Publication:

Benzodiazepine premedication in general anaesthesia: a clinical comparative study

Background The main aims of pre-anaesthetic medication are anxiolysis, analgesia, anti-emesis and reducing perioperative patient risk. Producing a state of amnesia for pre and post-operative events is desired by all. This study has been undertaken to evaluate the role of three of the benzodiazepines i.e. diazepam, lorazepam and midazolam during general anaesthesia, in providing anxiolysis, sedation and amnesia.

Methods The study included patients with ASA grade I and ASA grade II physical status of both sexes, age ranging between 18-60 years. Patients were divided into three groups of thirty patients each, every group receiving intramuscular injections of diazepam 0.1 mg/kg body weight, lorazepam 0.07 mg/kg body weight and midazolam 0.08 mg/kg body weight respectively; 45 minutes prior to induction of general anaesthesia. Anxiety assessment before premedication along with assessment of sedation after premedication was done.

Results Before premedication the mean values of pulse rate, blood pressure and respiratory rate were not significantly different among the three groups (p>0.05). Maximum changes in these parameters were observed with Midazolam followed by lorazepam and diazepam. The dose of thiopentone used as inducing agent was also lowered significantly in case of midazolam (p<0.05). One patient in midazolam group showed respiratory depression whereas four patients receiving lorazepam and diazepam showed delayed recovery and prolonged sedation, but the effects were self-limiting.

Conclusions Midazolam offers the maximum advantage in allaying anxiety and providing excellent sedation and amnesia during general anaesthesia and proves to be the most suitable premedicant before general anaesthesia.