Premedication with lorazepam for bronchoscopy under general anaesthesia.

Lorazepam 3 or 4 mg i.m. was given to 100 patients as premedication before bronchoscopy under thiopentone-suxamethonium anaesthesia. Forty-nine of the patients assessed as anxious received oral lorazepam as preoperative night sedation also. Lorazepam was an effective night sedative. Forty-two of the 49 patients slept well and were calm and co-operative in the morning. Following the i.m. injection of lorazepam, 64% of patients had complete lack of recall for 4--10 h following premedication. Only 5% recalled correctly a simple objective test of memory initiated in the anaesthetic room. The frequency of recall was higher in those who consumed alcohol regularly and in females. There was one case of awareness during bronchoscopy in a patient who received only a small dose of lorazepam (2.8 mg per 70 kg). Side-effects were minimal and patient acceptance was impressive. These results show an advance on previous studies using pethidine and diazepam. Further improvement is needed, particularly in adjusting the dose of lorazepam to body weight and to factors such as age, sex and alcohol intake.