Participant timeline {13}
Demographic and baseline data such as age, weight, height, and ASA score are collected soon after informed consent is granted, usually the day before surgery. On the day of surgery, data that define the type of surgery and the type and size of central venous cannulation will be noted. Also, hemodynamic data such as arterial pressure, heart frequency, and blood oxygen saturation before and soon after the performance of the PECS block will be recorded. At the end of the surgery, the amount of opioids and sedatives used during the surgery will be noted. The time of ICU admission and hemodynamic data will be noted at ICU admission.All opioids and other analgesics will be noted until the extubation and after 2, 4, 6, 8, 12, and 24 h. Also, the NRS score will be assessed at the defined time points.After 24 h, the OBAS assessment will be performed, and the study participation will end.