Évaluation du niveau d'analgésie sous anesthésie au propofol

An experimental model was developed in order to evaluate analgesia depth level. In 12 beagle dogs anesthetized with propofol, respiration, ECG, systemic and pulmonary arterial pressure were continously recorded and core temperature and end tidal CO2 were monitored. The nociceptive stimulation we used is an electrical pulse of 3 to 10 volts applied during one seconde on the tongue. This stimulation induces two type of response: bradycardia- arterial pressure decrease or tachycardia- arterial pressure increase. Both responses are inhibited by morphine. The mechanism involved may be the trigeminal reflexe. The two different type of response may be explained by the differences in the level of anesthesia. The proposed model may be useful for analgesia depth evaluation as 1/ the stimulation does not induce any injury and thus may be applied repeatedly and 2/ the evaluation may performed by analysing the heart rate changes.