Sparing effect of a low dose of intrathecal morphine on fentanyl requirements during spinal surgery: a preliminary clinical investigation in dogs.
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.


METHODS
Prospective randomized clinical study.


METHODS
Dogs (n=18) matched by surgical procedure administered intrathecal morphine (MG) or no-treatment (control group, CG).


METHODS
After premedication with romifidine (4 microg/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 microg/kg/h in MG and CG, respectively) was administered after a loading dose (5 and 10 microg/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.


CONCLUSIONS
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.
Novello
Lorenzo
L
Department of Anaesthetics, Queen's Veterinary School Hospital, Cambridge, UK. novello@isvra.org
Corletto
Federico
F
Rabozzi
Roberto
R
Platt
Simon R
SR
D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology*; D000768:Anesthesia, General / Q000662:veterinary*; D018686:Anesthetics, Intravenous / Q000008:administration & dosage* / Q000097:blood; D000818:Animals; D004285:Dogs / Q000502:physiology* / Q000601:surgery; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage* / Q000097:blood; D007262:Infusions, Intravenous / Q000662:veterinary; D007278:Injections, Spinal / Q000662:veterinary; D007796:Laminectomy / Q000662:veterinary; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D010147:Pain Measurement / Q000662:veterinary; D010149:Postoperative Pain / Q000517:prevention & control / Q000662:veterinary; D011446:Prospective Studies; D016896:Treatment Outcome
D000701:Analgesics, Opioid; D018686:Anesthetics, Intravenous; D009020:Morphine; D005283:Fentanyl