[The interarm blood pressure difference in the critically ill patient]

To evaluate the prevalence of a difference in systolic blood pressure (SBPd) ≥ 10 mmHg between arms in patients admitted in a Critical Care Unit and to examine the clinical characteristics associated with such blood pressure difference.

Observational cross-sectional study. Two blood pressure measurements in each arm were carried out at unit admission. The firstly measured arm was chosen at random.

One-hundred and sixty-eight patients were studied, with a mean age of 61 (SD=16), 67.3% male and 45% with a previous hypertension diagnosis. On admission, 27.4% presented SBPd ≥ 10 mmHg. Among them, 54% had higher SBP in the right arm and 46% in the left one. A SBPd ≥ 10 mmHg was associated with a previous hypertension diagnosis (67.4 versus 36.9%; P<.001) and with reduced consciousness (76.1 versus 52.5%; P=.006).

Over a quarter of critically ill patients have a SBPd ≥ 10 mmHg between arms. This feature is associated with a previous hypertension diagnosis and reduced consciousness. It should be assessed in the future if the choice of a control arm would help improve patient's care as it would become a more accurate guide for hemodynamic management.