title: Positive end-expiratory pressure in pressure-controlled ventilation improves ventilatory and oxygenation parameters during laparoscopic cholecystectomy.
abstract: BACKGROUND
  During laparoscopy, pneumoperitoneum may result in intraoperative atelectasis, which impairs normal gas exchange. This study investigated whether positive end-expiratory pressure (PEEP) of 5 cmH(2)O in pressure-controlled ventilation (PCV) mode can improve ventilatory and oxygenation parameters during pneumoperitoneum.
  
  
  METHODS
  Thirty patients, aged 18-65 years, undergoing laparoscopic cholecystectomy were randomly allocated to the ZEEP (PEEP = 0 cmH(2)O) or PEEP (PEEP = 5 cmH(2)O) group. PCV was started after induction of anesthesia. Apart from PEEP level, all other ventilator settings were identical for both groups. Peak airway pressure was set at induction and reset after pneumoperitoneum to deliver tidal volume of 8 ml/kg in both groups. Hemodynamic, ventilatory, and oxygenation parameters were measured after induction of anesthesia (T1) and 30 min after pneumoperitoneum (T2).
  
  
  RESULTS
  Oxygenation index (PaO(2)/FiO(2)) was significantly higher in the PEEP group than in the ZEEP group at T2 (P = 0.031). In both groups, dynamic compliance significantly decreased over 40 min from T1 to T2. There were no significant differences in hemodynamics between the two groups during the study period.
  
  
  CONCLUSIONS
  Application of PEEP of 5 cmH(2)O should be considered in PCV during laparoscopic surgeries to decrease intraoperative atelectasis caused by pneumoperitoneum to improve gas exchange and oxygenation.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Kim
authors.forename: Cheung Soo
authors.initials: CS
authors.lastname: Shin
authors.forename: Hong Soon
authors.initials: HS
authors.lastname: Kim
authors.forename: Wol Sun
authors.initials: WS
authors.lastname: Jung
authors.forename: Hyun Jeong
authors.initials: HJ
authors.lastname: Kwak
mesh_terms: D000328:Adult; D000368:Aged; D017081:Cholecystectomy, Laparoscopic / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D005705:Gallbladder Diseases / Q000601:surgery; D006801:Humans; D007430:Intraoperative Care / Q000379:methods*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D010101:Oxygen Consumption / Q000502:physiology; D011028:Pneumoperitoneum, Artificial; D011175:Positive-Pressure Respiration / Q000379:methods*; D011446:Prospective Studies; D001261:Pulmonary Atelectasis / Q000517:prevention & control; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D012123:Pulmonary Ventilation / Q000502:physiology*