Contrast agent substitution or corticosteroid premedication: association with emergency department throughput.

PURPOSE: To compare the operational efficiency of contrast agent substitution versus corticosteroid premedication in emergency department (ED) patients with prior mild allergic-like reactions to iodinated contrast media. METHODS: A retrospective study was performed 6/3/24-1/29/26 in EDs at two academic medical centers. Adult patients undergoing contrast-enhanced CT with a prior allergic-like reaction to iodinated contrast were included. Patients underwent either contrast agent substitution without corticosteroid premedication (if the agent inciting the index reaction was known) or standard corticosteroid premedication (if the agent inciting the index reaction was unknown) per institutional protocols. The primary outcomes were time from CT order entry to examination start and from order entry to ED discharge. Secondary outcome was breakthrough reaction rate in the contrast agent substitution group. RESULTS: 63 patients underwent contrast agent substitution and 727 patients were premedicated with corticosteroids (696 with a 5-h premedication regimen and 31 with a 13-h premedication regimen). Time from CT order entry to examination performance was 4.28 h faster when contrast agent substitution was utilized compared to corticosteroid premedication (95% confidence interval [CI]: 3.85-4.72 h). Time to ED discharge was also almost 4 h shorter (3.97 h, 95% CI: 2.72-5.30 h). Among the 63 patients who underwent contrast agent substitution, there were no breakthrough allergic-like reactions (95% CI: 0.0-5.7%). CONCLUSION: Contrast agent substitution was associated with reduced time to imaging and ED discharge compared to corticosteroid premedication. No breakthrough reactions were observed in the substitution group although the study was not designed to compare management strategies.