Double-blind study on the effects of topical anesthesia on laryngeal secretions

The application of topical anesthesia to the oropharynx is a common clinical practice during oral and nasal laryngoscopy. Clinically, questions have been raised about whether topical anesthesia alters laryngeal secretions, which distorts clinical impressions. A double-blind, placebo controlled design was employed to address this issue. Ten premenopausal women with healthy vocal folds and 10 premenopausal women with phonotraumatic lesions underwent oral videolaryngoscopic examinations on subsequent days under both anesthesia and placebo conditions, in counterbalanced order. Video segments were rated by three judges. Dependent variables were balling and pooling of secretions, as previously described in the literature. Statistical analyses failed to reveal any clear effect of topical anesthesia on either secretion balling or pooling for the collapsed data set, but one cannot exclude changes in individual cases. Moreover, there was no evidence that secretions were differentially affected by anesthesia across subject groups. Null results in this data set replicate and extend previously reported findings by other authors. An incidental but potentially interesting finding was that the order of treatment condition (anesthesia versus placebo first) seemed relevant for secretions: Subjects who received the anesthesia condition first tended to show more secretion balling in general, as compared with subjects who received the placebo condition first. Speculation is entertained regarding possible physiological pathways for these incidental findings, which could be relevant for some clinical practice.