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Sparing Effect of a Low Dose of Intrathecal Morphine on Fentanyl Requirements During Spinal Surgery: A Preliminary Clinical Investigation in Dogs
Author(s) -
NOVELLO LORENZO,
CORLETTO FEDERICO,
RABOZZI ROBERTO,
PLATT SIMON R.
Publication year - 2008
Publication title -
veterinary surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 79
eISSN - 1532-950X
pISSN - 0161-3499
DOI - 10.1111/j.1532-950x.2007.00358.x
Subject(s) - medicine , fentanyl , anesthesia , morphine , propofol , lumbar , ketamine , surgery
Objective— To evaluate the effect of preoperative intrathecal administration of a low dose of morphine on intraoperative fentanyl requirements in dogs undergoing cervical and thoracolumbar spinal surgery. Study Design— Prospective randomized clinical study. Animals— Dogs (n=18) matched by surgical procedure administered intrathecal morphine (MG) or no‐treatment (control group, CG). Methods— After premedication with romifidine (4 μg/kg, intravenously) and induction with propofol, anesthesia was maintained with sevoflurane in oxygen. Intrathecal morphine 0.03 (0.023–0.034) mg/kg was administered at lumbar level 41 (25–65) minutes before surgery in MG. Ketamine (0.5 mg/kg) was administered hourly, starting before incision. Fentanyl infusion (1.2 and 4.2 μg/kg/h in MG and CG, respectively) was administered after a loading dose (5 and 10 μg/kg in MG and CG, respectively), and boluses were given if an increase >20% in heart rate and arterial blood pressure was observed. Total amount of fentanyl administered was recorded, to calculate hourly requirements and predict plasma concentration using a computer simulation. Results— Hourly fentanyl consumption and predicted plasma concentrations at the time of response to surgery were significantly lower in MG compared with CG. Conclusions— Preoperative administration of a low dose of intrathecal morphine has a sparing effect on intraoperative fentanyl requirements. Clinical Relevance— Preoperative intrathecal administration of a low dose of morphine at the lumbar level represented a safe and effective mean of providing intraoperative analgesia in dogs undergoing cervical and thoracolumbar spinal surgery.