Partition Coefficients of I-653 in Human Blood, Saline, and Olive Oil

The purpose of this study was to determine partition coefficients for a new, inhaled anesthetic, I-653. Blood samples were taken from 11 patients scheduled for elective surgery who were ASA physical status I-III and ranged in age from 25 to 76 yr. At 37 degrees C, we found a blood/gas partition coefficient of 0.424 +/- 0.024 (mean +/- SD); a saline/gas partition coefficient of 0.225 +/- 0.002; and an oil/gas partition coefficient of 18.7 +/- 1.1. These values indicate that I-653 will have a minimum alveolar concentration (MAC) required for anesthesia that is four to five times that of isoflurane and that I-653 will produce a rapid induction of and recovery from anesthesia.