Effect of different doses of topical ketamine on hemodynamics in patients undergoing modified radical mastectomy

Background Ketamine has been administered by many routes with different adverse effects according to the selected route of administration and the given doses. Objectives We investigated the effect of three different doses of topical ketamine on hemodynamics and adverse effects. We aimed to find the most effective dose with the least hemodynamic derangements and minimal adverse effects. Study design A prospective, double-blind randomized dose finding study was conducted. Setting The study was done at the Cancer Institute. Patients and methods Patients scheduled for modified radical mastectomy were enrolled into three groups (n=30) to receive ketamine hydrochloride topical instillation. The study drug was diluted by 20-ml normal saline (0.9%) and instilled before wound closure by anesthesia assistant as follows: groups A, B, and C: in which patients received 1 mg, 2 mg, and 3 mg/kg ketamine, respectively. Hemodynamic assessments included the mean arterial blood pressure, heart rate, and respiratory rate recorded at baseline and 2, 4, 6, 12, 24, 36, and 48 h postoperatively. Results Intergroup comparison showed that the three doses of ketamine instillation (1, 2, and 3 mg/kg), showed no difference in the mean arterial blood pressure, either in the heart rate or respiratory rate at any time point during the study (P>0.05). Five patients versus 2 and 4 experienced postoperative nausea and two patients versus 6 and 6 vomited in groups A, B, and C, respectively. Limitations Small sample size was a limitation. Conclusion Topical instillation of ketamine in patients undergoing modified radical mastectomy is a safe technique. The three doses investigated were comparable regarding the hemodynamics with no significant adverse effects.