Systematic review and meta-analysis assessing the effectiveness of local anesthetic, vasoconstrictive, and lubricating agents in flexible fibre-optic nasolaryngoscopy.

Background: Flexible fibre-optic nasolaryngoscopy (FFN) is a common otolaryngology procedure that patients may find uncomfortable. Preparative agents, including topical anesthetic, vasoconstrictive, and lubricating agents, have been studied in randomized controlled trials (RCTs).

Methods: A systematic review and meta-analysis was conducted on RCTs published between January 1966 and October 2005 and indexed to MEDLINE, CINAHL, and Cochrane CENTRAL databases. Methodologic validity was evaluated. Primary outcomes were patients' evaluation of FFN. Secondary outcomes were endoscopists' evaluation of FFN.

Results: Eight RCTs were identified studying five preparative agent classes: vasoconstrictors plus topical anesthetics, vasoconstrictors alone, topical anesthetics alone, lubricating agents, saline, and no treatment. The systematic review found no difference in patients' evaluation of pain and discomfort for cocaine versus Co-phenylcaine (two RCTs), Co-phenylcaine versus no active agent (three RCTs), topical anesthetics versus no active preparative agent (two RCTs), vasoconstrictors versus no active preparative agent (two RCTs), and lubricating agents versus nothing. Two RCTs found that Co-phenylcaine causes higher taste unpleasantness, and one RCT found that topical anesthetics cause higher pain. Lubricating agents increase ease of examination but decrease quality of view (one RCT). Meta-analysis of two studies comparing Co-phenylcaine with other preparative agents found no difference on pain scores.

Conclusions: Cumulative evidence from eight RCTs shows no difference in pain scores when preparative agents with vasocontrictive, topical anesthetic, or lubricating properties are used. Co-phenylcaine may cause higher taste unpleasantness, and lidocaine may cause more pain. For the endoscopist, lubricating agents may aid in the examination but compromise the quality of the view.