Study objective: We assess the impact of emergency department (ED) pharmacists on reducing potentially harmful medication errors.
Methods: We conducted this observational study in 4 academic EDs. Trained pharmacy residents observed a convenience sample of ED pharmacists' activities. The primary outcome was medication errors recovered by pharmacists, including errors intercepted before reaching the patient (near miss or potential adverse drug event), caught after reaching the patient but before causing harm (mitigated adverse drug event), or caught after some harm but before further or worsening harm (ameliorated adverse drug event). Pairs of physician and pharmacist reviewers confirmed recovered medication errors and assessed their potential for harm. Observers were unblinded and clinical outcomes were not evaluated.
Results: We conducted 226 observation sessions spanning 787 hours and observed pharmacists reviewing 17,320 medications ordered or administered to 6,471 patients. We identified 504 recovered medication errors, or 7.8 per 100 patients and 2.9 per 100 medications. Most of the recovered medication errors were intercepted potential adverse drug events (90.3%), with fewer mitigated adverse drug events (3.9%) and ameliorated adverse drug events (0.2%). The potential severities of the recovered errors were most often serious (47.8%) or significant (36.2%). The most common medication classes associated with recovered medication errors were antimicrobial agents (32.1%), central nervous system agents (16.2%), and anticoagulant and thrombolytic agents (14.1%). The most common error types were dosing errors, drug omission, and wrong frequency errors.
Conclusion: ED pharmacists can identify and prevent potentially harmful medication errors. Controlled trials are necessary to determine the net costs and benefits of ED pharmacist staffing on safety, quality, and costs, especially important considerations for smaller EDs and pharmacy departments.
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