Anesthesia and CPB management
DISEASE, MUSCLE RELAXATION
All patients were treated using the same anesthesia and perioperative management protocol. Routine prophylactic antibiotics (mostly cefuroxime 1.0 g) were used from 30 min to 1 h before the operation. When the operation time exceeded 3 h, the drugs were administered again after 3 h. There was no other preoperative medication. Cefuroxime (1.0 g) was used routinely after the operation, twice daily for two consecutive days. Antibiotics were changed or upgraded according to the change in disease condition. The selection and time of antibiotic treatment were based on the Guidelines for Clinical Use of Antibiotics (2015 version) issued by the National Health Commission.After entering the operating room, a peripheral venous channel was established, and a five-lead electrocardiogram, pulse oximetry saturation, bispectral index (BIS), urine volume, and body temperature were monitored routinely. Left radial arterial puncture catheterization (20 G) and right internal jugular vein puncture catheterization (7F triple vena cava catheter) were performed under local anesthesia. The pressure sensors were connected to continuously monitor the invasive arterial pressure and central venous pressure.Anesthesia induction: midazolam 0.05 mg/kg and etomidate 0.2–0.3 mg/kg were successively injected intravenously, followed by cisatracurium 0.3 mg/kg and fentanyl 10 μg/kg, and following intubation, mechanical ventilation was initiated. During anesthesia induction, norepinephrine and ephedrine were used to ensure sufficient perfusion pressure of important organs and maintain the stability of vital signs. Mechanical ventilation parameters were: tidal volume 8–10 ml/kg, ventilation frequency 10–12 times/min, inspiratory/expiratory ratio 1:2, air oxygen mixture flow 2 L/min, inspiratory oxygen concentration 60%, and end-expiratory COAnesthesia maintenance: immediately after anesthesia induction, 1% propofol was pumped through the right internal jugular vein catheter at a constant rate of 2–8 mg/kg/h. The infusion rate of propofol was adjusted according to BIS to maintain the depth of anesthesia, so that BIS fluctuated within 40–55. During CPB, BIS was maintained at 30–40. During anesthesia, fentanyl 2 μg/kg was intermittently injected intravenously to maintain analgesia (total fentanyl 50 μg/kg), and cisatracurium 0.12 mg/kg/h was administered to maintain muscle relaxation. Dopamine, epinephrine, norepinephrine, and nitroglycerin micropump injection or small-dose single intravenous injection of vasoactive drugs such as norepinephrine, ephedrine and atropine, was used to maintain hemodynamic stability and maintain mean arterial pressure of 60–80 mmHg. At the end of anesthesia, infusion of all drugs was stopped except for continuous pumping of vasoactive drugs. The electrocardiogram, finger pulse oximetry monitoring and invasive blood pressure monitoring were transferred to the mobile monitor. After hemodynamic stability was assessed, the patients were escorted to the cardiothoracic surgery intensive care unit (ICU) together with the surgeon and operating room nurse.Sodium lactate Ringer’s solution, hydroxyethyl starch electrolyte injection, 10% human albumin, 5% NaHCO