The standard procedure during general anesthesia is to monitor vital functions, including cardiovascular functions such as cardiac electrical activity, using continuous ECG recording, blood pressure measurement with a sphygmomanometer, heart rate measurement, and tissue oxygenation measurement with a pulse oximeter. These are non-invasive methods, which are often insufficient in the case of extensive procedures within the abdominal aorta. In such cases, the anesthesiologist additionally use direct blood pressure measurements and central venous pressure measurements. To perform these measurements, it is necessary to insert a cannula into an artery (usually the radial artery) and a catheter into the central veins (through the internal jugular or subclavian vein). Vascular cannulation is an invasive method and may be associated with complications such as vascular thrombosis, infection at the puncture site or catheter-related infections, pneumothorax, air embolism, cardiac arrhythmias, neuropathies, hematomas, and bleeding. At the same time, they allow for a more accurate assessment of cardiovascular function and the implementation of appropriate treatment, including the administration of large amounts of infusion fluids, vasoconstrictors, and cardiac support drugs.
In the current study, the investigators will additionally use a special sensor and monitor to assess the heart's performance (cardiac output) and its response to the treatment used, optimizing and supporting the circulatory system. This monitoring requires the insertion of a catheter into a central vein and artery, which is necessary during vascular surgery procedures and does not involve any additional invasive procedures. In the postoperative period, the investigators will analyze the frequency of abnormalities in laboratory tests routinely collected after surgery and the function of the central nervous system by performing simple non-invasive cognitive function tests.
The benefits of using the method of assessing the patient's response to surgery and anesthesia in presented study are related to increased safety for each patient and improved perioperative treatment for all patients undergoing surgery.
Age ≥ 18 years
American Society of Anesthesiologists (ASA) physical status classification III or IV
Scheduled for elective major abdominal aortic surgery (open or endovascular repair) with an expected surgical duration exceeding 2 hours
Able to provide written informed consent
Emergency or urgent surgery
Pregnancy or breastfeeding or positive/uncertain pregnancy test
Severe aortic stenosis (aortic valve area < 1.5 cm²)
Moderate to severe aortic regurgitation
Parallel
HPI guided heamodynamic monitoring
DeviceThe investigators hypothesise that HPI-guided haemodynamic management, when implemented with protocol refinements to mitigate hypertensive overcorrection, will reduce the burden of intraoperative hypotension compared with standard APCO monitoring in patients undergoing major abdominal aortic surgery. Secondary objectives include evaluation of postoperative organ injury, assessment of intraoperative hypertension as a safety outcome, and characterisation of fluid and vasopressor requirements. By testing this hypothesis in a rigorously designed, adequately powered trial, the investigators aim to clarify whether predictive haemodynamic monitoring offers clinically meaningful advantages over current reactive approaches in this high-risk population.
Standard Heamodynamic Managament according to APCO Monitoring
DeviceStandard Heamodynamic Managament according to APCO Monitoring with MAP target of 75 mmHg
time-weighted average of mean arterial pressure below 65 mmHg (TWA-MAP < 65 mmHg)
The primary outcome is the time-weighted average of mean arterial pressure below 65 mmHg (TWA-MAP \< 65 mmHg) during the period from induction of anaesthesia to departure from the operating theatre.
Intraoperative hypertension
* Total time with MAP \> 90 mmHg (minutes and % of monitoring time) * Total time with MAP \> 100 mmHg (minutes and % of monitoring time) * TWA-MAP \> 90 mmHg and TWA-MAP \> 100 mmHg
All-cause mortality at 90 days
All-cause mortality at 90 days
Composite postoperative organ complications within 7 days
Composite endpoint: at least one of the following within 7 days after surgery. * Acute kidney injury (AKI) per KDIGO criteria. * Myocardial injury after non-cardiac surgery (MINS): troponin ≥ assay-specific 99th-percentile upper reference limit. * Stroke: new focal neurological deficit confirmed by neuroimaging. * Postoperative respiratory failure (within 7 days or before ICU discharge): failure to extubate within 48 h; unplanned reintubation for respiratory failure; or unplanned non-invasive ventilation / high-flow nasal oxygen ≥ 6 h after extubation. * Postoperative circulatory failure (within 48 h): norepinephrine ≥ 0.1 µg/kg/min for ≥ 6 h despite adequate fluid resuscitation; initiation/escalation of inotropes for tissue hypoperfusion; or mechanical circulatory support (IABP, ECMO, or equivalent). Full operational definitions are provided in the study protocol.
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