjunctive therapy for vasoplegic shock, hypothesized to restore vascular tone through inhibition of the nitric oxide-cyclic guanosine monophosphate (cGMP) pathway. However, its impact on clinical outcomes remains uncertain. We present a case series of five patients who developed vasoplegic shock following CABG and were treated with methylene blue. Methods Patients who underwent CABG at our institution from March 2024 to December 2024 and received methylene blue for shock were included. A total of five patients met these criteria. Common risk factors examined were gender, sex, tobacco use, heart failure, on-pump status, and renal disease. The time to methylene blue administration was analyzed as well as number of pressors at time of administration, time in shock post-administration, and survival. The results were averaged and reported. Results In this case series, methylene blue administration did not consistently result in a reduction in vasopressor dosage or improved overall outcomes. The sole survivor was younger, had preserved cardiac function, and received methylene blue early in the course of shock, suggesting that baseline patient characteristics and timing of intervention influences response. Among patients who received methylene blue within 24 hours of shock onset, one survived and another remained in shock for a prolonged period, indicating that early administration may be associated with benefit in select patients. However, given the lack of consistent hemodynamic improvement and survival benefit in this small cohort, the impact of methylene blue remains uncertain and may depend on individual patient factors and timing of therapy. Discussion Methylene blue inhibits the cGMP pathway in vascular smooth muscle, increasing SVR. It is used as a rescue therapy when standard vasopressors fail. Studies suggest early methylene blue administration reduces mortality, though evidence is mixed, and optimal timing and dosing are yet to be established. Methylene blue partially restores microvascular perfusion and reactivity in refractory vasoplegic shock; however, individual responses vary. While it represents a valuable adjunctive therapy in refractory cases further research is needed to identify optimal candidates. This abstract is funded by: None
Ramos et al. (Fri,) studied this question.