title: Effect of hypoventilation on bleeding during hepatic resection: a randomized controlled trial.
abstract: OBJECTIVE
  Blood loss in hepatic resection is an important determinant of operative outcome.
  
  
  OBJECTIVE
  To clarify whether reducing the tidal volume would be effective in decreasing blood loss during liver transection.
  
  
  METHODS
  Randomized controlled trial.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  Eighty patients scheduled to undergo hepatic resection were randomly assigned to receive liver transection under normoventilation (n = 40) or hypoventilation (n = 40).
  
  
  METHODS
  During liver transection, in the normoventilation group, the tidal volume was 10 mL/kg and the respiratory rate was 10/min; in the hypoventilation group, the tidal volume was reduced to 4 mL/kg and respiratory rate was increased to 15/min. Liver transection was performed under total or selective inflow occlusion.
  
  
  METHODS
  Blood loss.
  
  
  RESULTS
  Between the normoventilation and hypoventilation groups, no significant difference was found in total blood loss (median [range]: 630 mL [72-3600 mL] vs 630 mL [120-3520 mL]; P =.44) or blood loss per transection area (median [range]: 7.3 mL/cm(2) [1.2-55.4 mL/cm(2)] vs 9.8 mL/cm(2) [0.9-79.9 mL/cm(2)]; P =.55). During liver transection, the central venous pressure was significantly reduced in the hypoventilation group than in the normoventilation group (median [range]: -0.7 cm H(2)O [-3.0 to 1.8 cm H(2)O] vs -0.2 cm H(2)O [-4.0 to 2.0 cm H(2)O]; P =.007). The maximum end-tidal carbon dioxide level in the hypoventilation group was significantly higher than that in the normoventilation group (maximum [range]: 50 mm Hg [28-66 mm Hg] vs 37 mm Hg [27-60 mm Hg]; P<.001). Transection time, postoperative liver function, hospitalization length, morbidity, and mortality were similar in the 2 groups.
  
  
  CONCLUSIONS
  This randomized trial suggested no beneficial effect of reduction of tidal volume on bleeding during hepatic resection.
authors.affiliation: Division of Hepato-Biliary-Pancreatic and Transplantation Surgery, Department of Surgery, Faculty of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Hasegawa
authors.forename: Tadatoshi
authors.initials: T
authors.lastname: Takayama
authors.forename: Ryo
authors.initials: R
authors.lastname: Orii
authors.forename: Keiji
authors.initials: K
authors.lastname: Sano
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Sugawara
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Imamura
authors.forename: Keiichi
authors.initials: K
authors.lastname: Kubota
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Makuuchi
mesh_terms: D016063:Blood Loss, Surgical / Q000517:prevention & control*; D006498:Hepatectomy / Q000009:adverse effects* / Q000379:methods*; D006801:Humans; D008113:Liver Neoplasms / Q000503:physiopathology / Q000601:surgery; D019106:Postoperative Hemorrhage / Q000209:etiology / Q000517:prevention & control; D012119:Respiration; D013990:Tidal Volume; D016896:Treatment Outcome