Research 2018-08-05T02:20:07+00:00

Research

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Point-of-care ultrasound (POCUS) is the bedside assessment by ultrasound to quickly assess patients for both procedural and diagnostic purposes. Pediatric emergency physicians are finding more applications for it in patients, making it a necessary adjunct to physical examinations. Being aware of its current use and limitations is important to all members of the health-care team. This article will review common POCUS indications for pediatric patients in the emergency department in the areas of abdominal and pulmonary emergencies, musculoskeletal injuries, and urgent vascular access.

Background

Patients with uncomplicated biliary disease frequently present to the emergency department for assessment. To improve bedside clinical decision making, biliary point-of-care ultrasound (POCUS) in the emergency department has emerged as a diagnostic tool. The purpose of this study is to analyze the usefulness of POCUS in predicting the need for surgical intervention in biliary disease.

Methods

A retrospective study of patients visiting the emergency department who received a biliary POCUS from December 1, 2016 to July 15, 2017 was performed. The physician interpretations of the biliary POCUS scans were collected, as well as data from the electronic health records including lab values, the subsequent use of diagnostic imaging, surgical consultation or intervention, and 28 days follow-up for representation or complication.

Results

Two hundred and eighty-three patients were identified as having received biliary POCUS. Of the patients referred to general surgery who received biliary POCUS 43% received a cholecystectomy. For the outcome of cholecystectomy, the finding of gallstones on POCUS was 55% sensitive (95% CI 40% to 70%) and 92% specific (95% CI 87% to 95%). A sonographic Murphy’s sign was 16% sensitive (95% CI 7% to 30%) but 95% specific (95% CI 92% to 97%) and, gallbladder wall thickness was 18% sensitive (95% CI 9% to 33%) and 98% specific (95% CI 95% to 99%). Patients who received POCUS but did not proceed to confirmatory radiology department imaging had a shorter length of stay (433 min ± 50 min vs. 309 min ± 30 min, P<0.001).

Discussion

Point-of-care biliary ultrasound performed by emergency physicians provides timely access to diagnostic information. Positive findings of gallstones and increased gallbladder wall thickness are highly predictive of the need for surgical intervention, and use of POCUS is associated with shorter ER visits.

Level of evidence

Retrospective cohort study, level III.

Objectives

Although lung ultrasound (US) has been shown to have high diagnostic accuracy in patients presenting with acute dyspnea, its precision in critically ill patients is unknown. We investigated common areas of agreement and disagreement by studying 6 experts as they interpreted lung US studies in a cohort of intensive care unit (ICU) patients.

Methods

A previous study by our group asked experts to rate the quality of 150 lung US studies performed by 10 novices in a population of mechanically ventilated patients. For this study, experts were asked to interpret them without the clinical context, reporting the presence of pneumothorax, interstitial syndrome, consolidation, atelectasis, or pleural effusion.

Results

The rate of expert agreement depended on how it was defined, ranging from 51% (with a strict definition of agreement) to 57% (with a more liberal definition). Removing cases involving lung consolidation (the most common source of disagreement) improved the rates of agreement to 69% and 86%, respectively. Conclusions The frequency of agreement was lower than might have been expected in this study. Several potential reasons are identified, chief among them the fact that ICU patients often develop multiple pulmonary insults, making agreement on a specific primary diagnosis challenging. This finding suggests that the utility of lung US in identifying the main contributing lung condition in ICU patients may be lower than in dyspneic patients encountered in the emergency department. It also raises the possibility that the clinical context is more important for lung US than other imaging modalities.

The content of this issue of Journal supports the broad overall acceptance that point-of-care ultrasound (POCUS) has achieved across many medical specialties. Despite this progress, fundamental confusion persists surrounding the achievement of both competency and certification in POCUS. In this editorial, we seek to demystify and clarify these issues from a Canadian critical care perspective, with special consideration of the recently announced examination and certification pathway in advanced critical care echocardiography.

The landscape of competency and certification in POCUS cannot be understood without a firm grasp on the nomenclature that has been adopted thus far (Figure). For POCUS performed by intensivists, critical care ultrasound (CCUS) is the appropriate umbrella term, spanning the two main branches of critical care echocardiography (CCE) and general critical care ultrasound (GCCUS). Critical care echocardiography itself is divided into basic (BCCE) and advanced (ACCE) skill sets.

The use of point-of-care ultrasound in trauma provides diagnostic clarity and routinely influences management. A scanning protocol known as the Focused Assessment with Sonography in Trauma (FAST) has been widely adopted by trauma providers of all specialties. The FAST exam addresses a broad array of pathologic conditions capable of causing instability, including hemoperitoneum, hemopericardium, hemothorax, and pneumothorax. The exam is an integral component to the primary assessment of injured patients and an iconic application of point-of-care ultrasound.

In the unconscious patient, there is a diagnostic void between the neurologic physical exam, and more invasive, costly and potentially harmful investigations. Transcranial color-coded sonography and two-dimensional transcranial Doppler imaging of the brain have the potential to be a middle ground to bridge this gap for certain diagnoses. With the increasing availability of point-of-care ultrasound devices, coupled with the need for rapid diagnosis of deteriorating neurologic patients, intensivists may be trained to perform point-of-care transcranial Doppler at the bedside. The feasibility and value of this technique in the intensive care unit to help rule-in specific intra-cranial pathologies will form the focus of this article. The proposed scope for point-of-care transcranial Doppler for the intensivist will be put forth and illustrated using four representative cases: presence of midline shift, vasospasm, raised intra-cranial pressure, and progression of cerebral circulatory arrest. We will review the technical details, including methods of image acquisition and interpretation. Common pitfalls and limitations of point-of-care transcranial Doppler will also be reviewed, as they must be understood for accurate diagnoses during interpretation, as well as the drawbacks and inadequacies of the modality in general. Electronic supplementary material The online version of this article (doi:10.1186/s13089-017-0077-9) contains supplementary material, which is available to authorized users.

Background

The rapid adoption of point-of-care ultrasound (POCUS) has created a need to develop assessment tools to ensure that learners can competently use these technologies. In this study, the authors developed and tested a rating scale to assess the quality of point-of-care thoracic ultrasound studies performed by novices. In Phase 1, the Assessment of Competency in Thoracic Sonography (ACTS) scale was developed based on structured interviews with subject matter experts. The tool was then piloted on a small series of ultrasound studies in Phase 2. In Phase 3 the tool was applied to a sample of 150 POCUS studies performed by ten learners; performance was then assessed by two independent raters.

Results

Evidence for the content validity of the ACTS scale was provided by a consensus exercise wherein experts agreed on the general principles and specific items that make up the scale. The tool demonstrated reasonable inter-rater reliability despite minimal requirements for evaluator training and displayed evidence of good internal structure, with related scale items correlating well with each other. Analysis of the aggregate learning curves suggested a rapid early improvement in learner performance with slower improvement after approximately 25-30 studies.

Conclusions

The ACTS scale provides a straightforward means to assess learner performance. Our results support the conclusion that the tool is an effective means of making valid judgments regarding competency in point-of-care thoracic ultrasound, and that the majority of learner improvement occurs during their first 25-30 practice studies.

Cardiac arrest is one of the most challenging patient presentations managed by emergency care providers, and echocardiography can be instrumental in the diagnosis, prognosis, and treatment guidance in these critically ill patients. Transesophageal echocardiography has many advantages over transthoracic echocardiography in a cardiac arrest resuscitation. As transesophageal echocardiography is implemented more widely at the point of care during cardiac arrest resuscitations, guidelines are needed to assist emergency providers in acquiring the equipment and skills necessary to successfully incorporate it into the management of cardiac arrest victims.

The Advanced Trauma Life Support (ATLS) course remains the standard and tried approach to resuscitating the trauma patient in a hierarchal manner, serving to both prioritise and address the greatest threats to life rapidly. The initial approach to all serious trauma utilises the ABCDE concept. Thus, the airway is first addressed and either determined to be patent or secured with any number of airway maintenance devices, although a cuffed endotracheal tube remains standard. Once the airway has been secured, breathing is next assessed. This has traditionally consisted of assessing the anterior chest for the hyper-resonance associated with a tension pneumothorax (PTX), and the lateral chest for the dullness of a massive haemothorax (HTX). Penetrating mechanisms remains a common cause of traumatic injury, for which operative intervention is frequently required. When using ultrasound to assess the unstable patient after penetrating torso injury, the sequence of scanning is important.

Introduction

Recent studies have shown that point of care ultrasound is a valuable tool in the assessment and management of shock in the Emergency Department (ED). Despite proven utility, data is limited on the current utilization and quality assurance of POCUS in ED management of shock. The aim of this study was to determine the rate of POCUS use, characterize data collection methods and determine rate of quality assurance in both the ED and Intensive Care Unit (ICU) of a tertiary care academic center.

Methods

The study included all patients who visited the ED from Jan-Jun 2015 that were transferred to the ICU, and were in shock, as determined by sBP <90, diagnostic code or vasopressor use. Patient charts, as well as wirelessly archived ultrasound studies were reviewed to determine which patients had POCUS performed, and how the results were recorded. By reviewing formal worksheets archived online, it could be determined if a management change was recommended, if studies were over-read for quality assurance and if improvement was recommended to image acquisition or interpretation.

Results

Both departments used POCUS in roughly half of patients presenting in shock (53% ED, 41% ICU) with no statistical difference in usage (Δ12, 95% CI −0.01 to 0.25; p=0.06). Most ED studies (87%), had some form of documentation either on paper or online, however few (9%) had a formal worksheet completed. In comparison 71% of ICU studies had a worksheet. There was no difference in the number of performed scans that were saved electronically (66% ED vs 71% ICU; Δ5%, 95%CI −0.13 to 0.21; p=0.60).In the ICU the majority (77%) of the formal reports recommended a management change as a direct result of scan findings. Furthermore, of worksheets submitted for quality assurance (88%), over half the reviews (55%) suggested an improvement in image acquisition or interpretation.

Conclusion

To our knowledge, our study is the first to demonstrate that POCUS is only utilized in about half of the shock cases in ED and ICU. Given that the majority of the formally reported studies in the ICU that were over-read for quality assurance found areas for potential improvement and given that the majority of ED studies were reported informally, it stands to reason that POCUS operators in the ED could benefit from a formalized quality assurance program. Future studies should explore potential barriers to implementation of such a program.