Clonidine as a pre-anesthetic agent for flexible bronchoscopy

Abstract

Several drugs have been employed for sedation during flexible fiberoptic bronchoscopy (FOB). Clonidine attenuates stress-induced sympathoadrenal responses and has sedative properties. We investigate the effects of clonidine pre-medication on hemodynamic and comfort parameters of patients submitted to FOB under airway topical anesthesia only. Patients received placebo ( n=22; men=16; median age=50.5 years) or intravenous clonidine (3 μg/kg; n=20; men=15; median age=46.0 years) 15 min before FOB. Blood pressure (BP), heart rate (HR), plasma norepinephrine (nor) and cortisol levels were measured before, during, and 1 h after FOB. Comfort was assessed by the examiner and by the patients using a visual numerical scale (0–10). The placebo group showed significant increases in systolic BP, HR, and nor levels during FOB (SBP = 125 mmHg×145 mmHg; HR=74 bpm×85 bpm; nor = 316.2 pg/dl×483.1 pg/dl), whereas clonidine group did not display such changes. Clonidine group showed a lower frequency of cardiac arrhythmias than the placebo group during and after FOB (supraventricular = 39%×50%; ventricular=22%×40%). Levels of comfort were high and comparable in both groups. We concluded that although clonidine led to a somewhat better hemodynamic profile, it did not contribute to better comfort in this setting.