Comprehensive Intraoperative Monitoring and Management

The surgical procedure was performed under general anesthesia. The ECG, heart rate, arterial blood pressure, SpO₂, urine volume, end-tidal carbon dioxide pressure (ETCO₂), and depth of anesthesia were measured continuously upon entering the operation room for all patients. According to the results of blood gas analysis and gas monitoring, the respiratory rate or tidal volume was adjusted to maintain ETCO₂ at 35 ~ 45 mmHg. Intraoperative heat preservation treatment was performed as follows: the body temperature was maintained at 36 ~ 37 ℃. If the patient’s blood pressure was 30% lower than the blood pressure base value or systolic blood pressure was lower than 80 mmHg, an intravenous pump with a small dose of norepinephrine (0.2 ~ 0.4 µg kg⁻¹ h⁻¹) was used. Nicardipine was intravenously injected at 10 µg kg⁻¹ to maintain intraoperative blood pressure within the normal range if blood pressure was 30% higher than the base value or systolic pressure was higher than 160 mmHg. When the patient’s heart rate was lower than 50 beats h⁻¹, atropine was intravenously injected at 0.5 µg kg⁻¹, and when the heart rate was higher than 100 beats h⁻¹, 0.5 mg kg⁻¹ esmolol was slowly injected intravenously. If the intraoperative COP was < 20 mmHg, furosemide 5 mg was intravenously injected.