Identification of major hemorrhage in trauma patients in the prehospital setting: diagnostic accuracy and impact on outcome.

Background: Hemorrhage is the most common cause of potentially preventable death after injury. Early identification of patients with major hemorrhage (MH) is important as treatments are time-critical. However, diagnosis can be difficult, even for expert clinicians. This study aimed to determine how accurate clinicians are at identifying patients with MH in the prehospital setting. A second aim was to analyze factors associated with missed and overdiagnosis of MH, and the impact on mortality. Methods: Retrospective evaluation of consecutive adult (≥16 years) patients injured in 2019-2020, assessed by expert trauma clinicians in a mature prehospital trauma system, and admitted to a major trauma center (MTC). Clinicians decided to activate the major hemorrhage protocol (MHPA) or not. This decision was compared with whether patients had MH in hospital, defined as the critical admission threshold (CAT+): administration of ≥3 U of red blood cells during any 60-minute period within 24 hours of injury. Multivariate logistical regression analyses were used to analyze factors associated with diagnostic accuracy and mortality. Results: Of the 947 patients included in this study, 138 (14.6%) had MH. MH was correctly diagnosed in 97 of 138 patients (sensitivity 70%) and correctly excluded in 764 of 809 patients (specificity 94%). Factors associated with missed diagnosis were penetrating mechanism (OR 2.4, 95% CI 1.2 to 4.7) and major abdominal injury (OR 4.0; 95% CI 1.7 to 8.7). Factors associated with overdiagnosis were hypotension (OR 0.99; 95% CI 0.98 to 0.99), polytrauma (OR 1.3, 95% CI 1.1 to 1.6), and diagnostic uncertainty (OR 3.7, 95% CI 1.8 to 7.3). When MH was missed in the prehospital setting, the risk of mortality increased threefold, despite being admitted to an MTC. Conclusion: Clinical assessment has only a moderate ability to identify MH in the prehospital setting. A missed diagnosis of MH increased the odds of mortality threefold. Understanding the limitations of clinical assessment and developing solutions to aid identification of MH are warranted. Level of evidence: Level III-Retrospective study with up to two negative criteria. Study type: Original research; diagnostic accuracy study.

Updating and recalibrating causal probabilistic models on a new target population.

OBJECTIVE: Very often the performance of a Bayesian Network (BN) is affected when applied to a new target population. This is mainly because of differences in population characteristics. External validation of the model performance on different populations is a standard approach to test model's generalisability. However, a good predictive performance is not enough to show that the model represents the unique population characteristics and can be adopted in the new environment. METHODS: In this paper, we present a methodology for updating and recalibrating developed BN models - both their structure and parameters - to better account for the characteristics of the target population. Attention has been given on incorporating expert knowledge and recalibrating latent variables, which are usually omitted from data-driven models. RESULTS: The method is successfully applied to a clinical case study about the prediction of trauma-induced coagulopathy, where a BN has already been developed for civilian trauma patients and now it is recalibrated on combat casualties. CONCLUSION: The methodology proposed in this study is important for developing credible models that can demonstrate a good predictive performance when applied to a target population. Another advantage of the proposed methodology is that it is not limited to data-driven techniques and shows how expert knowledge can also be used when updating and recalibrating the model.

Methods used to evaluate usability of mobile clinical decision support systems for healthcare emergencies: a systematic review and qualitative synthesis.

Objective: The aim of this study was to determine the methods and metrics used to evaluate the usability of mobile application Clinical Decision Support Systems (CDSSs) used in healthcare emergencies. Secondary aims were to describe the characteristics and usability of evaluated CDSSs. Materials and Methods: A systematic literature review was conducted using Pubmed/Medline, Embase, Scopus, and IEEE Xplore databases. Quantitative data were descriptively analyzed, and qualitative data were described and synthesized using inductive thematic analysis. Results: Twenty-three studies were included in the analysis. The usability metrics most frequently evaluated were efficiency and usefulness, followed by user errors, satisfaction, learnability, effectiveness, and memorability. Methods used to assess usability included questionnaires in 20 (87%) studies, user trials in 17 (74%), interviews in 6 (26%), and heuristic evaluations in 3 (13%). Most CDSS inputs consisted of manual input (18, 78%) rather than automatic input (2, 9%). Most CDSS outputs comprised a recommendation (18, 78%), with a minority advising a specific treatment (6, 26%), or a score, risk level or likelihood of diagnosis (6, 26%). Interviews and heuristic evaluations identified more usability-related barriers and facilitators to adoption than did questionnaires and user testing studies. Discussion: A wide range of metrics and methods are used to evaluate the usability of mobile CDSS in medical emergencies. Input of information into CDSS was predominantly manual, impeding usability. Studies employing both qualitative and quantitative methods to evaluate usability yielded more thorough results. Conclusion: When planning CDSS projects, developers should consider multiple methods to comprehensively evaluate usability.

Diagnostic accuracy of clinical examination to identify life- and limb-threatening injuries in trauma patients.

BACKGROUND: Timely and accurate identification of life- and limb-threatening injuries (LLTIs) is a fundamental objective of trauma care that directly informs triage and treatment decisions. However, the diagnostic accuracy of clinical examination to detect LLTIs is largely unknown, due to the risk of contamination from in-hospital diagnostics in existing studies. Our aim was to assess the diagnostic accuracy of initial clinical examination for detecting life- and limb-threatening injuries (LLTIs). Secondary aims were to identify factors associated with missed injury and overdiagnosis, and determine the impact of clinician uncertainty on diagnostic accuracy. METHODS: Retrospective diagnostic accuracy study of consecutive adult (≥ 16 years) patients examined at the scene of injury by experienced trauma clinicians, and admitted to a Major Trauma Center between 01/01/2019 and 31/12/2020. Diagnoses of LLTIs made on contemporaneous clinical records were compared to hospital coded diagnoses. Diagnostic performance measures were calculated overall, and based on clinician uncertainty. Multivariate logistic regression analyses identified factors affecting missed injury and overdiagnosis. RESULTS: Among 947 trauma patients, 821 were male (86.7%), median age was 31 years (range 16-89), 569 suffered blunt mechanisms (60.1%), and 522 (55.1%) sustained LLTIs. Overall, clinical examination had a moderate ability to detect LLTIs, which varied by body region: head (sensitivity 69.7%, positive predictive value (PPV) 59.1%), chest (sensitivity 58.7%, PPV 53.3%), abdomen (sensitivity 51.9%, PPV 30.7%), pelvis (sensitivity 23.5%, PPV 50.0%), and long bone fracture (sensitivity 69.9%, PPV 74.3%). Clinical examination poorly detected life-threatening thoracic (sensitivity 48.1%, PPV 13.0%) and abdominal (sensitivity 43.6%, PPV 20.0%) bleeding. Missed injury was more common in patients with polytrauma (OR 1.83, 95% CI 1.62-2.07) or shock (systolic blood pressure OR 0.993, 95% CI 0.988-0.998). Overdiagnosis was more common in shock (OR 0.991, 95% CI 0.986-0.995) or when clinicians were uncertain (OR 6.42, 95% CI 4.63-8.99). Uncertainty improved sensitivity but reduced PPV, impeding diagnostic precision. CONCLUSIONS: Clinical examination performed by experienced trauma clinicians has only a moderate ability to detect LLTIs. Clinicians must appreciate the limitations of clinical examination, and the impact of uncertainty, when making clinical decisions in trauma. This study provides impetus for diagnostic adjuncts and decision support systems in trauma.

The Medial Rotation Knee replacement: Clinical and radiological results of a multi-centre surveillance study at five years.

BACKGROUND: The Medial Rotation Knee (MRK) has one of the lowest revision rates of total knee replacement designs in the National Joint Registry. While survival is one metric of performance of implants, patient-reported outcomes, combined with clinical and radiological evaluation, allow more complete analysis. We report the five-year results of a prospective, multi-centre surveillance study of the MRK. METHODS: A 16-surgeon, three-centre series of 520 total knee replacements were performed in 486 patients, comprising 182 males and 304 females. The mean age was 70.3 years (46-96) and BMI 29.5 kg/m2 (18-57). Study subjects were given questionnaires pre-operatively, at six months, and annually thereafter. Clinical and radiological reviews were scheduled pre-operatively, at six months, three and five years. RESULTS: At five years, 395 of the original 486 patients (427 of 520 knees) remained under active review. Twenty-six patients (27 knees) had withdrawn, 44 patients/knees had died and one was excluded. Thirteen patients (14 knees) were lost to follow-up, but were not revised. Seven knees were revised, equating to a survival probability of 98.6% at five years. There were significant improvements in mean Oxford Knee Score (21.23-35.79), EQ-5D (0.440-0.694) and Knee Society Score (Knee 43.00-83.97; Function 49.45-71.39). Of the radiographs available for evaluation, radiolucency was identified in 25 knees (14.6%) with one case of osteolysis of the tibial component. CONCLUSION: In addition to excellent survivorship, mid-term patient-reported, clinical and radiological results at five years are satisfactory, and consistent with other medial pivot designs.

When does ultrasonography influence management in suspected appendicitis?

BACKGROUND: Accurate diagnosis of appendicitis is challenging, particularly in children. Moreover, opinion is divided over the role of ultrasonography (US) in its diagnosis and how US may influence management. This study compares the use of US in two tertiary paediatric hospitals and how it influenced the management of suspected appendicitis. METHODS: Data from acute admissions, radiology, histopathology and theatre were cross-referenced to review all children who underwent an appendicectomy (with or without preoperative US) for suspected appendicitis in Christchurch (CH) in New Zealand and Aberdeen (AB) in Scotland in 2009. RESULTS: Five hundred and ninety-nine patients (442 CH; 157 AB) were included, with similar age and gender distributions. US was performed in 23% of patients with an overall appendix visualization rate of 29%. The overall positive and negative predictive values were 67% and 100%, respectively. Females were more likely to have US than males (P < 0.001, χ(2) ). In females with no appendix seen on US, in the presence or absence of other pathology, a normal appendix was confirmed in 50% and 58%, respectively. Visualizing the appendix resulted in a lower rate of normal appendix at operation (20%, 4/20) compared with when the appendix was not visualized (56%, 14/25). CONCLUSION: Identification of a normal appendix on US seems sufficiently accurate to exclude appendicitis with confidence, while positive US should be interpreted in conjunction with the clinical features in influencing the decision to operate. The incidence of a non-inflamed appendix at operation could be reduced with an increased rate of appendiceal visualization by sonographers.