The effect of drug concentration expression on epinephrine dosing errors: a randomized trial.

BACKGROUND

The expression of drug concentration as a ratio may cause dosing errors.

OBJECTIVE

To examine the effect of ratio expressions on drug administration.

DESIGN

Randomized, blinded, controlled study.

SETTING

Simulation center in an urban hospital.

PARTICIPANTS

28 physicians.

INTERVENTION

Participants managed a simulated pediatric acute anaphylaxis scenario by using epinephrine ampules labeled with mass concentration (1 mg in 1 mL) or a ratio (1 mL of a 1:1000 solution).

MEASUREMENTS

The amount of epinephrine given and the time taken to administer it.

RESULTS

Compared with providers using ampules with mass concentration labels, those using ratio labels gave more epinephrine (adjusted mean dose, 213 microg above target [95% CI, 76.4 to 350.1 microg]; P = 0.003), and took longer to do so (adjusted mean delay, 91 seconds, [CI, 61.0 to 122.1 seconds]; P < or = 0.0001).

LIMITATIONS

Performance in simulated scenarios may not reflect clinical practice. In reality, ampule labels provide both expressions of concentration.

CONCLUSION

The use of ratios to express drug concentration may be a source of drug administration error. Patient safety might be improved by expressing drug concentrations exclusively as mass concentration.