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.


METHODS
Randomized, blinded, controlled study.


METHODS
Simulation center in an urban hospital.


METHODS
28 physicians.


METHODS
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).


METHODS
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).


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


CONCLUSIONS
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.
Wheeler
Daniel W
DW
Division of Anaesthesia, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom. dww21@cam.ac.uk
Carter
Joseph J
JJ
Murray
Louise J
LJ
Degnan
Beverley A
BA
Dunling
Colin P
CP
Salvador
Raymond
R
Menon
David K
DK
Gupta
Arun K
AK
D000707:Anaphylaxis / Q000188:drug therapy; D002648:Child; D002985:Clinical Protocols; D004348:Drug Labeling / Q000592:standards*; D004837:Epinephrine / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D008297:Male; D008508:Medication Errors; D016544:Patient Simulation; D016037:Single-Blind Method; D013997:Time Factors; D014662:Vasoconstrictor Agents / Q000008:administration & dosage*
D014662:Vasoconstrictor Agents; D004837:Epinephrine