Effect of premedication on stress and plasma cortisol in patients bronchoscoped under local anaesthesia

Four groups of 8 patients undergoing bronchoscopy were premedicated with either pentobarbitone 1 mg/kg i.m. followed by i.v. saline, or diazepam 10 mg and saline i.v., or diazepam 10 mg i.m. followed by diazepam 20 mg i.v. and, diazepam 20 mg i.m. and then saline i.v. Both the patients and the bronchoscopist were asked to score the premedication as excellent, satisfactory, unsatisfactory or bad. Plasma cortisol was measured before premedication and before and after bronchoscopy. Preoperatively plasma cortisol increased in every group except that given diazepam 20 mg i.m., and during bronchoscopy it rose in all except the group who received 20 mg diazepam i.v. In patients who considered the premedication unsatisfactory, the rise in plasma cortisol from before premedication until after bronchoscopy was significantly higher than in satisfied subjects. It appears that in patients undergoing bronchoscopy higher doses of diazepam (20 – 30 mg) gave better suppression of stress than 10 mg diazepam, or 1 mg/kg pentobarbitone.