Evaluating Respiratory Effects of Driving Pressure Guided Mechanical Ventilation Using Electrical Impedance Tomography in Patients Undergoing Robot-Assisted Laparoscopic Radical Prostatectomy

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Robot-Assisted Laparoscopic Radical Prostatectomy is a method increasingly used for prostate cancer due to fewer complications, morbidity, and mortality compared to other methods. The technique involves inflating the abdomen with carbon dioxide to provide visualization and working in a steep Trendelenburg position, which puts pressure on the lungs and can cause them to collapse. The functional residual capacity reduction caused by general anesthesia, combined with the negative effects of the position, increases the risk of significant respiratory system complications during and after surgery. Lung protective ventilation strategies can reduce the incidence of postoperative pulmonary complications (PPC) by alleviating iatrogenic injury to previously healthy lungs. Apart from a low tidal volume (VT), applying positive end-expiratory pressure (PEEP) can minimize the risk of atelectasis and/or overdistension. There is limited information on how to adjust optimal PEEP under increased intra-abdominal pressure during laparoscopy. A meta-analysis study on acute respiratory distress syndrome (ARDS) patients showed that high driving pressure (plateau pressure - PEEP) is the most associated value with mortality. It was shown that VT, plateau pressure, and PEEP are not related to patient outcomes or only when they affect driving pressure. Subsequent retrospective and prospective studies confirmed the importance of driving pressure in ARDS patients and surgical patients. For patients under mechanical ventilation, applying a personalized PEEP that provides the lowest driving pressure, along with maneuvers to open closed alveoli (recruitment), reduces respiratory system complications during and after surgery. One method to visualize the effects of these maneuvers and the ideal PEEP application, which provides the lowest driving pressure for the patient, is electrical impedance tomography (EIT), a non-invasive, radiation-free bedside imaging technique. EIT, measured with 16 electrodes placed on an elastic belt around the patient\'s 4th to 6th ribs, shows impedance changes in the lungs. This method successfully visualizes and evaluates dynamic changes in gas distribution within the lungs and has been validated by computed tomography scans, proving safe for use in both adults and pediatric patients. EIT divides the lungs into four layers from ventral to dorsal, showing the percentage distribution of tidal volume in these regions. Examining the relative impedance changes allows for observing gas volume distribution entering the lungs and evaluating regional lung characteristics. Therefore, EIT can contribute to examining the PEEP value that ensures homogeneous gas distribution in the lungs and preventing ventilator-associated lung injury. The aim of our study is to evaluate the effect of driving pressure guided mechanical ventilation on lung gas distribution during robot-assisted laparoscopic radical prostatectomy through respiratory parameters recorded by EIT during surgery and perioperative period and to compare perioperative pulmonary complications with traditional ventilation methods

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