Not so FAST-Chest ultrasound underdiagnoses traumatic pneumothorax

Lung ultrasonography underdiagnoses clinically significant pneumothorax

BACKGROUND

Ultrasonography for trauma is an integral part of the Advanced Trauma Life Support algorithm and supported extensively in the literature. The reliability of chest ultrasonography as a screening examination for pneumothorax during initial trauma evaluation is unclear. We performed a prospective study where we hypothesized that chest ultrasonography would have low sensitivity for detecting clinically significant pneumothorax.

METHODS

A prospective observational analysis of patients with blunt chest trauma at a level 1 trauma center was performed. Patients included had supine chest radiography and chest ultrasonography performed prior to intervention as well as confirmatory computed tomographic imaging. All chest ultrasonography was performed in the trauma bay by a registered sonographer. All imaging was evaluated by an attending trauma surgeon and radiologist in real time.

RESULTS

Of 2,185 patients screened with a diagnosis of blunt thoracic trauma, 1,489 patients had chest radiography, chest ultrasonography, and confirmatory computed tomography and were included for analysis. Patients were 71% male, with median age of 42 years, and mean Injury Severity Score of 6. The sensitivity of chest ultrasonography to detect pneumothorax was low. Chest ultrasonography had a false negative rate of 72% (n = 58), with 22% (n = 13) undergoing tube thoracostomy. Patients with false negative examinations had lower initial O2 saturation and systolic blood pressure and were more likely to have rib fractures compared with true negative chest ultrasonography examinations.

CONCLUSION

Chest ultrasonography performed on initial trauma evaluation has low sensitivity with a high rate of false negative examinations. Because many of these false negative results are clinically significant requiring thoracostomy, using chest ultrasonography alone to screen for pneumothorax should be done with caution.

Low Diagnostic Accuracy of Transthoracic Ultrasound for the Assessment of Spontaneous Pneumothorax in the Emergency Setting: A Multicentric Study

Background: Pneumothorax (PNX) represents a common clinical condition in emergency departments (EDs), requiring prompt recognition and treatment. The role of transthoracic ultrasounds (TUSs) in the diagnosis of PNX is still debated. We aimed to prospectively evaluate the accuracy of TUSs in the detection of spontaneous PNX in EDs. Methods: A total of 637 consecutive adult patients who presented to the EDs of four Italian hospitals complaining of acutely onset chest pain and dyspnoea were included in the study. Exclusion criteria were previous traumatic events, cardiogenic causes of pain/dyspnoea and suspected tension PNX. The absence of "lung sliding" (B-mode) and the "bar-code" sign (M-mode) were considered indicative of PNX in a TUS. Accuracy, sensitivity, specificity, and positive and negative predictive values (PPVs, NPVs) were calculated using a chest CT scan as reference. Results: Spontaneous PNX occurred in 93 patients: of those, 83 (89.2%) were correctly identified by TUSs. However, 306 patients with suspected PNX at TUS were not confirmed by chest CTs. The diagnostic accuracy of both the absence of "lung sliding" and "bar-code" sign during TUS was 50.4% (95% CI: 46.4-54.3), sensitivity was 89.2% (95% CI: 81.1-94.7), specificity was 43.8% (95% CI: 39.5-48.0), the PPV was 21.3% (95% CI: 19.7-23.1) and the NPV was 96.0% (95% CI: 92.9-97.7). Conclusions: TUS showed high sensitivity but low specificity in the identification of PNX in EDs. Relying exclusively on TUSs results for patients' management in ED settings is neither suitable nor recommendable. TUS examination can be useful to strengthen the clinical suspicion of PNX, but its results should be confirmed by a chest X-ray or CT scan.

Automated Real-Time Detection of Lung Sliding Using Artificial Intelligence: A Prospective Diagnostic Accuracy Study

BACKGROUND

Rapid evaluation for pneumothorax is a common clinical priority. Although lung ultrasound (LUS) often is used to assess for pneumothorax, its diagnostic accuracy varies based on patient and provider factors. To enhance the performance of LUS for pulmonary pathologic features, artificial intelligence (AI)-assisted imaging has been adopted; however, the diagnostic accuracy of AI-assisted LUS (AI-LUS) deployed in real time to diagnose pneumothorax remains unknown.

RESEARCH QUESTION

In patients with suspected pneumothorax, what is the real-time diagnostic accuracy of AI-LUS to recognize the absence of lung sliding?

STUDY DESIGN AND METHODS

We performed a prospective AI-assisted diagnostic accuracy study of AI-LUS to recognize the absence of lung sliding in a convenience sample of patients with suspected pneumothorax. After calibrating the model parameters and imaging settings for bedside deployment, we prospectively evaluated its diagnostic accuracy for lung sliding compared with a reference standard of expert consensus.

RESULTS

Two hundred forty-one lung sliding evaluations were derived from 62 patients. AI-LUS showed a sensitivity of 0.921 (95% CI, 0.792-0.973), specificity of 0.802 (95% CI, 0.735-0.856), area under the receiver operating characteristic curve of 0.885 (95% CI, 0.828-0.956), and accuracy of 0.824 (95% CI, 0.766-0.870) for the diagnosis of absent lung sliding.

INTERPRETATION

In this study, real-time AI-LUS showed high sensitivity and moderate specificity to identify the absence of lung sliding. Further research to improve model performance and optimize the integration of AI-LUS into existing diagnostic pathways is warranted.

[Prehospital ultrasound in emergency medicine]

Small, portable hand-held ultrasound devices nowadays enable a widespread use of prehospital point-of-care ultrasound (pPOCUS), which has so far only been used hesitantly, especially in ground-based emergency services. Many critical or even life-threatening conditions or internal injuries can often be better diagnosed or ruled out using pPOCUS, which can enable faster and more suitable goal-directed treatment and hospital transport. This article critically discusses relevant data, clinical benefits, limitations and challenges to be overcome when using pPOCUS for the most important life-threatening situations and aims to call for intensifying training and the extensive use of pPOCUS.

European society for trauma and emergency surgery member-identified research priorities in emergency surgery: a roadmap for future clinical research opportunities

BACKGROUND

European Society for Trauma and Emergency Surgery (ESTES) is the European community of clinicians providing care to the injured and critically ill surgical patient. ESTES has several interlinked missions - (1) the promotion of optimal emergency surgical care through networked advocacy, (2) promulgation of relevant clinical cognitive and technical skills, and (3) the advancement of scientific inquiry that closes knowledge gaps, iteratively improves upon surgical and perioperative practice, and guides decision-making rooted in scientific evidence. Faced with multitudinous opportunities for clinical research, ESTES undertook an exercise to determine member priorities for surgical research in the short-to-medium term; these research priorities were presented to a panel of experts to inform a 'road map' narrative review which anchored these research priorities in the contemporary surgical literature.

METHODS

Individual ESTES members in active emergency surgery practice were polled as a representative sample of end-users and were asked to rank potential areas of future research according to their personal perceptions of priority. Using the modified eDelphi method, an invited panel of ESTES-associated experts in academic emergency surgery then crafted a narrative review highlighting potential research priorities for the Society.

RESULTS

Seventy-two responding ESTES members from 23 countries provided feedback to guide the modified eDelphi expert consensus narrative review. Experts then crafted evidence-based mini-reviews highlighting knowledge gaps and areas of interest for future clinical research in emergency surgery: timing of surgery, inter-hospital transfer, diagnostic imaging in emergency surgery, the role of minimally-invasive surgical techniques and Enhanced Recovery After Surgery (ERAS) protocols, patient-reported outcome measures, risk-stratification methods, disparities in access to care, geriatric outcomes, data registry and snapshot audit evaluations, emerging technologies interrogation, and the delivery and benchmarking of emergency surgical training.

CONCLUSIONS

This manuscript presents the priorities for future clinical research in academic emergency surgery as determined by a sample of the membership of ESTES. While the precise basis for prioritization was not evident, it may be anchored in disease prevalence, controversy around aspects of current patient care, or indeed the identification of a knowledge gap. These expert-crafted evidence-based mini-reviews provide useful insights that may guide the direction of future academic emergency surgery research efforts.

Chest X-Ray Remains a Vital Component Prior to Tube Thoracostomy

INTRODUCTION

The identification and treatment of traumatic pneumothorax (PTX) has long been a focus of bedside imaging in the trauma patient. While the emergence of bedside ultrasound (BUS) provides an opportunity for earlier detection, the need for tube thoracostomy (TT) based on bedside imaging, including BUS and supine AP chest X-ray (CXR) is less established in the medical literature.

METHODS

Retrospective data from 2017 to 2020 were collected of all adult trauma activations at a level 1 rural trauma facility. Every adult patient included in this study received a CXR and BUS (eFast) upon arrival. The need for TT was determined by the emergency medicine attending or the trauma surgery attending evaluating the patient. McNemar's chi-squared test and conditional logistic regression analysis were performed comparing BUS, CXR, and the combination of BUS and CXR findings for the need for TT. Subgroup analyses were performed comparing BUS, CXR, and the combination of BUS and CXR for the detection of PTX compared to CT scan.

RESULTS

Of the 12,244 patients who underwent trauma activation during this timeframe, 602 were included in the study. 74.9% were males with an age range of 36-63 years. Of the 602 patients, 210 received TT. Positive PTX was recorded with BUS in 128 (21%) patients with 16 false negatives (FNs) and 98 false positives (FPs), 100 (17%) PTX were identified with CXR with 114 FNs and 4 FPs, and 72 (11.9%) were noted on both CXR and BUS with 140 FNs and 2 FPs. The odds ratio of TT placement was 22 times with positive BUS alone (P < .0001, 95% CI: 10.9-43.47), 47 times with positive CXR alone (P < .0001, 95% CI: 16.99-127.5), and 70 times with both positive CXR and BUS (P < .0001, 95% CI: 17.08-288.4).

CONCLUSION

A positive finding of PTX on BUS combined with CXR is more indicative of the need for TT in the trauma patient when compared with BUS or CXR alone.

[Recommendations for Education in Sonography in Prehospital Emergency Medicine (pPOCUS): Consensus paper of DGINA, DGAI, BAND, BV-ÄLRD, DGU, DIVI and DGIIN]

Point-of-care sonography is a precondition in acute and emergency medicine for the diagnosis and initiation of therapy for critically ill and injured patients. While emergency sonography is a mandatory part of the training for clinical acute and emergency medicine, it is not everywhere required for prehospital emergency medicine. Although some medical societies in Germany have already established their own learning concepts for emergency ultrasound, a uniform national training concept for the use of emergency sonography in the out-of-hospital setting is still lacking. Experts of several professional medical societies have therefore joined forces and developed a structured training concept for emergency sonography in the prehospital setting. The consensus paper serves as quality assurance in prehospital emergency sonography.

[Recommendations for Education in Sonography in Prehospital Emergency Medicine (pPOCUS): Consensus paper of DGINA, DGAI, BAND, BV-ÄLRD, DGU, DIVI and DGIIN]

Point-of-care sonography is a precondition in acute and emergency medicine for the diagnosis and initiation of therapy for critically ill and injured patients. While emergency sonography is a mandatory part of the training for clinical acute and emergency medicine, it is not everywhere required for prehospital emergency medicine. Although some medical societies in Germany have already established their own learning concepts for emergency ultrasound, a uniform national training concept for the use of emergency sonography in the out-of-hospital setting is still lacking. Experts of several professional medical societies have therefore joined forces and developed a structured training concept for emergency sonography in the prehospital setting. The consensus paper serves as quality assurance in prehospital emergency sonography.

Are Chest Radiographs or Ultrasound More Accurate in Predicting a Pneumothorax or Need for a Thoracostomy Tube in Trauma Patients?

BACKGROUND

Historically, chest radiographs (CXR) have been used to quickly diagnose pneumothorax (PTX) and hemothorax in trauma patients. Over the last 2 decades, chest ultrasound (CUS) as part of Extended Focused Assessment with Sonography in Trauma (eFAST) has also become accepted as a modality for the early diagnosis of PTX in trauma patients.

METHODS

We queried our institution's trauma databases for all trauma team activations from 2021 for patients with eFAST results. Demographics, injury variables, and the following were collected: initial eFAST CUS, CXR, computed tomography (CT) scan, and thoracostomy tube procedure notes. We then compared PTX detection rates on initial CXR and CUS to those on thoracic CT scans.

RESULTS

580 patients were included in the analysis after excluding patients without a chest CT scan within 2 hours of arrival. Extended Focused Assessment with Sonography in Trauma was 68.4% sensitive and 87.5% specific for detecting a moderate-to-large PTX on chest CT, while CXR was 23.5% sensitive and 86.3% specific. Extended Focused Assessment with Sonography in Trauma was 69.8% sensitive for predicting the need for tube thoracostomy, while CXR was 40.0% sensitive.

DISCUSSION

At our institution, eFAST CUS was superior to CXR for diagnosing the presence of a PTX and predicting the need for a thoracostomy tube. However, neither test is accurate enough to diagnose a PTX nor predict if the patient will require a thoracostomy tube. Based on the specificity of both tests, a negative CXR or eFAST means there is a high probability that the patient does not have a PTX and will not need a chest tube.

The potential of point-of-care diagnostics to optimise prehospital trauma triage: a systematic review of literature

PURPOSE

In the prehospital care of potentially seriously injured patients resource allocation adapted to injury severity (triage) is a challenging. Insufficiently specified triage algorithms lead to the unnecessary activation of a trauma team (over-triage), resulting in ineffective consumption of economic and human resources. A prehospital trauma triage algorithm must reliably identify a patient bleeding or suffering from significant brain injuries. By supplementing the prehospital triage algorithm with in-hospital established point-of-care (POC) tools the sensitivity of the prehospital triage is potentially increased. Possible POC tools are lactate measurement and sonography of the thorax, the abdomen and the vena cava, the sonographic intracranial pressure measurement and the capnometry in the spontaneously breathing patient. The aim of this review was to assess the potential and to determine diagnostic cut-off values of selected instrument-based POC tools and the integration of these findings into a modified ABCDE based triage algorithm.

METHODS

A systemic search on MEDLINE via PubMed, LIVIVO and Embase was performed for patients in an acute setting on the topic of preclinical use of the selected POC tools to identify critical cranial and peripheral bleeding and the recognition of cerebral trauma sequelae. For the determination of the final cut-off values the selected papers were assessed with the Newcastle-Ottawa scale for determining the risk of bias and according to various quality criteria to subsequently be classified as suitable or unsuitable. PROSPERO Registration: CRD 42022339193.

RESULTS

267 papers were identified as potentially relevant and processed in full text form. 61 papers were selected for the final evaluation, of which 13 papers were decisive for determining the cut-off values. Findings illustrate that a preclinical use of point-of-care diagnostic is possible. These adjuncts can provide additional information about the expected long-term clinical course of patients. Clinical outcomes like mortality, need of emergency surgery, intensive care unit stay etc. were taken into account and a hypothetic cut-off value for trauma team activation could be determined for each adjunct. The cut-off values are as follows: end-expiratory CO2: < 30 mm/hg; sonography thorax + abdomen: abnormality detected; lactate measurement: > 2 mmol/L; optic nerve diameter in sonography: > 4.7 mm.

DISCUSSION

A preliminary version of a modified triage algorithm with hypothetic cut-off values for a trauma team activation was created. However, further studies should be conducted to optimize the final cut-off values in the future. Furthermore, studies need to evaluate the practical application of the modified algorithm in terms of feasibility (e.g. duration of application, technique, etc.) and the effects of the new algorithm on over-triage. Limiting factors are the restriction with the search and the heterogeneity between the studies (e.g. varying measurement devices, techniques etc.).

Empfehlungen zur Sonografieausbildung in der prähospitalen Notfallmedizin (pPOCUS): Konsensuspapier von DGINA, DGAI, BAND, BV-ÄLRD, DGU, DIVI und DGIIN

Die Point-of-Care-Sonografie ist in der Akut- und Notfallmedizin ein fester Bestandteil der Diagnostik und Therapieeinleitung von kritisch kranken und verletzten Patienten. Während die Notfallsonografie im Rahmen der Zusatzweiterbildung für klinische Akut- und Notfallmedizin vorausgesetzt wird, wird diese für die prähospitale Notfallmedizin lediglich im (Muster-)Kursbuch Allgemeine und spezielle Notfallbehandlung als Weiterbildungsinhalt definiert. Obwohl einige Fachgesellschaften in Deutschland bereits eigene Lernkonzepte für die Notfallsonografie etabliert haben, fehlt bis dato ein einheitliches nationales Ausbildungskonzept für den Einsatz der Notfallsonografie im prähospitalem Umfeld. Experten mehrerer Fachgesellschaften haben daher als Empfehlung für die notfallmedizinische Weiterbildung ein Kurskonzept für die spezielle Ausbildung in der prähospitalen Notfallsonografie erarbeitet, welche gleichermaßen zu deren Qualitätssicherung beitragen soll.

Effect of the Extended Focused Assessment With Sonography for Trauma on the Screening Performance of the National Emergency X-Radiography Utilization Study Chest Decision Instrument

STUDY OBJECTIVE

Developed to decrease unnecessary thoracic computed tomography use in adult blunt trauma patients, the National Emergency X-Radiography Utilization Study (NEXUS) Chest clinical decision instrument does not include the extended Focused Assessment with Sonography in Trauma (eFAST). We assessed whether eFAST improves the NEXUS Chest clinical decision instrument's diagnostic performance and may replace the chest radiograph (CXR) as a predictor variable.

METHODS

We performed a secondary analysis of prospective data from 8 Level I trauma centers from 2011-2014. We compared performance of modified clinical decision instruments that (1) added eFAST as a predictor (eFAST-added clinical decision instrument), and (2) replaced CXR with eFAST (eFAST-replaced clinical decision instrument), in screening for blunt thoracic injuries.

RESULTS

One thousand nine hundred fifty-seven patients had documented computed tomography, CXR, clinical NEXUS criteria, and adequate eFAST; 624 (31.9%) patients had blunt thoracic injuries, and 126 (6.4%) had major injuries. Compared to the NEXUS Chest clinical decision instrument, the eFAST-added clinical decision instrument demonstrated unchanged screening performance for major injury (sensitivity 0.98 [0.94 to 1.00], specificity 0.28 [0.26 to 0.30]) or any injury (sensitivity 0.97 [0.95 to 0.98], specificity 0.21 [0.19 to 0.23]). The eFAST-replaced clinical decision instrument demonstrated unchanged sensitivity for major injury (sensitivity 0.93 [0.87 to 0.97], specificity 0.31 [0.29 to 0.34]) and decreased sensitivity for any injury (0.93 [0.91 to 0.951] versus 0.97 [0.953 to 0.98]).

CONCLUSION

In our secondary analysis, adding eFAST as a predictor variable did not improve the diagnostic screening performance of the original NEXUS Chest clinical decision instrument; eFAST cannot replace the CXR criterion of the NEXUS Chest clinical decision instrument.

Thoracic point-of-care ultrasound is an accurate diagnostic modality for clinically significant traumatic pneumothorax

OBJECTIVE

There are conflicting data regarding the accuracy of thoracic point-of-care ultrasound (POCUS) in detecting traumatic pneumothorax (PTX). The purpose of our study was to determine the accuracy of thoracic POCUS performed by emergency physicians for the detection of clinically significant PTX in blunt and penetrating trauma patients.

METHODS

We conducted a retrospective institutional review board-approved study of trauma patients 15 years or older presenting to our urban Level I academic trauma center from December 2021 to June 2022. All study patients were imaged with single-view chest radiography (CXR) and thoracic POCUS. The presence or absence of PTX was determined by multidetector computed tomography (CT) or CXR and ultrasound (US) with tube thoracostomy placement.

RESULTS

A total of 846 patients were included, with 803 (95%) sustaining blunt trauma. POCUS identified 13/15 clinically significant PTXs (defined as ≥35 mm of pleural separation on a blinded overread or placement of a tube thoracostomy prior to CT) with a sensitivity of 87% (95% confidence interval [CI] 58-97), specificity of 100% (95% CI 99-100), positive predictive value of 81% (95% CI 54%-95%), and negative predictive value of 100% (95% CI 99%-100%). The positive likelihood ratio was 484 and the negative likelihood ratio was 0.1. CXR identified eight (53%) clinically significant PTXs, with a sensitivity of 53% (95% CI 27%-78%) and a specificity of 100%, when correlated with the CT. The most common reason for a missed PTX identified on expert-blinded overread was failure to recognize a lung point sign that was present on US.

CONCLUSIONS

Thoracic POCUS accurately identifies the majority of clinically significant PTXs in both blunt and penetrating trauma patients. Common themes for false-negative thoracic US in the expert-blinded overread process identified key gaps in training to inspire US education and medical education research.

Chest Tube Placement in Mechanically Ventilated Trauma Patients: Differences between Computed Tomography-Based Indication and Clinical Decision

The rate of occult pneumothorax in intubated and mechanically ventilated trauma patients until initial computed tomography (CT) remains undetermined. The primary aims of this study were to analyze initial chest CTs with respect to the thoracic pathology of trauma, the clinical injury severity, and chest tube placement (CTP) before and after CT. In a single-center retrospective analysis of 616 intubated and mechanically ventilated adult patients admitted directly from the scene to the emergency department (ED), 224 underwent CTP (36%). Of these, 142 patients (62%) underwent CTP before CT, of which, 125 (88%) had significant chest injury on CT. Seventeen patients had minor or absent chest injuries, most of which were associated with transient or unrecognized tracheal tube malposition. After CT, CTP was performed in another 82 patients, of which, 56 (68.3%) had relevant pneumothorax and 26 had minor findings on CT. Sixty patients who had already undergone CTP before CT received another CTP after CT, of which, 15 (25%) had relevant pneumothorax and 45 (75%) had functionality issues or malposition requiring replacement. Nine patients showed small pneumothorax on CT, and did not undergo CTP (including four patients with CTP before CT). The physiological variables were unspecific, and the trauma scores were dependent on the CT findings for identifying patients at risk for CTP. In conclusion, the clinical decisions for CTP before CT are associated with relevant false-negative and false-positive cases. Clinical assessment and CT imaging, together, are important indicators for CTP decisions that cannot be achieved by using clinical assessment or CT alone.