Brachial-to-Radial Pressure Gradient in Critically Ill Patients Treated With Vasoactive Agents: A Prospective...

To determine the incidence of a significant noninvasive brachial-to-radial arterial pressure gradient (NIBR-APG) and its clinical associations in critically ill patients receiving vasoactive agents.

Prospective, multicenter, observational study.

Thirteen ICUs in Poland.

Adult ICU patients with radial arterial catheters receiving vasoactive agents hospitalized between April 2025 and July 2025.

None.

Invasive radial mean arterial pressure (MAP) and noninvasive brachial MAP were measured twice and averaged. A NIBR-APG greater than 11 mm Hg was predefined as clinically significant. Baseline characteristics, hemodynamic variables, and outcomes were recorded. Among 303 patients, 49.5% were surgical admissions and 33.3% had septic shock. The median NIBR-APG was 4.5 mm Hg (interquartile range, 0.0-10.0 mm Hg). Fifty-six patients (18.4%) exhibited a NIBR-APG greater than 11 mm Hg. Compared with patients without a significant gradient, these patients received higher norepinephrine-equivalent doses (0.23 vs. 0.10 µg/kg/min), had higher Sequential Organ Failure Assessment scores (11 vs. 10), prolonged capillary refill time (3.0 vs. 2.5 s), and higher lactate concentrations (2.7 vs. 1.3 mmol/L). In multivariable analysis, only vasoactive drug dose was independently associated with NIBR-APG greater than 11 mm Hg (odds ratio, 1.68; 95% CI, 1.12-2.52). ICU mortality was higher in patients with significant gradients (48.0% vs. 30.1%).

Nearly one in five critically ill patients receiving vasoactive agents demonstrated a clinically significant NIBR-APG. The presence of this gradient was independently associated with higher vasoactive drug requirements and was accompanied by greater illness severity and higher ICU mortality.