effects of clonidine premedication on hemodynamic responses during fiberoptic bronchoscopy

Background: Fiberoptic bronchoscopy is occasionally associated with significant hemodynamic complications such as hypertension, tachycardia and arrhythmia. The ability of a2 adrenoreceptor agonists to inhibit central sympathic outflow may benefit the patients undergoing bronchoscopy by reducing the incidence and severity of hemodynamic abnormalities. Materials and Methods: We designed this study to examine whether clonidine given as an oral premedication would attenuate the hemodynamic stress response during fiberoptic bronchoscopy. We performed a prospective,randomized, double blind study on one hundred patients scheduled for bronchoscopy to evaluate the effects of 300mg oral clonidine premedication on the hemodynamic alteration and incidence of ECG changes. Results: During the procedure, patients receiving placebo exhibited a significant increase in mean arterial pressure (97±18 to 120±17mmHg) and heart rate (90±16 to 109±17) compared with the clonidine group (mean arterial pressure 100±15 to 110±17 and heart rate 89±19 to 97×19, P 0.05). Conclusion: Pretreatment with oral clonidine significantly attenuates MAP and HR changes following bronchoscopy. It is especially beneficial in patients with cardiac disease.