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A simplified gentamicin dosing chart is quicker and more accurate for nurse verification than the BNFc
  1. E Wong1,
  2. Z Taylor2,
  3. J Thompson1,
  4. D Tuthill2
  1. 1
    Cardiff University, Cardiff, UK
  2. 2
    Cardiff and Vale NHS Trust, Children’s Hospital for Wales, Cardiff, UK
  1. David Tuthill, Department of Paediatrics, Children’s Hospital for Wales, Cardiff CF14 2XX, Wales, UK; David.Tuthill{at}


Background: At least 5% of paediatric admissions are complicated by medication error. Nurses can prevent some errors by correctly verifying prescriptions before administering drugs, which requires adequate drug calculation skills and familiarity with the BNFc. We wished to explore whether a newly devised chart would improve nurses’ dose calculation ability and thus potentially reduce doctors’ prescription errors.

Aims: To explore nurses’ ability to calculate doses of gentamicin for neonates and children using a new simple dosing chart compared with the BNFc.

Methods: Two gentamicin dosing charts (paediatric and neonatal) devised by a multidisciplinary group to simplify dose calculation and selection of frequency were compared with the BNFc using four questions (two neonatal, two paediatric) asking ward nurses to calculate gentamicin doses. Answers were scored for both the correct dosage and correct frequency.

Results: 51 nurses participated. 11 nurses (22%) answered all four questions correctly. A higher proportion correctly answered both the dosage and frequency questions simultaneously when using the chart compared with the BNFc: paediatric questions 100% (51/51 chart) versus 80% (41/51 BNFc) (OR 0.20) and neonatal questions 55% (28/51 chart) versus 35% (18/51 BNFc) (OR 0.2). Errors when using the BNFc were due to selection of the incorrect regimen (23%), wrong frequency (17%) and one 10-fold dosing error. When using the chart, there were no dosing errors, only frequency errors for the neonatal regimen.

Conclusion: The chart was more reliable, quicker and may be useful for patient safety. Revising the format of the BNFc may be beneficial for nurses.

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  • Funding: None.

  • Competing interests: None.