Impact of adding pethidine on disinhibition during bronchoscopy with midazolam: a propensity score matching analysis

Abstract

Background: We sometimes experience disinhibition during bronchoscopy with sedation. However, the impact of adding pethidine on disinhibition has not yet been investigated. This study aimed to examine the additive impact of pethidine on disinhibition during bronchoscopy with midazolam.

Methods: This retrospective study involved consecutive patients who underwent bronchoscopy between November 2019 and December 2020 (sedated with midazolam: Midazolam group) and between December 2020 and December 2021 (sedated with midazolam plus pethidine: Combination group). The severity of disinhibition was defined as follows: moderate, disinhibition that always needed restraints by assistants; and severe, disinhibition that needed antagonization of sedation by flumazenil to continue bronchoscopy. One-to-one propensity score matching was used to match baseline characteristics between both groups.

Results: After propensity score matching with depression, the type of bronchoscopic procedure, and the dose of midazolam, 142 patients matched in each group. The prevalence of moderate-to-severe disinhibition significantly decreased from 16.2% to 7.8% (P = 0.028) in the Combination group. The Combination group had significantly better scores for sensation after bronchoscopy and feelings toward bronchoscopy duration than did the Midazolam group. Although the minimum SpO₂ during bronchoscopy was significantly lower (88.0 ± 6.2 mmHg vs. 86.7 ± 5.0 mmHg, P = 0.047) and the percentage of oxygen supplementation significantly increased (71.1% vs. 86.6%, P = 0.001) in the Combination group, no fatal complications were observed.

Conclusions: Adding pethidine could reduce disinhibition occurrence in patients undergoing bronchoscopy with midazolam, with better subjective patient outcomes during and after bronchoscopy. However, whether more patients may need oxygen supplementation and whether hypoxia occurs during bronchoscopy should be considered.

Clinical trial registration: UMIN000042635.

Keywords: Disinhibitory reaction; Opioid; Paradoxical reaction; Sedation.