An interventional study of Maintain HPI < 85 and Maintain MAP>=73 in Hypotension During Surgery, sponsored by National Taiwan University Hospital. Active, not recruiting at 2 sites in Taiwan. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-12-17.
Sponsored by National Taiwan University Hospital · Not applicable, Interventional, and Treatment
Intraoperative hypotension (IOH) is a common and serious complication during surgery, closely associated with poor postoperative outcomes. Traditionally, anesthesiologists rely on real-time physiological parameters and alarms to monitor blood pressure, but the low alarm thresholds may lead to delayed interventions. The Hypotension Prediction Index (HPI) is a novel predictive tool that uses arterial waveform signals and advanced algorithms to forecast hypotensive events in advance. Recent observational studies have shown that HPI's accuracy in predicting hypotension is highly consistent with setting the physiological monitor's alarm threshold to 73 mmHg. This study will compare the effectiveness of HPI and a raised alarm threshold of 73 mmHg in preventing IOH. While HPI is promising with its AI-assisted approach to patient care, its high cost due to the advanced technology raises concerns. If its accuracy is comparable to simply raising the traditional monitor threshold, it may not lead to substantial changes in clinical practice.
Intraoperative hypotension (IOH) is a significant complication that affects surgical patients, potentially leading to adverse outcomes postoperatively. Standard practices involve relying on monitoring devices with low alarm thresholds for blood pressure, which may result in delayed interventions. The Hypotension Prediction Index (HPI) offers a predictive approach by analyzing arterial waveform signals and using complex algorithms to detect potential hypotensive episodes early. Recent observational studies have suggested that HPI's accuracy in predicting hypotension aligns closely with raising the physiological monitor alarm threshold to 73 mmHg. To further investigate this, this study will compare the effects of setting a traditional monitor alarm threshold at 73 mmHg with using HPI to prevent IOH.
In this study, patients will be randomly assigned to two groups. In the HPI group, interventions will be initiated when the HPI value exceeds 85. These interventions will follow a protocol that includes fluid administration, norepinephrine, and dobutamine to prevent hypotension. The control group will have their alarm threshold set at 73 mmHg. For these patients, interventions will be based on stroke volume variation (SVV) and clinical judgment, utilizing fluid and norepinephrine as needed. HPI is an attractive AI-based tool for medical care, but its high cost due to advanced technology raises questions. If its accuracy proves to be similar to simply raising the alarm threshold to 73 mmHg, it may not lead to meaningful changes in clinical practice. The study aims to compare the efficacy of these two methods in reducing the incidence of IOH.
National Taiwan University Hospital is the lead sponsor of 2,563 studies on the registry; 569 are open to participants now.
Of its 11 completed or terminated interventional studies of FDA-regulated products, 2 (18%) have results posted.
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ASA Class II or higher. Estimated surgery duration of three hours or more. High cardiovascular risk, such as poorly controlled hypertension, diabetes, coronary artery disease, chronic kidney disease, or chronic emphysema.
Exclusion Criteria:
Use the hypotension predictive index (HPI)-guided protocol to prevent intraoperative hypotension, initiating treatmentusing the fluid administration or intravenous norepinephrine infusion to keep intraoperative HPI below 85.
Device: Maintain HPI < 85
Intraoperative maintenance of the mean arterial pressure (MAP) at 73 mmHg or higher by using the fluid administration or intravenous norepinephrine infusion.
Drug: Maintain MAP>=73
Protocolized treatment with fluid administration, norepinephrine, and dobutamine to prevent intraoperative hypotension. The two arms are triggered by different alarms: one from a traditional monitor with an elevated MAP threshold of 73 mmHg, and the other from an HPI threshold of 85.
Protocolized treatment with fluid administration, norepinephrine, and dobutamine to prevent intraoperative hypotension. The two arms are triggered by different alarms: one from a traditional monitor with an elevated MAP threshold of 73 mmHg, and the other from an HPI threshold of 85.
Comparison of Time-Weighted Average (TWA) for MAP below 65 mmHg During Surgery
The primary outcome will assess the time-weighted average (TWA) for both groups, comparing the duration and magnitude of mean arterial pressure (MAP) below 65 mmHg during surgery. This will help determine the effectiveness of the interventions in preventing intraoperative hypotension and hypertension.
Time frame: From the start of surgery to the end of surgery, approximately up to 12 hours, depending on the duration of the operation.
Comparison of Time-Weighted Average (TWA) for MAP above 100 mmHg During Surgery
The primary outcome will assess the time-weighted average (TWA) for both groups, comparing the duration and magnitude of mean arterial pressure (MAP) above 100 mmHg during surgery. This will help determine the effectiveness of the interventions in preventing intraoperative hypotension and hypertension.
Time frame: From the start of surgery to the end of surgery, approximately up to 12 hours, depending on the duration of the operation.
30-day mortality rate
30-day mortality rate from the day of the surgery.
Time frame: From the day of surgery to 30 days postoperatively.
dosage of intraoperative interventions (such as vasopressors and fluids)
The type, and dosage of intraoperative interventions (such as vasopressors and fluids) administered during surgery.
Time frame: During the surgery (from induction of anesthesia to the end of surgery, approximately up to 12 hours, depending on the duration of the surbery).
hospital stay
Total hospital stay duration in days.
Time frame: Approximately 7 days from the date of enrollment
Plan to share: No
This study is active, not recruiting, as verified in Nov 2025. You cannot join it, but the record below documents what was studied.
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National Taiwan University Hospital