Objective To evaluate the effectiveness of combined use of propofol and ketamine for total intravenous anesthesia (TIVA) in adults and to determine their optimal doses. Methods 100 adults with general anesthesia were randomly divided into five groups 〔K0, K0.5, K1, K1.5 and K2, with 0, 0.5, 1, 1.5 and 2 mg/(kg·h) ketamine, respectively〕. The dose of propofol administered during surgery and hemodynamics, respiratory recovery time, awakening time, steward score of recovery and adverse reactions of the patients were recorded. Ten patients from each group were randomly chosen to have plasma concentrations of propofol and ketamine examined. Results The dose of propofol and total price of the two drugs decreased with the increase of dosage of ketamine (PPP
