2.2 Anesthesia application
The patient was admitted to the operating room for pulse oxygen saturation, electrocardiogram and non-invasive blood pressure monitoring. Following placement of a 20-gage intravenous line, all patients received 14 mL•kg−1•h−1isotonic Lactic acid Ringer’s solution intravenously (i.v.). Anesthesia induction: midazolam (0.05 mg/kg body weight), sufentanil (0.5µg/kg), propofol (2 mg/kg) and cis atracurium (0.15 mg/kg) were injected intravenously 3-5 minutes after denitrification and oxygenation. A single-lumen endotracheal catheter was used to complete ventilation. The ventilator ventilation mode is volume control mode, and the patient’s end-expiratory carbon dioxide level is maintained at 35-40 mmHg throughout the anesthesia process.
During the anesthesia maintenance phase, 2% sevoflurane mixed with 60% oxygen, remifentanil (0.5 µg/kg/min) and propofol (100 µg/kg/min) were continuously pumped. Cisatracurium (0.15 mg/kg) was given every hour during the operation. If the non-invasive blood pressure is more than 20% of the base value, remifentanil (0.1–1.0 µg/kg/min) is added intravenously. If the blood pressure is more than 20% lower than the baseline, give a rapid intravenous drip of saline 250mL or ephedrine 0.1 mg/kg. If the heart rate decreased to less than 50 bpm, atropine (0.5 mg/kg) was administered. At the end of the modified radical mastectomy (MRM) procedure, neostigmine (0.05mg/kg) and atropine (0.02mg/kg) can reverse the muscle relaxation effect of cisatracurium. After the operation, the patient is transferred to the postoperative recovery room, and the endotracheal tube can be extubated after being evaluated by the anesthesiologist.