Thoracic Epidural Clonidine Attenuates Haemodynamic Responses Induced by Endobronchial Intubation

Abstract

Laryngoscopyand endobronchial intubation usually cause transient hypertension and tachycardia. We investigated whether thoracic epidurally injected 3 µg/kg clonidine attenuates cardiovascular responses to intubation compared with 2 µg/kg fentanyl and 1 mg/kg lidocaine. Epidural catheterization was performed at the T6 -T7 or T7 -T8 intervertebral space, and saline or clonidine in saline was injected 20 min before anaesthetic induction. Anaesthesia was induced using 5 mg/kg thiopental sodium and 0.1 mg/kg vecuronium. Laryngoscopy and endobronchial intubation were performed 2 min later. Mean blood pressure and heart rate were measured throughout anaesthetic induction. In the control group and the fentanyl group, mean blood pressure and heart rate 3 min after endobronchial intubation were elevated significantly compared with baseline. In the clonidine group, however, mean blood pressure and heart rate did not increase compared with baseline. The control group had higher mean blood pressure and heart rate than the clonidine group 3 min after endobronchial intubation. Thoracic epidural clonidine may attenuate the haemodynamic response to endobronchial intubation.

Influence of head flexion after endotracheal intubation on intraocular pressure and cardio-respiratory response in patients undergoing cataract surgery

“…Laryngoscopy and intubation are associated with tachycardia and a rise in blood pressure. 16 These changes have been observed to be associated with rise in plasma noradrenaline levels, confirming a predominantly sympathetic response to it. 17 Head flexion causes displacement of the endotracheal tube tip toward the carina.…”

“…Predominant response after laryngoscopy and intubation is sympathetic. 16 In contrast, parasympathetic response is dominant following stimulation of tracheal mucosa by endotracheal tube movement. 5 As fig 1 shows, increase in HR was more sustained than the increase in SAP.…”

Preinductive use of clonidine and ketamine improves recovery and reduces postoperative pain after bariatric surgery

“…Moreover, low doses of clonidine improve postoperative analgesia in the absence of relevant clinical side effects [17][18][19]. In fact, intravenous and intrathecal clonidine are widely used for multimodal analgesia [20,21].…”