title: Effects of adding small amounts of oxygen to a carbon dioxide-pneumoperitoneum of increasing pressure in rabbit ventilation models.
abstract: OBJECTIVE
  To evaluate the metabolic consequences of the addition of oxygen to the CO(2)-pneumoperitoneum.
  
  
  METHODS
  Prospective randomized study in rabbits. After 30 minutes of ventilation pneumoperitoneum was maintained for 90 minutes with pure CO(2) or CO(2) with 2% or 6% of oxygen. The intraperitoneal pressure was increased from 10 to 15 and 20 mm Hg every 30 minutes. Ventilation rate was either fixed or a progressive hyperventilation. End points were changes in arterial blood gases (Pco(2), Po(2)), pH, acid-base balance (actual base excess [ABE], standard bicarbonate [SBC], standard base excess [SBE], hydrogen carbonate [HCO(3)(-)], concentration of total carbon dioxide [Tco(2)]); oxygen and oximetry (oxyhemoglobin [O(2)Hb], oxygen saturation [So(2)], reduced hemoglobin [RHb], total oxygen concentration [To(2)], and oxygen tension at half saturation assessing hemoglobin oxygen affinity [p50]); and lactate concentrations assayed every 15 minutes.
  
  
  METHODS
  University research center.
  
  
  METHODS
  Twenty-four adult female New Zealand white rabbits.
  
  
  METHODS
  Anesthesia, mechanical ventilation, and pneumoperitoneum.
  
  
  RESULTS
  The effects of CO(2)-pneumoperitoneum on all end points increased with the elevated intraperitoneal pressure and were more pronounced when ventilation was fixed. Changes were less when 2% or 6% of oxygen had been added to the CO(2)-pneumoperitoneum. With use of logistic regression, the addition of oxygen, intraperitoneal pressure, and ventilation were found to be independent variables affecting Pco(2), pH, ABE, SBE, HCO(3)(-), O(2)Hb, So(2), p50, and end-tidal CO(2).
  
  
  CONCLUSIONS
  The metabolic consequences of the combined effect of increased intraperitoneal pressure and CO(2)-pneumoperitoneum were less when 2% to 6% of oxygen was added or when animals were hyperventilated. We suggest that metabolic and mesothelial hypoxemia caused by CO(2) absorption can be reduced by adding small amounts of oxygen and by hyperventilation.
authors.affiliation: Department of Operative Gynaecology, Scientific Centre for Obstetrics, Gynaecology, Perinatalogy, Moscow State University of Medicine and Dentistry, Moscow, Russia. ospanmynbaev@hotmail.com
authors.forename: Ospan A
authors.initials: OA
authors.lastname: Mynbaev
authors.forename: Leila V
authors.initials: LV
authors.lastname: Adamyan
authors.forename: Karina
authors.initials: K
authors.lastname: Mailova
authors.forename: Bernard
authors.initials: B
authors.lastname: Vanacker
authors.forename: Philippe R
authors.initials: PR
authors.lastname: Koninckx
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000008:administration & dosage*; D010100:Oxygen / Q000008:administration & dosage*; D011028:Pneumoperitoneum, Artificial / Q000379:methods*; D011312:Pressure; D011817:Rabbits; D012121:Respiration, Artificial / Q000379:methods*
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen