ABSTRACT
Objective To evaluate the effect of ventilation with different positive end-expiratory pressures (PEEPs) on intracranial pressure in the patients undergoing gynecological laparoscopic surgery.Methods Sixty American Society of Anesthesiologists physical status Ⅰ or Ⅱ patients,aged 25-55 yr,with body mass index of 18-27 kg/m2,scheduled for elective gynecological endoscopic surgery,were divided into 3 groups (n=20 each) using a random number table method:routine ventilation group (group A),4 cmH2O PEEP group (group B) and 8 cmH2O PEEP group (group C).The patients were mechanically ventilated with PEEP 4 or 8 cmH2O at 5 min of head-down tilt after start of pneumoperitoneum in group B and group C.The patients were mechanically ventilated in volume-controlled mode,with tidal volume 7 ml/kg,inspired oxygen concentration 50％ and inspiratory/expiratory ratio 1 ∶ 2.Blood samples were collected from the radial artery for measurement of PaCO2 and PaO2 at 5 min after tracheal intubation (T0),5,15 and 30 min of head-down tilt (T1-3),and 5 min of the supine position after the end of pneumoperitoneum (T4).The peak airway pressure (Ppeak) was recorded,dynamic pulmonary compliance (Cdyn)was calculated,and optic nerve sheath diameter was measured using an ultrasonic apparatus at T0-4.Cognitive function was assessed at 1 day before surgery and 7 days after surgery using Mini-Mental State Examination.Results Compared with group A,Ppeak was significantly increased at T1-4,and PaO2 was increased at T2 in group B,and Ppeak and PaO2 were increased at T1-4,and Cdyn was increased at T1,2 in group C (P＜0.05).Compared with group B,Ppeak was significantly increased at T4,and Cdyn was increased at T2 in group C (P＜0.05).There was no significant difference in optic nerve sheath diameter or Mini-Mental State Examination score at each time point among three groups (P＞0.05).No patients developed cognitive dysfunction at 7 days after surgery in three groups.Conclusion Ventilation with different PEEPs causes no increase in intracranial pressure of the patients undergoing gynecological laparoscopic surgery.