Anesthesia process
hypertension, hypotensive, residual neuromuscular block
MUSCLE RELAXATION, INTRAOPERATIVE HYPERTENSION, EVENTS, HYPERTENSION, HYPOTENSIVE
The anesthetic dosage in the OFA group was determined based on previously reported methods and its feasibility was assessed in a pilot series before this study [After the patient entered the operating room and the venous access was opened, general anesthesia was induced using etomidate 0.3 mg/kg and remifentanil 1-2 μg/kg (pumping completed within 60 s) in the control group, while patients in the OFA group were premedicated with dexmedetomidine 1 μg/kg over 10 min, and then induced with etomidate 0.3 mg/kg, s-ketamine 0.5 mg/kg, lidocaine 1.5 mg/kg and maintained with dexmedetomidine 0.5 μg/kg/h, s-ketamine 0.25 mg/kg/h, and propofol 3-4 mg/kg/h. Patients in the control group were maintained with propofol 4-6 mg/kg/h and remifentanil 0.05–0.2ug/kg/min. Rocuronium bromide 0.6 mg/kg was used in both groups for muscle relaxation. Endotracheal intubation was performed in both groups after pre-oxygenation. For better blinding, all patients' necks were treated with a dressing after intubation.After intubation, patients in the OFA group received ultrasound-guided ICPB performed by an experienced anesthesiologist. The ICPB procedures described below were similar to the method described in a previous study [Intermediate cervical plexus blockPatients in both groups were ventilated with air/oxygen mixed inhalation (FiOIntraoperative hemodynamic parameters were recorded every 5 min. Baseline values were taken 5 min after induction and a 20% rise from baseline in the mean arterial pressure (MAP) or pulse rate (PR) ≥ 100 beats/min prompted the administration of a 40 μg remifentanil bolus in the control group vs. 1 mg nicardipine or 1 mg metoprolol in the OFA group. The selection of blood pressure reduction methods for the two groups was based on the results of the pre-experiment. During the operation, if hypertension occurred, we first thought that it was caused by insufficient analgesia. Therefore, in the control group, remifentanil was given first to control blood pressure, and good hypotensive effect was achieved in the pre-experiment. However, in the pre-experiment of the OFA group, when hypertension occurred during surgery, increasing the dosage of anesthesia or administering non-opioid analgesics did not achieve satisfactory analgesic effects. On the contrary, when we administered antihypertensive drugs, we achieved better antihypertensive effects, so we believed that intraoperative hypertension in the OFA group was caused by side effects of s-ketamine. In case of uncontrollable hypertension, sevoflurane should be inhaled to maintain hemodynamic stability during surgery. Patients with uncontrollable hypertension were excluded and the total number of these patients was recorded. Uncontrollable hypertension was defined as that when remifentanil was pumped or hypotensive drugs were injected intravenously and the efficacy disappears, the blood pressure rose to more than 20% of the basic value for three consecutive times. When the MAP decreased by over 20%, patients in both groups were provided with norepinephrine (8 ug). Besides, 0.5 mg of atropine was given when the pulse rate was less than 40 times/min. The number of patients with adverse hemodynamic events in the two groups was recorded. Additionally, regular doses of neostigmine and atropine were adopted to block the residual neuromuscular block. Extubation was performed when the patient reached a normal spontaneous breathing mode. The surgical duration was defined as the time from the first incision to the completion of suture. The anesthesia duration was defined as the time from the beginning of anesthesia induction to the withdrawal of endotracheal intubation. The extubation duration was defined as the time between the end of surgery and endotracheal extubation. After extubation, the patient was transferred to the PACU.In the PACU and ward, all patients received oxygen inhalation only when SpO