From 2011, Advanced Paediatric Life Support (APLS) candidates learn three formulae for paediatric weight estimation,1 covering infants from 1 to 12 months (0.5×age in months +4), children aged 1–5 years (2×age in years +8) and children aged 6–12 years (3×age in years +7). Previously, one formula was taught for ages 1–10 years ((age in years+4)×2)) and is still used in the European Paediatric Life Support course (EPLS); this formula is equivalent to the current APLS formula for 1–5 years.

We note some colleagues say they have difficulty recalling the new APLS formulae and age ranges for children over 1 year of age. To gauge the extent of this difficulty, we conducted a survey of 25 UK paediatric trainees (ST1–ST3) at a regional training day; trainees were asked, without prior notice, to state from memory the APLS formula they would use (with corresponding age ranges) for 2 children, aged 3 and 7 years.

In terms of training acquired, 68% of participants (n=17) had passed an APLS course; of these, 53% (n=9) passed on 2011 or after (when the new formulae were widely taught), while 47% (n=8) passed APLS prior to 2011. 12% (n=3) had passed the EPLS course, 4% (n=1) had attended Paediatric Intermediate Life Support (PILS) and 16% (n=4) reported they had not sat an external resuscitation course.

Our results showed that only 8% (n=2) of participants were able to correctly recall new APLS formulae and their respective age ranges. These two participants had completed APLS—one prior to the introduction of the new formulae.

The remaining 92% (n=23) were unable to recall the correct formulae and age ranges for either question. We were interested to see that the ‘old’ APLS weight estimation formula ((age in years+4)×2) was stated in many of the incorrect answers: 52% (n=12) for a child of 3 years and 57% (n=13) for a child of 7 years.

This survey suggests that paediatric trainees may find the new APLS formulae difficult to commit to memory—and may fall back to the ‘old’ APLS formula.

We understand that the introduction of the ‘Luscombe’ formula (3×age in years +7) into APLS was based on a retrospective study which showed that the ‘old’ APLS formulae underestimated children's weights.2 Whereas the study authors concluded that the new formula could be used safely in a UK population from 1 year to puberty,2 APLS limits its use to 6–12 years. We have not been able to find a clear rationale for this approach from a literature search.

Mosley et al3 have shown that knowledge and skills gained from similar courses such as Neonatal Life Support (NLS) course can deteriorate markedly with time. An ADC editorial suggests locally delivered medical simulation training may be part of the solution.4 Simplifying course content where possible would also help this aim; we therefore suggest that unless there is evidence of impact to patient safety, having two formulae for children aged 1–12 years adds unnecessary complexity to emergency paediatric weight estimation.