Comparison between different atropine doses as an antisialagogue for patients receiving ketamine-midazolam undergoing gamma knife radiosurgery

Objectives Comparing different atropine doses to detect the least effective dose as an antisialagogue, in patients receiving ketamine-midazolam sedation for gamma knife radiosurgery. Patients and methods The study included 120 American Society of Anesthesiologists Physical Status I, II patients (age range 1860 years) undergoing gamma knife radiosurgery. The patients were randomly divided into three equal groups. Patients in group A received atropine 0.5 mg intravenously, atropine 0.3 mg intravenously in group B, whereas patients in group C received 0.1 mg atropine intravenously. All patients received intravenous ketamine 0.5 mg/kg, plus intravenous midazolam 1 mg. Baseline heart rate and blood pressure, change in heart rate, and occurrence of increased secretions were recorded. Results A total of 120 patients undergoing gamma knife radiosurgery were included in the study. Only one patient in group A and two patients in group B showed increased secretions (2.5 and 5%, respectively), whereas in group C 15 patients experienced increased secretions (37.5%). None of the patients who experienced increased secretions required suctioning of secretions. With regard to the change in heart rate, group A patients had significant increase in heart rate, whereas the changes in heart rate in group B and C were not significant. Conclusion The dose of 0.3 mg atropine used in group B showed the same efficacy as an antisialagogue as the dose of 0.5 mg atropine that was used in group A, and was significantly more efficient than the dose of 0.1 mg atropine used in group C patients, who experienced significant increase of secretions. In addition, group B patients did not experience the significant increase in heart rate that was experienced by group A patients.