Estimating the Weight of Children in Kenya: Do the Broselow Tape and Age-Based Formulas Measure Up?

doi:10.1016/j.annemergmed.2012.07.110

Annals of Emergency Medicine

Volume 61, Issue 1, January 2013, Pages 1-8

Presented as an abstract at the Society for Academic Emergency Medicine annual meeting, May 9–12, 2012, Chicago, IL; and the Pediatric Academic Societies annual meeting, April 28–May 1, 2012, Boston, MA.

https://doi.org/10.1016/j.annemergmed.2012.07.110 Get rights and content

Study objective

Validated methods for weight estimation of children are readily available in developed countries; however, their utility in developing countries with higher rates of malnutrition and infectious disease is unknown. The goal of this study is to determine the validity of a height-based estimate, the Broselow tape, compared with age-based estimations among pediatric patients in Western Kenya.

Methods

A prospective cross-sectional study of all sick children presenting to the emergency department of a government referral hospital in Eldoret, Kenya, was performed. Measured weight was compared with predicted weights according to the Broselow tape and commonly used advanced pediatric life support (APLS) and Nelson's age-based formulas. A Bland-Altman analysis was used to determine agreement between each method and actual weight. The method for weight prediction was determined a priori to be equivalent to the actual weight if the 95% confidence interval for the mean percentage difference between the predicted and actual weight was less than 10%.

Results

Nine hundred sixty-seven children were included in analysis. The overall mean percentage difference for the actual weight and Broselow predicted weight was −2.2%, whereas APLS and Nelson's predictions were −5.2% and −10.4%, respectively. The overall agreement between Broselow color zone and actual weight was 65.5%, with overestimate typically occurring by only 1 color zone.

Conclusion

The Broselow tape and APLS formula predict the weights of children in western Kenya. According to its better performance, ease of use, and provision of drug dosing and equipment size, the Broselow tape is superior to age-based formulas for estimation of weight in Kenyan children.

Introduction

When clinicians resuscitate children, it is paramount that they know or can accurately estimate the child's weight. This information allows them to administer proper medication doses, determine defibrillation energy, and use equipment of the correct size. Because delaying a resuscitation to weigh a child is impractical, it is important to have an accurate method to estimate weights. Two commonly used methods are age-based formulas and the Broselow tape,1, 2 which uses height-to-weight correlations to predict weight and provides corresponding predetermined medication dosages and equipment sizes. Because calculation of medication dosages has been shown to be a significant source of medical error,3, 4, 5 the Broselow tape can alleviate stress surrounding pediatric resuscitation and reduce adverse drug events.6, 7

Broselow height-based weight estimation has been validated in several developed countries (Table 1).1, 2, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 The majority of these studies suggest that the Broselow tape is still useful for estimating weight of children. Recent studies, however, show that as obesity rates increase, the Broselow tape may be underestimating weights; these studies have small sample size and therefore will require further investigation to determine whether this trend is real. Conversely, the utility of these methods in developing countries where malnutrition is prevalent is not well studied. Only 3 studies have been performed in middle-income developing countries; no studies exist for low-income countries, to the authors' knowledge (Table 1).24, 25, 26 The 3 studies conducted in middle-income developing countries have conflicting results: A South African and Indian study reported the Broselow tape to be valid, whereas another study in India reported overestimation of weights by more than 10%.24, 25, 26 This implies that validated methods for weight estimation among pediatric populations in developed nations may not transfer to developing nations in which higher rates of malnutrition and an increased burden of morbidity and mortality caused by infectious diseases are prevalent. This highlights the need for further study in low-income developing countries, which are among the most resource-limited settings in the world. Among resource-limited settings, children living in sub-Saharan Africa are among those with the highest rates of malnutrition and diseases such as HIV.²⁷ Because, to our knowledge, there are no published studies validating weight estimation methods in these pediatric populations, it is important to ascertain what methods of pediatric weight estimation, if any, are valid in sub-Saharan Africa.

Kenya is one such country in sub-Saharan Africa in which children face high morbidity from malnutrition and wasting diseases such as tuberculosis and HIV and for which pediatric resuscitation procedures have seldom been validated. According to experiential evidence, most clinicians in Kenya estimate weights with age-based formulas. Problems with these formulas arise when caregivers are unsure of the child's age, which is common in Kenya. Additionally, malnutrition is prevalent in Kenya. These children often have a low weight for age.²⁸ As malnutrition becomes chronic, children have a diminished height for age as well, making them appear more normally proportioned.²⁹ As a result, approximately 35% of children younger than 5 years are stunted because of malnutrition.²⁸ Therefore, given that many Kenyan children are overall smaller for age, height-based estimates, such as the Broselow tape, may be better at estimating weights than age-based formulas. Our objective was to assess the validity of the Broselow tape and age-based formulas for the estimation of weights among children in Kenya.

Section snippets

Study Design

To compare the validity of the Broselow tape and age-based formulas at estimating weights in Kenyan children, a prospective, cross-sectional study of sick children presenting to Moi Teaching and Referral Hospital in Eldoret, Kenya, was performed between May and June 2011. The study was approved by both the Indiana University Institutional Review Board and the Institutional Research and Ethics Committee at Moi Teaching and Referral Hospital.

Setting

Eldoret is a town of approximately 220,000 people,

Results

The study included 967 children ranging in age from 2 days to 14 years, with an adequate sample size in each Broselow category (Table 2). The interrater reliability analysis demonstrated good reliability, with a weighted κ coefficient of 0.98 (95% CI 0.96 to 1.00); the color code agreement was 96.5% (43/45), with 2 disagreements being by only 1 color zone.

Compared with age-based formulas, the Broselow tape was a better predictor of actual weights, with a mean percentage difference of −2.2% (95%

Limitations

This study has several potential limitations. Given the limited resources and personnel in the Sick Child Clinic, we were unable to track every patient for eligibility. In general, most patients were eligible and included in the study, making our results, we believe, generalizable to this patient population. Although we did not collect data on sex, previous studies have not shown any differences in the performance of the Broselow tape or age-based formulas between boys and girls. Also,

Discussion

To our knowledge, this study provides the first evidence that the Broselow tape and APLS formula provide valid estimates for children's weights in western Kenya. Overall, the Broselow tape outperformed age-based formulas. We believe these results will help clinicians in the resuscitation of critically ill children in other countries within sub-Saharan Africa.

As a single estimate of a child's weight, the Broselow tape provided the best agreement with actual weight. When used with age-based

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Cited by (34)

Estimating children's weight in a Rwandan emergency centre
2018, African Journal of Emergency Medicine
Citation Excerpt :
Wells et al. identified only one study from either East or Central Africa [8]. This study, from Kenya, did not present adequate data to assess the precision of age-based and Broselow Tape methods [12]. Even if it had, Rwanda has a much lower prevalence of underweight children one to five years old (11%) [13] than does Kenya (16.4%) [8].
Most drugs, fluids and ventilator settings depend on the weight of a paediatric patient. However, knowledge of the weight is often unavailable as the urgency of the situation may impede measurement. The most common methods for paediatric weight estimation are based on height or age. This study aimed to compare the accuracy of various weight estimation methods and to derive a dedicated age-based tool within a Rwandan setting.
This was a retrospective study using age, weight and height data from randomly selected charts of Rwandan children, aged between one and ten years, who attended the paediatric emergency centre, Centre Hospitalier Universitaire de Kigali, Rwanda. Weights were estimated using four versions of the Broselow Tape and several age-based formulae. Linear regression was used to derive a new age-based weight estimation formula, the Rwanda Rule. Weight estimations were then compared with actual weight using Bland-Altman analysis, and the proportions of estimates within 10 and 20% of actual weight.
There were 327 children included in the study. The derived Rwanda Rule was: weight (kg) = [1.7 × age (years)] + 8. This formula and the original Advanced Paediatric Life Support formula (weight = [2 × age] + 8) performed similarly. Both were better than other age-based formulae (69% of estimates within 20% of actual weight). All editions of the Broselow Tape performed better than age-based rules. The 1998 version performed best with 84.8% of estimates within 20% of actual weight.
This study is the first to compare paediatric weight estimation methods in Rwanda. Locally, and until we have evidence from further research that other methods are superior, we would advise use of the 1998 Broselow Tape in children aged one to ten years old. Where the Broselow Tape is not available, the original Advanced Paediatric Life Support formula should be used.
The accuracy of the Broselow tape as a weight estimation tool and a drug-dosing guide – A systematic review and meta-analysis
2017, Resuscitation
Citation Excerpt :
This suggests that, even in the same study population, the Broselow tape was unable to estimate weight consistently in children of the same length. If habitus is not taken into account in the weight estimation, as has been recommended by previous authors, this is inevitable [2,5,16,17,32,44,55,58,73,81]. The pooled data showed an overall bias to underestimate weight, but with estimates as much as 30% below actual weight to 20% above actual weight.
The Broselow tape is widely used as a weight-estimation device and drug-dosing guide aid, but concerns about its accuracy and its efficacy have emerged in the last decade. The aim of this study was to systematically review the literature to analyse the accuracy of the Broselow tape as a weight estimation device and review evidence of its utility as a drug-dosing guide.
This was a MOOSE-driven systematic review and meta-analysis, which focused on studies evaluating the accuracy of the Broselow tape and studies reviewing its use as a drug-dosing aid.
The tape has undergone substantial changes over the years, but there was no evidence to show that the changes have improved weight-estimation performance. The weight-estimation accuracy of the tape was suboptimal in all populations, with just over 50% of children receiving an estimation within 10% of their actual weight. The overestimation of weight in low- and middle-income countries was often extreme. This indicated a significant potential for potentially harmful medication errors. The limited available evidence on the value of the tape as a drug-dosing guide indicated that the tape was frequently used incorrectly and contained insufficient information to function without additional resources.
The Broselow tape lacked sufficient accuracy as a weight estimation and drug-dosing tool when compared to other available techniques. In addition, the Broselow tape contains insufficient drug-dosing information to function as a complete resuscitation aid without additional material. The frequent rate of incorrect usage of the tape indicated that appropriate training with the tape is mandatory to reduce errors.
A systematic review and meta-analysis of the accuracy of weight estimation systems used in paediatric emergency care in developing countries
2017, African Journal of Emergency Medicine
When weight cannot be measured during the management of medical emergencies in children, a convenient, quick and accurate method of weight estimation is required, as many drug doses and other interventions are based on body weight. Many weight estimation methodologies in current use have been shown to be inaccurate, especially in low- and middle-income countries with a high prevalence of underweight children. This meta-analysis evaluated the accuracy of weight estimation systems in children from studies from low- and middle-income countries.
Articles from low- and middle-income countries were screened for inclusion to evaluate and compare the accuracy of existing systems and the newer dual length- and habitus-based methods, using standard meta-analysis techniques.
The 2D systems and parental estimates performed best overall. The PAWPER tape, parental estimates, the Wozniak method and the Mercy method were the most accurate systems with percentage of weight estimates within 10% of actual weight (PW10) accuracies of 86.9%, 80.4%, 72.1% and 71.4% respectively. The Broselow tape (PW10 47.1%) achieved a moderate accuracy and age-based estimates a very low accuracy (PW10 11.8–47.5%).
The PAWPER tape, the Wozniak method and the Mercy method achieved an acceptable level of accuracy in studies from low- and middle-income countries and should preferentially be used and further advanced for clinical emergency medicine practice. Parental estimates may be considered if the regular caregiver of the child is present and a recent measured weight is known. The Broselow tape and age-based formulas should be abandoned in low- and middle-income country populations as they are potentially dangerously inaccurate.
Weight Estimation Methods in Children: A Systematic Review
2016, Annals of Emergency Medicine
Citation Excerpt :
We screened the abstracts of 131 studies and excluded 16 after screening and an additional 35 after full-text review (Figure). We thus included 80 studies on the topic of estimating weight in pediatric patients that met our inclusion criteria in this review.2,4,6-83 Studies were published from 1986 to 2016 and were conducted in 23 countries, although more were from the United States.
We seek to collect, review, evaluate, and synthesize the current literature focusing on all published methods of pediatric weight estimation.
We conducted a literature review using PubMed and Web of Science databases, and the Google Scholar search engine, with the “similar articles” feature, as well as review of the bibliographies of identified studies. We excluded studies estimating weight of neonates, predominantly adults without separate information for children, child self-reported weight, and studies estimating outcomes other than weight. Quantitative outcomes of accuracy (proportion within 10% of actual weight), mean percentage error, and mean bias were preferred.
Eighty studies met inclusion criteria with predominant methods: parent or health care worker weight estimation, age-based formulae, and length-based estimation without (eg, Broselow) or with adjustment for body habitus (eg, Pediatric Advanced Weight-Prediction in the Emergency Room, Mercy). Parent estimation was the most accurate at predicting total (actual) body weight, with length-based methods with habitus adjustment next. Length-based methods outperformed age-based formulae, and both tended to underestimate the weight of children from populations with high obesity rates and overestimate the weight of children from populations with high malnourishment rates. Health care worker estimation was not accurate.
Parent estimation and length-based methods with adjustment for body habitus are the most accurate methods to predict children’s total (actual) body weight. Age-based formulae and length-based methods without habitus adjustment likely tend to predict ideal body weight.
Development of a Japanese scale for assessment of paediatric normal weight
2016, Resuscitation
Use of the broselow tape in a Mexican emergency department
2015, Journal of Emergency Medicine
Citation Excerpt :
Our findings are similar to more recent literature as well. To wit, in a study of 967 Kenyan children, House et al. found that the Broselow tape provided a valid estimate of weight, overestimating weight by a mean of only 2.2% and accurately predicting the correct color-zone 65.5% of the time, with the majority of misestimates of only one color zone (9). A study of South African children by Geduld et al. found that the Broselow tape estimated weight had a mean error of only 0.9% and was within 10% of the measured weight in 64.19% of subjects (10).
The Broselow tape is one method for rapid weight estimation in pediatric patients undergoing resuscitation, but it does not perform equally in all populations. To date, we are unaware of any study evaluating its use in a Latin American population.
To investigate the accuracy of the Broselow tape in a Mexican emergency department (ED).
We conducted a prospective, observational study of children presenting to a Mexican ED. Patient weight was estimated using the Broselow tape and the estimate compared to their weight measured on a scale. Researchers were blinded to scale weight and Broselow categories. For analysis, the Broselow tape's nine color zones were divided into three weight categories.
Of 815 subjects, 356 (43.7%) were female. In children weighing <10 kg, the tape tended to underestimate weight, whereas it overestimated weight in the other two weight categories. The mean percentage difference between the actual weight and the Broselow tape-predicted weight was <3% in each category, although it differed significantly across the three weight categories. Accuracy of the predicted weight to within 10% of actual weight was lowest for children weighing <10 kg, at 46.2% (confidence interval [CI] ± 6.4%), and greatest for those in the 10–18-kg weight category, at 64.1% (CI ± 5.1%). However, the correlation of color zones predicted by both methods was highest for subjects <10 kg at 64.4% (CI ± 6.1%). It was significantly lower in the other weight categories at 54.5% (CI ± 5.3) for subjects weighing 10–18 kg, and 50.1% (CI ± 6.4%) for subjects weighing >18 kg. The percentage of children for whom the color code differed by two or more categories was <4% overall and for each weight category.
The Broselow tape-estimated weight was different from the scale weight by more than 10% in a substantial percentage of Mexican children. Nevertheless, the mean percentage difference was <3%, and Broselow tape color zone estimation was accurate in the majority of subjects, suggesting its use would result in clinically appropriate dosing and equipment estimations. Further research is needed to validate its use in this clinical setting.

View all citing articles on Scopus

: Please see page 2 for the Editor's Capsule Summary of this article.

: Supervising editor: Kelly D. Young, MD, MS

: Author contributions: DRH developed the idea for study in Kenya with the mentorship of DER. EN and RCV helped with development of protocol, given experience in Kenya. DRH, EN, RCV, and DER supervised the conduct of the study and managed data collection. DRH and DER analyzed the data. DRH wrote article, with EN, RCV, and DER providing significant contribution to editing and approval of final draft. DRH takes responsibility for the paper as a whole.

: Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article as per ICMJE conflict of interest guidelines (see www.icmje.org). The authors have stated that no such relationships exist.

: Publication date: Available online August 31, 2012.

: A feedback survey is available with each research article published on the Web at www.annemergmed.com.

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Pediatrics/original researchEstimating the Weight of Children in Kenya: Do the Broselow Tape and Age-Based Formulas Measure Up?

Study objective

Methods

Results

Conclusion

Introduction

Section snippets

Study Design

Setting

Results

Limitations

Discussion

Ann Emerg Med

Ann Emerg Med

Br J Anaesth

Am J Emerg Med

Resuscitation

Are methods used to estimate weight in children accurate?

Emerg Med (Fremantle)

Evaluation of the accuracy of different methods used to estimate weights in the pediatric population

Pediatrics

Incidence of adverse drug events and potential adverse drug events: implications for prevention

JAMA

Errors by paediatric residents in calculating drug doses

Arch Dis Child

Incidence and nature of dosing errors in paediatric medications: a systematic review

Drug Saf

Effect of an intervention standardization system on pediatric dosing and equipment size determination: a crossover trial involving simulated resuscitation events

Arch Pediatr Adolesc Med

Emergency medical services system changes reduce pediatric epinephrine dosing errors in the prehospital setting

Pediatrics

A comparison of two commonly used methods of weight estimation

Arch Dis Child

Emergency weight estimation in Pacific Island and Maori children who are large-for-age

Emerg Med Australas

Use of the Broselow tape may result in the underresuscitation of children

Acad Emerg Med

Parental weight estimation of their child's weight is more accurate than other weight estimation methods for determining children's weight in an emergency department?

Emerg Med J

Accuracy of weight estimation methods for children

Pediatr Emerg Care

Pediatrics/original research
Estimating the Weight of Children in Kenya: Do the Broselow Tape and Age-Based Formulas Measure Up?