PROPOFOL CONCENTRATION REQUIRED FOR ENDOTRACHEAL INTUBATION WITH A LARYNGOSCOPE OR FIBERSCOPE AND ITS INTERACTION WITH FENTANYL

The administration of fentanyl with propofol reduces the blood concent ration of propofol required to achieve adequate anesthesia for trachea l intubation. However, different intubation procedures have variable i ntensities of noxious stimulation and may require different levels of anesthesia. The goal of this study was to determine the propofol blood concentration at which 50% of patients did not respond to stimulation (Cp-50) for laryngoscopy, intubation with a laryngoscope, insertion o f a slotted oral-pharyngeal airway (Ovassapian airway), and intubation with a fiberscope when administered in conjunction with fentanyl. Pat ients undergoing elective surgery were given varying amounts of propof ol or propofol with fentanyl, and their responses to the four procedur es listed above were assessed. These experiments demonstrated that the propofol concentration required for intubation with a laryngoscope wa s similar to that for intubation with a fiberscope, and that the requi red level was reduced by fentanyl. Hemodynamic responses to intubation were lower with a fiberscope than with a laryngoscope. We conclude th at almost the same concentrations of propofol or fentanyl are necessar y for suppressing both of the somatic responses to tracheal intubation with a fiberscope or a laryngoscope. Hemodynamic responses were atten uated more during intubation with a fiberscope. Implications: The prop ofol blood concentrations at which 50% of patients did not respond to stimulation for laryngoscopy, tracheal intubation with a laryngoscope, and tracheal intubation with a fiberscope were 10.9, 19.6, and 19.9 m u g/mL, respectively. These were reduced by fentanyl. Hemodynamic resp onses to intubation were less with a fiberscope than with a laryngosco pe.