This is a randomized trial (1) investigating whether continuous invasive arterial blood pressure monitoring using an arterial catheter reduces the area under a mean arterial pressure (MAP) of 65 mmHg within the first 15 minutes of anesthetic induction compared to intermittent arterial blood pressure monitoring using oscillometry in patients having major surgery under general anesthesia; and (2) investigating the effect of continuous invasive arterial blood pressure monitoring using an arterial catheter on cardiac output, stroke volume, and heart rate within the first 15 minutes of anesthetic induction compared to intermittent blood pressure monitoring using upper-arm cuff oscillometry in patients having major surgery under general anesthesia.

not provided

Inclusion Criteria:

Patients...

• at least 18 years of age
• scheduled for elective major surgery under general anesthesia that requires continuous invasive arterial blood pressure monitoring using a radial arterial catheter for clinical indications not related to the study

Exclusion Criteria:

• Clinical indication to insert the arterial catheter before anesthetic induction ("awake arterial catheter"; this is usually the case in patients with severe cardiovascular diseases, such as heart failure or left ventricular assist device)
• emergency surgery
• American Society of Anesthesiologists physical status classification V or VI
• need for femoral artery catheterization
• heart rhythms other than sinus rhythm.