Antiemetic Efficacy of Small Doses of Propofol Following Modified Radical Mastectomy

BACKGROUND: Breast cancer surgeries under general anesthesia have been associated with relatively high incidence of post-operative nausea and vomiting. Propofol possesses direct antiemetic properties at sub-anaesthetic doses and is devoid of side effects and is cost effective. AIMS AND OBJECTIVES: To study the antiemetic efficacy of propofol when compared to a placebo. To study the minimum effective dose of propofol as an antiemetic among three dosages 0.25mg/kg, 0.5mg/kg & 1mg/kg. MATERIALS AND METHODS: 120 women in the age group of 35-74 years belonging to ASA grade 1 & 2 who were scheduled to undergo modified radical mastectomy under general anesthesia were randomly divided into 4 groups. Group 1-n=30 received placebo (Normal saline) Group 2-n=30 received 0.25mg/kg of propofol Group 3-n=30 received 0.5mg/kg of propofol Group 4-n=30 received 1mg/kg of propofol After skin suture either placebo or propofol in 3 different doses were administered intravenously as bolus doses over 2 minutes randomly to patients according to the group to which they were allocated. Once the patients regained protective airway reflexes they were reversed and extubated. The patients were observed for 24 hrs postoperatively. They were followed up every an hour for first 2 hrs, every 1 hr for the next 4 hrs and thereafter 4 th hourly till 24 hrs. Parameters observed were retching and vomiting, and sedation. RESULTS: Study results consisting of data were analysed by Fishers exact probability test and Chi-Square test. A p value less than 0.05 was considered to be statistically significant Samples of 4 groups of age and weight matched with P>0.05. Statistically significant difference in the incidence of vomiting was seen with Group C & Group D at and 1 hour intervals. No statistically significant difference in the incidence of PONV was noted in the four groups at 5 to 24 hours period. Statistically significant difference in sedation was noted with Group C and D at 1 hour and 2 hour interval when compared with placebo. No difference in sedation was noted with any of the four Groups at 5 to 24 intervals. There was a statistically significant decrease in the incidence of nausea and vomiting with doses of 0.5mg/kg and 1mg/kg of propofol at 0-2hrs. We can infer that the therapeautic (Antiemetic) concentrations were achieved and maintained for 2hrs by 0.5 mg/kg and 1 mg/kg of propofol beyond which the dose has decreased to suboptimal levels due to rapid elimination half-life of 1-3 hrs. Dosage of 0.25mg/kg was inadequate to achieve therapeautic plasma concentrations. CONCLUSION: