Clonidine versus nitroglycerin infusion in laparoscopic cholecystectomy

Laparoscopic surgery offers the advantages of minimally invasive surgery; however, pneumoperitoneum and the patient's position induce pathophysiological changes that may complicate anesthetic management. We studied the effect of clonidine and nitroglycerin on heart rate and blood pressure, if any, in association with these drugs or the procedure, as well as the effect of these drugs, if any, on end-tidal carbon dioxide pressure and intraocular pressure.

Sixty patients (minimum age of 20 years and maximum age of 65 years, American Society of Anesthesiologists class I or II) undergoing laparoscopic cholecystectomy were randomized into 3 groups and given an infusion of clonidine (group I), nitroglycerin (group II), or normal saline solution (group III) after induction and before creation of pneumoperitoneum. We observed and recorded the following parameters: heart rate, mean arterial blood pressure, end-tidal carbon dioxide pressure, and intraocular pressure. The mean and standard deviation of the parameters studied during the observation period were calculated for the 3 treatment groups and compared by use of analysis of variance tests. Intragroup comparison was performed with the paired t test. The critical value of P, indicating the probability of a significant difference, was taken as < .05 for comparisons.

Statistically significant differences in heart rate were observed among the various groups, whereas comparisons of mean arterial pressure, intraocular pressure, and end-tidal carbon dioxide pressure showed statistically significant differences only between groups I and III and between groups II and III.

We found clonidine to be more effective than nitroglycerin at preventing changes in hemodynamic parameters and intraocular pressure induced by carbon dioxide insufflation during laparoscopic cholecystectomy. It was also found not to cause hypotension severe enough to stop the infusion and warrant treatment.