Hypotension Prediction Index versus Mean Arterial Pressure Alarm for Preventing Intraoperative Hypotension in...

Intraoperative hypotension is common during surgery and has been retrospectively associated with acute kidney injury, myocardial injury, and increased mortality. The Hypotension Prediction Index was developed to support proactive blood pressure management, but shows a strong correlation with mean arterial pressure. Observational data suggest that a mean arterial pressure alarm set at 72 mmHg may perform similarly to the default Hypotension Prediction Index alarm (>85). We hypothesized that a 72 mmHg mean arterial pressure alarm is non-inferior to the Hypotension Prediction Index in preventing intraoperative hypotension.

In this single-center, blinded, randomized controlled trial, adults undergoing moderate- or high-risk elective non-cardiac surgery with continuous arterial pressure monitoring were assigned to either a mean arterial pressure alarm (<72 mmHg) or a Hypotension Prediction Index alarm (>85). The primary outcome was the area under the threshold for mean arterial pressure <65 mmHg. Secondary outcomes included the incidence and severity of hypo- and hypertension, duration of active alarms, incidence of acute kidney and myocardial injury, 30-day mortality, hospital length of stay, and cumulative dosages of vasoactive medication and fluids.

143 participants were included in the final analysis. The median area under the hypotension threshold was 3.75 [0.00-22.62] mmHg⋅min in the mean arterial pressure group and 4.00 [0.00-19.00] mmHg⋅min in the Hypotension Prediction Index group. After log-transformation, the mean difference was 0.03 (95% CI: -0.24 to 0.29), with the lower bound remaining above the predefined non-inferiority margin (-0.4). No differences were observed in secondary hemodynamic metrics, alarm characteristics, patient outcomes, or administered medications and fluids.

A mean arterial pressure alarm of 72 mmHg is non-inferior to the Hypotension Prediction Index >85 in preventing intraoperative hypotension. Given its simplicity and broad availability, a MAP alarm of 72 mmHg represents a pragmatic and cost-effective alternative for proactive blood pressure management.