Anesthesia Induction with Propofol Using a Target Controlled Infusion (TCI)

Kil, Ho Yeong; Yang, Jung Hwa; Yoo, Hong Seong; Kim, Tae Kyoun; Lee, Seong Ik; Lee, Seong Joon; Yoon, Young Joon

Abstract

BACKGROUND: Target Controlled Infusion (TCI) is designed to achieve a predicted target blood concentration based on population pharmacokinetics and it provides the closest approximation for any individual patients. This study determined which target is appropriate for propofol induction using a TCI in korean adullt patients premedicated with midazolam.
METHODS
Sixty six patients (ASA I or II, 18~55 years) premedicated with midazolam were allocated randomly to receive an infusion to achieve and maintain a target blood concentration of 3, 4, 5 and 6 microgram/ml using a TCI. Induction time was measured as the interval from the start of the infusion to loss of verbal contact and induction within 3 min was considered as successful. Calculated concentration, induction dose, context sensitive decrement time, vital signs, pain score and side effects were checked and compared each other during induction period.
RESULTS
The success rate when the target was 3 microgram/ml was 25%, 58.8%, 77.8% and 100% when targets were 4 microgram/ml, 5 microgram/ml and 6 microgram/ml respectively. EC50 for induction was 3.87 microgram/ml and EC95 was 5.71 microgram/ml. Calculated concentration, induction dose, context sensitive decrement time in 3, 4, 5 microgram/ml group showed no differences among groups, but 6 microgram/ml group showed statistically significant differences compared with other groups. Vital signs, pain score and side effects showed no differences among groups.
CONCLUSIONS
Target concentration of 5~6 microgram/ml would successfully induce anesthesia in the majority of patients premedicated with midazolam without major hemodynamic changes.