OBJECTIVES

The objectives of this study were the evaluation of the intraoperatory analgesia of remifentanil in dogs, comparing with fentanyl and a placebo solution, and the study of the hemodynamic and respiratory response and the patient recovery after two hours of anesthesia.

MATERIALS

Seven beagles dogs ASA I were anesthetized three times. All dogs were anaesthetized with medetomidine (10 mcg/kg IV), propofol (3 mg/kg IV, sevoflurane and atracurium (150 mcg/kg IV every 30 minutes. Three different analgesic protocols were evaluated: RMF: (remifentanil: 0,5 mcg/kg IV + 0,25 mcg/kg/min. FEN (2 mcg/kg IV + 0,1 mcg/kg/min IV). PCB (glucosade fluid infusion). In all cases the following postanesthetic analgesic protocol was used: morphine (0,2 mg/kg IM) and meloxicam (0,2 mg/kg IV) 20 minutes before the end of the procedure. Several cardiovascular and respiratory variables were studied every 5 minutes. Pain response was observed evaluated with a pinch with a forceps in the back paws. Recovery times were also evaluated.

RESULTS

 RMF and FEN groups showed a significantly lower EtSev than PCB group with a decrease of 28.5%.

 RMF has the highest values in arterial pressures and PVC and intermediate values in HR and compliance. In this group EtCO2 was lower than in the others.

 FEN has the lowest values in HR and arterial pressures.

 PCB showed the highest HR and intermediate values in arterial pressures. SpO2 were similar in the three groups.

 Recovery times were lower in RMF dogs.

CONCLUSION

Remifentanil is a very good analgesic when it's used intraoperatively, getting less the anesthetic requests. Respiratory depression caused by remifentanil and fentanyl infusions is well offset with mechanical ventilation. Recovery is excellent and shorter than the others groups