The Results of Effect Site Targeting on Anesthetic Induction Using Propofol-Target Controlled Infusion (TCI) / 대한마취과학회지

BACKGROUND: The effect site is the theoretical compartment in which a drug exerts its action and thus the concentration at this site is a direct determinant of a drug,s effect. This study was performed to compare effect site targeting with plasma targeting with regard to induction phenomena and vital sign changes using propofol target controlled infusion (TCI). METHODS: Forty patients were randomly assigned to one of two groups. Groups were defined as propofol administered via TCI to either a target plasma propofol concentration (group P) or to a target effect site (group E) propofol concentration. We used Master TCI for plasma targeting and a stelpump program for effect site targeting. The concentration targeted for all subjects was 5.7 microgram/ml. We compared the time to loss of consciousness, change of concentration, BP and pulse pressure between groups until the effect site concentration was reached at 5.7 microgram/ml. RESULTS: The median time to LOC in group P was 58.1 +/- 11.8 s and 35.8 +/- 7.9 s in group E (P <0.05). The mean time to achieve the effect site concentration of 5.7 microgram/ml was 18.5 +/- 0.1 min in group P and 3.6 +/- 0.1 min in group E (P < 0.05). Systolic and diastolic blood pressure showed significant changes in group E. CONCLUSIONS: We concluded that anesthetic induction time can be significantly reduced when the effect site concentration is targeted. However, we recommended effect site targeting in anesthesia induction with propofol TCI only in cases of healthy young patients because of possible undesirable hemodynamic changes.

Influence of Fentanyl, Fentanyl-Midazolam, and Fentanyl-Ketorolac as Analgesic Supplementations on the Induction of Propofol Anesthesia with Dipifusor TCI / 대한마취과학회지

BACKGROUND: The pharmacologic interactions between propofol and adjuvant agents have increasingly been recognized as clinically important and the improved knowledge of these is being used to optimise the quality of total intravenous anesthesia. The aim of the present study was to investigate the effects of fentanyl, fentanyl-midazolam, and fentanyl-ketorolac as analgesic supplementations on the induction of propofol anesthesia with Diprifusor TCI. METHODS: Sixty ASA 1 patients undergoing elective diagnostic laparoscopy were randomly allocated to three groups equally according to injected adjuvant agents : group F, fentanyl 1 microgram/kg; group FM, fentanyl 1 microgram/kg-midazolam 0.05 mg/kg; group FK, fentanyl 1 microgram/kg-ketorolac 0.5 mg/kg IV before induction. Propofol target concentration of 4 microgram/ml was preset and unconsciousness with 3 min was considered as successful. Induction dose, time, success rate of induction, calculated and effective concentration, context sensitive decrement time when awakening concentration was 1.2 microgram/ml, vital signs and side effects were checked. RESULTS: Successful induction rate was 55% in the group F, 100% in the group FM, and 85% in the group FK (P< 0.05). Induction time and dose were significantly decreased in the group FM compared with the group F and FK. Calculated concentration, effective concentration, and context sensitive decrement time were significantly lower in the group FM than other groups. Injection pain score and postoperative pain score showed no differences between groups, but incidence of apnea was significantly increased in the group FM. CONCLUSIONS: Fentanyl-midazolam as a analgesic supplementation offered better quality of propofol induction using TCI, but showed increased incidence of apnea compared with fentanyl or fentanyl- ketorolac.

The Effect of Midazolam Premedication on Propofol Induction Using a Target Controlled Infusion (TCI) / 대한마취과학회지

BACKGROUND: Many studies indicated that the predictive accuracy of propofol TCI may be compromised by premedication with benzodiazepine which has been shown to reduce markedly the induction dose. This study was designed to examine the influence of midazolam premedication on certain parameters of treatment using the propofol TCI. METHODS: One hundred and sixty ASA I or II patients undergoing elective surgery were randomly allocated to two groups according to premedication: Group 1, glycopyrrolate 0.2 mg; Group 2, glycopyrrolate 0.2 mg and midazolam 0.07 mg/kg IM 1hr before induction. Each group divided to four subgroups (n=20 for each subgroup) according to expected target propofol concentration (4~7 microgram/ml for group 1 and 3~6 microgram/ml for group 2). Anesthesia induction within 3 min was considered as successful. Induction dose and time, success rate of induction, calculated concentration when successful induction, context sensitive decrement time when awakening concentration was 1.2 microgram/ml and side effects were checked. RESULTS: Successful induction rate was higher in group 2 (53.3% vs 77.8% at target concentration of 5 microgram/ml, P<0.05). Mean target concentration of propofol were lower in group 2 (5.18 vs 3.87 microgram/ml, P<0.05). Induction time and dose were decreased 48.4% and 36.8% at target concentration of 4 g/ml, respectively in group 2 (P<0.05). Vital signs, average pain score and incidence of pain showed no differences between groups, but incidence of apnea was significantly increased in group 2 (P<0.05). CONCLUSION: Group 2 showed better quality of propofol induction using a TCI in terms of induction time, induction dose and lower selected target without significant vital sign changes, but showed increased incidence of apnea compared with group 1.