The Impact of Hydroxocobalamin on Vasodilatory Shock: A Systematic Review and Meta-analysis Study

Background: Vasodilatory shock, defined as systemic vasodilation and impaired tissue perfusion, is a critical condition associated with high morbidity and mortality in critically ill patients. Current treatments often include norepinephrine as the first-line vasopressor, but there is limited guidance on secondary agents for refractory vasodilatory shock. Hydroxocobalamin (HCB), a Vitamin B12 derivative, has emerged as a potential therapy due to its nitric oxide binding and antioxidant properties. This systematic review and meta-analysis evaluated the impact of HCB on vasodilatory shock in critically ill patients. Methods: A systematic search was conducted across a comprehensive literature search through PubMed, Web of Science, Scopus, and Cochrane. Eligible studies included randomized controlled trials (RCTs) and observational studies comparing HCB pre–postadministration, placebo, and methylene blue. The primary outcomes were vasopressor requirements and mean arterial pressure (MAP), while the secondary outcomes included systemic vascular resistance (SVR), intensive care unit (ICU), hospital length of stay (LOS), mortality, and renal replacement therapy (RRT). The meta-analysis assessed the quality using the Newcastle-Ottawa scale and the ROB2 tool. Results: Of 1793 studies screened, eight studies (one RCT and seven observational) with 467 patients were included. HCB significantly reduced vasopressor requirements within 30–60 min of postadministration (mean difference [MD]: −0.07 mcg/kg/min, 95% confidence interval [CI]: −0.11 to − 0.03) and increased MAP (MD: 7.91 mmHg, 95% CI: 5.36 to 10.47) compared to preadministration. However, no significant differences were observed in hospital or ICU LOS, mortality, MAP after 24 h, SVR, or the need for RRT. Conclusion: HCB demonstrates a reduction in vasopressor requirements and a transient increase in MAP in vasodilatory shock. However, it does not have a statistically significant impact on longer-term outcomes such as ICU LOS or mortality. Further high-quality studies and RCTs are needed to confirm the HCB impact on vasodilatory shock.