title: Ventilation during laparoscopic-assisted bariatric surgery: volume-controlled, pressure-controlled or volume-guaranteed pressure-regulated modes.
abstract: BACKGROUND
  Managing ventilation and oxygenation during laparoscopic procedures in severely obese patients undergoing weight loss surgery presents many challenges. Pressure-controlled ventilation, volume-guaranteed (PCV-VG) is a dual-control mode of ventilation and an alternative to pressure (PC) or volume (VC) controlled ventilation. PCV-VG features a user-selected tidal volume target, that is auto-regulated and pressure controlled. We hypothesized that PCV-VG ventilation would provide improved oxygenation and ventilation during laparoscopic bariatric surgery with a lower peak inflating pressure (PIP) than either PC or VC ventilation.
  
  
  METHODS
  This was a prospective cross-over cohort trial (n = 20). In random sequence each patient received the three modes of ventilation for 20 minutes during the laparoscopic portion of the procedure. For all modes of ventilation the goal tidal volume was 6-8 mL/kg, and the respiratory rate was adjusted to achieve normocarbia. The PIP, exhaled tidal volume, respiratory rate, and oxygen saturation were recorded every five minutes. At the end of 20 minutes, an arterial blood gas was obtained. Data were analyzed using a paired t-test.
  
  
  RESULTS
  PCV-VG and PC ventilation both resulted in significantly lower PIP (cmH2O) than VC ventilation (30.5 ± 3.0, 31.6 ± 4.9, and 36.3 ± 3.4 mmHg respectively; p < 0.01 for PCV-VG vs. VC and PC vs. VC). There was no difference in oxygenation (PaO2), ventilation (PaCO2) or hemodynamic variables between the three ventilation modes.
  
  
  CONCLUSIONS
  In adolescents and young adults undergoing laparoscopic bariatric surgery, PCV-VG and PC were superior to VC ventilation in their ability to provide ventilation with the lowest PIP.
authors.affiliation: Department of Anesthesiology & Pain Medicine, Nationwide Children's Hospital and The Ohio State University 700 Children's Drive, Columbus 43205, Ohio, US.
authors.forename: Joanna M
authors.initials: JM
authors.lastname: Dion
authors.affiliation: Department of Anesthesiology & Pain Medicine, Nationwide Children's Hospital and The Ohio State University 700 Children's Drive, Columbus 43205, Ohio, US.
authors.forename: Chris
authors.initials: C
authors.lastname: McKee
authors.affiliation: Department of Anesthesiology & Pain Medicine, Nationwide Children's Hospital and The Ohio State University 700 Children's Drive, Columbus 43205, Ohio, US.
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Tobias
authors.affiliation: Department of Anesthesiology & Pain Medicine, Nationwide Children's Hospital and The Ohio State University 700 Children's Drive, Columbus 43205, Ohio, US.
authors.forename: Paul
authors.initials: P
authors.lastname: Sohner
authors.affiliation: Department of Urology , Nationwide Children's Hospital and The Ohio State University 700 Children's Drive, Columbus 43205, Ohio, US.
authors.forename: Daniel
authors.initials: D
authors.lastname: Herz
authors.affiliation: Department of Surgery, Nationwide Children's Hospital and The Ohio State University 700 Children's Drive, Columbus 43205, Ohio, US.
authors.forename: Steven
authors.initials: S
authors.lastname: Teich
authors.affiliation: Department of Anesthesiology & Pain Medicine, Nationwide Children's Hospital and The Ohio State University 700 Children's Drive, Columbus 43205, Ohio, US.
authors.forename: Julie
authors.initials: J
authors.lastname: Rice
authors.affiliation: Department of Anesthesiology & Pain Medicine, Nationwide Children's Hospital and The Ohio State University 700 Children's Drive, Columbus 43205, Ohio, US.
authors.forename: N' Diris
authors.initials: ND
authors.lastname: Barry
authors.affiliation: Department of Surgery, Nationwide Children's Hospital and The Ohio State University 700 Children's Drive, Columbus 43205, Ohio, US.
authors.forename: Marc
authors.initials: M
authors.lastname: Michalsky
keywords: Bariatric surgery; adolescent; arterial blood gas analysis; obesity; ventilation