Can age-based estimates of weight be safely used when resuscitating children?

Variation in Prehospital Protocols for Pediatric Seizure Within the United States

OBJECTIVE

The objective of this study was to compare statewide prehospital protocols for the management of pediatric seizures.

METHODS

We performed a descriptive analysis comparing statewide protocols for emergency medical services management of pediatric seizures within the United States, excluding states for which no statewide protocol/model was available. We compared antiepileptic drugs (AEDs), routes and doses of administration, and differences in febrile seizure management.

RESULTS

Of 50 states, 34 had either statewide protocols or models and were included. All had a protocol for the management of seizures and provided specific recommendations for the management of pediatric seizures. Twelve states (35%) preferentially recommended midazolam over other benzodiazepines. Thirty-two (94%) of 34 allowed for use of midazolam, with variable use of other AEDs. All allowed for use of intramuscular AED. Twenty-six (77%) allowed for intranasal AED. Nine (27%) allowed emergency medical services to administer a patient's own abortive AED, and 6 (18%) allowed for use of a patient's vagal nerve stimulator, when present. There was a wide variability with respect to dosing ranges for medications. Thirty-two (94%) of 34 included blood glucose measurement within the protocol. Twenty-one protocols (62%) provided recommendations for febrile seizures, including recommending active/passive cooling (8/34, 24%) and antipyretic administration (9/34, 26%).

CONCLUSIONS

All statewide protocols carried specific guidelines for the prehospital management of pediatric seizures; however, there was wide variability with respect to specific AEDs, routes of administration, and drug dosages. In addition to broader availability of statewide guidance, areas of potential protocol improvement and research include AED dose optimization, reprioritization of blood glucose, and greater emphasis on intranasal or intramuscular medication dosing.

Paediatric weight estimation practices of advanced life support providers in Johannesburg, South Africa

INTRODUCTION

The choice of weight estimation method to use during prehospital paediatric emergency care is important because it needs to be both accurate and easy to use. Accuracy is important to ensure optimum drug dosing while ease-of-use is important to minimise user errors and the cognitive load experienced by healthcare providers. Little is known about which weight estimation systems are used in the prehospital environment anywhere in the world. This knowledge is important because if the use of inappropriate weight estimation practices is identified, it could be remedied through education and institutional policies.

METHODS

This was a prospective questionnaire study conducted in Johannesburg, South Africa, which obtained information on the knowledge, attitude and practice of weight estimation amongst advanced life support (ALS) paramedics.

RESULTS

Forty participants were enrolled, from both the public and private sectors. The participants' preferred method of weight estimation was visual estimation (7/40; 18%), age-based formulas (16/40; 40%), parental estimation (3/40; 8%), the Broselow tape (2/40; 5%) and the PAWPER tape (11/40; 28%). No participant was familiar with or used the Mercy method. All participants were very confident in the accuracy of their selected system.

DISCUSSION

The knowledge and understanding of weight estimation systems by many advanced life support paramedics was poor and the use of inappropriate weight estimation systems was common. Further education and intervention is needed in order to change the sub-optimal weight estimation practices of ALS paramedics in Johannesburg.

Accuracy of weight estimation by the Broselow tape is substantially improved by including a visual assessment of body habitus

BackgroundThe Broselow tape (BT) has been shown to estimate weight poorly primarily because of variations in body habitus. The manufacturers have suggested that a visual assessment of habitus may be used to increase its performance. This study evaluated the ability of habitus-modified models to improve the accuracy thereof.MethodsA post hoc analysis of prospectively collected data from four hospitals in Johannesburg, South Africa, on a population of 1,085 children. Sixteen a priori models generated a modified weight estimation or drug dose based on the BT weight and a gestalt assessment of habitus.ResultsThe habitus-modified method suggested by the manufacturer did not improve the accuracy of the BT. Five dosing and four weight-estimation models were identified that markedly improved dosing and weight estimation accuracy, respectively. The best dosing model improved dosing accuracy (doses within 10% of correct dose) from 52.0 to 69.6% and reduced critical dosing errors from 16.5 to 4.3%. The best weight-estimation model improved accuracy from 59.4 to 81.9% and reduced critical errors from 11.8 to 1.9%.ConclusionThe accuracy of the BT as a drug-dosing and weight-estimation device can be substantially improved by including an appraisal of body habitus in the methodology.

A Comparison of the Performance of Different Age-Based Paediatric Weight Estimation Formulae in Hong Kong Children

Objective

To evaluate the performance of five existing age-based weight estimation formulae - the original and updated Advanced Paediatric Life Support (APLS) formulae, Luscombe formula, Best Guess formula, Chinese Age Weight Rule (CAWR) - as well as a new two-part weight estimation formula, the Chinese Age Weight Rule-3 (CAWR-3), in Hong Kong children presenting to the emergency department (ED).

Methods

Data based on children aged 1-12 who presented to the ED of a tertiary referral centre in Hong Kong over a six-month period. Actual weight was compared against estimated weight from the weight estimation formulae. Level of agreement was assessed by Bland-Altman analysis using mean percentage difference (MPD) and 95% limits of agreement (LOA). Root mean squared error (RMSE) and proportions of weight estimates within 10%, 15% and 20% of actual weight were calculated.

Results

A total of 4600 children were included. The CAWR-3 outperformed the five existing weight estimation formulae. The CAWR-3 had the least MPD in age 4-12 (MPD +3.2%), as well as the second least MPD in age 1-12 (MPD -0.7%). The CAWR-3 had narrowest 95% LOA in age 1-3 (95% LOA -32.6% to 21.9%) and the second narrowest 95% LOA in age 1-12 (95% LOA -37.5% to 36.1%). The CAWR-3 had the smallest RMSE of 6.33 kg in age 4-12 and the smallest RMSE of 4.90 kg in age 1-12. Furthermore, the CAWR-3 had the highest proportion of weight estimates within 10%, 15% and 20% of actual weight.

Conclusion

The CAWR-3 outperforms the five existing age-based weight estimation formulae in Hong Kong children presenting to the emergency department.

The accuracy of the Broselow tape as a weight estimation tool and a drug-dosing guide - A systematic review and meta-analysis

AIMS

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.

METHODS

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.

MAIN RESULTS

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.

CONCLUSIONS

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.

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.

Validity of Broselow tape for estimating weight of Indian children

BACKGROUND & OBJECTIVES

The Broselow tape has been validated in both ambulatory and simulated emergency situations in the United States and is believed to reduce complications arising from inaccurate drug dosing and equipment sizing in paediatric population. This study was conducted to determine the relationship between the actual weight and weight determined by Broselow tape in the Indian children and to derive an equation for determination of weight based on height in the Indian children.

METHODS

This cross-sectional study was conducted at a tertiary care hospital in Mumbai, India. The participants' weights were divided into three groups <10 kg, 10-18 kg and >18 kg with a total sample size estimated to be 210 (70 in each group). Using the tape, the measured weight was compared to Broselow-predicted weight and percentage weight was calculated. Accuracy was defined as agreement on Broselow colour-coded zones, as well as agreement within 10 per cent between the measured and Broselow-predicted weights. The resulting data were compared with weights estimated by advanced paediatric life support (APLS) and updated APLS formulae using Pearson's correlation coefficient.

RESULTS

The mean percentage differences were -11.78, -17.09 and -14.27 per cent for <10, 10-18 and >18 kg weight-based groups, respectively. The Broselow colour-coded zone agreement was 33.3 per cent in children weighing <10 kg, but only 7.4 per cent in the 10-18 kg group and 33.9 per cent in the >18 kg group. Agreement within 10 per cent was 53.13 per cent for the <10 kg group, but only 21.08 per cent for the 10-18 kg group and 33.9 per cent for the >18 kg group. Application of 10 per cent weight correction factor improved the percentages to 79.2 per cent for the <10 kg category, to 55.70 per cent for the 10-18 kg group and to 61.0 per cent for the >18 kg group. The correlation coefficient between actual weight and weights estimated by Broselow tape (r=0.89) was higher than that between actual weight and weight estimated by APLS method or updated APLS formulae (r=0.68) in 12-60 months age group as well as in >60 months age group (r=0.76).

INTERPRETATION & CONCLUSIONS

Broselow weight overestimated weight by >10 per cent in majority of Indian children. The weight overestimation was greater in children belonging to over 18 and 10-18 kg weight groups. Applying 10 per cent weight correction factor to the Broselow-predicted weight may provide a more accurate estimation of actual weight in children attending public hospital. Weights estimated using Broselow tape correlated better with actual weights than those calculated using APLS and updated APLS formulae.

The Broselow and Handtevy Resuscitation Tapes: A Comparison of the Performance of Pediatric Weight Prediction

OBJECTIVES

To assess the performance of two pediatric length-based tapes (Broselow and Handtevy) in predicting actual weights of US children.

METHODS

In this descriptive study, weights and lengths of children (newborn through 13 years of age) were extracted from the 2009-2010 National Health and Nutrition Examination Survey (NHANES). Using the measured length ranges for each tape and the NHANES-extracted length data, every case from the study sample was coded into Broselow and Handtevy zones. Mean weights were calculated for each zone and compared to the predicted Broselow and Handtevy weights using measures of bias, precision, and accuracy. A sub-sample was examined that excluded cases with body mass index (BMI)≥95th percentile. Weights of children longer than each tape also were examined.

RESULTS

A total of 3,018 cases from the NHANES database met criteria. Although both tapes underestimated children's weight, the Broselow tape outperformed the Handtevy tape across most length ranges in measures of bias, precision, and accuracy of predicted weights relative to actual weights. Accuracy was higher in the Broselow tape for shorter children and in the Handtevy tape for taller children. Among the sub-sample with cases of BMI≥95th percentile removed, performance of the Handtevy tape improved, yet the Broselow tape still performed better. When assessing the weights of children who were longer than either tape, the actual mean weights did not approximate adult weights; although, those exceeding the Handtevy tape were closer.

CONCLUSIONS

For pediatric weight estimation, the Broselow tape performed better overall than the Handtevy tape and more closely approximated actual weight. Lowe CG , Campwala RT , Ziv N , Wang VJ . The Broselow and Handtevy resuscitation tapes: a comparison of the performance of pediatric weight prediction. Prehosp Disaster Med. 2016;31(4):364-375.

Review of commonly used age-based weight estimates for paediatric drug dosing in relation to the pharmacokinetic properties of resuscitation drugs

AIM

To study which weight estimate calculation used in paediatric resuscitation results in optimal drug dosing; Advanced Paediatric and Life Support (APLS) or the UK Resuscitation Council age-based formula.

METHOD

Commonly used drugs used in paediatric resuscitation were selected and a literature search conducted for each drug's pharmacokinetic properties, concentrating on the volume of distribution (Vd). Hydrophobic drugs have a higher Vd than hydrophilic drugs as they distribute preferentially to fat mass (FM). The larger the Vd, the higher the initial dose required to achieve therapeutic plasma concentrations. Actual body weight (ABW) estimates are a good indicator of Vd for hydrophobic drugs as they correlate well with FM. Ideal body weight (IBW) estimates may be a better indicator of Vd for hydrophilic drugs, as they correlate better with lean body mass. This highlights potential variation between ABW and IBW, which may result in toxic or sub-therapeutic dosing.

RESULTS

The new APLS formulae give higher estimates of expected weight for a wider age range. This may be a more accurate reflection of ABW due to increasing prevalence of obesity in children. The UK Resuscitation Council's formula appears to result in a lower estimate of weight, which may relate more closely to IBW.

CONCLUSION

The main drugs used in paediatric resuscitation are hydrophilic, thus the APLS formulae may result in too much being given. Therefore the UK Resuscitation Council's single formula may be preferred. In addition, a single formula may minimize error in the context of a child of unknown weight requiring administration of emergency resuscitation drugs.

Emergency weight estimation in Aboriginal and Torres Strait Islander children in the Northern Territory: are the current methods accurate?

OBJECTIVE

During a paediatric emergency, it is often impractical to weigh a child. Many resuscitative measures require a child's weight; therefore, estimation is often used. Different methods are available to do this, usually based on a child's age or length. The accuracy of these methods has not been validated in Aboriginal and Torres Strait Islander children from remote communities. The objective of this study was to determine how well these paediatric emergency weight estimation methods predict weight for this group of children.

METHOD

A retrospective descriptive study using the measured weights and heights of Aboriginal and Torres Strait Islander children from remote locations across the Northern Territory (NT) was used. The weight estimation methods chosen to evaluate were the APLS, 'Best Guess', Luscombe and Nelson's formulae, Argall's modification, the Broselow® and Sandell® tapes, and the World Health Organization standard reference growth charts. Adjusted R-squared values for each method are reported, and agreement was measured in terms of mean percentage error (MPE).

RESULTS

A total of 2102 children were included. The length-based methods performed the best. The Broselow Tape had the highest adjusted R-squared value at 0.8886 in all age groups. The APLS, Luscombe and Argall's methods were the worst performing methods. The Broselow® Tape was also the best performing in terms of accuracy and precision, with an MPE of -0.35% (95% CI -0.82-0.1).

CONCLUSION

Our data support the use of the Broselow® Tape as the recommended method when estimating weight in an emergency for remote Aboriginal and Torres Strait Islander children in the NT for the 0-5 year age group.

CORKSCREW 2013 CORK study of children's realistic estimation of weight

BACKGROUND

In a resuscitation situation involving a child (age 1-15 years) it is crucial to obtain a weight as most interventions and management depend on it. The APLS formula, '2×(age+4)', is taught via the APLS course and is widely used in Irish hospitals. As the prevalence of obesity is increasing the accuracy of the formula has been questioned and a newer formula has been suggested, the Luscombe and Owens (LO) formula, '(3×age)+7'.

AIMS AND OBJECTIVES

To gather data on the weights and ages of the Cork paediatric population (ages 1-15 years) attending services at the Cork University Hospital (CUH), and to identify which of the two age-based weight estimation formulae has best diagnostic accuracy.

SETTING

CUH, Ireland's only level one trauma centre.

METHODS

Retrospective data collection from charts in the Emergency Department, Paediatric Assessment Unit and the Paediatric wards of CUH.

RESULTS

3155 children aged 1-15 years were included in the study. There were 1344 girls and 1811 boys. The formula weight='2×(age+4)' underestimated children's weights by a mean of 20.3% (95% CI 19.7% to 20.9%) for the ages of 1-15 years. The LO formula weight='(3×age)+7' showed a mean underestimation of 4.0% (95% CI 3.3% to 4.6%) for the same age range.

CONCLUSIONS

The LO formula has been validated in several studies and proven to be a superior age-based weight estimation formula in many western emergency departments. This study shows that the LO formula leads to less underestimation of weights in Irish children than the APLS formula. It is a simple, safe and more accurate age-based estimation formula that can be used over a large age range (1-15 years).