- Design
- Prospective multicentre observational study
- Population
- 303 adult ICU patients on vasoactive agents with radial lines, 13 Polish ICUs
- Primary outcome
- Brachial-to-radial MAP gradient >11 mmHg
- Effect
- 18.4% had a significant gradient; ICU mortality 48.0% vs 30.1%
This prospective study in 13 Polish ICUs compared invasive radial mean arterial pressure (MAP) with non-invasive brachial cuff MAP in 303 adults receiving vasoactive drugs, a third with septic shock. Published in Critical Care Medicine on 23 October 2026.
The median gradient was 4.5 mmHg, but 18.4% had a gradient above 11 mmHg, the predefined threshold. These patients were on higher noradrenaline-equivalent doses (0.23 vs 0.10 µg/kg/min), had higher lactate and longer capillary refill, and ICU mortality was 48% versus 30%. Only vasopressor dose was independently associated with a large gradient (OR 1.68, 95% CI 1.12 to 2.52).
At high vasopressor doses the radial artery can read lower than central pressure. Titrating noradrenaline to a falsely low radial reading risks giving more drug than the patient needs.
The direction of the gradient for individual patients is not reported here, and this is observational. The practical step is simple: check a cuff pressure against the arterial line when doses are high.
- Compare a brachial cuff MAP with the radial line in patients on high vasopressor doses
- Suspect a misleading radial reading when doses climb without clinical change
- Consider a femoral line when radial and cuff readings differ widely
- Use lactate, capillary refill and urine output alongside the MAP target
Why it matters
The number used to titrate vasopressors may be least reliable in the patients receiving the most.
Don't overread it
This was observational; it does not show that acting on the gradient improves outcomes.
The statistics, in plain English
The higher mortality in patients with a large gradient reflects how ill they were; the study cannot say the gradient itself caused deaths. The odds ratio of 1.68 links higher vasopressor dose to a large gradient after adjustment.
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