Hypotension Prediction Index (HPI) and Assisted Fluid Management (AFM) for Perioperative Hemodynamic Optimization in Patients Under General Anesthesia

Intraoperative hypotension is a common complication during general anesthesia and is associated with an increased risk of postoperative organ dysfunction (acute kidney injury, myocardial ischemia). Even short episodes of mean arterial pressure (MAP) below accepted thresholds have been shown to adversely affect patient outcomes.

The Hypotension Prediction Index , (HPI)is a software that predicts the likelihood of hypotension minutes before it occurs, based on the arterial waveform. Thus clinicians have the opportunity to identify patients at risk of hypotension and intervene early.

The Assisted Fluid Management (AFM) software is designed to optimize perioperative fluid administration based on the Frank-Starling curve. The AFM provides guidance on crystalloid admininistration only when it is expected to increase stroke volume and cardiac output.

This prospective , randomized study evaluates whether the use of HPI coupled with AFM within a goal directed hemodynamic protocol improves perioperative hemodynamic management and reduces the incidence and duration of adult patients undergoing surgery under general anesthesia.

A total of 100 adult patients will be enrolled , for elective surgery with invasive blood pressure monitoring and intraoperative mean arterial pressure target of at least 65 mm Hg.

Patients in the intervention group will undergo goal directed hemodynamic management guided by HPI and AFM algorithms via the Hemosphere monitor and Acumen IQ sensor. The AFM software will determine the timing of fluid administration. Elevated HPI values indicating impending hypotension will be managed in a targeted manner with fluids, vasopressors or inotropes.

Patients in the control group will receive conventional hemodynamic management , based on clinical judgement, in accordance with international guidelines. Although an Acumen IQ sensor will be placed, HPI and AFM indications will not be visible to the attending anesthesiologist and will not influence clinical decision making.

Intraoperative hemodynamic data will be continuously recorded in both groups. A member of the research team will be present to supervise the procedure. The primary outcome is the time-weighted average of hypotension, defined as MAP below 65 mm Hg for at least one minute. Secondary outcomes include the incidence and duration of hypotension, type and dose of administered therapies and protocol adherence.

Inclusion criteria

• Age > 18 years
• Intraoperative monitoring > 2 hours or general anesthesia > 2 hours
• Invasive arterial pressure monitoring
• Target MAP ≥ 65 mm Hg intraoperatively
• Written informed consent preoperatively
• ASA Physical Status ≤ 4

Exclusion criteria

• Target MAP other than 65 mm Hg
• Severe preoperative hypotension (MAP < 65 mm Hg)
• Severe heart failure (e.g. LVEF < 20%)
• Emergency surgery