REMIFENTANIL INTRAOPERATIVE ANALGESIA. A COMPARATIVE STUDY

WITH FENTANYL IN DOGS

REMIFENTANIL INTRAOPERATIVE ANALGESIA. A COMPARATIVE STUDY

WITH FENTANYL IN DOGSRubio M, Redondo JI, Carrillo JMª, Sopena JJ, Soler G*

Facultad de Ciencias Experimentales y de la Salud.Universidad Cardenal Herrera -CEU.Valencia

* Hospital Veterinario Marina Alta. Denia.Alicante

RESULTSRESULTS

CONCLUSIONSCONCLUSIONS

The results of the study showed that the RMF and FEN groups presented a significantly lower EtSev than PCB group, with a decrease of 28.57% and 29,73% respectively. RMF showed the highest values in arterial pressures and PVC and intermediate values in heart rate and compliance. In this group, EtCO2 was lower than in the others. The lowest values in heart rate and arterial pressures were found in FEN group, while the highest heart rate and intermediate values in arterial pressures were observed in PCB`s group.

The only value that was similar in the three groups was SpO2, because of the animals were inhalating 100% O2.

The recuperation period was good and peaceful in all the animals, but recovery times were significantly lower in RMF dogs.

OBJECTIVESOBJECTIVES

MATERIALS AND METHODSMATERIALS AND METHODS1. Anesthetic protocol

Seven beagles dogs ASA I were anesthetized three times. All of them were anesthetized with the following anesthetic protocol: medetomidine (10 g/kg IV), propofol (3 mg/kg IV), sevoflurane and atracurium (150 g/kg IV), every 30 minutes. At the end of the procedure we reverted the effects of atracurium with a combination of atropine (0.01 mg/kg) and neostigmine (5 g/kg) intravenously.

2. Analgesic protocolsThree different analgesic protocols were used and they were classified in these groups:• RMF: (remifentanil: 0,5 g/kg IV induction doses + 0,25 g/kg/min

maintenance doses). • FEN: (Fentanyl: 2 g/kg IV induction doses + 0,1 g/kg/min IV

maintenance doses). • PCB (glucosade fluid infussion).

3. Postanesthetic protocolThe following postanesthetic analgesic protocol was used in all groups:morphine (0,2 mg/kg IM) and meloxicam (0,2 mg/kg IV) 20 minutes

before the end of the procedure 4. Painful evaluation

During the procedure, several cardiovascular and respiratory variables were studied every 5 minutes. Pain response was evaluated pinching with a forceps in the back paws for 1 minute. It was found that the animals were painful when the arterial pressure and heart rate increased by 10% in relation to the last measure. Times and quality of the recuperation were also evaluated comparing all groups.

The aim of this study was to evaluate the intraoperative analgesia of remifentanil in dogs, comparing with fentanyl and a placebo solution as well as the study of the haemodynamic and respiratory responses, and the patient recovery after two hours of anesthesia.

    Both remifentanil and fentanyl are useful drugs in the achievement of intraoperative analgesia in the dog.Both drugs produce a significant decrease in needed concentration of sevofluorane (28.57 and 29.73 % respectively) to allow negative response of the patient to pain induction.Remifentanil produces superior hemodynamic and cardiovascular stability than fentanyl when administered at a continuous perfusion rate. After a 120 minutes anesthesia period, postsurgical recovery showed no complications in all cases. The RMF group shows siginificatively lower recovery times when compared to FEN and PCB groups. The meloxicam / Morphine assay resulted in a good analgesic cover for postoperative pain management.Both fentanyl and remifentanil induced respiratory depression. Thus, mechanical ventilation is recommended to assure a proper oxygenation and normocapnia in the patient.

PAMPSPD

basalstatus

medetomidine10 g/kg IV

medetomidine10 g/kg IV

propofol3 mg/kg IVpropofol3 mg/kg IV

anesthetic phaseanesthetic phase

monitoriingmonitoriing FCFRTª

preanesthetic period

drugsdrugs

manteinance

induction

recovery TTR

extubationextubation sternalrecumbencysternalrecumbency

time to standtime to stand-5-20 -10-25 -15-30

TE TDE TP

ANESTHETIC PROTOCOL

PAMPSPD

SpO2

EtCO2

EtSEV

FCFRTº

PMIPSIPDI

VTVMFiO2

FCFRTª

FCFRTª

PAMPSPD

V0.5ComplETO2

0 120 remifentanil0,5 g/kg IVremifentanil0,5 g/kg IV

sevofluranosevoflurano

remifentanil0,25 g/kg/min IVremifentanil0,25 g/kg/min IV

100

morphine0,02 mg/kg IMmorphine0,02 mg/kg IM

meloxicam0,2 mg/kg SCmeloxicam0,2 mg/kg SC neostigmine

0,01 mg/kg IVneostigmine0,01 mg/kg IV

atropine0,01 mg/kg IVatropine0,01 mg/kg IV

+

AS/3Datex-Ohmeda

Every 5 minutes-B- -S-

fentanyl2g/kg IVfentanyl2g/kg IV

fentanyl0,1 g/kg/min IVfentanyl0,1 g/kg/min IV

placebo IVplacebo IV

placebo IVplacebo IV

analgesic manintenance analgesic manintenance

analgesic induction analgesic induction

ANALGESIC PROTOCOL

RMFRMF FENFEN PCBPCB