Double-blind randomized noninferiority study of the effect of pharyngeal lidocaine anesthesia on EUS

EUS is typically performed under sedation, often with concomitant analgesics to reduce pain. Traditionally used pharyngeal anesthesia, commonly with lidocaine, may cause pharyngeal discomfort and allergic reactions. This study investigated whether lidocaine-based pharyngeal anesthesia is necessary for EUS under sedation with analgesics.

A double-blind, randomized, noninferiority study was conducted on EUS cases that met the selection criteria. Patients were randomly assigned to receive either 5 sprays of 8% lidocaine (lidocaine group: LG) or saline spray (placebo group: PG) as endoscopy pretreatment. The primary outcome was EUS tolerability, analyzed separately for endoscopists and patients, with a noninferiority margin set at 15%. Secondary outcomes included endoscopist and patient satisfaction, midazolam/pethidine doses, number of gag events, number of esophageal insertion attempts, use of sedative/analgesic antagonists, interruptions due to body movements, throat symptoms after endoscopy, and sedation-related adverse events.

Favorable tolerance was 85% in LG and 88% for PG among endoscopists (percent difference: 3.0 [95% confidence interval, -6.6 to 12.6]) and 90% in LG and 91% in PG among patients (percent difference, 0.94 [95% confidence interval, -7.5 to 9.4]). Both groups exceeded the noninferiority margin (P = 0.0002 for endoscopists and patients). Patient satisfaction was significantly higher in PG (P = 0.0080), but no intergroup differences were found in other secondary outcomes.

PG was noninferior to LG for pharyngeal anesthesia during EUS with sedation and analgesics. These results suggest that pharyngeal anesthesia with lidocaine can be omitted when performing EUS under sedation with concomitant analgesics. Omitting pharyngeal anesthesia with lidocaine may prevent discomfort and complications caused by pharyngeal anesthesia, shorten examination times, and reduce medical costs.