REMIFENTANIL INTRAOPERATIVE ANALGESIA. A COMPARATIVE STUDY WITH FENTANYL IN DOGS Rubio 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 RESULTS CONCLUSIONS 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. OBJECTIVES MATERIALS AND METHODS 1. 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 protocols Three 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 protocol The 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 % 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. PAM PS PD basal status medetomidine 10  g/kg IV medetomidine 10  g/kg IV propofol 3 mg/kg IV propofol 3 mg/kg IV anesthetic phase anesthetic phase monitoriing FC FR Tª preanesthetic period drugs manteinance induction recovery TTR extubation sternal recumbency sternal recumbency time to stand TETDETP ANESTHETIC PROTOCOL PAM PS PD SpO 2 EtCO 2 Et SEV FC FR Tº PMI PSI PDI VT VM FiO 2 FC FR Tª FC FR Tª PAM PS PD V0.5 Compl ETO remifentanil 0,5  g/kg IV remifentanil 0,5  g/kg IV sevoflurano remifentanil 0,25  g/kg/min IV remifentanil 0,25  g/kg/min IV 100 morphine 0,02 mg/kg IM morphine 0,02 mg/kg IM meloxicam 0,2 mg/kg SC meloxicam 0,2 mg/kg SC neostigmine 0,01 mg/kg IV neostigmine 0,01 mg/kg IV atropine 0,01 mg/kg IV atropine 0,01 mg/kg IV + AS/3 Datex-Ohmeda Every 5 minutes -B- -S- fentanyl 2  g/kg IV fentanyl 2  g/kg IV fentanyl 0,1  g/kg/min IV fentanyl 0,1  g/kg/min IV placebo IV placebo IV placebo IV placebo IV analgesic manintenance  analgesic induction   ANALGESIC PROTOCOL  RMF FEN PCB