title: The effect of drug concentration expression on epinephrine dosing errors: a randomized trial.
abstract: 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.
authors.affiliation: Division of Anaesthesia, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom. dww21@cam.ac.uk
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Wheeler
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Carter
authors.forename: Louise J
authors.initials: LJ
authors.lastname: Murray
authors.forename: Beverley A
authors.initials: BA
authors.lastname: Degnan
authors.forename: Colin P
authors.initials: CP
authors.lastname: Dunling
authors.forename: Raymond
authors.initials: R
authors.lastname: Salvador
authors.forename: David K
authors.initials: DK
authors.lastname: Menon
authors.forename: Arun K
authors.initials: AK
authors.lastname: Gupta
mesh_terms: 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*
chemical_list: D014662:Vasoconstrictor Agents; D004837:Epinephrine