Introduction.The aim of the study was to assess changes of regional ventilation distribution at the level of the 3rd intercostal space in\nthe lungs ofmorbidly obese patients as a result of general anaesthesia and laparoscopic surgery aswell as the relation of these changes\nto lung mechanics.We also wanted to determine if positive end-expiratory pressure of 10 cm H2O prevents the expected atelectasis\nin themorbidly obese patients during general anaesthesia. Materials and Methods. 49 patients completed the examination and were\nrandomized to 2 groups: ventilated without positive end-expiratory pressure (PEEP 0) and with PEEP of 10 cm H2O (PEEP 10)\npreceded by a recruitment maneuver with peak inspiratory pressure of 40 cm H2O. Impedance Ratio (IR) was utilized to examine\nventilation distribution changes as a result of anaesthesia, pneumoperitoneum, and change of body position. We also analyzed\nintraoperative respiratory mechanics and pulse oximetry values. Results. In both groups general anaesthesia caused a ventilation\nshift towards the nondependent lungs which was not further intensified after pneumoperitoneum. Reverse Trendelenburg position\npromoted homogeneous ventilation distribution. Respiratory system compliance was reduced after insufflation and improved\nafter exsufflation of pneumoperitoneum. There were no statistically significant differences in ventilation distribution between the\nexamined groups. Respiratory system compliance, plateau pressure, and pulse oximetry values were higher in PEEP 10. Conclusions.\nChanges of ventilation distribution in the obese do occur at cranial lung regions. During pneumoperitoneum alterations of\nventilation distribution may not follow the direction of the changes of lung mechanics. In the obese patients PEEP level of 10 cm\nH2O preceded by a recruitment maneuver improves respiratory compliance and oxygenation but does not eliminate atelectasis\ninduced by general anaesthesia.
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