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.

Lack of patient and primary care physician follow-up in geriatric emergency department patients with head trauma from a fall.

STUDY OBJECTIVE: Falls are the leading cause of injuries in the US for older adults. Follow-up after an ED-related fall visit is essential to initiate preventive strategies in these patients who are at very high risk for recurrent falls. It is currently unclear how frequently follow-up occurs and whether preventive strategies are implemented. Our objective is to determine the rate of follow-up by older adults who sustain a fall related head injury resulting in an ED visit, the rate and type of risk assessment and adoption of preventive strategies. METHODS: This 1-year prospective observational study was conducted at two South Florida hospitals. All older ED patients with an acute head injury due to a fall were identified. Telephone surveys were conducted 14 days after ED presentation asking about PCP follow-up and adoption of fall prevention strategies. Clinical and demographic characteristics were compared between patients with and without follow up. RESULTS: Of 4951 patients with a head injury from a fall, 1527 met inclusion criteria. 905 reported follow-up with their PCP. Of these, 72% reported receiving a fall assessment and 56% adopted a fall prevention strategy. Participants with PCP follow-up were significantly more likely to have a history of cancer or hypertension. CONCLUSION: Only 60% of ED patients with fall-related head injury follow-up with their PCP. Further, 72% received a fall assessment and only 56% adopted a fall prevention strategy. These data indicate an urgent need to promote PCP fall assessment and adoption of prevention strategies in these patients.

Low Incidence of Delayed Intracranial Hemorrhage in Geriatric Emergency Department Patients on Preinjury Anticoagulation Presenting with Blunt Head Trauma.

BACKGROUND: Delayed intracranial hemorrhage (ICH) after head injury in older patients taking anticoagulants has been reported to be as high as 7.2%. Other studies suggest much lower rates. Its incidence and clinical management are controversial, with some recommending observation and repeat head imaging at 24 h. OBJECTIVE: Our study aims to assess the incidence of delayed ICH in geriatric Emergency Department (ED) head trauma patients prescribed preinjury anticoagulants. METHODS: We performed a prospective cohort study conducted at two hospital EDs from August 2019 to July 2020. All patients aged 65 years or older with acute head injury were eligible for enrollment. We conducted telephone follow-up at 14 and 60 days, and a chart review at 90 days. The primary study outcome was incidence of delayed ICH, which was defined as an initial negative head computed tomography scan followed by subsequent ICH believed to be caused by the initial traumatic event. We compared the rates of delayed ICH between patient cohorts based on anticoagulant use. RESULTS: There were 3425 patients enrolled: 2300 (67.2%) were not on an anticoagulant, 249 (7%) were on preinjury warfarin, 780 (22.7%) were on a direct-acting oral anticoagulant, and 96 (2.8%) were on enoxaparin or heparin. The median age was 82 years (interquartile range 65-107), the majority were female (55.2%), and almost all were Caucasian (84.3%). An acute ICH was identified in 229 of 3425 (6.7%, 95% confidence interval 6-8%) and delayed ICH in 13 (0.4%, 95% confidence interval 0.2-0.6%). There were no differences in rates of delayed ICH between those who had been prescribed anticoagulants vs. those who had not (p = 0.45). CONCLUSIONS: The incidence of delayed ICH is very low in older ED head trauma patients on prescribed pre-injury anticoagulants. Our data have important clinical implications for the management of blunt head trauma among older ED patients on anticoagulants.

Development and validation of a length- and habitus-based method of total body weight estimation in adults.

BACKGROUND: Erroneous weight estimation during the management of emergency presentations in adults may contribute to patient harm and poor outcomes. Patients can often not be weighed during emergencies and a weight estimation is required to facilitate weight-based therapies. Many existing methods of weight estimation are either unacceptably inaccurate or very difficult to use during the provision of emergency care. METHODS: The weight estimation system developed in this study was based on and modified from the PAWPER XL-MAC method, a pediatric weight estimation system that uses recumbent length and mid-arm circumference (MAC) to predict total body weight. This model was validated in the 2015-2018 National Health and Nutrition Examination Survey (NHANES) datasets. The primary outcome measure was to achieve >95% of estimations within 20% of measured weight (P20 > 95%). RESULTS: The modified PAWPER XL-MAC model achieved a P20 of 96.0% and a P10 of 71.3% in the validation dataset (N = 11,520). This accuracy (P20 > 95%) was maintained in both sexes, all ages, all ethnic groups, all lengths and in all habitus-types, except for the subgroup of severely obese individuals. CONCLUSIONS: The modified PAWPER XL-MAC model proved to be a very accurate method of weight estimation. It is more accurate than most other published reports of existing methods of weight estimation, except for patients' own estimations. It therefore could have a role in facilitating emergency drug dose calculations, if prospective studies bear out the accuracy found in this study.

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.

The Use of Body Habitus Reference Images Improves the Ability of Novices to Accurately Estimate Children's Weight Using the PAWPER XL Tape System.

BACKGROUND: The original methodology of the PAWPER (Pediatric Advanced Weight Prediction in the Emergency Room) tape relies on a gestalt visual assessment of a child's body habitus to adjust a length-based weight estimation. This assessment is dependent on the user's subjective opinion, which may result in aberrations in accuracy between users and populations. With the development of the second-generation PAWPER XL tape, a more objective method of habitus evaluation was desired. OBJECTIVE: The aim of this study was to evaluate a new, more objective figural reference image system and a new checklist system for quantifying body habitus. METHODS: Volunteers were asked to assess the body habitus score of 90 children from a sequence of photographic images using the standard gestalt visual assessment system, a new checklist system, and a system using figural reference images. PAWPER XL tape weight estimations were generated from these scores, which were compared between the three test groups. Participants were also surveyed on their preferences for the different methodologies. RESULTS: There were 11,505 habitus score assessments from 138 doctor, nurse, and paramedic participants. The figural reference image system significantly outperformed the checklist system and the gestalt visual assessment system in terms of weight estimation accuracy, achieving 70.9%, 61.1%, and 60.9% of estimations within 10% of measured weight, respectively. The participants expressed a strong subjective preference for the image system because of speed of use, ease of use, perceived accuracy, objectivity, and low cognitive load. CONCLUSIONS: The figural reference image system was objectively much more accurate than, and subjectively preferable to, the original gestalt visual estimation methodology.

Ultrasound evaluation of the respiratory changes of the inferior vena cava and axillary vein diameter at rest and during positive pressure ventilation in spontaneously breathing healthy volunteers.

INTRODUCTION: Ultrasound assessment of the inferior vena cava (IVC) has gained favour in aiding fluid management decisions for controlled, mechanically ventilated patients as well as in non-mechanically ventilated, spontaneously breathing patients. Its utility in spontaneously breathing patients during positive pressure non-invasive ventilation has not yet been determined. The use of the axillary vein, as an alternative option to the IVC due to its ease of accessibility and independence from intra-abdominal pressure, has also not been evaluated. The aim of this study was to assess respiratory variation in IVC and axillary vein diameters in spontaneously breathing participants (Collapsibility Index) and with the application of increasing positive end-expiratory pressure (PEEP) via positive pressure non-invasive ventilation (Distensibility Index). METHODS: The IVC and axillary vein diameters of 28 healthy adult volunteers were measured, using ultrasound, at baseline and with increasing PEEP via non-invasive ventilation. The Collapsibility Index and Distensibility Index of these vessels were calculated and compared for each vessel. The association between increasing PEEP levels and the indices was evaluated. RESULTS: Positive pressure delivered via non-invasive ventilation produced a similar degree of diameter change in the IVC and the axillary vein, that is, the Distensibility Index was similar whether measured in the IVC or the axillary vein (P=0.21, 0.47 and 0.17 at baseline, 5 and 10 cmH2O PEEP, respectively). Individual study participants' IVC and axillary veins, however, had variable responses to PEEP; that is, there appeared to be no consistent relationship between PEEP and the diameter changes. CONCLUSION: While the axillary vein could potentially be used as an alternative vessel to the IVC to assess for volume responsiveness in controlled, mechanically ventilated patients as well as in non-mechanically ventilated, spontaneously breathing patients, neither vein should be used to guide fluid management decisions in spontaneously breathing patients during positive pressure non-invasive ventilation.

Emergency department noise: mental activation or mental stress?

BACKGROUND: Healthcare professionals working in emergency medicine are often exposed to noisy environments. We determined if there is any difference in cognitive task performance required for clinical decision-making of healthcare professionals in a quiet compared with noisy environment and to assess the subjective experience of participants with regard to performance in a noisy environment. METHODS: This was a prospective cross-over study conducted at three academic hospitals in Johannesburg, South Africa. 41 doctors involved in the emergency management of patients were administered six matched and prevalidated medical questions over a 30-min period. Each doctor completed half of the questions with exposure to ambient noise (range 40-52 dB(A)) and the other half with exposure to pre-recorded background emergency department noise at 80-85 dB(A). The questions were completed in alternating quiet and noise: half of the physicians answered the odd questions in noise and half answered even numbered questions in noise. Each question was scored out of 10 and the time taken to complete each question was recorded. RESULTS: Overall median test scores in quiet and noise were 18.5/30 and 20/30 (p=0.2), respectively; time for test completion was longer in quiet (836 s in quiet and 819 s in noise (p=0.006)). While there was no statistically significant difference in task performance, 65% of the doctors found the noise distracting with 88% experiencing varying degrees of stress. CONCLUSIONS: Performance of mental tasks is maintained during noise exposure but noise exposure is associated with significant degrees of self-reported distress.

Total body weight estimation by 3D camera systems: Potential high-tech solutions for emergency medicine applications? A scoping review.

Background: Weight estimation is required in adult patients when weight-based medication must be administered during emergency care, as measuring weight is often not possible. Inaccurate estimations may lead to inaccurate drug dosing, which may cause patient harm. High-tech 3D camera systems driven by artificial intelligence might be the solution to this problem. The aim of this review was to describe and evaluate the published literature on 3D camera weight estimation methods. Methods: A systematic literature search was performed for articles that studied the use of 3D camera systems for weight estimation in adults. Data on the study characteristics, the quality of the studies, the 3D camera methods evaluated, and the accuracy of the systems were extracted and evaluated. Results: A total of 14 studies were included, published from 2012 to 2024. Most studies used Microsoft Kinect cameras, with various analytical approaches to weight estimation. The 3D camera systems often achieved a P10 of 90% (90% of estimates within 10% of actual weight), with all systems exceeding a P10 of 78%. The studies highlighted a significant potential for 3D camera systems to be suitable for use in emergency care. Conclusion: The 3D camera systems offer a promising method for weight estimation in emergency settings, potentially improving drug dosing accuracy and patient safety. Weight estimates were satisfactorily accurate, often exceeding the reported accuracy of existing weight estimation methods. Importantly, 3D camera systems possess characteristics that could make them very appropriate for use during emergency care. Future research should focus on developing and validating this methodology in larger studies with true external and clinical validation.

Alcohol use is associated with intracranial hemorrhage in older emergency department head trauma patients.

Objectives: Falls are common in adults aged 65 years and older and are the leading cause of traumatic brain injuries in this age group. Alcohol use may increase the risk of falls as well as the severity of resultant injuries. The aim of this study was to examine the association between self-reported alcohol use and the prevalence of intracranial hemorrhage (ICH) in this patient group. Methods: This was a secondary analysis of the Geriatric Head Trauma Short Term Outcomes Project (GREAT STOP), a study of older adults with blunt head trauma from a fall. We determined the characteristics of every fall event, including patient demographics and medical history, and clinical signs and symptoms related to head trauma. Self-reported alcohol use was categorized as none, occasionally, weekly, or daily. We defined ICH as any acute ICH detected by computed tomography scan. We evaluated the association between alcohol use frequency and ICH, adjusted for patient factors and head injury risk factors. Results: Of 3128 study participants, 18.2% (n = 567) reported alcohol use: 10.3% with occasional use, 1.9% with weekly use, and 6.0% with daily use. ICH was more common in patients who used alcohol (20.5%, 22.0%, and 25.1% for occasional, weekly, and daily alcohol users, respectively, vs. 12.0% for non-users, p < 0.001). The frequency of alcohol use was independently associated with ICH, adjusted for patient and head injury risk factors. The adjusted odds ratios (with 95% confidence intervals) for occasional, weekly, and daily alcohol users increased from 2.0 (1.5‒2.8) to 2.1 (1.1‒4.1) and 2.5 (1.7‒3.6), respectively, and showed the characteristics of dose‒response effect. Conclusions: Alcohol use in older adult emergency department patients with head trauma is relatively common. Self-reported alcohol use appears to be associated with a higher risk of ICH in a dose-dependent fashion. Fall prevention strategies may need to consider alcohol mitigation as a modifiable risk factor.

The Florida Geriatric Head Trauma CT Clinical Decision Rule.

BACKGROUND: Several clinical decision rules have been devised to guide head computed tomography (CT) use in patients with minor head injuries, but none have been validated in patients 65 years or older. We aimed to derive and validate a head injury clinical decision rule for older adults. METHODS: We conducted a secondary analysis of an existing dataset of consecutive emergency department (ED) patients >65 years old with blunt head trauma. The main predictive outcomes were significant intracranial injury and Need for Neurosurgical Intervention on CT. The secondary outcomes also considered in the model development and validation were All Injuries and All Intracranial Injuries. Predictor variables were identified using multiple variable logistic regression, and clinical decision rule models were developed in a split-sample derivation cohort and then tested in an independent validation cohort. RESULTS: Of 5776 patients, 233 (4.0%) had significant intracranial injury and an additional 104 (1.8%) met CT criteria for Need for Neurosurgical Intervention. The best performing model, the Florida Geriatric Head Trauma CT Clinical Decision Rule, assigns points based on several clinical variables. If the points totaled 25 or more, a CT scan is indicated. The included predictors were arrival via Emergency Medical Services (+30 points), Glasgow Coma Scale (GCS) <15 (+20 points), GCS <14 (+50 points), antiplatelet medications (+17 points), loss of consciousness (+16 points), signs of basilar skull fracture (+50 points), and headache (+20 points). Utilizing this clinical decision rule in the validation cohort, a point total ≥25 had a sensitivity and specificity of 100.0% (95% CI: 96.0-100) and 12.3% (95% CI: 10.9-13.8), respectively, for significant intracranial injury and Need for Neurosurgical Intervention. CONCLUSIONS: The Florida Geriatric Head Trauma CT Clinical Decision Rule has the potential to reduce unnecessary CT scans in older adults, without compromising safe emergency medicine practice.

Weight Estimation for Drug Dose Calculations in the Prehospital Setting - A Systematic Review.

BACKGROUND: Weight estimation is required to enable dose calculations for weight-based drugs administered during emergency care. The accuracy of the estimation will determine the accuracy of the administered dose. This is an important matter of patient safety. The objective of this systematic review was to collect, review, evaluate, and create a synthesis of the current literature focusing on the accuracy of weight estimation in the prehospital environment. METHODS: This systematic review followed the PRISMA guidelines. Studies were identified and included if they were peer reviewed, full length, published in English, and contained original data. Studies utilizing any form of weight estimation methodology in the prehospital setting (in children or adults) were included. Data on the quality of the studies and accuracy of the weight estimation systems were extracted. Common themes were also identified. RESULTS: Twenty-five studies met the inclusion criteria, with only nine studies (36.0%) containing useful weight estimation accuracy data. The overall quality of the studies was poor. The Broselow tape and paramedic estimates were the most studied methods of weight estimation, but there was insufficient evidence to support conclusions about accuracy. The major themes identified included the importance of accurate weight estimation and drug dosing as critical matters of patient safety, and the need for training to ensure these processes are performed accurately. CONCLUSIONS: There were limited robust data identified on the accuracy of different weight estimation methods used in the prehospital setting. Future high-quality clinical research in this area is of critical importance to ensure patient safety in the prehospital environment.

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.

An observational simulation-based study of the accuracy of intercostal drain placement and factors influencing placement.

Introduction: South Africa's significant burden of trauma and respiratory disease requires the regular need for intercostal drain (ICD) insertion. ICD misplacement is associated with significant complications. The aim of this study was to assess ICD insertion site accuracy and the factors affecting accuracy by Emergency Department doctors. Methods: This was a prospective, observational simulation-based study. Prior to participant admission, pertinent thoracic structures were marked on two simulated patients using an invisible marker which could only be seen using ultraviolet light. One by one, study participants were then asked to place a sticker on each side of each patient's chest to indicate where they would insert an ICD. Sticker placements were photographed under ultraviolet light. Placement sites were compared according to the most appropriate and accurate position for insertion (within the area superior to the 6th rib, posterior to pectoralis major and 1cm anterior to the mid-axillary line) as well as the British Thoracic Society's 'triangle of safety'. Comparisons of accuracy were made between participant rank (junior vs senior doctor), participant experience, simulated patient BMI category and placement side. Results: Insertion site was accurate in 47% of placements and within the 'triangle of safety' in 51% of placements. Improved accuracy was associated with greater participant experience (61% vs. 37%, p<0.01), and left-sided chest placement (54% vs 40%, p = 0.02). No difference was found when comparing simulated patient BMI category (low vs high, 43% vs 51%, p=0.18) or participant rank (junior vs senior, 41% vs 51%, p=0.10). Conclusion: Overall accuracy of ICD insertion site was low, and appropriate accuracy was only associated with greater participant experience and left sided placement. Further studies to determine methods to improve ICD placement accuracy are needed.

Development and Validation of a Length- and Habitus-Based Method of Ideal and Lean Body Weight Estimation for Adults Requiring Urgent Weight-Based Medical Intervention.

BACKGROUND AND OBJECTIVE: Accurate drug dosing in obese patients requires an estimation of ideal body weight (IBW) or lean body weight (LBW) for dosing hydrophilic medications. Erroneous weight estimates during the management of adults requiring weight-based treatment may contribute to poor outcomes. Existing methods of IBW and LBW estimation or measurement are very difficult to use during emergency care. A new point-of-care model would be useful to provide rapid estimates of IBW and LBW for this purpose. METHODS: A model was derived based on the PAWPER XL-MAC tape, a pediatric weight estimation system which uses recumbent length and mid-arm circumference to estimate IBW and LBW. The new adult model was used to generate IBW and LBW estimations for a derivation sample (n = 33155) and a validation sample (n = 5926) from National Health and Nutrition Examination Survey (NHANES) datasets. The model was developed in two steps, with calibration at each step, before being validated on an unused dataset. The outcome measure was to achieve >95% of IBW and LBW estimations within 20% of recognized reference standards (P20 > 95%) and >70% of estimations within 10% of these standards (P10 > 70%). RESULTS: The new model achieved a P20 of 100% and a P10 of 99.9% for IBW and a P20 of 98.3% and a P10 of 78.3% for LBW. This accuracy was maintained in both sexes, all ages, all ethnic groups, all lengths, and in all habitus types, except for the severely obese female subgroup. CONCLUSIONS: The modified PAWPER XL-MAC model proved to be an accurate method of IBW and LBW estimation. It could, therefore, have an important role in facilitating emergency drug dose calculations in 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.