Equianalgesic Concentration of Fentanyl Comparable to 67% N2O during Propofol Based General Anesthesia
Year: 2002
Type: article
Study design: Clinical Trial
Abstract: Background: When using a target controlled infusion (TCI) of propofol, combination with N2O or fentanyl as an analgesic adjuvant is common in clinical practice.In a previous study, a minimal steady state plasma concentration necessary to prevent a response in 50% of the patients following a skin incision (Cp50i) for propofol was reduced from 6μg/ml to 4.5μg/ml with 67% nitrous oxide/oxygen compared to air/oxygen.The goal of this study was to quantify the effect site concentration of fentanyl required to replace 67% N2O at a propofol effect site target concentration of 4.5μg/ml.Methods: Forty six ASA class I or II adult patients scheduled for lower extremity surgery were randomly allocated to one of three groups according to assigned effect site concentration of fentanyl.Group 1, n = 15; 0.5 ng/ml, Group 2, n = 15; 1.0 ng/ml, Group 3, n = 15; 1.5 ng/ml.Patients received propofol with target concentration 4.5μg/ml and predetermined target concentration of fentanyl in three groups.A laryngeal mask airway was placed after anesthesia induction and all patients were controlled ventilation with 67% air/33% oxygen.The response to the skin incision was observed and the patients categorized as movers or non-movers according to Eger's criteria.Cp50i for fentanyl was evaluated using nonlinear regression analysis.Results: Non-movers to skin incision was 20%, 43.7%, 73.7% in groups 1-3 respectively.Cp50i for fentanyl combined with propofol 4.5μg/ml was 1.08 ng/ml. Conclusions:We concluded that the MAC for 67% N2O is equivalent to an effect site target fentanyl concentration of 1.08 ng/ml in terms of no movement to skin incision.(Korean J Anesthesiol 2002; 42: 715∼721)
Source: Korean Journal of Anesthesiology
Authors: Ho Yeong Kil, Hong Seong Yoo, Hyun Hee Ahn, Yoon Sook Lee, Hyun Hwa Lee
Institution: Hallym University
Language: English
Subfield: Anesthesiology and Pain Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W2327685298