Assessing anaesthetic depth

Withdrawal reflexes

We can assess withdrawal reflexes in most animals. In rodents, the tail pinch and the pedal withdrawal reflexes are usually assessed. The tail pinch response is usually lost at light to medium planes of anaesthesia, and this is followed by loss of the pedal withdrawal response at medium to deep planes of anaesthesia. Most surgical procedures can be carried out when the pedal withdrawal reflex is absent or barely detectable.