Intraoperative management
Blood loss, Stroke, SVV, blood loss, postoperative nausea and vomiting, normocapnia
BLOOD LOSS, STROKE, BLOOD LOSS, EDWARDS
All patients received basic anesthetic monitoring by five-lead-electrocardiogram, pulse oximetry, blood pressure cuff and bispectral index (BIS), at least one peripheral i.v., a central venous catheter and invasive radial arterial blood pressure monitoring. All patients received bilateral quadratus lumborum muscle block with 0.375% ropivacaine 40 ml 30 min before induction under sedation with midazolam (0.02 mg/kg). In both groups, standard general anesthesia was induced with sufentanyl 0.4–0.5 μg/kg, propofol 1.5-2 mg/kg and cisatracrurium 0.15 mg/kg. After intubation of the trachea, the lungs were ventilated with tidal volume of 8 ml/kg of ideal body weight and positive end expiratory pressure (PEEP) of 4 mmHg, respiratory rate was set to maintain normocapnia using a constant fresh gas flow of 2 L/min. Maintenance of anesthesia was performed with 0.9–1.8% end tidal sevoflurane, remifentanyl and propofol to maintain the BIS value of 40%-60% and cisatracrurium boluses were given as needed.In group G, the arterial line was connected to the Vigileo monitor (software version 1.14; Edwards Lifesciences, Irvine, CA, USA) via the FloTrac pressure transducer and all intravascular pressure measurements were referenced to mid-axillary line level. The shape of the arterial curve was checked visually for damping throughout the study period. SVV and cardiac index (CI), as indicators for fluid responsiveness during mechanical ventilation and sinus rhythm, were continuously measured. SVV ≤ 12% and CI of at least 2.5L/min/mAlgorithm for fluid therapy in the operating room in the goal-directed fluid therapy group; CI: cardiac index; MAP: mean arterial pressure; IBW: ideal body weight; PEEP: positive end expiratory pressure; SVV: Stroke volume variationIn group C, MAP was kept between 65 and 90 mmHg, and central venous pressure (CVP) between 8 and 12 mmHg. 500 ml of crystalloids was infused during induction, followed by a continuous infusion of crystalloids (4 ml/kg/h). If the MAP decreased below 65 mmHg, or if the CVP decreased below 8 mmHg, a 250 mL bolus of crystalloids was given. Another 250 ml bolus of colloid was administrated after waiting 5 min if CVP still decreased below 8 mmHg. If the MAP decreased below 65 mmHg and remained unresponsive to fluids, vasopressor or inotrope was given to maintain the MAP above 65 mmHg (Fig. Algorithm for fluid therapy in the operating room in the control group; CVP: central venous pressure; MAP: mean arterial pressure. * The goal did not reach after 500 ml colloid administration, consider inotropes or vasopressorsNormothermia was achieved during surgery with a forced-air warming blanket. Intermittent pneumatic leg compression devices were applied to all patients. No nasogastric tube was given. All patients were given a single intravenous dose of 4 mg of ondansetron as prophylaxis against postoperative nausea and vomiting at the end of surgery. Blood loss was substituted with fluids according to the protocols and a hemoglobin value below 8 mg/dL was considered to be a trigger for transfusion of packed red blood cells. At the end of surgery total catecholamine administration, estimated blood loss, urine output and infused fluids were recorded.