Co-adminstration of alfentanil-propofol improves laryngeal mask airway insertion compared to fentanyl-propofol

Abstract

Purpose: Insertion of the laryngeal mask airway (LMA) requires sufficient depth of anesthesia to relax the jaw and obtund airway reflexes. Recent studies suggest that the short-acting opioid alfentanil provides the best insertion conditions. We therefore compared the insertion conditions following co-administration of alfentanil-propofol with more commonly used fentanyl-propofol. Methods: One hundred forty ASA I or II patients, age 18-81 yr, requiring minor surgery were recruited. They were randomized to receive either alfentanil (10 μg·kg-1; n = 73) or fentanyl (1 μg·kg-1; n = 67) with propofol (2.5 mg·kg-1) 90 sec prior to LMA (size 3 or 4) insertion. A six variable (mouth opening, ease of insertion, swallowing, coughing, movement and laryngospasm) three-point (nil / partial / total) score was used to assess insertion conditions. Duration of postinsertion apnea was recorded. Insertion conditions were compared using Chi-square for trends. Results: The two groups were demographically similar. Mouth opening and ease of insertion were not improved with alfentanil co-administration. Alfentanil-propofol reduced the incidence of swallowing, gagging, movement and laryngospasm (P < 0.05), with 29% (alfentanil) compared to 45% (fentanyl) of patients responding (P = 0.05) to LMA insertion. Apnea [mean (SD)] following alfentanil lasted 154 (139) sec compared to 82 (61) sec following fentanyl (P = 0.001). Conclusion: Co-administration of alfentanil-propofol provided better insertion conditions than fentanyl-propofol, though apnea was prolonged by 72 sec.