Objective There is limited evidence to support metaraminol use in critically ill patients. Metaraminol is not included as a vasopressor choice in international guidelines for the management of shock. Nevertheless, metaraminol is used in rates up to 42% in this patient population. The objective of this study was to investigate the effectiveness of metaraminol for the treatment of critically ill patients with shock.

Methods A single-centre retrospective matched observational study was conducted in a 54-bed intensive care unit of a tertiary hospital. Patients aged 16 years or older who were admitted from 2017 to 2019 with shock were included. Patients treated with metaraminol and norepinephrine (MET-NOR) were compared with those treated with norepinephrine without metaraminol (NOR). The primary outcome was the time to resolution of shock defined as the time to cessation of vasopressors. The secondary outcome was vasopressor-free days until 28 days.

Results There were 286 patients included in this study, including 143 patients in each group. The median time to resolution of shock was 44 hours (IQR 28–66 hours) in the MET-NOR group compared with 27 hours (IQR 14–63 hours) in the NOR group (95% CI of median difference 7 to 19 hours; p<0.01). The Cox regression analysis for the time to resolution of shock showed no significant difference between groups (HR 1.24, 95% CI 0.96 to 1.60; p=0.10). However, the proportional hazards assumption was not met (p<0.01). The median number of vasopressor-free days until 28 days was 26 days (IQR 24–27 days) in the MET-NOR group compared with 27 days (IQR 25–27 days) in the NOR group (95% CI of median difference −0.8 to −0.1 day; p<0.01).

Conclusion In critically ill patients, metaraminol may be associated with a longer time to resolution of shock compared with those who do not receive metaraminol.