title: The effect of fluid overload in the presence of an epidural on the strength of colonic anastomoses.
abstract: BACKGROUND
  Despite the beneficial effects of epidurals in intra-abdominal surgery, the incidence of anastomotic leak remains controversial when used. Moreover, studies have also shown that fluid overload may be deleterious to anastomoses. The purpose of this paper is to evaluate the effects of varying intraoperative fluid protocols, in the presence of an epidural, on the burst pressure strength of colonic anastomoses.
  
  
  METHODS
  An epidural was installed in 18 rabbits, divided into three groups. Group 1 received 30 mL/kg/h Ringer's lactate, Group 2 received 100 mL/kg/h Ringer's lactate, and Group 3 received 30 mL/kg/h Pentaspan. Two colo-colonic anastomoses were performed per rabbit. On postoperative day 7 the anastomoses were resected and their burst pressures measured as a surrogate for anastomotic leak.
  
  
  RESULTS
  When comparing the average burst pressures of all three groups, there was a significant difference (P = 0.04). The anastomoses in the 100 mL/kg/h Ringer's lactate group were shown to be the weakest, with 64% of the anastomoses having burst under 120 mm Hg. The rabbits hydrated with Pentaspan had the highest strength, with no anastomoses bursting under 120 mm Hg. This translated into significant burst pressure differences (P = 0.02) between Group 2 and Group 3.
  
  
  CONCLUSIONS
  These results suggest that fluid overload with a crystalloid, in the presence of an epidural, may be deleterious to the healing of colonic anastomoses, creating a higher risk of anastomotic leak. Intraoperative resuscitation should thus focus on goal-directed euvolemia with appropriate amounts of colloids and/or crystalloids to prevent the risk of weakening anastomoses, especially in patients with epidurals.
authors.affiliation: Department of Surgery, Division of General Surgical Oncology, Maisonneuve-Rosemont Hospital, University of Montreal, Montreal, Canada. cnessim@hotmail.com
authors.forename: Carolyn
authors.initials: C
authors.lastname: Nessim
authors.forename: Lucas
authors.initials: L
authors.lastname: Sidéris
authors.forename: Simon
authors.initials: S
authors.lastname: Turcotte
authors.forename: Petros
authors.initials: P
authors.lastname: Vafiadis
authors.forename: Annie-Claude
authors.initials: AC
authors.lastname: Lapostole
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Simard
authors.forename: Patricia
authors.initials: P
authors.lastname: Koch
authors.forename: Louis-Philippe
authors.initials: LP
authors.lastname: Fortier
authors.forename: Pierre
authors.initials: P
authors.lastname: Dubé
mesh_terms: D000714:Anastomosis, Surgical / Q000379:methods; D057868:Anastomotic Leak / Q000453:epidemiology* / Q000503:physiopathology; D000767:Anesthesia, Epidural; D000818:Animals; D003106:Colon / Q000601:surgery*; D005440:Fluid Therapy / Q000009:adverse effects; D007432:Intraoperative Period; D008297:Male; D023421:Models, Animal; D011817:Rabbits; D012307:Risk Factors; D014945:Wound Healing / Q000502:physiology
keywords: Anastomotic leak; Colloid; Colon; Colonic anastomoses; Crystalloid; Epidural; Euvolemia; Fluid balance; Fluid overload; Sympathetic block