Overview

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.

Eligibility

Inclusion Criteria:

1. Age ≥ 18 years
2. American Society of Anesthesiologists (ASA) physical status classification III or IV
3. Scheduled for elective major abdominal aortic surgery (open or endovascular repair) with an expected surgical duration exceeding 2 hours
4. Able to provide written informed consent

Exclusion Criteria:

1. Emergency or urgent surgery
2. Pregnancy or breastfeeding or positive/uncertain pregnancy test
3. Haemodynamically significant valvular heart disease:
   • Severe aortic stenosis (aortic valve area \< 1.5 cm\^2)
   • Moderate to severe aortic regurgitation
   • Moderate to severe mitral regurgitation
   • Moderate to severe mitral stenosis
4. Severe heart failure with left ventricular ejection fraction \< 35%
5. Permanent atrial fibrillation (reduces accuracy of pulse contour analysis)
6. Inability to provide informed consent
7. Participation in another interventional trial that may influence haemodynamic management or study outcomes