title: Restrictive strategy of intraoperative fluid maintenance during optimization of oxygen delivery decreases major complications after high-risk surgery.
abstract: BACKGROUND
  Optimal fluid management is crucial for patients who undergo major and prolonged surgery. Persistent hypovolemia is associated with complications, but fluid overload is also harmful. We evaluated the effects of a restrictive versus conventional strategy of crystalloid administration during goal-directed therapy in high-risk surgical patients.
  
  
  METHODS
  We conducted a prospective, randomized, controlled study of high-risk patients undergoing major surgery. For fluid maintenance during surgery, the restrictive group received 4 ml/kg/hour and the conventional group received 12 ml/kg/hour of Ringer's lactate solution. A minimally invasive technique (the LiDCO monitoring system) was used to continuously monitor stroke volume and oxygen delivery index (DO₂I) in both groups. Dobutamine was administered as necessary, and fluid challenges were used to test fluid responsiveness to achieve the best possible DO₂I during surgery and for 8 hours postoperatively.
  
  
  RESULTS
  Eighty-eight patients were included. The patients' median age was 69 years. The conventional treatment group received a significantly greater amount of lactated Ringer's solution (mean ± standard deviation (SD): 4, 335 ± 1, 546 ml) than the restrictive group (mean ± SD: 2, 301 ± 1, 064 ml) (P < 0.001). Temporal patterns of DO₂I were similar between the two groups. The restrictive group had a 52% lower rate of major postoperative complications than the conventional group (20.0% vs 41.9%, relative risk = 0.48, 95% confidence interval = 0.24 to 0.94; P = 0.046).
  
  
  CONCLUSIONS
  A restrictive strategy of fluid maintenance during optimization of oxygen delivery reduces major complications in older patients with coexistent pathologies who undergo major surgery.
  
  
  BACKGROUND
  ISRCTN: ISRCTN94984995.
authors.affiliation: Division of Intensive Care, Department of Internal Medicine, Faculdade de Medicina de São José do Rio Preto, Av Faria Lima-5544, São José do Rio Preto, CEP-15090-000, Brazil. suzana-lobo@uol.com.br
authors.forename: Suzana M
authors.initials: SM
authors.lastname: Lobo
authors.forename: Luis S
authors.initials: LS
authors.lastname: Ronchi
authors.forename: Neymar E
authors.initials: NE
authors.lastname: Oliveira
authors.forename: Paulo G
authors.initials: PG
authors.lastname: Brandão
authors.forename: Adriano
authors.initials: A
authors.lastname: Froes
authors.forename: Geni S
authors.initials: GS
authors.lastname: Cunrath
authors.forename: Kátia G
authors.initials: KG
authors.lastname: Nishiyama
authors.forename: João G
authors.initials: JG
authors.lastname: Netinho
authors.forename: Francisco R
authors.initials: FR
authors.lastname: Lobo
mesh_terms: D000368:Aged; D004305:Dose-Response Relationship, Drug; D005260:Female; D005440:Fluid Therapy / Q000379:methods*; D006801:Humans; D007430:Intraoperative Care / Q000379:methods*; D007552:Isotonic Solutions / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D011183:Postoperative Complications / Q000517:prevention & control*; D011446:Prospective Studies; D000077325:Ringer's Lactate; D018570:Risk Assessment; D016896:Treatment Outcome
chemical_list: D007552:Isotonic Solutions; D000077325:Ringer's Lactate