Effects of low tidal volume protective lung ventilation versus pressure controlled ventilation on oxygenation in patients un-dergoing gynecologic laparoscopic surgery

Objective To evaluate the effectiveness and safety of low tidal volume protective lung ventilation (PLV) and pressure controlled ventilation (PCV) in patients undergoing gynecologic laparoscopic surgery. Methods A total of 144 patients who were scheduled for gynecologic laparoscopic surgery in our hospital were enrolled. According to the random number table method, they were divided into two groups (n=72): a PLV group and a PCV group. The PLV group used a tidal volume of 6 ml/kg, an inspiration and expiration ratio of 1∶2, a respiratory rate of 16 breaths per minute, and a positive end expiratory pressure of 5 cmH2O (1 cmH2O=0.098 kPa). In the PCV group, the ventilation pressure was maintained at a tidal volume of 8 ml/kg, with an inspiration and expiration ratio of 1∶2, and a respiratory rate of 12-16 breaths per minute. Their airway peak pressure (Ppeak) and mean airway pressure (Pmean) were recorded 5 min after tracheal intubation (T1), 10 min after pneumoperitoneum (T2), 20 min af-ter pneumoperitoneum (T3), and 10 min after pneumonectomy (T4), while dynamic lung compliance (Cdyn) was calculated. Blood gas analysis was performed at T3 and T4 to record arterial oxygen partial pressure (PaO2), arterial CO2 partial pressure (PaCO2), and alveolar-arterial oxygen partial pressure difference (A-aDO2), while oxygenation index (OI) was calculated. Results At T3, the PLV group presented remarkably increased Ppeak and Pmean and decreased Cdyn, compared with the PCV group (P 0.05). There was no significant differ-ence in the incidence of respiratory complications and the length of hospitalization stay between the two groups (P>0.05). Conclusions For patients undergoing gynecologic laparoscopic surgery, PCV is helpful to maintain stable respiratory dynamics, while low tidal volume PLV is helpful to maintain oxygenation function during surgery. There is no significant difference in safety be-tween the two types of treatment. Key words: Gynaecology; Laparoscopy; Protective lung ventilation mode; Pressure controlled ventilation; Oxygenation function