Diphenhydramine as an Adjunct to Moderate Sedation in Outpatient Flexible Bronchoscopy

Abstract

Background Diphenhydramine is commonly used to decrease sedative usage in outpatient bronchoscopy, however, data to
support this practice is lacking. Methods We conducted a single-center retrospective analysis of all outpatient bronchoscopies
from November 2013 to February 2016. Each subject that was included had two bronchoscopies: no diphenhydramine used
(control) versus diphenhydramine used (intervention). The primary objective was to determine if diphenhydramine
administration decreases total midazolam usage. Additionally, we explored potential medication cost savings. Results Of 1164
patients with greater than 1 outpatient bronchoscopy, 61 unique subjects fulfilled the primary inclusion criteria resulting in
122 procedures. The mean dose of diphenhydramine was 38.3±15.12 mg. Procedure time was 22.9±16 mins in the
intervention group and 23.2±17.8 mins in the control group (p= 0.907). Mean opiate dose administered was 5.6±2.6 mg versus
6.2±2.4 mg in the intervention and control group, respectively (p= 0.113). Mean midazolam dose was 8.4 ± 3.2 mg in
intervention group and 10.2±3.8 mg in control group (difference: -1.795 mg, p= 0.005). In a multivariate analysis, mean
midazolam use remained lower in the diphenhydramine group after adjusting for age, procedure time and opiates used,
(difference -1.29±3.53 mg, p= .004). There was no significant difference for the total cost of medication between the control
and the diphenhydramine group ($6.21±2.70 vs. $6.23±2.53, p= .968). Conclusions Intravenous administration of
diphenhydramine during outpatient bronchoscopy resulted in a small but statistically significant reduction in midazolam usage
with no notable cost advantage