Clonidine for reduction of hemodynamic and psychological effects of S+ ketamine anesthesia for dressing changes in patients with major burns: an RCT.

Abstract

Clonidine has anesthetic-sparing properties and it may reduce the hemodynamic and psychological effects of S+ ketamine. The objectives of this study were to evaluate the interactions between clonidine and ketamine in hemodynamic and the psychological effects. Psychological effects were evaluated in a very detailed way. A prospective, double-blind, placebo-controlled study designed for 48 patients with major burns, aged 18-60 years, ASA II or III, who were scheduled for dressing changes was conducted. Midazolam, S+ ketamine, placebo, or clonidine was used for the anesthesia. Intraoperative hemodynamic alterations over time were assessed. The psychological effects were evaluated in detail using 13 variables, the return of conscience, and analgesia during the first 2h after the procedures. The clonidine group had low arterial pressure during the procedure. At the 30-min evaluation of the psychological variables, five out of 13 were lower in the clonidine group. At the 2-h evaluation, only the Anxious variable was lower in the clonidine group. Cardiac frequency, postoperative analgesia, delirium, and dreaming were not different between both groups. There was no difference in complication rates between both groups. Clonidine in S+ ketamine plus midazolam anesthesia reduces the arterial pressures and the postoperative psychological effects.