Hypotension During SurgeryNCT06631482
Comparison Bewteen Intraoperative HPI vs. High Mean Arterial Pressure Threshold
A study testing Maintain HPI < 85 and Maintain MAP>=73 in people with Hypotension During Surgery, run by National Taiwan University Hospital at 2 sites in Taiwan.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Hypotension During Surgery
- What is being tested?
- Maintain HPI < 85 and Maintain MAP>=73
- Type of treatment
- Injection or infusion, Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 100 participants
- Where
- 2 sitesTaiwan
- Study dates
- 16 Sep 2024to 31 May 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- A: Patients undergoing surgeries requiring general anesthesia lasting more than two hours, and requiring continuous arterial blood pressure monitoring via arterial catheter according to standard medical practice. This includes:
- 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.
- B: Patients aged 18 years or older.
Who cannot join
- ASA Class I: Patients with mild systemic disease.
- Pregnancy: Pregnant women.
- End-stage renal disease: Patients with eGFR below 30 ml/min/1.73 m².
- Cardiac shunt: Presence of intracardiac shunt.
- Severe arrhythmias: Including supraventricular tachycardia (heart rate \&amp;gt;100 bpm), ventricular tachycardia, or ventricular fibrillation.
- Factors affecting SVV accuracy: Conditions such as atrial fibrillation (A-Fib) or thoracic surgery that can invalidate stroke volume variation (SVV) measurements.
Trial locations and contacts
2 sites in 1 country.
Taiwan2 sites
National Taiwan University Hospital Hsin-Chu Branch
Hsinchu, 302
National Taiwan University Hosipital
Taipei, 100
About this study
Official title: Randomized Controlled Trial Comparing HPI and Elevated Threshold Monitor Alarms in Preventing Intraoperative Hypotension
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.
Read the detailed description
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.
- Conditions
- Hypotension During Surgery
- Being tested
- Maintain HPI < 85, Maintain MAP>=73
- Keywords
- HPI, intraopeartive hypotension, overtreatment
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Maintain HPI < 85Device
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.
Maintain MAP>=73Drug
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.
| Study group | Role | What they receive |
|---|---|---|
| HPI Group | Experimental | 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. Receives: Device: Maintain HPI < 85 |
| 73mmHg MAP Alarm Group | Active comparator | Intraoperative maintenance of the mean arterial pressure (MAP) at 73 mmHg or higher by using the fluid administration or intravenous norepinephrine infusion. Receives: Drug: Maintain MAP>=73 |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 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.
Measured: From the start of surgery to the end of surgery, approximately up to 12 hours, depending on the duration of the operation.
Secondary outcomes (3)
30-day mortality rate
30-day mortality rate from the day of the surgery.
Measured: 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.
Measured: 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.
Measured: Approximately 7 days from the date of enrollment
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Oct 2024
- Study start16 Sep 2024
- Primary completion14 Oct 2025
- Study completion31 May 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Hypotension During SurgeryStudies of the same condition, open and under way.
- More trials run by National Taiwan University HospitalThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- National Taiwan University Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Tsung Ta Wu, MD., Principal investigator, National Taiwan University Hospital Hsinchu branch
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06631482
- Sponsor's protocol ID
- 202406137RIND
- Status last verified
- Nov 2025
- First submitted
- 18 Sep 2024
- Last updated
- 17 Dec 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- No
Publications
Mulder MP, Harmannij-Markusse M, Fresiello L, Donker DW, Potters JW. Hypotension Prediction Index Is Equally Effective in Predicting Intraoperative Hypotension during Noncardiac Surgery Compared to a Mean Arterial Pressure Threshold: A Prospective Observational Study. Anesthesiology. 2024 Sep 1;141(3):453-462. doi: 10.1097/ALN.0000000000004990.
PubMed 38558038Hatib F, Jian Z, Buddi S, Lee C, Settels J, Sibert K, Rinehart J, Cannesson M. Machine-learning Algorithm to Predict Hypotension Based on High-fidelity Arterial Pressure Waveform Analysis. Anesthesiology. 2018 Oct;129(4):663-674. doi: 10.1097/ALN.0000000000002300.
PubMed 29894315
Study at a glance
From the registry record, last updated by the sponsor on 17 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Randomized Controlled Trial Comparing HPI and Elevated Threshold Monitor Alarms in Preventing Intraoperative Hypotension
- ClinicalTrials.gov ID
- NCT06631482
- Acronym / sponsor ID
- 202406137RIND
- Conditions
- Hypotension During Surgery
- Keywords
- HPI, intraopeartive hypotension, overtreatment
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- National Taiwan University HospitalUniversity, hospital or other
- Study start
- 16 Sep 2024 (actual)
- Primary completion
- 14 Oct 2025 (actual)
- Study completion
- 31 May 2026 (estimated)
- First posted
- 8 Oct 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
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.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| HPI Group | Experimental | Device: Maintain HPI < 85Use 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. |
| 73mmHg MAP Alarm Group | Active comparator | Drug: Maintain MAP>=73Intraoperative maintenance of the mean arterial pressure (MAP) at 73 mmHg or higher by using the fluid administration or intravenous norepinephrine infusion. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- A: Patients undergoing surgeries requiring general anesthesia lasting more than two hours, and requiring continuous arterial blood pressure monitoring via arterial catheter according to standard medical practice. This includes:
- 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.
- B: Patients aged 18 years or older.
Key exclusion criteria (6 listed)
- ASA Class I: Patients with mild systemic disease.
- Pregnancy: Pregnant women.
- End-stage renal disease: Patients with eGFR below 30 ml/min/1.73 m².
- Cardiac shunt: Presence of intracardiac shunt.
- Severe arrhythmias: Including supraventricular tachycardia (heart rate \&amp;gt;100 bpm), ventricular tachycardia, or ventricular fibrillation.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Maintain HPI < 85Protocolized 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. | Device | HPI Group |
| Maintain MAP>=73Protocolized 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. | Drug | 73mmHg MAP Alarm Group |
Primary outcome
Comparison of Time-Weighted Average (TWA) for MAP below 65 mmHg During Surgery
Time frame: From the start of surgery to the end of surgery, approximately up to 12 hours, depending on the duration of the operation.
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.
Comparison of Time-Weighted Average (TWA) for MAP above 100 mmHg During Surgery
Time frame: From the start of surgery to the end of surgery, approximately up to 12 hours, depending on the duration of the operation.
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.
3 secondary outcomes
30-day mortality rate
Time frame: From the day of surgery to 30 days postoperatively.
dosage of intraoperative interventions (such as vasopressors and fluids)
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
Time frame: Approximately 7 days from the date of enrollment
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Dec 2025.
- Background: PubMed 38558038Mulder MP, Harmannij-Markusse M, Fresiello L, Donker DW, Potters JW. Hypotension Prediction Index Is Equally Effective in Predicting Intraoperative Hypotension during Noncardiac Surgery Compared to a Mean Arterial Pressure Threshold: A Prospective Observational Study. Anesthesiology. 2024 Sep 1;141(3):453-462. doi: 10.1097/ALN.0000000000004990.
- Background: PubMed 29894315Hatib F, Jian Z, Buddi S, Lee C, Settels J, Sibert K, Rinehart J, Cannesson M. Machine-learning Algorithm to Predict Hypotension Based on High-fidelity Arterial Pressure Waveform Analysis. Anesthesiology. 2018 Oct;129(4):663-674. doi: 10.1097/ALN.0000000000002300.
- Individual participant dataSharing planned: No
Related trials for Hypotension During Surgery
Not yet recruitingPhase 4
OB VEGA-Phenylephrine vs Norepinephrine Outcomes
Hypotension During Surgery, Cesarean Birth
Not yet recruitingPhase 4
Effects of Ondansetron Timing During Spinal Anesthesia for Urologic Surgery
Spinal Anesthesia-Induced Hypotension, Cerebral Oxygenation
Recruiting
Effects of Different MAP Targets on Ocular Perfusion and Optic Nerve Microvasculature During Rhinoplasty
Controlled Hypotension for Nasal Surgeries
Not yet recruitingObservational study
Carotid Artery Blood Flow, Blood Pressure, and Cardiac Output During Anesthesia in Children Aged 0-5 Years
Hypotension (MeSH: D007022)
Not yet recruiting
Feasibility Study of E-Fusion Vasopressor Titration-Assist During Multi-Level Spine Surgery
Intraoperative Hypotension
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Tsung Ta Wu, MD. principal investigator
National Taiwan University Hospital Hsinchu branch
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Maintain HPI < 85 and Maintain MAP>=73 in people with Hypotension During Surgery, run by National Taiwan University Hospital at 2 sites in Taiwan.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 17 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Taiwan. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Comparison of Time-Weighted Average (TWA) for MAP below 65 mmHg During Surgery (time frame: From the start of surgery to the end of surgery, approximately up to 12 hours, depending on the duration of the operation.). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06631482, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Dec 2025.