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.

Comparison of Acoustic Variability Index (AVI) and Pulse Pressure Variation (PPV) for Predicting Fluid Responsiveness in Mechanically Ventilated Patients

The goal of this clinical trial is to learn if a new medical device called ResQ works to predict fluid needs in adults undergoing surgery under general anesthesia. The main questions it aims to answer are: * Can the Acoustic Variability Index (AVI) measured by ResQ predict if a participant needs more fluids as accurately as the standard arterial blood pressure-based method (PPV)? * Is the ResQ device safe to use during surgery? Researchers will compare the new method (AVI) to the standard method (PPV) to see if ResQ provides reliable information for managing patient fluids. Participants will: * Undergo their planned surgery as scheduled. * Have a soft probe placed in the esophagus to monitor heart and lung sounds. * Receive a set amount of intravenous (IV) fluid as part of their regular surgery care. * Have their heart function checked before and after the fluids are given.

Study Of Ultrasound Windows For Measuring Inferior Vena Cava Changes Before Cardiac Surgery

This research study will compare two ultrasound methods for assessing the inferior vena cava (IVC), a major vein that reflects intravascular fluid status and cardiac function before and after surgery. The standard method uses a subcostal ultrasound view obtained below the breastbone, but this approach may be limited in patients with obesity, surgical dressings, or postoperative discomfort. An alternative approach, the transhepatic view, uses the liver as an acoustic window and may provide improved feasibility in these situations. The study will evaluate whether the transhepatic view provides measurements comparable to the standard subcostal view and whether operators with different levels of ultrasound experience obtain consistent results using both methods. Adult patients who are awake and scheduled for cardiac surgery at Sunnybrook Health Sciences Centre will undergo a brief ultrasound examination before surgery. The scan takes less than 10 minutes, involves no discomfort, and does not alter clinical care. This is a minimal-risk observational study with no therapeutic interventions. Participation is voluntary, and all personal health information will remain confidential. Findings may inform future approaches to ultrasound-guided assessment and training in perioperative care.

Evaluation of Cerebral Oxygenation During Orthopedic Surgeries Performed in the Beach Chair Position Under General Anesthesia

The goal of this observational study is to determine the correlation between cerebral oxygenation values measured by near-infrared spectroscopy (NIRS) and other routine monitoring parameters in patients placed in the semi-sitting position. The primary questions investigated are : Do NIRS values correlate with heart rate, invasive mean arterial pressure, and end-tidal carbon dioxide? Do NIRS values reflect changes observed in arterial blood gas analysis? Are cerebral perfusion-related parameters associated with patients' comorbidities such as diabetes, obesity, and hypertension? Researchers will compare routine noninvasive monitoring (heart rate, blood pressure, peripheral oxygen saturation) with invasive arterial monitoring and NIRS to assess whether NIRS provides additional information for evaluating cerebral perfusion. Participants will be monitored for: Heart rate Invasive mean arterial pressure End-tidal carbon dioxide Arterial blood gas changes Cerebral oxygenation with NIRS Patients' comorbidities (e.g., diabetes, obesity, hypertension) will also be recorded, and their association with perfusion-related parameters will be analyzed.

Hemodynamic Monitoring and Fluid Responsiveness in Venoarterial Extracorporeal Membrane Oxygenation (VA ECMO) - "HemodynamECMOnitoring-VA Study"

In extracorporeal membrane oxygenation (ECMO), blood is drawn out of the body via tubes, oxygenated in an artificial lung; and then pumped back into the blood vessels. This allows the supply of oxygen-rich blood to the organs (brain, heart, lungs, kidneys, liver, intestines, etc.) to be maintained. Continuous monitoring of cardiac function and circulatory status (blood pressure, blood flow to organs) is very important in intensive care medicine in order to control the administration of circulation-supporting medication and infusions. Various devices are routinely used for this task. However, in the specific situation of ECMO treatment, the measurements of these devices could be affected due to the artificial circulation; outside the body. The purpose of this study is therefore to test the accuracy of different methods of circulation monitoring during ECMO treatment.

Hemodynamic Monitoring and Fluid Responsiveness in Venovenous Extracorporeal Membrane Oxygenation (VV ECMO) - "HemodynamECMOnitoring-VV Study"

In extracorporeal membrane oxygenation (ECMO), blood is drawn out of the body via tubes, oxygenated in an artificial lung; and then pumped back into the blood vessels. This allows the supply of oxygen-rich blood to the organs (brain, heart, lungs, kidneys, liver, intestines, etc.) to be maintained. Continuous monitoring of cardiac function and circulatory status (blood pressure, blood flow to organs) is very important in intensive care medicine in order to control the administration of circulation-supporting medication and infusions. Various devices are routinely used for this task. However, in the specific situation of ECMO treatment, the measurements of these devices could be affected due to the artificial circulation; outside the body. The purpose of this study is therefore to test the accuracy of different methods of circulation monitoring during ECMO treatment.

The Role of Swan-Ganz Catheter in Hemodynamic Resuscitation for Patients With Cardiogenic Shock

This clinical trial examines whether the use of the Swan-Ganz catheter, a specialized pulmonary artery catheter, can improve hemodynamic management and treatment outcomes in patients experiencing cardiogenic shock due to acute myocardial infarction (AMI). Cardiogenic shock is a critical condition marked by the heart's inability to supply adequate blood to the organs, often resulting from a severe heart attack. Despite advancements in care, the condition remains associated with high mortality. Effective monitoring of cardiovascular status is crucial in guiding timely and tailored treatment decisions. Participants in this study will undergo advanced hemodynamic monitoring using the Swan-Ganz catheter, which provides continuous data on cardiac output and other key parameters. This information enables physicians to better assess circulatory function and adjust therapies accordingly. The research will evaluate clinical characteristics, response to treatment, and 30-day outcomes in patients managed with this technique. The study also aims to identify factors associated with successful hemodynamic stabilization and potential complications related to catheter use. A total of 108 adult patients meeting specific eligibility criteria will be enrolled at Bach Mai Hospital over 3 years. Participation is voluntary, and all patients will continue to receive standard-of-care treatment. All personal and medical data will be handled with strict confidentiality.

Concordance Study of Therapeutic Decision-making in Patients With Shock Based on Hemodynamic Monitoring

Shock is a serious complication corresponding to acute circulatory failure resulting in multiorgan failure and death. In order to improve cellular oxygen utilization, several therapies can be used. To select one of them, the monitoring of cardiac output is helpful. However, there are several methods used in current practice in intensive care for evaluating hemodynamic. Currently, in patients with acute circulatory failure, no study has compared the concordance of therapeutic decision-making based on transpulmonary thermodilution or transthoracic echocardiography. The objective of the PICC-ECHO study is thus to assess the concordance of therapeutic decision-making by several experts, based on data from transpulmonary thermodilution or transthoracic echocardiography. Indeed, the investigators hypothesize that performing hemodynamic monitoring based on transpulmonary thermodilution or transthoracic echocardiography does not lead to the same therapeutic management in patients in shock.

Comparison of Cardiac Index and Stroke-volume-index Measured by Pulmonary Artery Catheter, FloTrac® and Argos® in Cardiac Surgery Patients.

A comparison of cardiac performance determined by stroke-volume-index measured by different mechanisms in patients during and after cardiac surgery: 1. Pulmonary artery catheter 2. Flo Trac 3. Argos Monitor Investigations will be done in theater and on ICU in ventilated and spontaneously breathing patients.

Assessment of Paravalvular Leak After TAVI by Hemodynamic Measurements and Cardiac MRI

Rationale: Transcatheter aortic valve implantation (TAVI) has become the standard therapy for elderly patients with high surgical risks. Paravalvular leakage after TAVI is relatively common and there is conflicting evidence regarding the clinical impact of mild paravalvular leakage in self-expanding devices. Prospective data for self-expanding devices are required to compare the extent of paravalvular leakage as a result of device design. Grading paravalvular leakage after TAVI is difficult. Echocardiography and angiography systematically underestimate paravalvular leakage (PVL) as compared to cardiac MRI. Hemodynamic measurements are used to aid decision making directly after TAVI implantation. Prospective data comparing hemodynamic measurements with cardiac MRI are needed to design an optimal strategy to grade paravalvular leakage peri-operatively in order to optimize TAVI outcomes. The combination of aortic valve stenosis, angiodysplasia and von Willebrand Disease type 2A (vWD-2A) is known as Heyde syndrome. Previous studies have shown a decrease in angiodysplastic lesions after TAVI. However, since PVL after TAVI is relatively common, angiodysplastic lesions tend to reoccur. Prospective data comparing the severity of PVL to the severity of both vWD-2A and angiodysplasia are lacking. Objective: To assess procedural hemodynamic measurements in patients with paravalvular regurgitation quantified by means of cardiac MRI (CMR) and to analyse its association with impaired clinical outcome during 5-year follow-up. Secondary objectives are to assess whether the severity of vWD-2A correlates with the severity of PVL measured by cardiac MRI, and to prospectively assess the success percentage of TAVI in the treatment of angiodysplasia. Study design: This is a prospective, single-center clinical trial. Patients will receive a TAVI. After implantation different hemodynamic indices of PVL will be assessed. Within 4-8 weeks after TAVI a cardiac MRI will be performed to quantify the amount of PVL. Standardized clinical follow-up will take place at discharge, 30 days, 3 months, 6 months and 1 year. Telephone follow-up will take place at 2, 3, 4 and 5 years after TAVI. In patients with known angiodysplasia or iron deficiency anemia e.c.i., a videocapsule endoscopy (VCE) will take place before TAVI and 6 months after TAVI. Of note, for the substudy on Heyde syndrome, patients with a different type of TAVI valve (i.e. no Abbott Portico valve) are also allowed to participate. Study population: Approximately 80 patients with severe symptomatic aortic valve stenosis with an indication for TAVI will be included. At least 76 patients with a cardiac MRI that is of sufficient quality to quantify the amount of PVL will be included. Intervention: Patients will undergo cardiac MRI on top of standard clinical care within 4-8 weeks after TAVI. A subgroup of patients will also undergo a VCE. Main study parameters/endpoints: The primary endpoint is defined as PVL regurgitation fraction as measured by cardiac MRI. One secondary endpoint will comprise a composite of device success, early safety and clinical efficacy as defined by the Valve Academic Research Consortium-2 (VARC-2) (1) and will comprise death, vascular complications, stroke/TIA, life-threatening bleeding requiring transfusion, and acute kidney injury requiring dialysis. Another secondary endpoint will be the reduction of angiodysplastic lesions after TAVI as determined by VCE. Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The hemodynamic indices can be assessed in a standard fashion using a fluid filled pigtail catheter that is placed in the left ventricle as part of the routine protocol. Following TAVI, enrolled patients will undergo cardiac MRI to assess PVL. The risk of cardiac MRI after TAVI implantation is negligible. Extra blood samples will be taken. After one year, patients will be followed by telephonic follow-up. Risk/benefit: the expected benefit is a structured clinical follow-up at 1, 2, 3, 4 and 5 years, at the cost of an extra visit to undergo cardiac MRI.