Clinical Research Directory

Machine Learning-Assisted Management of Intraoperative Hypotension for Personalized Treatment

Intraoperative hypotension, defined as a drop in blood pressure during surgery, is a frequent event in patients undergoing general anesthesia. Even brief episodes of low blood pressure may reduce blood flow to vital organs such as the brain, heart, and kidneys, and have been associated with an increased risk of postoperative complications, prolonged recovery, and worse clinical outcomes. Despite its clinical importance, the management of intraoperative hypotension is often based on general guidelines and individual clinician experience rather than patient-specific physiological mechanisms. Low blood pressure during surgery can occur for different underlying reasons, including reduced circulating blood volume, excessive vasodilation caused by anesthetic agents, impaired heart contractility, or abnormalities in heart rate. In routine practice, these mechanisms are not always clearly distinguished, and similar treatment strategies may be applied to patients with different physiological causes of hypotension. As a result, the response to treatment can vary widely between patients. This prospective observational study aims to improve the understanding of intraoperative hypotension by collecting detailed hemodynamic data during surgery and analyzing these data using machine learning methods. The study is designed to observe current clinical practice without altering or interfering with routine patient care. All decisions regarding anesthesia management and treatment of hypotension will be made by the attending anesthesiologists according to standard clinical practice. The research team will not provide treatment recommendations during surgery. Adult patients undergoing elective surgery under general anesthesia with continuous invasive arterial blood pressure monitoring will be included. During the intraoperative period, blood pressure, heart rate, cardiac output, stroke volume, systemic vascular resistance, and other advanced hemodynamic parameters will be continuously recorded at regular intervals. When hypotension occurs, the onset, duration, and severity of the episode will be documented, along with the treatment applied, such as fluid administration, vasopressor agents, or inotropic medications. The time required for blood pressure to recover to an acceptable level will also be recorded. The collected data will be analyzed using machine learning techniques to identify distinct subtypes of intraoperative hypotension based on physiological patterns. These subtypes may reflect different underlying mechanisms, such as hypovolemia, vasodilation, myocardial depression, or heart rate-related causes. In addition, the study will evaluate how different treatment strategies perform across these hypotension subtypes and how quickly hemodynamic stability is restored. Patient-related factors such as age, sex, body mass index, physical status classification, and comorbid conditions will also be examined to determine their relationship with the occurrence, severity, and treatment response of hypotension episodes. By combining patient characteristics, physiological data, and treatment responses, the study aims to generate data-driven insights into personalized hypotension management. The ultimate goal of this research is to support the development of individualized treatment recommendations for intraoperative hypotension based on objective physiological data rather than a one-size-fits-all approach. The findings of this study are expected to provide a strong scientific foundation for future clinical decision-support systems that can assist anesthesiologists in selecting the most appropriate treatment strategy for each patient. By improving the precision of blood pressure management during surgery, this approach has the potential to enhance patient safety and perioperative outcomes while maintaining standard clinical workflows.

Effect of Remimazolam Versus Propofol Total Intravenous Anesthesia on Intraoperative Hemodynamic Stability in Patients Undergoing Thoracic or Abdominal Endovascular Aortic Repair

The purpose of this study is to compare two intravenous anesthetics, remimazolam and propofol, for their effects on intraoperative hemodynamic stability in patients undergoing thoracic or abdominal endovascular aortic repair. Maintaining blood pressure during these procedures is important to preserve organ perfusion, yet anesthetic-induced hypotension often requires vasopressor support. Since direct comparisons of these two anesthetics on hemodynamic outcomes in this population are limited, this randomized, single-blind, controlled trial will compare the intraoperative vasopressor requirement between the two groups to provide evidence for selecting a more hemodynamically stable anesthetic in these high-risk patients.

Intelligent Classification of Intraoperative Hemodynamic Phenotypes Based on CADFlow Doppler Monitoring

The goal of this observational study is to learn about intraoperative hemodynamic phenotypes in adult patients undergoing elective surgery under general anesthesia, using a new wearable ultrasound patch (CADFlow) that continuously monitors carotid and jugular blood flow. The main question it aims to answer is: Can a machine learning model built solely on non-invasive carotid and jugular Doppler data accurately identify and classify a patient's hemodynamic phenotype in real time during surgery? Participants undergoing routine elective surgery who are monitored with the CADFlow device as part of standard care will be recorded continuously from after tracheal intubation until the end of surgery. The collected signals will be used to discover distinct hemodynamic phenotypes and to train a model that classifies each patient's phenotype in real time.

Perioperative Personalized Blood Pressure Management: IMPROVE-multi

Rates of major complications and mortality in the first weeks after surgery remain very high: postoperative mortality is still around 2% in central Europe and the United States. Postoperative deaths are a consequence of postoperative complications. Postoperative complications that are most strongly associated with postoperative death include acute kidney injury and acute myocardial injury. To avoid postoperative complications it is thus crucial to identify and address modifiable risk factors for complications. One of these modifiable risk factors may be intraoperative hypotension. Intraoperative hypotension is associated with major postoperative complications including acute kidney injury, acute myocardial injury, and death. It remains unknown which blood pressure value should be targeted in the individual patient during surgery to avoid physiologically important intraoperative hypotension. In current clinical practice, an absolute mean arterial pressure threshold of 65mmHg is used as a lower "one-size-fits-all" intervention threshold. This "population harm threshold" is based on the results of retrospective studies. However, using this population harm threshold for all patients ignores the obvious fact that blood pressure varies considerably among individuals. In contrast to current "one-size-fits-all" perioperative blood pressure management, the investigators propose the concept of personalized perioperative blood pressure management. Specifically, the investigators propose to test the hypothesis that personalized perioperative blood pressure management reduces the incidence of a composite outcome of acute kidney injury, acute myocardial injury, non-fatal cardiac arrest, and death within 7 days after surgery compared to routine blood pressure management in high-risk patients having major abdominal surgery. The investigators will perform preoperative automated blood pressure monitoring for one night to define individual intraoperative blood pressure targets. Automated blood pressure monitoring is the clinical reference method to assess blood pressure profiles. The mission of the trial is to reduce postoperative morbidity and mortality after major surgery. The vision is to achieve this improvement in patient outcome by using the innovative concept of personalized perioperative blood pressure management. This trial is expected to change and improve current clinical practice and will have a direct impact on perioperative blood pressure management guidelines.

Dural Sac Area-Guided Spinal Anesthesia Dosing for TURP

This randomized controlled study will evaluate whether individualizing the dose of spinal anesthesia according to the ultrasound-derived dural sac cross-sectional area (DSCSA) can improve hemodynamic stability in patients undergoing transurethral resection of the prostate (TURP). Participants aged 40 years or older will be randomly assigned to one of two groups. In the individualized-dose group, the anteroposterior diameter of the dural sac will be measured by ultrasound at the L3-L4 level, and DSCSA will be calculated from this measurement. The dose of intrathecal bupivacaine will then be individualized according to the calculated DSCSA. In the control group, participants will receive a fixed dose of intrathecal bupivacaine. Both groups will also receive intrathecal fentanyl. The main outcome is the incidence of intraoperative hypotension. The study will also evaluate the number of hypotensive episodes, minimum mean arterial pressure, vasopressor and atropine requirements, sensory and motor block characteristics, respiratory monitoring parameters, cerebral oxygenation, and adverse events. The study aims to determine whether a DSCSA-guided dosing strategy can reduce excessive spinal block and improve hemodynamic stability while maintaining effective spinal anesthesia.

CEReBral AutorEgulation in Non-cardiac SuRgery and Relationship to Postoperative DeliriUm State

The goal of this observational study is to learn the how to determine the mean arterial pressure(MAP) or blood pressure level to be maintained during non-cardiac surgery for optimal brain health in patients above the age of 60 undergoing major non-cardiac surgery. The main question\[s\] it aims to answer are: * Is there a way to tailor the blood pressure to be maintained in such patients during surgery for optimal brain health using non-invasive monitors that check the brains electrical activity, the electroencephalogram(EEG) monitor, and the brain's blood oxygen levels, the cerebral oximetry(CO) monitor? * How much does this optimal blood pressure level vary between patients? Participants will be asked to: * Complete a questionnaire at the time they enroll into the study, as well as a daily questionnaire to help determine their level of thinking and brain health. This questionnaire will be administered by a member of the study team. * They will also have an EEG and CO monitoring sticker placed on their foreheads. This will be connected to a monitor that will collect this data just before, during, and after their surgery. The data collected through these monitors will help us with our study goals.

Feasibility Study of E-Fusion Vasopressor Titration-Assist During Multi-Level Spine Surgery

This is a single-arm feasibility study of E-Fusion Vasopressor Titration-Assist, a clinical decision support software, in 10 adults undergoing multi-level spine surgery. E-Fusion monitors blood pressure from the patient monitor and displays recommended changes to the norepinephrine infusion rate. The anesthesia provider independently reviews each recommendation and may accept or ignore it. The software does not connect to or control the infusion pump. The primary objective is to assess safety by evaluating adverse events attributable to E-Fusion during surgery. Secondary objectives evaluate clinician agreement with the recommendations and blood pressure management.

Noradrenaline Versus Standard Blood Pressure Management for Perioperative Hypotension in Non-cardiac Surgery

The effect of noradrenaline infusion versus standard blood pressure management on perioperative HYPotension in NOn-caRdiac surgery. The study aims to determine whether perioperative noradrenaline infusion is superior to standard blood pressure management for the occurrence of perioperative hypotension.

Hypotension Prediction Index (HPI) in Lung Resections

Perioperative hypotension is a risk factor for perioperative complications. Advances in machine learning and artificial intelligence have produced an algorithm that predicts the occurrence of hypotension episodes by analyzing an arterial pressure waveform. This technology has not been validated in thoracic surgical patients undergoing lung resections with the use of one-lung ventilation (OLV). We planned an observational, prospective multi-centre cohort validation study of the Hypotension Prediction Index (HPI) in patients undergoing lung resection procedures with the use of one-lung ventilation and a lung-protective strategy.

Internal Jugular Vein Ultrasound and Acute Kidney Injury After Abdominal Surgery

This observational study aims to learn whether changes in the internal jugular vein during anesthesia induction can help predict low blood pressure and kidney injury after surgery. The main questions it aims to answer are: 1. Can the internal jugular vein collapsibility index before anesthesia predict low blood pressure during induction? 2. Can the change in internal jugular vein collapsibility from before to just after anesthesia predict low blood pressure during surgery and acute kidney injury after surgery? Participants will have routine ultrasound scans of the neck before anesthesia and again shortly after they fall asleep for surgery. Researchers will also record blood pressure during surgery and measure kidney function after surgery using routine blood tests. and again shortly after they fall asleep for surgery. Researchers will also record blood pressure during surgery and measure kidney function after surgery using routine blood tests.

A Comparative Study Protocol Investigating the Association Between Intraoperative Hypotension and the Use of Ring- Versus Propofol-Based Anesthesia in Elderly Patients Undergoing Non-Cardiac Surgery

we conducted this multicentre retrospective cohort study to evaluate the association between the choice of induction agent (ciprofol versus propofol) and the incidence of IOH in geriatric patients having non-cardiac surgery. We hypothesized that ciprofol use would be associated with a lower risk of clinically significant intraoperative hypotension and a reduced overall hypotension burden compared with propofol in routine clinical practice.

Superiority of Phenylephrine Versus Norepinephrine in Complex Spine Surgery (SPiNeS)

The purpose of this research is to compare two commonly used medications, phenylephrine and norepinephrine, that are used to treat low blood pressure during complex spine surgery. The goal is to determine whether one medication better maintains blood flow to the body's organs during surgery and whether it leads to better recovery and fewer complications after surgery.

Remimazolam Versus Propofol for Maintenance of Anaesthesia During Major Hepatectomy Under Low Central Venous Pressure

The goal of this clinical trial is to learn whether remimazolam helps prevent low blood pressure better than propofol during major liver surgery in adults. All participants will have planned surgery to remove at least three liver segments. The main question is whether participants who receive remimazolam have less low blood pressure while the surgeon removes liver tissue. Researchers will measure both how low the blood pressure falls and how long it stays low. Researchers will randomly assign 224 participants to receive remimazolam or propofol to maintain general anesthesia. Participants will not know which drug they receive until their postoperative assessments are complete. The anesthesiologist giving the drug will know the assignment for safety reasons. Participants will: * Receive one of the two study drugs during surgery * Have their blood pressure monitored continuously * Receive standard treatment if their blood pressure becomes low * Complete follow-up through 30 days after surgery Researchers will also compare the use of medicines to support blood pressure, bleeding, blood transfusion, recovery after anesthesia, organ complications, heart injury, and adverse events.

Maintaining Intraoperative Mean Arterial Pressure at 85 mmHg or Higher to Reduce Postoperative Delirium in Older Patients With Arterial Hypertension Having Non-cardiac Surgery

In older patients having surgery, postoperative delirium (an acute disturbance in awareness, attention, or cognition) is common and associated with short-term and long-term morbidity and mortality. The pathophysiology of postoperative delirium is multifactorial - but presumably includes inadequate brain perfusion during surgery caused by low intraoperative blood pressure. Therefore, the investigators aim to determine in a multicenter randomized-controlled trial if targeted intraoperative blood pressure management reduces postoperative delirium. The investigators will test the primary hypothesis that maintaining intraoperative mean arterial pressure at 85 mmHg or higher - compared to at 65 mmHg or higher (routine care) - reduces the incidence of postoperative delirium within the first 3 postoperative days in older patients with arterial hypertension having non-cardiac surgery. The investigators will also assess the duration of postoperative delirium, postoperative complications, and the patients' quality of life. The results of this trial will have a direct impact on guidelines and will help improve medical care for patients and the patients' health. Effective strategies to prevent postoperative delirium are missing. The hypothesis that targeted intraoperative blood pressure management can help reduce postoperative delirium is supported by previous observational studies and interventional trials. This trial is supposed to confirm the causal relationship between intraoperative blood pressure and postoperative delirium and to demonstrate the effectiveness of the therapeutic approach.

Continuous Finger-cuff Arterial Pressure Monitoring and Intraoperative Hypotension During Non-cardiac Surgery: the Randomized DETECT II Trial

This is a randomized trial (1) investigating whether continuous finger-cuff - compared to intermittent oscillometric - arterial pressure monitoring reduces the amount of intraoperative hypotension (specifically, from the start of induction of general anesthesia until the end of surgery) in low-to-moderate risk patients having elective non-cardiac surgery.

Impact of Intraoperative Blood Pressure Components on Postoperative AKI: A Phenotype-Stratified Analysis

Postoperative acute kidney injury (AKI) is a serious complication often linked to low blood pressure during surgery. This study aims to better protect patients' kidneys by personalizing how blood pressure is managed during an operation. The project has two main goals: First, researchers will analyze data from over 44,000 past surgeries to identify which specific blood pressure measurements are the most critical warning signs for kidney damage. Second, using this knowledge, they will build a smart tool (a machine learning model) to predict a unique, safe blood pressure target for each individual patient before their surgery begins. This personalized approach is intended to give doctors a specific target to maintain during surgery, helping to prevent kidney injury and improve patient safety.

Remimazolam Versus Midazolam for General Anesthesia Induction in Elderly Patients Undergoing Non-Cardiac Surgery

This prospective observational cohort study evaluates the effectiveness and safety of two benzodiazepine sedatives-remimazolam and midazolam-used for general anesthesia induction in elderly patients (≥65 years) undergoing elective non-cardiac surgery. Elderly patients have reduced organ reserve and altered pharmacokinetics/pharmacodynamics, increasing their susceptibility to anesthesia-related complications such as intraoperative hypotension, delayed emergence, and postoperative delirium. Remimazolam, an ultra-short-acting benzodiazepine metabolized by organ-independent tissue esterases, is hypothesized to offer greater hemodynamic stability, faster recovery, and a more favorable safety profile than midazolam in this vulnerable population. Investigators prospectively observe and collect data without altering routine clinical care; the choice of sedative is made by the attending anesthesiologist according to standard practice. Propensity score methods will be used to reduce confounding by indication.

Internal Jugular Vein Collapsibility Index as a Predictor of Hypotension

The internal jugular vein (IJV) collapsibility index has been proposed as a practical alternative of of the inferior vena cava collapsibility index (IVC-CI), as it is easily accessible using bedside ultrasonography. Several studies have demonstrated a correlation between IJV collapsibility and central venous pressure as well as right atrial pressure.

Effect of Terlipressin for Intraoperative Blood Pressure Management in Kidney Transplantation

Prospective double blind randomized controlled trial. By randomizing patients undergoing kidney transplantation into a conventional catecholamine drug (dobutamine) blood pressure maintenance group and a terlipressin-complexed dobutamine group, the investigators compared the effect of intraoperative blood pressure maintenance and the dosage of the vasoactive drug, postoperative graft function, delayed graft function, and other related complications between the two groups, in order to demonstrate whether the use of terlipressin for blood pressure regulation during kidney transplantation is superior to the existing treatments.

PRO STRESS Trial: Proactive Low-Dose Norepinephrine to Reduce Intraoperative Fluid Administration in Patients at High-Risk for Postoperative Pulmonary Complications Undergoing Laparoscopic Abdominal Surgery

Intraoperative hypotension is commonly treated with fluid administration; however, excessive fluid therapy may contribute to postoperative pulmonary complications. This randomized double-blind controlled trial evaluates whether proactive administration of fixed low-dose norepinephrine reduces intraoperative crystalloid administration while maintaining hemodynamic stability in high-risk patients undergoing laparoscopic abdominal surgery. One hundred and thirty patients will be randomized to receive either norepinephrine infusion (0.03 µg/kg/min) or placebo from induction until skin closure within a protocolized hemodynamic strategy guided by mean arterial pressure and pulse pressure variation.

Peri-operative Vasopressor Support in Patients Operated for an Acute Hip Fracture (AHF)

The incidence of hypotension perioperatively during operation of an acute hip fracture is unknown. As a surrogate factor the usage of vasopressor support is more adequate as the registration of vasopressor drugs are many times not complete in records. The investigators retrospectively investigated the anesthetic journals of 1100 patients with an acute hip fracture (AHF) noting confounding factors and the usage of vasopressors either by injections or infusions and then correlated these results to mortality at 30-, 90- and 365- days

Hemodynamic Effects of Intradermal Methylene Blue During Breast Surgery Under General Anesthesia

This prospective observational study aims to evaluate the effects of intradermal methylene blue injection on intraoperative hemodynamic stability in patients undergoing breast surgery under general anesthesia. While methylene blue is commonly used for sentinel lymph node mapping, its potential systemic vasopressor effects remain unclear. To provide a comprehensive analysis, the study will compare patients receiving methylene blue with a control group of patients undergoing similar breast procedures without the use of any dye. Hemodynamic parameters such as blood pressure, heart rate, and oxygen saturation will be recorded and compared between the two groups to determine the specific impact of methylene blue on the incidence of intraoperative hypotension and the need for vasopressor support.

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

This study investigates if the Hypotension Prediction Index (HPI) combined with the Assisted Fluid Management (AFM) software can improve perioperative hemodynamic management in adult patients undergoing general anesthesia. The main question is : Does the HPI and AFM software reduce the incidence and duration of intraoperative hypotension? Does the HPI and AFM software optimize fluid and vasopressor administration? Does the HPI and AFM software improve perioperative outcomes? Participants will be randomly allocated to either an experimental group receiving goal directed hemodynamic therapy guided by HPI and AFM or a control group receiving conventional hemodynamic management.

AI-Assisted Blood Pressure Control During Anesthesia

This proof-of-concept randomized controlled trial evaluates a reinforcement learning (RL)-based clinical decision support system for intraoperative hemodynamic management during non-cardiac surgery. Background: Intraoperative hypotension is common during general anesthesia and is associated with adverse outcomes including acute kidney injury, myocardial injury, and increased mortality. Current hemodynamic management relies on the individual anesthesiologist's clinical judgment, which can vary in consistency and timeliness. An RL-based system that learns optimal vasoactive agent dosing strategies from clinical data may help standardize and improve real-time hemodynamic decision-making. Purpose: The primary objective is to evaluate whether the RL-based decision support system can learn intraoperative hemodynamic management decisions comparable to those of experienced anesthesiologists, as measured by the mean absolute error (MAE) between RL-recommended and clinician-executed vasoactive agent doses. The secondary objective is to assess whether RL-guided management improves clinical hemodynamic outcomes, including the time-weighted average of hypotension and the percentage of time with mean arterial pressure within the target range. Participants: Adult patients (aged 18 to 85 years, ASA I-IV) scheduled for elective non-cardiac surgery under general anesthesia with continuous invasive arterial blood pressure monitoring. Procedures: Participants will be randomly assigned (1:1) to one of two groups. In the RL-guided group, the anesthesiologist will receive real-time vasoactive agent dosing recommendations from the decision support system displayed on a bedside screen; the anesthesiologist retains full clinical autonomy over all final decisions. In the standard care group, the anesthesiologist will manage hemodynamics according to institutional standard practice without input from the system. The patient and the outcomes assessor will be masked to group assignment. Data collection covers the intraoperative period and 30-day postoperative follow-up.