Study intervention
ESPB
Upon entering the anesthetic induction room, patients underwent regular monitoring including electrocardiogram, heart rate, blood oxygen saturation and non-invasive blood pressure. The nerve blocks were administered approximately 30 mins before the induction of general anesthesia. Patients receiving ESPB and SAPB were not routinely sedated. Skilled consultant anesthesiologists, experienced in ESPB and SAPB, performed or supervised the procedures. Regardless of the specific block performed, each patient received 20 ml of 0.5% ropivacaine. The blocks were performed using a 20-gauge echogenic needle (001156–72, PAJUNK, USA) and an ultrasound machine equipped with a linear ultrasound transducer (L38Xi, Sonosite,USA).