A standardised anaesthesia protocol for drug administration during RALP was exclusively conducted by three anaesthesiologists throughout the entire study. Drug dosing was based on the calculated PBW (PBW formula: PBW [men] = 50 + 0.91 × [cm of height—152.4] in kg) [17 (link)]. Anaesthesia was induced with sufentanil (initial 0.5 µg/kg bolus), propofol (2–3 mg/kg) and atracurium (0.5 mg/kg). After tracheal intubation with a 7.5 mm or an 8.0 mm endotracheal tube, anaesthesia was maintained with sufentanil (repetition of 10 µg every 30 to 45 min until 30 min before the end of surgery) and propofol (4–6 mg/kg/h) as total intravenous anaesthesia (TIVA). TIVA was used as standard anaesthesia for RALP to minimise the influence on pulmonary function by volatile anaesthetics. A Bispectral Index™ (BIS Vista Monitor, Aspect Medical, Germany) between 40 and 50 was upheld during anaesthesia. Invasive blood pressure was measured directly after the induction of anaesthesia using a radial artery catheter. All patients were placed by default in STP to check the correct positioning and solid fixation on the operating table. In this context, the individualised PEEP group received one recruitment manoeuvre (RM) followed by a decremental PEEP titration in STP.
The RM was performed in volume-controlled mode and consisted of 10 respiratory cycles with a PEEP level of 22 cmH2O, a peak inspiratory pressure of 40 cmH2O and a ventilation frequency of 6 breaths per min with an I/E of 1:2. For the decremental PEEP titration PEEP was set to 20 cmH2O and decreased stepwise by 2 cmH2O every 3 min. At each PEEP step, the best lung compliance value was observed, and this individual PEEP level was maintained throughout mechanical ventilation during surgery. No RM were employed in the standard PEEP group.
During RALP, the target values for SpO2 were defined as higher than 92% and those of mean arterial pressure (MAP) as 60 mmHg. Otherwise, FiO2 or noradrenaline concentration was adapted. All patients received volume-controlled ventilation with PEEP according to the levels predefined for the respective group, using an inspiration-to-expiration ratio of 1:1, a basic respiratory rate of 12 and a constant VT of 7–8 mL/kg PBW. At the beginning of RALP, pneumoperitoneum was created by intraperitoneal insufflation of CO2 to a standard value of 15 mmHg with the patient in supine position. Subsequently, each patient was consequently placed in 45 degrees STP. Surgery was exclusively conducted by three urologists. Neuromuscular transmission was monitored with a peripheral nerve stimulator to maintain one twitch of the train-of-four (TOF). Relaxation with rocuronium was finished 45 min before the end of surgery. For extubation, the TOF ratio had to be >0.9 at the end of RALP. Individualised high PEEP values were reduced to 8 cmH2O at the end of surgery after positioning the patient in supine position prior to extubation.
The RM was performed in volume-controlled mode and consisted of 10 respiratory cycles with a PEEP level of 22 cmH2O, a peak inspiratory pressure of 40 cmH2O and a ventilation frequency of 6 breaths per min with an I/E of 1:2. For the decremental PEEP titration PEEP was set to 20 cmH2O and decreased stepwise by 2 cmH2O every 3 min. At each PEEP step, the best lung compliance value was observed, and this individual PEEP level was maintained throughout mechanical ventilation during surgery. No RM were employed in the standard PEEP group.
During RALP, the target values for SpO2 were defined as higher than 92% and those of mean arterial pressure (MAP) as 60 mmHg. Otherwise, FiO2 or noradrenaline concentration was adapted. All patients received volume-controlled ventilation with PEEP according to the levels predefined for the respective group, using an inspiration-to-expiration ratio of 1:1, a basic respiratory rate of 12 and a constant VT of 7–8 mL/kg PBW. At the beginning of RALP, pneumoperitoneum was created by intraperitoneal insufflation of CO2 to a standard value of 15 mmHg with the patient in supine position. Subsequently, each patient was consequently placed in 45 degrees STP. Surgery was exclusively conducted by three urologists. Neuromuscular transmission was monitored with a peripheral nerve stimulator to maintain one twitch of the train-of-four (TOF). Relaxation with rocuronium was finished 45 min before the end of surgery. For extubation, the TOF ratio had to be >0.9 at the end of RALP. Individualised high PEEP values were reduced to 8 cmH2O at the end of surgery after positioning the patient in supine position prior to extubation.
Free full text: Click here
