Authors: Hill et al.
Journal: Anesthesia & Analgesia published: June 2026
Summary:
This retrospective cohort study looked at how much variation exists between intensive care units in the maximum doses of vasopressors used to treat patients with shock. The study included 28,397 adult ICU admissions from 21 ICUs in Alberta, Canada. Patients were included if they received one or more vasopressors for at least 6 hours.
The authors focused on the highest vasopressor infusion rate each patient received for at least 30 minutes. They also calculated the highest combined vasopressor dose when patients were receiving more than one vasopressor at the same time. These combined doses were reported as norepinephrine-equivalent doses.
The study found substantial variation between ICUs. Across the full cohort, the 90th percentile for maximum combined vasopressor dose was 0.7 µg/kg/min in norepinephrine equivalents. However, the percentage of patients receiving high-dose vasopressors varied widely by ICU, ranging from 3.6% to 32.1%. Even after adjusting for patient factors and severity of illness, there remained significant variation between ICUs.
The 90th percentile high-dose thresholds were 0.5 µg/kg/min for norepinephrine, 0.5 µg/kg/min for epinephrine, 316.5 µg/min for phenylephrine, 15.0 µg/kg/min for dopamine, and 3.6 units/hour for vasopressin.
Patients who received high-dose vasopressors had much lower hospital survival than those who received lower doses. Hospital survival was 31.6% in the high-dose group compared with 79.7% in the lower-dose group. However, the authors found no clear vasopressor dose above which survival was impossible.
Why this matters:
This study shows that ICUs differ significantly in how aggressively they dose vasopressors in patients with shock. Some of this variation may reflect differences in clinician preference, institutional policy, comfort with multiple vasopressors, or beliefs about futility. Importantly, even patients receiving very high vasopressor doses sometimes survived, suggesting that rigid maximum-dose cutoffs may not be appropriate for every patient.
Take-home point:
Maximum vasopressor dosing varies widely between ICUs, even after adjusting for patient illness severity. High vasopressor doses are associated with much lower survival, but survival is still possible, and there does not appear to be a single dose threshold where continued treatment is always futile.
Thank you to Anesthesia & Analgesia for publishing this article and allowing us to summarize it.