Comparing Clonidine and Lidocaine on Attenuation of Hemodynamic Responses to Laryngoscopy and Tracheal Intubation in Controlled Hypertensive Patients: A Randomized, Double-Blinded Clinical Trial.

BACKGROUND: Hemodynamic fluctuations in response to laryngoscopy and tracheal intubation and their potential hazards have been well-recognized, especially in hypertensive patients. Many drugs in various combinations have been used to attenuate these adverse responses.

OBJECTIVES: We conducted a study to compare lidocaine with clonidine on the attenuation of hemodynamic responses to laryngoscopy and tracheal intubation, in controlled hypertensive patients undergoing general anesthesia.

PATIENTS AND METHODS: Eighty-six patients of American society of anesthesiologists (ASA) class II, who were aged 18 to 65-years-old and were scheduled for elective surgeries under general anesthesia, were included. The patients were randomly divided into two equal groups. The clonidine group received 0.2 mg oral clonidine 90 minutes before surgery and the lidocaine group received a placebo tablet at the same time. All patients in both groups were anesthetized with the same technique, including: intravenous fentanyl 3 mcg/kg, sodium thiopental 5 mg/kg, and atracurium 0.5 mg/kg. The lidocaine group received 1.5 mg/kg lidocaine but the clonidine group received the same volume of saline ninety seconds before intubation. Hemodynamic parameters were recorded before intubation and 1, 3, 5, and 10 minutes after endotracheal intubation.

RESULTS: There were no significant differences between the two groups' hemodynamic parameters, including heart rate and systolic, diastolic, and mean arterial blood pressures at the measured points. There were also no significant differences within each group in hemodynamic responses at the measured points (P > 0.05). Twenty patients in the clonidine and three patients in the lidocaine group complained of mouth dryness (P = 0.001). Fourteen patients in the clonidine and four patients in the lidocaine group had bradycardia (P = 0.008). Nineteen patients in the clonidine and six patients in the lidocaine group had orthostatic hypotension (P = 0.002).

CONCLUSIONS: There were no statistical differences between oral clonidine and intravenous lidocaine regarding attenuation of hemodynamic responses after tracheal intubation in controlled hypertensive patients, although the rate of complications including mouth dryness, bradycardia, and orthostatic hypotension was significantly higher in the clonidine group before induction of anesthesia.