Weight estimation guidelines – Part 2

Cite this article as:
Mike Wells. Weight estimation guidelines – Part 2, Don't Forget the Bubbles, 2019. Available at:
https://doi.org/10.31440/DFTB.18947

Getting an accurate drug dose into a critically ill or injured child is a complex process that is highly vulnerable to error at each of the steps from weight estimation to drug delivery. As ethical healthcare providers, we need to be passionate about paediatric patient safety and minimise the potential for patient harm at our hands.

Weight estimation guidelines – Part 1

Cite this article as:
Mieke Foster. Weight estimation guidelines – Part 1, Don't Forget the Bubbles, 2019. Available at:
https://doi.org/10.31440/DFTB.18165

When a child is picked up by paramedics or brought into an emergency department, their weight is not always known and cannot always be formally measured. Many research teams across the globe are trying to find the best method to estimate a child’s weight, so medication can be dosed and equipment sized appropriately. Traditionally, age-based formulae have been used, but these are known to be very inaccurate. More reliable methods are available, however all require input of more information than just age, whether that be height, mid-arm circumference, a parent estimate or a smartphone image. You can find a summary of weight estimation techniques in this post from Andy Tagg. The question is, what method is sufficiently accurate and will work best in practice?

At the moment, Australian guidelines still use age-based formulae (namely the original APLS formula, weight = 2 x (age+4)). Even though they are very inaccurate, they have a number of advantages:

  • They are very quick. Most prescribers use these formulae in conjunction with resuscitation aids, emergency manuals or clinical practice guidelines which mean they do not need to remember the formula or do the calculation themselves as they are given a table with corresponding weight to age.

  • Given age-to-weight conversions are often provided, staff do not need to be trained on how to gather the estimate.
  • They do not require any additional equipment, which may be hard to find if an ambulance or emergency department rarely sees paediatric critical cases.
  • An emergency department can predict the weight of the child that is about to arrive by ambulance if they have the child’s age, and can therefore start drawing up medications in advance.
  • Stress and cognitive load have been shown to be the key precipitating factors of human error in paediatric critical events. Human errors in these scenarios include significant medication errors, such as ten-fold errors (where 10x the medication is prescribed or administered because the decimal point is moved or the concentration incorrectly calculated). These have been shown to cause significant patient morbidity and mortality. Efforts to gather the further information needed to make the weight estimate more accurate (e.g. measuring the child, taking a sufficient quality image, finding a parent) increase the complexity of the weight estimation phase. Increased complexity is likely to increase cognitive load, and thus increase the risk of human error at all phases in the dosing process.

    We need to find a weight estimation tool that can be used by anyone who might need to manage a paediatric critical event. This includes paramedics, junior medical staff and adult emergency department personnel that may need to manage patients before they reach a tertiary children’s hospital or paediatric emergency department. This means we need clear, easy-to-follow guidelines and associated training that can be rolled out broadly. It also emphasises the need to ensure we keep the cognitive burden as low as possible, as many prescribers will be in an unfamiliar, stressful situation, both of which further precipitate human error. Future protocols may also differ based on the paediatric emergency expertise and training available in that setting, for example, a paediatric emergency department may choose a more accurate method with higher cognitive load than an ambulance service.

    Another important consideration is the time delay involved in each weight estimation strategy. Most events requiring weight estimation are time-critical in nature. It is important to not only consider the time involved in getting the estimate, but also the time needed to find the appropriate equipment, make subsequent dose calculations and prepare the dose for administration. This highlights the significant advantage of emergency departments being able to draw up medications prior to the child’s arrival, as having doses pre-calculated and pre-prepared would significantly reduce the time delay in drug administration.

    Given rising rates of childhood obesity, we need to find a weight estimation strategy that will work for all body types and medication types. Some drugs should be dosed based on ideal body weight (IBW) whilst others should be dosed based on total body weight (TBW), depending on their pharmacokinetic properties. Similarly, dosing medication by TBW in obese children can lead to overdose. Sydney Children’s Hospital has given a nice overview to some of the adjustments which should be made for specific medications. However, adjusting weights for specific medications in a paediatric emergency may further add to the cognitive load.

    Overall, the pros and cons of each group of techniques can be summarised in a table:

    So, how important is it that we have an accurate weight estimate? And how important are other considerations such as reducing cognitive load and practicality (eg. speed, equipment and staff training requirements)?

    Unfortunately, there is very limited data on patient outcomes available to help guide us. The small number of studies into the impact of weight errors look at incorrectly documented weights, such as where the wrong weight unit was recorded (pounds instead of kilograms) or where a decimal point was moved (6). No study has looked specifically at the harms caused by weight estimation error in paediatric emergencies. There is no suggestion that using the original APLS formula in Australia is currently causing harm to patients, but there is also no evidence that proves that it is not. Reducing error should always be the goal, however increasing the complexity of generating a weight estimate could increase the cognitive load, and thus increase the risk of more significant errors. When deciding on which weight estimation technique to use, we need to find a middle ground between accuracy and practicality with an emphasis on reducing overall cognitive load.

    Selected References

    Wells M, Goldstein LN, Bentley A. The accuracy of emergency weight estimation systems in children – a systematic review and meta-analysis. Int J Emerg Med. 2017;1:1. Available from: https://intjem.biomedcentral.com/articles/10.1186/s12245-017-0156-5

    Sutherland A, Ashcroft DM, Phipps DL. Exploring the human factors of prescribing errors in paediatric intensive care units. Arch Dis Child. 2019;0:1-8. Available from: https://adc.bmj.com/content/104/6/588.long

    Khoo TB, Tan JW, Ng HP, Choo CM, bt Abdul Shukor INC, Teh SH. Paediatric in-patient prescribing errors in Malaysia: a cross-sectional multicentre study. Int J Clin Pharm. 2017;39(3):551-9.

    Doherty C, McDonnell C. Tenfold medication errors: 5 years’ experience at a university-affiliated pediatric hospital. Pediatrics. 2012;129(5):916-24. Available from: https://pediatrics.aappublications.org/content/129/5/916.long

    Foster M, Tagg A, Klim S, Kelly AM. Accuracy of parental estimate of child’s weight in a paediatric emergency department. Emerg Med Australas. 2019; in press.

    Shaw KN, Lillis KA, Ruddy RM, Mahajan PV, Lichenstein R, Olsen CS, et al. Reported medication events in a paediatric emergency research network: sharing to improve patient safety. Emerg Med J. 2013;30(10):815-9. Available from: https://emj.bmj.com/content/30/10/815.long

    There are people with games: Vic Brazil at DFTB18

    Cite this article as:
    Team DFTB. There are people with games: Vic Brazil at DFTB18, Don't Forget the Bubbles, 2019. Available at:
    https://doi.org/10.31440/DFTB.19086

    The  audience at DFTB18 were privileged to attend a series of sessions from team at Simulcast, the premier podcast for all things sim and debriefing. 

    In this first talk of the session Vic Brazil interviews Kara Allen about the place of simulation and asks ‘Is at really all that?‘ Kara Allen is a consultant anaesthetist at the Royal Melbourne Hospital and Clinical Lead at Monash Simulation. Whilst sim seems like an exciting way of doing ‘stuff’ and we all love the chance to get out of our respective departments and play let’s- pretend is it fit for purpose?

    This talk was recorded live at DFTB18 in Melbourne, Australia. With the theme of ‘Science and Story‘ we pushed our speakers to step out of their comfort zones and consider why we do what we do. Caring for children is not just about acquiring the scientific knowhow but also about taking a look beyond a diagnosis or clinical conundrum at the patient and their families.

    DFTB19 has just a handful of main conference tickets left but there are still spots for some of the pre-conference workshops.

    If you want our podcasts delivered straight to your listening device then subscribe to our iTunes feed or check out the RSS feed. If you are more a fan of the visual medium then subscribe to our YouTube channel. Please embrace the spirit of FOAMed and spread the word.

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    Catch 22

    Cite this article as:
    Ana Waddington. Catch 22, Don't Forget the Bubbles, 2019. Available at:
    https://doi.org/10.31440/DFTB.19122

    James was 13 the first time I treated him in A&E. He was rushed in after being hit on the head with a metal bar, but he wouldn’t tell us what had happened. Some others had seen him, rushed him, started beating him with bats and bars – that was all he said he remembered. It was clear that James was already deeply involved in the world of gang violence, and it was equally clear that if he wasn’t saved from it soon this world would destroy him. We tried to get James to stay in A&E long enough to hear the results of his scan, but as soon as he got a chance he slipped out and back onto the streets. My fear was that before long the streets would deliver him back to us, only this time he wouldn’t be able to walk out again.

    Paediatric Chest Drains

    Cite this article as:
    Andrew Tagg. Paediatric Chest Drains, Don't Forget the Bubbles, 2019. Available at:
    https://doi.org/10.31440/DFTB.18913

    We know that critical procedures are rare in clinical practice but that when they do need to be done they need to be done right. Whether for relieving a haemo-pneumothorax or a large empyema it is incumbent upon us to know what to do when the need arises. With the exception of our South African colleagues most of us may only ever insert a chest drain every other year. So let’s take a look at what you need to know with the help of this paper from the trauma team at the Royal Children’s Hospital in Melbourne.

    The Collapsed Cardiac Child: Kath Browning Carmo at DFTB18

    Cite this article as:
    Team DFTB. The Collapsed Cardiac Child: Kath Browning Carmo at DFTB18, Don't Forget the Bubbles, 2019. Available at:
    https://doi.org/10.31440/DFTB.18978

    There is nothing like the thought of dealing with a shocked neonate to strike the fear of the almighty into the most experienced doctor. If you are lucky enough to have Kath Browning Carmo on speed dial then you may be a little more relaxed but if you don’t here she is to offer some words of comfort.

    (Kath has chosen Moonlight Sonata as her ringtone so she gets woken gently rather than in a fluster – what a great idea: Ed)

    Here’s a sketch note from the talk by @char_durand

    If you want to get a better idea of some of the congenital abnormalities that can occur then take a look at these animations from Cincinatti Children’s.

    This talk was recorded live at DFTB18 in Melbourne, Australia. With the theme of ‘Science and Story‘ we pushed our speakers to step out of their comfort zones and consider why we do what we do. Caring for children is not just about acquiring the scientific knowhow but also about taking a look beyond a diagnosis or clinical conundrum at the patient and their families.

    DFTB19 has already sold out but there are still spots for some of the pre-conference workshops.

    If you want our podcasts delivered straight to your listening device then subscribe to our iTunes feed or check out the RSS feed. If you are more a fan of the visual medium then subscribe to our YouTube channel. Please embrace the spirit of FOAMed and spread the word.

    iTunes Button

    Selected References

    Evans NJ, Archer LN. Postnatal circulatory adaptation in healthy term and preterm neonates. Archives of disease in childhood. 1990 Jan 1;65(1 Spec No):24-6.

    The illusion of patient choice

    Cite this article as:
    Amit Bali. The illusion of patient choice, Don't Forget the Bubbles, 2019. Available at:
    https://doi.org/10.31440/DFTB.19010

    “Pick a card…any card”, as the saying goes.

    I remember being the recipient of this common trick when a medical student, at a friend’s for dinner where a magician was a fellow guest. The scientist in me wanted to know how it was done, so I prepared to follow my card studiously. I chose carefully and deliberately, feinting to pick one card from the fan offered to me, before choosing – in my eyes – a less obvious card. However, after returning the card to the deck, the magician threw his arms up with a flourish, the pack hitting th eceiling with a thud, causing cards to scatter across the room. Amazingly, my chosen card was stuck to the ceiling, fixed in place by a drawing pin.

    I made peace with the fact I was always going to choose that card, and applauded in awe.

     

    The ‘magician’s choice’

    A few years ago, during a lecture, I was introduced to the concept of the‘magician’s choice’ by Daniel Sokol (a medical ethicist and magician). He used it as an innovative analogy to illustrate how, in obtaining consent, the presentation of the different options is nothing like the free choice it is intended to be. Rather, the possibilities are presented, much like a deck of cards, only this time the ‘trick’ is that the clinician– whether consciously or not – weights information, making a certain choice more likely. I was reminded of this concept recently, after reading about a new app due to be rolled out in the English National Health System. This new platform, it is claimed, will enable patients to see waiting times at different emergency departments, the implication being that they will choose to go to the one with the shortest wait. Unsurprisingly, this sparked Twitter debate about whether or not this actually was a useful tool to help patient flow, with strong opinions on either side.

    To my surprise, however, the assumption from everyone seemed to be that this app would offer choice. To which my first thought was: ‘choice, what choice?’

     

    Patient choice?

    For many years, the NHS has offered explicit patient choice for specialist outpatient care, offering a range of different hospitals at the point of referral. In recent years, the system has evolved to display waiting times. Sounds good so far? To an extent, I agree. A transparent system that allows patients, in conjunction with their GP, to book in to an appointment – even obtaining a date and time – is a pretty simple but effective use of technology. My objection is that the offered choice is nothing but an illusion.

    The patient is given little idea of the constraints through which their choice is being made. As an example, many of the children I see have a long-term condition (epilepsy). Effective, joined-up care is much more than a quick hospital consultation, achieved through a combination of having a point of contact via their specialist nurse, close liaison with school, tracking of development progress, and surveillance of mental health and wellbeing. This is best achieved through local, networked care, a system which has been carefully developed over many years.When I see a patient outside this framework, the care is not just difficult to deliver – in what is far from a delicious irony, it actually gets delayed. When I have to inform families that ‘I can’t access that information’, ‘they won’t accept that referral from me’, or ‘our nurse doesn’t cover that area’ (all recurring themes from my practice over the last year), I empathise with the fact that they took a decision that they thought would get quicker access to care for their child, only to now discover that delay was just shifted further down the road. There are potential ways around this – not least patient record systems that speak to each other. Yet that sort of change doesn’t happen overnight so, until it does, surely patients deserve better? Until then, this resembles the ‘three cup and ball’ trick. The patient believes they have options, when actually the system is too constrained to offer the truly free choice that is advertised. No matter how much you try to pick the cup with the ball under it, the pieces move and the magician ensures you never can.

    Paediatric Placements – from the eyes of a medical student

    Cite this article as:
    Amie Hilder. Paediatric Placements – from the eyes of a medical student, Don't Forget the Bubbles, 2019. Available at:
    https://doi.org/10.31440/DFTB.18800

    Paediatric medicine is notoriously challenging for medical students. Not only does it encompass as many different medical fields as we see in adult medicine; but there is also the challenge of learning to manage and care for children of all different ages (as well as managing parents!).

    Legal and Ethical Quandaries: Ian Summers at DFTB18

    Cite this article as:
    Team DFTB. Legal and Ethical Quandaries: Ian Summers at DFTB18, Don't Forget the Bubbles, 2019. Available at:
    https://doi.org/10.31440/DFTB.18919

    When most of us think of ethics and law our eyes roll and we picture Rumpole of the Bailey and quiet Sunday afternoons in front of the television. But his time Ian Summers came up with something unique. Pushing the boundaries of simulation as an educational medium he introduced us to a series of hypotheticals. Take your time to watch rather than just listen to your iDevice. You’ll learn about ethical practice in paediatrics but if you pause, take a step back, and press play again, you’ll see a masterclass of simulation in action.

     

     

     

    This talk was recorded live at DFTB18 in Melbourne, Australia. With the theme of ‘Science and Story‘ we pushed our speakers to step out of their comfort zones and consider why we do what we do. Caring for children is not just about acquiring the scientific knowhow but also about taking a look beyond a diagnosis or clinical conundrum at the patient and their families.

     

    If you want our podcasts delivered straight to your listening device then subscribe to our iTunes feed or check out the RSS feed. If you are more a fan of the visual medium then subscribe to our YouTube channel. Please embrace the spirit of FOAMed and spread the word.

     

    iTunes Button

     

    Respiratory Tract Infections in children

    Cite this article as:
    Patel,S and Munro, A. Respiratory Tract Infections in children, Don't Forget the Bubbles, 2019. Available at:
    https://doi.org/10.31440/DFTB.18906

    Emily is a 2 year old girl brought to the emergency department with her mum, following two days of fever and poor intake. She has a temperature of 39°C and looks a little unhappy, but has no red flags for sepsis. On examination of her throat you see she has enlarged, red tonsils bilaterally with exudate. Her examination is otherwise normal. Should you prescribe her antibiotics?

    Paediatric Murmurs: Ari Horton at DFTB18

    Cite this article as:
    Team DFTB. Paediatric Murmurs: Ari Horton at DFTB18, Don't Forget the Bubbles, 2019. Available at:
    https://doi.org/10.31440/DFTB.18861

    Ari Horton is many things – an advocate for kindness, a Cordon Bleu trained pastry chef and, just very occasionally, a paediatric cardiologist. Andrew Tagg remembers the day Ari found his calling. Working as a paediatric ED resident in Melbourne’s inner west he came to present a patient. He could barely sit still and his grin threatened to infect the fishbowl as he announced, “I found a murmur!”

    We may not all be as acoustically gifted as Ari but that thing we wield around our necks is not just for listening for wheezes or for distracting toddlers.

    At 3:30am in emergency overnight,
    You got a seriously worrisome fright.
    That harsh sound whooshing through the chest,
    Try hide your concern, you say “It’s for the best”.
    Is it innocent or the beginning of the end,
    Go back to the basics they’re your best friend.

    Horton’s distraught, his heart is fraught.
    Stress fills his tired mind, luckily he left his steth behind.
    Numbers and statistics running through his head,
    But he stood still watching the child from the end of his bed.
    By 9am poor old Horton, more dead than alive,
    Had picked, searched and listened to more than 9005

    Examination is a dynamic process they say,
    Watching the kid run this and that way.
    See them feed, sleep, run, jump and cry,
    Do some special tests before you say goodbye.
    A person’s a person no matter how small

    It’s the real story that captures us all.
    A murmur’s just a murmur no matter how loud
    I’ve learnt my lessons and I’m so proud.
    This child is healthy and safe because we cared
    Cardiac fellowship awaits because I dared.

    Horton Hears A What? Ari Horton (2018)

     

     

     

    Here is a little sketchnote by @gracie_leo of the talk:

     

    This talk was recorded live at DFTB18 in Melbourne, Australia. With the theme of ‘Science and Story‘ we pushed our speakers to step out of their comfort zones and consider why we do what we do. Caring for children is not just about acquiring the scientific knowhow but also about taking a look beyond a diagnosis or clinical conundrum at the patient and their families.

    DFTB19 has just a handful of main conference tickets left but there are still spots for some of the pre-conference workshops.

     

    If you want our podcasts delivered straight to your listening device then subscribe to our iTunes feed or check out the RSS feed. If you are more a fan of the visual medium then subscribe to our YouTube channel. Please embrace the spirit of FOAMed and spread the word.

     

    iTunes Button

     

    Daily JA, Bolin E, Eble BK. Teaching pediatric cardiology with meaning and sense. Congenital heart disease. 2018 Jan;13(1):154-6.
    Haney I, Ipp M, Feldman W, McCrindle BW. Accuracy of clinical assessment of heart murmurs by office based (general practice) paediatricians. Archives of disease in childhood. 1999 Nov 1;81(5):409-12.
    Keren R, Tereschuk M, Luan X. Evaluation of a novel method for grading heart murmur intensity. Archives of pediatrics & adolescent medicine. 2005 Apr 1;159(4):329-34.
    Lefort B, Cheyssac E, Soulé N, Poinsot J, Vaillant MC, Nassimi A, Chantepie A. Auscultation While Standing: A Basic and Reliable Method to Rule Out a Pathologic Heart Murmur in Children. The Annals of Family Medicine. 2017 Nov 1;15(6):523-8.
    Mahnke CB, Nowalk A, Hofkosh D, Zuberbuhler JR, Law YM. Comparison of two educational interventions on pediatric resident auscultation skills. Pediatrics. 2004 May 1;113(5):1331-5.
    Noponen AL, Lukkarinen S, Angerla A, Sepponen R. Phono-spectrographic analysis of heart murmur in children. BMC pediatrics. 2007 Dec;7(1):23.

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    The Paediatric Assessment Triangle

    Cite this article as:
    Andrew Tagg. The Paediatric Assessment Triangle, Don't Forget the Bubbles, 2019. Available at:
    https://doi.org/10.31440/DFTB.18616

    This post accompanies the talk I was asked to give to a fantastic group of Ambulance Victoria paramedics. I was given the title “Everything you NEED to know about paediatrics”  but given that I don’t know everything I need to know yet I thought I would drill down and focus on doing one thing well.