The accuracy of total body weight estimation in adults - A systematic review and meta-analysis.

BACKGROUND: Weight estimation is required in adult patients when weight-based medication must be administered during emergency care, as measuring weight is often impossible. Inaccurate estimations may lead to inaccurate drug doses, which may cause patient harm. Little is known about the relative accuracy of different methods of weight estimation that could be used during resuscitative care. The aim of this study was to evaluate the performance and suitability of existing weight estimation methods for use in adult emergency care. METHODS: A systematic literature search was performed for suitable articles that studied the accuracy of weight estimation systems in adults. The study characteristics, the quality of the studies, the weight estimation methods evaluated, the accuracy data, and any information on the ease-of-use of the method were extracted and evaluated. RESULTS: A total of 95 studies were included, in which 27 different methods of total body weight estimation were described, with 42 studies included in the meta-analysis. The most accurate methods, determined from the pooled estimates of accuracy (the percentage of estimates within 10% of true weight, with 95% confidence intervals) were 3-D camera estimates (88.8% (85.8 to 91.8%)), patient self-estimates (88.7% (87.7 to 89.7%)), the Lorenz method (77.5% (76.4 to 78.6%)) and family estimates (75.0% (71.5 to 78.6%)). However, no method was without significant potential limitations to use during emergency care. CONCLUSION: Patient self-estimations of weight were generally very accurate and should be the method of choice during emergency care, when possible. However, since alternative estimation methods must be available when confused, or otherwise incapacitated, patients are unable to provide an estimate, alternative strategies of weight estimation should also be available.

Estimating Lean Body Weight in Adults With the PAWPER XL-MAC Tape Using Actual Measured Weight as an Input Variable.

Introduction Accurate drug dose calculation in obese patients requires an estimation of lean body weight (LBW) for dosing hydrophilic medications. Inaccurate weight estimates during the management of critically ill obese adults may contribute to inaccurate drug doses and consequential poor outcomes. Existing methods of LBW estimation or measurement may be very difficult or impossible to use during emergency care. A point-of-care model that could provide rapid, accurate estimates of LBW would, therefore, be of significant clinical value. Methods A model was derived based using the adult version of the PAWPER XL-MAC tape. This derived model used recumbent length and measured total body weight (TBW) to estimate LBW. The derived model was used to generate LBW estimations in a random sample from National Health and Nutrition Examination Survey (NHANES) datasets (n=33,215). The benchmark outcome measure was to achieve >95% of LBW estimations within 20% of DXA-measured fat-free mass (P20>95%) and >70% of estimations within 10% of DXA-measured fat-free mass (P10>70%). Results The new model achieved a P20 of 99.7% and a P10 of 86.4% for LBW in the pooled sample and exceeded the minimum accuracy standards. This accuracy was maintained in both sexes, all ages, all ethnic groups, all lengths and in all habitus types. Conclusions The modified PAWPER XL-MAC model, using TBW as an input variable, proved to be an accurate method of LBW estimation. It could potentially have an important role in facilitating emergency drug dose calculations in critically ill or injured obese adult patients.

CT Utilization in a Level One Trauma Center in South Africa.

Introduction Computed tomography (CT) imaging forms an important component in the evaluation and management of patients with traumatic injuries. Many South African emergency departments (EDs) have a significant trauma-related workload, especially in the public sector, where there are limitations in resources relating to CT scanners. It is important to gauge the impact of traumatic injuries on CT utilization. The primary objectives were to quantify the number and type of CT imaging studies trauma patients received, as well as to determine the frequency of radiologically significant findings in a level one trauma center. The secondary objectives were to determine the CT utilization rate and describe the demographics of patients who received imaging. Methods This was a retrospective, quantitative, descriptive, cross-sectional study undertaken over two months at the level one trauma center of a tertiary, academic, public sector teaching hospital in Johannesburg, South Africa. The radiology department's picture archiving and communication system (PACS) was used to evaluate the reports of trauma patients who were referred for a CT scan. The trauma center register was used to calculate the CT utilization rate. Results There were 5,058 trauma patients seen in the two months. A total of 1,277 CT scans were performed on 843 patients. CT brain accounted for 52% of all scans performed. Radiologically significant findings were demonstrated in 407 scans (354 patients), i.e. 31.9% of scans and 42% of patients. CT chest and peripheral angiogram demonstrated radiologically significant findings in 60.5% and 50.9% of scans respectively. Assault accounted for 55.8% of the injuries sustained and road traffic accidents accounted for 33.2%. The overall CT utilization rate was 16.7% i.e. 843 out of the 5,058 trauma patients underwent a CT scan. Conclusions South Africa has a substantial trauma burden which commonly necessitates CT utilization. It is concerning that blunt and penetrating assault continues to dominate these traumatic presentations. Worldwide, there is a broad range of described CT utilization rates and the findings at this level one trauma center fall within that range. ED clinicians are encouraged to continue carefully using this scarce resource in the trauma setting.

Human Factor Errors in the use of the PAWPER Tape Systems: An Analysis of Inter-Rater Reliability.

Background International guidelines have promoted the use of length-based tapes for emergency weight estimation in children. This is primarily because of a perception that more modern methods might require more training than can practically be achieved. This study aimed to evaluate the inter-rater reliability of novice users of the PAWPER XL (paediatric advanced weight-prediction in the emergency room) tape as an indicator of the ability to use the device effectively with limited training. Methods This was a secondary analysis of unpublished data from three previous studies. Inter-rater reliability analyses were performed for each study for the accuracy of weight estimations and for the assignment of body habitus score. Inter-rater reliability was analysed using percentage agreement and Cohen's Kappa for Study 1 and intraclass correlation (ICC) for Study 2 and Study 3. A value of <0.7 was considered to indicate inadequate agreement, 0.7 to 0.89 was considered to indicate good agreement and ≥0.9 was considered to indicate excellent agreement. Main Results A total of 7034 data points were available for analysis in the three studies. In Study 1, the percentage agreement of an accurate weight estimation in 50 children, with two raters, was 47/50 (94%) with a Cohen's Kappa of 0.93 (0.81 - 1.0). In Study 2, the ICC for 6720 habitus score assessments, with 112 raters, was 0.73 (0.68 - 0.80). In Study 3, the ICC for 264 weight estimations (in terms of an accurate weight estimation, with 33 raters) was 0.88 (0.72 - 0.97). Conclusions There was good inter-rater reliability in the assessment of habitus and the accuracy of weight estimation for the PAWPER XL tape in this secondary analysis. The findings suggest that reasonable proficiency with the system can be achieved with minimal training. It is therefore unlikely that systems such as this require too much training to be practical in emergency care.

Using the Mercy Method to Estimate Ideal Body Weight in Children: A Description and Validation of a New Methodology.

Background In obese children, lipophilic medications should be dosed to total body weight (TBW) and hydrophilic medications to ideal body weight (IBW). During emergencies, these weights need to be estimated to ensure that urgent drug therapy is accurate and safe. The Mercy method is a well-established weight estimation system that has recently been adapted to provide estimations of body length in children. It was therefore conceivable that this could be further modified to provide estimations of IBW. Methods A model was developed a priori using the Mercy method's humeral length (HL) segments to predict IBW. The accuracy of this model was then tested in a sample of 13,134 children from the National Health and Nutrition Examination Survey (NHANES) datasets. The accuracy of IBW estimation was determined from the percentage of estimations falling within 10% (p10) and 20% (p20) of true IBW. The model was also tested to see the accuracy of the detection of obesity in the study sample. Results From the sample of 13,134 children, a subset of 1,318 obese children were identified. In this subset, the new Mercy method model achieved an IBW estimation accuracy p10 of 66.9% and a p20 of 95.1%. For the detection of the obese child, the model had a sensitivity of 88.6% and a specificity of 75.8%. Conclusions This study established that the Mercy method can be modified to provide a reasonably accurate estimation of IBW in obese children, with very few critical errors. The ability of the model to identify the obese child was also reasonably accurate, on a par with other such predictive methods. While other accurate methods of estimating both TBW and IBW exist, such as the Paediatric Advanced Weight Prediction in the Emergency Room eXtra-Long tape (PAWPER XL tape), the modified Mercy method is an acceptable alternative if such other devices are not available.

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.

Point-of-care Ultrasound Trumps Computed Tomography in a Case of Abdominal Aortic Aneurysm Assessment.

Patients who present to the emergency department (ED) with aortic emergencies can be some of the highest acuity patients that we manage. Ultrasonography performed at the bedside is traditionally considered to be a screening test that is especially useful in the unstable patient. Computed tomography (CT) with angiography is the imaging modality of choice to confirm the diagnosis and plan the management of abdominal aortic aneurysm (AAA), as an ultrasound is generally thought not to provide the clinician with sufficient anatomical information. We present a case of a patient with an abdominal aortic aneurysm where evidence obtained from the ultrasound provided more useful information regarding aneurysm structure and stability than did CT.

Smart watch-detected tachycardia: a case of atrial flutter.

The use of smart watches like the Apple watch and other wearable electronic devices by the general public has been increasing dramatically. Until their accuracy for detecting dysrhythmias has been well-established, however, it would not be appropriate to rely on them solely to rule-in or rule-out pathology. Nonetheless, unusual findings from these devices should be followed up with more conventional investigations, and this approach may prove highly beneficial to patients and treating clinicians alike. This case demonstrates a diagnosis of atrial flutter that was suspected based on the Apple watch and iPhone Health app findings.

Optimising emergency weight estimation in underweight and obese children: the accuracy of estimations of total body weight and ideal body weight.

OBJECTIVE: During medical emergencies, underweight and obese children are at a higher risk of weight-estimation errors than 'average' children, which may lead to poorer outcomes. In obese children, optimum drug dosing requires a measure of both total body weight (TBW) and ideal body weight (IBW) for appropriate scaling. We evaluated the ability of the Broselow tape, the Mercy method and the PAWPER XL tape to estimate TBW and IBW in obese and underweight children. PARTICIPANTS AND METHODS: Data for children aged 0-18 years were extracted and pooled from three previous weight-estimation studies. The accuracy of estimation of TBW and IBW by each method was evaluated using percentage of estimations within 10% of target weight (PW10) as the primary outcome measure. RESULTS: The Broselow tape estimated TBW poorly in obese and underweight children (PW10: 3.9 and 41.4%), but estimated IBW extremely accurately (PW10: 90.6%). The Mercy method estimated TBW accurately in both obese and underweight children (PW10: 74.3 and 76.3%) but did not predict IBW accurately (PW10: 14.3%). The PAWPER XL tape predicted TBW well (PW10: 73.0% in obese children and 74.9% in underweight children) and predicted IBW extremely accurately (PW10: 100%). CONCLUSION: The Broselow tape predicted IBW, but not TBW, accurately. The Mercy method estimated TBW very accurately, but not IBW. The PAWPER XL tape estimated both TBW and IBW accurately. The PAWPER XL tape should be considered when choosing a weight-estimation strategy for obese and underweight children.

A retrospective analysis of time delays in patients presenting with stroke to an academic emergency department.

BACKGROUND: Stroke presents commonly to the emergency department (ED), and is a common cause of morbidity and mortality in South Africa. Early ED presentation and early neuroimaging are required in order for thrombolysis to be a potential therapeutic modality. OBJECTIVES: To determine the time to ED presentation, time to computed tomography (CT) scan and the potential influencing factors for patients with stroke. METHODS: A retrospective record review of all patients who presented with clinical features of stroke to a tertiary academic ED in Johannesburg, South Africa, from 01 January to 31 December 2014. RESULTS: Data from 232 eligible stroke patients were analysed. The median time to presentation to the ED was 33 h with the majority of patients (81.3%) presenting after the 4.5 h window for thrombolysis. The median time to CT was 8 h. Only 3.9% of patients had a CT scan within one hour of arrival. Patients with loss of consciousness were associated with earlier hospital presentation (p = 0.001). None of the patients were thrombolysed. CONCLUSION: Patients with stroke commonly present late to hospital. If we are to make a difference in this group of vulnerable patients, further education and training needs to be emphasised regarding 'time is brain'. Communication and commitment is also required by the emergency medical services, ED and radiology staff in order to prioritise stroke patients and to reduce delays.

A retrospective analysis of time delays in patients presenting with stroke to an academic emergency department

Background: Stroke presents commonly to the emergency department (ED), and is a common cause of morbidity and mortality in South Africa. Early ED presentation and early neuroimaging are required in order for thrombolysis to be a potential therapeutic modality. Objectives: To determine the time to ED presentation, time to computed tomography (CT) scan and the potential influencing factors for patients with stroke. Methods: A retrospective record review of all patients who presented with clinical features of stroke to a tertiary academic ED in Johannesburg, South Africa, from 01 January to 31 December 2014. Results: Data from 232 eligible stroke patients were analysed. The median time to presentation to the ED was 33 h with the majority of patients (81.3%) presenting after the 4.5 h window for thrombolysis. The median time to CT was 8 h. Only 3.9% of patients had a CT scan within one hour of arrival. Patients with loss of consciousness were associated with earlier hospital presentation (p = 0.001). None of the patients were thrombolysed. Conclusion: Patients with stroke commonly present late to hospital. If we are to make a difference in this group of vulnerable patients, further education and training needs to be emphasised regarding 'time is brain'. Communication and commitment is also required by the emergency medical services, ED and radiology staff in order to prioritise stroke patients and to reduce delays