Size does matter--age-related weight estimation in "tall n' thin" and "tiny n' thick" children and a new habitus-adapted alternative to the EPLS-formula

Assessment of body weight from percutaneous widths of the bones and joints-Implications in forensic and clinical examinations

BACKGROUND

Estimation of age, stature, sex, and ancestry contributes to the establishment of the biological profile of the deceased in forensic examinations. Assessment of the body weight aids in the approximation of the overall body size of the individual which may help in the forensic identification process. In clinical examinations, body weight assessment assumes importance in cases where body weight measurement is a challenging task due to illness and body deformity.

OBJECTIVE

The present research was conducted to estimate the body weight from the percutaneous width of the bones and joints with the help of prediction equations.

METHODS

The study was carried out on 344 adults (172 Females and 172 Males) aged between 18 and 25 years from the Himachal Pradesh State of North India. Eleven anthropometric measurements including height vertex, mid-arm circumference, humerus bicondylar width, transverse chest breadth, sagittal chest breadth, bi-iliac breadth, handbreadth, femur bicondylar breadth, ankle breadth, foot breadth, and body weight were taken on each individual. The sex differences were evaluated by using independent student t-test and Mann-Whitney U test and the correlation between the body weight and the anthropometric variables was investigated by using both Karl Pearson's correlation coefficient and Spearman's rank correlation coefficient depending upon the normality of the data. Regression models for the estimation of body weight were calculated. Further, a validation study was carried out to check the accuracy and utility of the derived regression models by calculating the mean absolute percent prediction error (MAPPE).

RESULTS

Significant sex differences were observed among all the anthropometric variables. The transverse chest breadth and mid-arm circumference were strongly correlated with the body weight, whereas, a good correlation was also observed in other measurements except for the ankle breadth. The SEE (Standard error of estimate) of the derived linear regression models was compared, and it was found that multiple linear regression models show better accuracy than simple linear regression models. The MAPPE was found to be less in the case of multiple linear regression models than the linear ones.

CONCLUSION

The present investigation concludes that regression models can be used in the estimation of body weight from the percutaneous measurements and joint widths with reasonable accuracy in an Indian population.

The utility of pediatric age-based weight estimation formulas for emergency drug dose calculations in obese children

OBJECTIVES

In obese children, when drug therapy is required during emergency care, an estimation of ideal body weight is required for certain drug dose calculations. Some experts have previously speculated that age-based weight estimation formulas could be used to predict ideal body weight. The objectives of this study were to evaluate how accurately age-based formulas could predict ideal body weight and total body weight in obese children.

METHODS

Three age-based weight estimation formulas were evaluated in a secondary analysis, using a pooled sample of children from 3 academic emergency departments in South Africa. The estimates produced by the 3 formulas (and the PAWPER XL tape as a control) were compared against measured total body weight and ideal body weight. The percentages of estimates falling within 10% of the standard weight were used as the primary outcome measure (PW10).

RESULTS

This study included 1026 children. For ideal body weight estimations in obese children, the old Advanced Life Support formula, the new Advanced Life Support formula, and the Best Guess formula achieved PW10s (with 95% confidence intervals [CIs]) of 29% (27.2%, 30.8%), 41.4% (38.9%, 43.9%), and 48.3% (45.3%, 51.3%), respectively. For total body weight estimations, the formulas achieved PW10s of 3.6% (3.4%, 3.8%), 5.2% (4.9%, 5.5%), and 19.0% (17.8%, 20.2%). The PAWPER XL tape achieved an accuracy of ideal body weight estimation of 100% (93.9%, 100%) and total body weight estimation of 49.7% (46.7%, 52.7%) in obese children.

CONCLUSIONS

The age-based formulas were substantially less accurate at estimating total body weight and ideal body weight than existing length-based methods such as the PAWPER XL tape, and should not be used for this purpose.

Drug dosing errors in simulated paediatric emergencies - Comprehensive dosing guides outperform length-based tapes with precalculated drug doses

BACKGROUND

The accuracy of drug dosing calculations during medical emergencies in children has not been evaluated extensively. The objectives of this study were to evaluate the accuracy of drug dose calculations using the Broselow tape, the PAWPER XL tape plus its companion drug-dosing guide, a custom-designed mobile phone app and no drug-dosing aid (control group).

METHODS

This was a prospective study in which 32 emergency medicine volunteers participated in eight simulations of common paediatric emergency conditions, using children models. The participants used the three methods to estimate the children's weight and calculate drug doses. The accuracy of and time taken for the drug dose determinations were then evaluated for each of the methods.

RESULTS

The overall accuracy of drug dose determinations was extremely and potentially dangerously low in the control group in which no dosing guide was used as well as in the Broselow tape group (<20% of doses were correct). The accuracy was significantly higher with the PAWPER XL tape group and the mobile app group (47% and 31% respectively). The times taken to obtain the required information did not differ in a clinically meaningful magnitude.

CONCLUSIONS

Both an accurate weight estimation and a dosing guide with comprehensive information were necessary to produce an accurate prescription. The information on the Broselow tape was not sufficient for this purpose. The current guidelines recommending the use of tapes with limited information should be revised. The results from the comprehensive dosing guides were substantially better, but still had a lower proportion of accurate prescriptions than desirable. The role of training in every aspect of the emergency paediatric weight estimation and drug dosing procedure cannot be underestimated and should be routine in any environment where emergency care may be needed.

"Weighing Cam": A New Mobile Application for Weight Estimation in Pediatric Resuscitation

Objective: We evaluated the validity of a newly developed mobile application (i.e. the Weighing Cam) for pediatric weight estimation compared with that of the Broselow tape. Methods: We developed an application that estimates the weight of pediatric patients using a smartphone camera and displays the drug dosage, device size, and defibrillation energy on the screen of the smartphone. We enrolled a convenience sample of pediatric patients aged <16 years who presented at two pediatric emergency departments of two tertiary academic hospitals in South Korea. The pediatric patients' heights and weights were measured; then, one researcher estimated the weights using the application. Using the measured height, we determined the weight estimated by the Broselow tape. We compared the estimated measurements by determining the mean percentage error (MPE), mean absolute percentage error, root mean square percentage error, and percentages predicted within 10% and 20% of the actual. Results: In total, 480 patients were enrolled in 16 age categories, each with 15 males and 15 females of different ages. The Weighing Cam demonstrated a lower bias (mean difference: -1.98% [95% confidence interval -2.91% to -1.05%] for MPE) and a higher proportion of estimated weights within 10% of the actual weights than the Broselow tape (mean difference: 9.1% [95% confidence interval 3.0% to 15.1%]). The Weighing Cam showed better performance in terms of accuracy and precision than the Broselow tape in all subgroups stratified by age or body mass index percentile. Conclusions: The Weighing Cam may estimate pediatric patients' weights more accurately than the Broselow tape. The Weighing Cam may be useful for pediatric resuscitation in both prehospital and hospital settings.

How and Why Paediatric Weight Estimation Systems Fail - A Body Composition Study

Background Weight estimation during medical emergencies in children is essential, but fraught with errors if the wrong techniques are used, which may result in critical drug dosing errors. Individualised weight estimation is required to allow for accurate dosing in underweight and obese children in particular. This study was designed to evaluate the associations between weight estimations from different systems and body composition in order to establish how and why they may perform well or poorly. Methods A convenience sample of 332 children aged from one month to 16 years had weight estimations using four age-based formulas: the Broselow™ Pediatric Emergency Tape (Armstrong Medical Industries, Inc., Lincolnshire, IL), the Mercy Method, and the Pediatric Advanced Weight Prediction in the Emergency Room, Extra-large/Extra-long Tape (PAWPER XL) Tape. They also had an assessment of body composition using dual x-ray absorptiometry (DXA). The weight estimates were compared against total body weight (TBW), calculated ideal body weight (IBW), and DXA-measured fat-free mass (FFM). Analyses of associations between age, length, weight estimation outcomes, and body composition were performed. Results Age-based formulas were very inaccurate because of the erratic relationship between age and body composition. The Broselow tape estimated IBW well in obese children because of the strong relationship between length and fat-free mass. It predicted TBW poorly in underweight and obese children, however, because of the poor relationship between length and fat mass. The Mercy Method's performance was unrelated to body composition, but estimated TBW reasonably well and could not predict IBW or FFM. The PAWPER XL Tape's performance was the most closely associated with body composition and, therefore, achieved an acceptable accuracy for estimations of TBW, IBW, and FFM. Conclusions Of the systems evaluated, the PAWPER XL Tape has the best association with body composition and the most accurate estimations of TBW, IBW, and FFM.

Paediatric weight estimation by age in the digital era: optimising a necessary evil

BACKGROUND

Age-based weight estimation methods are regularly used in paediatric emergency medicine despite their well-established inaccuracy.

AIM

Determine the potential improvement in accuracy achievable by the use of a new mobile application, based on CDC/WHO weight-for-age centile data, which incorporates a gender assignment, a body habitus assessment, and which is capable of an age-in-months based calculation.

METHODS

A theoretical, simulated validation study, comparing the performance of the widely used APLS/EPALS formulae against two contemporary habitus-adjusted methods, and the Helix Weight Estimation Tool. 1,070,743 children from the 2015/2016 UK National Child Measurement Program dataset, aged between 4 and 5 and 11 and 12 years, had age-based weight estimates made by all five methods.

RESULTS

Primary outcomes were the percentage of weight estimations within 10%, 20%, and those greater than 20% discrepant from actual weight for each method. Our theoretical, gender-dependent, habitus-adjusted method performed better than all other methods across all error thresholds. The overall number of estimations within 10% was 70.4%, and within 20% was 95.45%. The mean percentage error was -1% compared to actual weight.

CONCLUSION

The use of a digital tool incorporating a subjective assessment of body habitus, gender assignment, and the ability to estimate weight based on age-in-months might be able optimise the process of paediatric weight estimation by age, making this practice as safe and accurate as possible for the occasions when weight estimation by age is chosen over length-based methods.

A systematic review and meta-analysis of the accuracy of weight estimation systems used in paediatric emergency care in developing countries

Introduction

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.

Methods

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.

Results

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%).

Conclusions

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.

The accuracy of emergency weight estimation systems in children-a systematic review and meta-analysis

The safe and effective administration of fluids and medications during the management of medical emergencies in children depends on an appropriately determined dose, based on body weight. Weight can often not be measured in these circumstances and a convenient, quick and accurate method of weight estimation is required. Most methods in current use are not accurate enough, but the newer length-based, habitus-modified (two-dimensional) systems have shown significantly higher accuracy. This meta-analysis evaluated the accuracy of weight estimation systems in children. Articles were screened for inclusion into two study arms: to determine an appropriate accuracy target for weight estimation systems; and to evaluate the accuracy of existing systems using standard meta-analysis techniques. There was no evidence found to support any specific goal of accuracy. Based on the findings of this study, a proposed minimum accuracy of 70% of estimations within 10% of actual weight (PW10 > 70%), and 95% within 20% of actual weight (PW20 > 95%) should be demonstrated by a weight estimation system before being considered to be accurate. In the meta-analysis, the two-dimensional systems performed best. The Mercy method (PW10 70.9%, PW20 95.3%), the PAWPER tape (PW10 78.0%, PW20 96.6%) and parental estimates (PW10 69.8%, PW20 87.1%) were the most accurate systems investigated, with the Broselow tape (PW10 55.6%, PW20 81.2%) achieving a lesser accuracy. Age-based estimates achieved a very low accuracy. Age- and length-based systems had a substantial difference in over- and underestimation of weight in high-income and low- and middle-income populations. A benchmark for minimum accuracy is recommended for weight estimation studies and a PW10 > 70% with PW20 > 95% is suggested. The Mercy method, the PAWPER tape and parental estimates were the most accurate weight estimation systems followed by length-based and age-based systems. The use of age-based formulas should be abandoned because of their poor accuracy.

A Comparative Study on the Results of Estimating Children's Weights Based on Arm Circumference, Height, and Body Habitus against Estimated Weight Broselow on 2-24 Months Children in Isfahan

Background:

Resuscitation of children in different treatment wards is a challenge. Given that the pediatric drug dosing is based on weight and weighing is not practical in emergency situations, it is critical to employ a fast, easy, and reliable technique. Hence, this study attempted to evaluate the real weight children against Broselow estimation.

Materials and Methods:

This cross-sectional study involved 1500 children of 2–24 months referred to Isfahan urban and rural health centers in 2015. Children's estimated weights were measured based on the standard Broselow tape and real weights through a digital scale. The factors such as age, sex, height, arm circumference, head circumference, and living place of children were recorded. The collected data were analyzed through independent t-test, ANOVA, and linear regression using SPSS (version 20).

Results:

The weight difference of children through Broselow estimation was 0.019 kg, and the correlation coefficient was 0.893 (P > 0.05). The difference sorted by age ranges was significant only in >12 months (P < 0.05). It was estimated at error of 10% to be 68.9% correctly. The mean weight estimation error was significant sorted by weight, sex, habitus, and living place of children (P < 0.001).

Conclusion:

Although Broselow tape has been proved to be accurate it led to a significant error at different age ranges. Hence, the present study estimated the age, arm circumference, and height of Iranian children based on new formulas providing more successful tool through controlling the confounding factors in estimating the real weight.

It is time to abandon age-based emergency weight estimation in children! A failed validation of 20 different age-based formulas

AIM

When children's weight cannot be measured during medical emergencies, it must be estimated, as weight is required for many interventions. Age-based formulas are the oldest weight estimation systems in children, but have been shown to be very inaccurate in many studies. This aim of this study was to evaluate the accuracy of age- and length-based formulas and to see if a measure of body habitus could be used to improve the performance of these formulas.

METHODS

This was an analysis of data from a sample of 1085 children aged from 1 month to 16 years, collected from four Emergency Departments in Johannesburg, South Africa. Basic demographic and anthropometric data was collected and each child had a visual assessment of body habitus, quantified as a habitus score. Weight estimates from 20 existing age-based formulas and two length-based formulas were then compared against measured weight to determine their accuracy. Age- and length-based, habitus-modified models were developed and similarly evaluated.

Estimating the weight of ethnically diverse children attending an Australian emergency department: a prospective, blinded, comparison of age-based and length-based tools including Mercy, PAWPER and Broselow

OBJECTIVE

To prospectively compare the actual weights of Australian children in an ethnically diverse metropolitan setting with the predicted weights using the Paediatric Advanced Weight Prediction in the Emergency Room (PAWPER) tape, Broselow tape, Mercy system and calculated weights using the updated Advanced Paediatric Life Support (APLS), Luscombe and Owens and Best Guess formulae.

METHODS

A prospective, cross-sectional, observational, blinded, convenience study conducted at the Children's Hospital at Westmead Paediatric Emergency Department in Sydney, Australia. Comparisons were made using Bland-Altman plots, mean difference, limits of agreement and estimated weight within 10% and 20% of actual weight.

RESULTS

199 patients were enrolled in the study with a mean actual weight of 27.2 kg (SD 17.2). Length-based tools, with or without body habitus adjustment, performed better than age-based formulae. When measuring estimated weight within 10% of actual weight, PAWPER performed best with 73%, followed by Mercy (69%), PAWPER with no adjustment (62%), Broselow (60%), Best Guess (47%), Luscombe and Owens (41%) and revised APLS (40%). Mean difference was similar across all methods ranging from 0.4 kg (0.0, 0.9) for Mercy to -2.2 kg (-3.5, -0.9) for revised APLS. Limits of agreement were narrower for the length-based tools (-5.9, 6.8 Mercy; -8.3, 5.6 Broselow; -9.0, 7.1 PAWPER adjusted; -12.1, 9.2 PAWPER unadjusted) than the age-based formulae (-18.6, 17.4 Best Guess; -19.4, 15.1 revised APLS, -21.8, 17.7 Luscombe and Owens).

CONCLUSION

In an ethnically diverse population, length-based methods with or without body habitus modification are superior to age-based methods for predicting actual body weight. Body habitus modifications increase the accuracy and precision slightly.