Cardiac Surgery Patients

Myocardial strain analysis provides additional and valuable information about left ventricular function, particularly in the perioperative setting with its dynamic changes in ventricular load conditions. This allows for earlier risk assessment and, if necessary, the initiation of faster and more targeted therapy. Unfortunately, conventional strain analysis using conventional methods currently takes approximately 5 minutes. However, this amount of time is often not available in a dynamically changing intraoperative setting during cardiac surgery. Therefore, the benefits of strain analysis have not yet been routinely utilized during the intraoperative course. However, new software solutions exist that can perform strain analysis fully automatically and reduce the examination time to a few seconds. However, it remains unclear whether these fully automated analyses also function reliably intraoperatively using transesophageal echocardiography (TEE). The aim of this study is to assess the reliability of these new methods.

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.

Hypotension prediction index (HPI) was applied in various types of non-cardiac surgery with convincing benefits of preventing hypotensive events and clinical sequelae. Although HPI was validated in cardiac surgery, its clinical benefits are not proven yet. We aim to evaluate its effects on intraoperative hypotension and postoperative adverse events in cardiac surgery. In this randomized, single-blind trial, we will enroll adults scheduled for elective primary cardiac surgery under general anesthesia. Participants will be randomly assigned to intraoperative HPI-guided or non-HPI-guided hemodynamic management. The primary endpoint is the time-weighted average intraoperative hypotension below a mean arterial pressure threshold of 65 mmHg. The secondary endpoints are postoperative complications.