Induction dose-responses studies with propofol and thiopentone.
The relative potencies of propofol and thiopentone were assessed using different indicators of induction of anaesthesia: abolition of the response to verbal commands and eyelash stimulation. Log-probit dose-response curves for these end-points were determined 30, 60 and 90 s after induction in 96 unpremedicated ASA group I patients. For propofol, ED50 values for abolition of the response to verbal commands and eyelash stimulation at different time intervals were in the ranges 1.16-1.42 and 1.23-1.72 mg kg-1, respectively; corresponding ED95 values were 2.18-2.67 and 2.42-3.27 mg kg-1, respectively. For thiopentone, the calculated ED50 values for verbal commands and eyelash stimulation at the same time intervals were 1.81-2.23 and 3.55-3.40 mg kg-1; corresponding ED95 values were 5.11-6.29 and 6.41-6.70 mg kg-1, respectively. The potency ratio of propofol to thiopentone observed in this study varied from 1:1.27 to 1:2.88. It is concluded that a dose-response curve reflecting one end-point of anaesthesia cannot be used to define another end-point of anaesthesia.
Naguib
M
M
Department of Critical Care Medicine, Faculty of Medicine and Health Sciences, United Arab Emirates University, Al-Ain.
Sari-Kouzel
A
A
Seraj
M
M
el-Gammal
M
M
Gomma
M
M
D000328:Adult; D000771:Anesthesia, Intravenous; D001307:Auditory Perception / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005140:Eyelashes / Q000502:physiology; D006801:Humans; D010812:Physical Stimulation; D015742:Propofol; D011897:Random Allocation; D013874:Thiopental; D013997:Time Factors
D013874:Thiopental; D015742:Propofol