When performing septoplasty or septorhinoplasty, we have observed that patients blink on injection of local anaesthetic (lidocaine 1 per cent with adrenaline 1:80 000) into the nasal mucosa of the anterior septum or vestibular skin, despite appropriate general anaesthesia. This study sought to quantify this phenomenon by conducting a prospective audit of all patients undergoing septoplasty or septorhinoplasty.

Patients were observed for a blink reflex at the time of local anaesthetic infiltration into the nasal vestibule. Also measured at this point were propofol target-controlled infusion levels, remifentanil rate, bispectral index, blood pressure, heart rate, pupil size and position, and patient movement.

There were 15 blink reflexes in the 30 patients observed. The average bispectral index value was 32.75 (range, 22–50) in the blink group and 26.77 (range, 18–49) in the non-blink group. No patients moved on local anaesthetic injection.

The blink reflex appears to occur in 50 per cent of patients, despite a deep level of anaesthesia. Without an understanding and appreciation of the blink reflex, this event may result in a request to deepen anaesthesia, but this is not necessary and surgery can proceed safely.