title: A comparison of different dosages of a continuous preperitoneal infusion and systemic administration of ropivacaine after laparotomy in rats.
abstract: BACKGROUND
  To further explain the mechanisms of action involved in the analgesic effect of a local anesthetic wound infusion, we evaluated parietal and visceral sensitivity as well as indices of inflammation after laparotomy and administration of a local anesthetic. Ropivacaine was administered at different dosages by a continuous infusion using a multiholed catheter in the preperitoneal position or systemically in rats.
  
  
  METHODS
  Nine groups of rats received 2 injections after laparotomy or sham surgery: (1) a bolus injection (ropivacaine or saline) via a preperitoneal catheter and (2) an IM injection (IM) (ropivacaine or saline). These injections were followed by a continuous infusion (ropivacaine or saline) in the preperitoneal catheter for 24 hours and 1 IM injection every 8 hours. Mechanical and visceral thresholds after stimulation were evaluated 3 times during the 48 hours after surgery. Stimulated production of tumor necrosis factor α, and interleukin 1β in whole-blood cultures were measured by enzyme-linked immunosorbent assay. The ropivacaine plasma concentration was measured by gas chromatography.
  
  
  RESULTS
  Preperitoneal infusion of high doses of ropivacaine and systemic ropivacaine similarly prevented mechanical and visceral sensitivity alterations and led to a better functional recovery. The analgesic effect of systemic administration was associated with an anti-inflammatory effect.
  
  
  CONCLUSIONS
  In the current study, high-dose ropivacaine administered via a preperitoneal infusion or systemic boluses had the same effect on mechanical and visceral sensitivity after laparotomy. Moreover, systemic administration was associated with an anti-inflammatory effect. The merits of the comparable benefit of systemic and high-dose preperitoneal infusion of ropivacaine need to be confirmed with further studies.
authors: Université Paris-Sud, Laboratoire d'Anesthesie, INSERM U788, Departement d'anesthesie, 78 av du general leclerc, F-94276 Le Kremlin Bicêtre, France.
authors: Toni
authors: T
authors: Kfoury
authors: Jean-Xavier
authors: JX
authors: Mazoit
authors: Michael
authors: M
authors: Schumacher
authors: Dan
authors: D
authors: Benhamou
authors: Helene
authors: H
authors: Beloeil