Anesthesia and block procedure
ESPB, pain
BLOOD, HYPERTENSION, MUSCLE RELAXATION
Granisetron and dexamethasone were used to premedicate all patients prior to surgery. Using noninvasive methods such noninvasive electrocardiography, pulse oximetry, capnography, temperature monitoring, and bispectral index (BIS), all patients were observed in the operating room. A 22G, 50 mm block needle (SONOTAP, Pajunk, Geisingen, Germany) was inserted sterilely at a 30°–40° angle from cranial to caudal into the plane between the fascia of the ESM and the transverse process. The right needle tip position was confirmed by visualizing the linear fluid spread separating the transverse process from the erector spinae muscle. 20 cc of 0.25% bupivacaine was then injected deeply into the erector spinae muscle. On the other side, the same procedure was used. The control group had the same technique but received a sham injection instead (20 ml of saline).After the ESPB, the patient received a standard anaesthetic induction using intravenous fentanyl (1 μg /kg) and propofol (2 mg/kg). Before tracheal intubation and the mechanical ventilator were employed to maintain the end-tidal CO2 between 30 and 35 mmHg, atracurium (0.5 mg/kg) was given. Depending on the requirements of the patient, both inhaled (Sevoflurane) and intravenous (IV) atracurium were utilized for anaesthetic maintenance.Sevoflurane was used to sustain the anesthesia at a flow rate of 3 L/min in a 50% oxygen/air combination. Sevoflurane was administered initially at a concentration of 2%, and the concentration was increased to achieve an appropriate level of anesthesia by titrating the dose in accordance with the BIS monitoring (BIS Complete Monitoring System P/N 185–0151 Covidien IIc, 15 Hampshire Street, Mansfield, MA 02048 USA) to maintain the BIS value between 40 and 60. Inadequate (or excessive) sedation was treated by increasing (or decreasing) the concentration of sevoflurane by 0.4 units until the desired effect was reached.Blood pressure was assessed every five minutes. If the SBP was less than 90 mmHg and the BIS readings were between 40 and 60, a repeat bolus of 5 mg ephedrine was intravenously administered. If the SBP was less than 90 mmHg and the BIS value was less than 40, the sevoflurane vaporizer was decreased by 0.4% until a BIS value of 40 or higher was attained. The sevoflurane vaporizer was increased by 0.4% until a BIS value of 60 or less was attained. When the BIS value exceeded 60 and the SBP was more than 165 mmHg, Assuming that inadequate analgesia was the primary cause of hypertension, a bolus of 1 μg /kg of fentanyl was administered until the SBP was satisfactory if the SBP was higher than 165 mmHg and the BIS values were between 40 and 60. If the heart rate dropped below 50 beats per minute during the operation, 1 mg of atropine was administered intravenously.After the surgery, sevoflurane was terminated, and neostigmine (0.04 mg/kg) and atropine (0.01 mg/kg) were used for the reversal of muscle relaxation. Once spontaneous breathing started again, the patient was extubated.The total sevoflurane consumption was calculated according to the formula previously described by Biro [At the end of the operation, all patients were checked into the Post-Anesthesia Care Unit (PACU). With a 10 µg/ml concentration, a 25 g bolus, a 15-min lockout period, and a 100 µg/hr maximum dose with no background dose, all patients received IV fentanyl via patient-controlled analgesia (PCA). In addition, 1 g of IV paracetamol was administered every 8 h. The patient's pain was measured using a 10-cm Visual Analogue Scale (VAS) in the PACU immediately following surgery, as well as at 4, 8, 12, 16, and 24 h later within the ward.