Out of hospital point of care ultrasound: current use models and future directions

Point-of-care ultrasonography in Ukraine: a survey of anesthesiologists-intensivists participating in ultrasonography courses

PURPOSE

Despite the potential value of point-of-care ultrasonography (POCUS) in resource-limited environments, it is not widely used in low- and middle-income countries compared with high-income countries. We sought to evaluate the current POCUS practice of Ukrainian anesthesiologists who attended POCUS courses to guide future POCUS training in Ukraine.

METHODS

We conducted a 25-question web-based survey. It was distributed to 255 participants of POCUS courses held in Ukraine in 2023. The survey sections described current POCUS practice, perception of POCUS value, POCUS skills self-assessment, and perceived barriers to implementing POCUS in clinical practice.

RESULTS

Two hundred and forty-four out of 255 course participants completed the survey, representing 214 unique respondents. Those who self-rated their skills identified themselves as either novices or beginners in areas of POCUS knowledge (118/157, 75%), image acquisition (110/158, 70%), image interpretation (117/158, 74%), and integration into clinical decision-making (105/155, 68%). Among all survey responders, 55% (118/214) reported using POCUS for vascular access procedures, 45% (97/214) for trauma assessment, and 44% (93/214) for regional anesthesia. Reported barriers to POCUS implementation included lack of ultrasound devices (101/214, 47%) and lack of trained faculty (112/214, 52%).

CONCLUSION

Among anesthesiologists who participated in POCUS courses in Ukraine, the majority were in early stages of ultrasound practice. Respondents identified POCUS applications not currently practiced and evaluated barriers to POCUS use. Based upon these survey findings, we propose the following measures in Ukraine: 1) developing a standardized national POCUS curriculum; 2) increasing the number of experienced instructors of POCUS; and 3) acquiring ultrasound devices to support clinical applications of POCUS, especially in the Central, Southern, and Eastern regions.

A National Survey on Point of Care Ultrasonography Use Among Veterans Affairs Clinicians in Home Care and Skilled Nursing Facilities

INTRODUCTION

Older adults who are homebound and those in skilled nursing facilities (SNFs) often have limited access to point of care imaging to inform clinical decision making. Point-of-care ultrasonography (POCUS) can help span this gap by augmenting the physical examination to aid in diagnosis and triaging. Although training in POCUS for medical trainees is becoming more common and may focus on settings such as the emergency department, intensive care unit, and inpatient care, little is known about POCUS training among practicing clinicians who work outside of these settings. We conducted a national needs assessment survey around experience with POCUS focused on practicing clinicians in the sub-acute, long-term, and home-based care settings in the Veterans Affairs (VA) health system.

METHODS

An electronic survey was developed and sent out to clinicians via Listservs for the VA long-term and sub-acute care facilities [Community Living Centers (CLCs)], Home Based Primary Care outpatient teams, and Hospital in Home teams to assess current attitudes, previous training, and skills related to POCUS.

RESULTS

Eighty-eight participants responded to the survey, for an overall response rate of 29% based on the number of emails on each Listserv, representing CLC, home-based primary care, and hospital in home. Sixty percent of clinicians reported no experience with POCUS, and 76% reported that POCUS and POCUS training would be useful to their practice. More than 50% cited lack of training and lack of equipment as 2 significant barriers to POCUS use.

DISCUSSION

This national needs assessment survey of VA clinicians reveals important opportunities for training in POCUS for clinicians working with older adults who are receiving home care homebound or living in SNFs.

Branched Convolutional Neural Networks for Receiver Channel Recovery in High-Frame-Rate Sparse-Array Ultrasound Imaging

For high-frame-rate ultrasound imaging, it remains challenging to implement on compact systems as a sparse imaging configuration with limited array channels. One key issue is that the resulting image quality is known to be mediocre not only because unfocused plane-wave excitations are used but also because grating lobes would emerge in sparse-array configurations. In this article, we present the design and use of a new channel recovery framework to infer full-array plane-wave channel datasets for periodically sparse arrays that operate with as few as one-quarter of the full-array aperture. This framework is based on a branched encoder-decoder convolutional neural network (CNN) architecture, which was trained using full-array plane-wave channel data collected from human carotid arteries (59 864 training acquisitions; 5-MHz imaging frequency; 20-MHz sampling rate; plane-wave steering angles between -15° and 15° in 1° increments). Three branched encoder-decoder CNNs were separately trained to recover missing channels after differing degrees of channelwise downsampling (2, 3, and 4 times). The framework's performance was tested on full-array and downsampled plane-wave channel data acquired from an in vitro point target, human carotid arteries, and human brachioradialis muscle. Results show that when inferred full-array plane-wave channel data were used for beamforming, spatial aliasing artifacts in the B-mode images were suppressed for all degrees of channel downsampling. In addition, the image contrast was enhanced compared with B-mode images obtained from beamforming with downsampled channel data. When the recovery framework was implemented on an RTX-2080 GPU, the three investigated degrees of downsampling all achieved the same inference time of 4 ms. Overall, the proposed framework shows promise in enhancing the quality of high-frame-rate ultrasound images generated using a sparse-array imaging setup.

Prehospital Extended FAST Exams Improve Clinical Decision Making by Helicopter EMS Crews: A Retrospective Case Series

Point of Care Ultrasound (POCUS) has seen increasing use in the prehospital environment over the last decade, primarily with the extended focused assessment with sonography in trauma (eFAST) exam. Previous studies have shown prehospital eFAST exams are feasible in the helicopter transport environment but have yet to demonstrate effects on clinical care. This retrospective case series identified 655 patients with blunt thoraco-abdominal trauma or concern for pneumothorax due to penetrating injury transported by a single helicopter EMS (HEMS) program over a two-year period after introducing POCUS. Of those patients, 258 received prehospital ultrasound which was reported to change clinical care in seven cases (2.7%, 95%-CI [1.1-5.5]). This was primarily through preventing unnecessary needle thoracostomy and initiating blood transfusion for treatment of hemorrhagic shock in cases where the degree of shock was unclear due to inconsistent vital signs. This study highlights the improvements in clinical care that may result from the introduction of eFAST exams in the prehospital environment.

Teleguidance for Patient Self-Imaging of Hemophilic Joints Using Mobile Ultrasound Devices: A Pilot Study

BACKGROUND

Teleguidance on portable devices opens the possibility of joint self-imaging in persons with hemophilia (PWH).

AIMS

Determine the feasibility of patient self-imaging with/without teleguidance.

METHODS

Adult PWH received ultrasound teaching including 11 views for hemarthrosis detection in ankles, elbows, and knees. The patients acquired five randomly selected views with the Butterfly/IQ probe without assistance at 2, 6-8 weeks, and 3-4 months later, followed by teleguidance. Image acquisition was timed, patients identified anatomic landmarks, and image quality was graded. Questionnaires assessed the imaging experience. Hemophilia Joint Health Score (HJHS) indicated arthropathy status.

RESULTS

Of 132 PWH, 10 (median age 52 years) opted for study inclusion. Most had severe Hemophilia A, were white/non-Hispanic, with at least a high school degree and, overall, similar to the other 122 PWH. At 2 and 6 weeks after training, ~80% images were acquired correctly compared with 53% at 12 weeks. Accuracy of landmark recognition was ~55%. With teleguidance, all images were acquired correctly, with near-perfect image quality (P ≤ .01 compared with the 3-4 month time point). Median HJHS of scanned joints was 11.5 at each time point, demonstrating a similar spectrum of arthropathic changes. Median time of image acquisition was fast, and similar with or without teleguidance (median 01:04 [mm:ss] vs median 01:02), but differed slightly between arthropathic and non-arthropathic joints. Study participants and the imaging facilitator rated that it was easy to navigate mobile technology and acquire images with teleguidance.

CONCLUSION

Mobile ultrasound with teleguidance for joint self-imaging is feasible and warrants further exploration.

Commentary on Ultrasound Instruction in Undergraduate Medical Education: Perspective from Two Students

BACKGROUND

Ultrasound integration in undergraduate medical education (UME) has been a focused endeavor in recent years. According to the American Institute of Ultrasound in Medicine, more than a third of all US medical schools have adopted a focused ultrasound training program for medical students. Medical student perspectives on best practices in ultrasound education are lacking in the literature.

CURRICULA EXPERIENCES

Two students' reflections are presented regarding two different didactic approaches, flipped classroom and self-study learning models, to teaching ultrasound in the pre-clinical medical education curriculum. Students present reflections on these didactic approaches to facilitate further improvement in ultrasound education curricula.

DISCUSSION

The self-directed learning model enabled students to learn foundational ultrasound exam techniques efficiently in a low-stress environment and subsequently optimized the efficiency of later faculty-led learning events. However, we noted that in both the flipped classroom and self-study learning models of education, the training on basic physical properties of ultrasound, tissue characteristics, and probe manipulation was limited.

CONCLUSION

A self-study learning model ultrasound curricula improves perceived learning efficiency and student confidence, especially when followed by faculty-guided didactics and scanning opportunities. We suggest a framework for ultrasound education curricula that includes components of both formats of ultrasound education alongside faculty-led sessions as an ideal model of ultrasound education. Further, we propose the added benefit of inanimate object scanning to optimize students' knowledge of waveform physics (image acquisition and physical properties of materials) early in the ultrasound education process.

Prehospital Ultrasound: A Narrative Review

Background: Point-of-care ultrasound is rapidly becoming more prevalent in the prehospital environment. Though considered a relatively new intervention in this setting, there is growing literature that aims to explore the use of prehospital ultrasound by EMS personnel.Methods: To better understand and report the state of the science on prehospital ultrasound, we conducted a narrative review of the literature.Results: Following a keyword search of MEDLINE in Ovid from inception to August 2, 2022, 2,564 records were identified and screened. Based on review of abstracts and full texts, with addition of seven articles via bibliography review, 193 records were included. Many included studies detail usage in air medical and other critical care transport environments. Clinicians performing prehospital ultrasound are often physicians or other advanced practice personnel who have previous ultrasound experience, which facilitates implementation in the prehospital setting. Emerging literature details training programs for prehospital personnel who are novices to ultrasound, and implementation for some study types appears feasible without prior experience. Unique use scenarios that show promise include during critical care transport, for triage in austere settings, and for thoracic evaluation of patients at risk of life-threatening pathology.Conclusion: There is a growing mostly observational body of literature describing the use of ultrasound by prehospital personnel. Prehospital ultrasound has demonstrated feasibility for specific conditions, yet interventional studies evaluating benefit to patient outcomes are absent.

Feasibility of Self-Performed Lung Ultrasound with Remote Teleguidance for Monitoring at Home COVID-19 Patients

During the COVID-19 pandemic, use of telemedicine with the aim of reducing the rate of viral transmission increased. This proof-of-concept observational study was planned to test the feasibility of a home-based lung ultrasound (LUS) follow-up performed by patients with mild COVID-19 infection on themselves. We enrolled patients presenting to the emergency department with SARS-CoV-2 infection without signs of pneumonia and indication to discharge. Each patient received a brief training on how to perform LUS and a handheld ultrasound probe. Then, patients were contacted on a daily basis, and LUS images were acquired by the patients themselves under “teleguidance” by the investigator. Twenty-one patients were enrolled with a median age of 44 years. All evaluations were of sufficient quality for a follow up. Probability of a better LUS quality was related to higher degree (odds ratio, OR, 1.42, 95% CI 0.5–3.99) and a lower quality to evaluation time (from 0.71, 95% CI 0.55–0.92 for less than 7 min, to 0.52, 95% CI 0.38–0.7, between 7 and 10 min, and to 0.29, 95% CI 0.2–0.43, for evaluations longer than 10 min). No effect related to gender or age was detected. LUS performed by patients and remotely overseen by expert providers seems to be a feasible and reliable telemedicine tool.

Helicopter Emergency Medical Services Performed Extended Focused Assessment With Sonography: Training, Workflow, and Sustainable Quality

The extended focused assessment of trauma (EFAST) examination is an invaluable tool for the initial evaluation of the trauma patient. Miniaturization of ultrasound has enabled helicopter emergency medical services (HEMS) to use point-of-care ultrasound to care for trauma patients on scene. Our study demonstrated that HEMS crews accurately performed EFAST examinations after the implementation of a novel HEMS EFAST workflow, multifaceted training, and ongoing quality assurance. The HEMS crews' overall sensitivity was 53%, and specificity was 98%. The obtained image quality was highest for the lung, cardiac, and right upper quadrant components of the EFAST. Our results suggest that with a structured multifaceted training program, user-friendly workflow, and ongoing quality assurance, HEMS crews can perform EFAST examinations safely and reliably in the field. This would allow HEMS crews to detect life-threatening, time-sensitive conditions such as a pneumothorax, pericardial effusion, and intraperitoneal hemorrhage. HEMS EFAST has the potential to triage certain trauma patients directly to the operating room or newly emerging hybrid suites, bypassing the emergency room and saving crucial time.

Use of Point-of-Care Ultrasound in the Pediatric and Neonatal Emergency Transport Realm

Point-of-care ultrasound (POCUS) is a tool often used by clinical providers in the care of critically ill or acutely injured patients. POCUS can be used to evaluate for potentially harmful conditions during transport and to optimize downstream management. Although available literature primarily focuses on adults in the prehospital, critical care, and austere environment realm, more literature supporting POCUS use during pediatric and neonatal transport has emerged over the last few years. What is currently available is often from diverse operators and a wide variety of applications. The goal of this article is to describe current pediatric and neonatal POCUS applications and to identify its barriers and limitations in the transport realm. [Pediatr Ann. 2021;50(10):e432-e436.].

Utility of Point of Care Ultrasound in Humanitarian Assistance Missions

INTRODUCTION

Point of care ultrasound (POCUS) is increasingly used in primary care in the USA and has been shown to provide significant benefit to care in deployed military settings and during disaster relief efforts. It is less studied as a tool during humanitarian assistance missions. We sought to determine the utility of POCUS in a humanitarian assistance setting during the February 2019 joint U.S.-Brazilian hospital assistance mission aboard the Hospitalar Assistance Ship Carlos Chagas along the Madeira River in the Brazilian Amazon.

MATERIALS AND METHODS

Point of care ultrasound was offered as a diagnostic modality to primary care physicians during the course of a month-long mission. A handheld IVIZ ultrasound machine was loaned for use during this mission by Sonosite. A P21v phased array (5-1 MHz) or an L38v linear (10-5 MHz) transducer was used for scanning. Requests for POCUS examinations, their findings, and changes in patient management were recorded.

RESULTS

Point of care ultrasound examinations were requested and performed in 24 of 814 (3%) outpatient primary care visits. Ten of these studies (42% of POCUS examinations, 1.2% of all patient visits) directed patient management decisions, in each case preventing unnecessary referral.

CONCLUSIONS

In this austere setting, POCUS proved to be an inexpensive, effective tool at preventing unnecessary referrals. Future medical humanitarian assistance missions may likewise find POCUS to be a primary care force-multiplier.

Handheld Ultrasound Video High-Quality Reconstruction Using a Low-Rank Representation Multipathway Generative Adversarial Network

Recently, the use of portable equipment has attracted much attention in the medical ultrasound field. Handheld ultrasound devices have great potential for improving the convenience of diagnosis, but noise-induced artifacts and low resolution limit their application. To enhance the video quality of handheld ultrasound devices, we propose a low-rank representation multipathway generative adversarial network (LRR MPGAN) with a cascade training strategy. This method can directly generate sequential, high-quality ultrasound video with clear tissue structures and details. In the cascade training process, the network is first trained with plane wave (PW) single-/multiangle video pairs to capture dynamic information and then fine-tuned with handheld/high-end image pairs to extract high-quality single-frame information. In the proposed GAN structure, a multipathway generator is applied to implement the cascade training strategy, which can simultaneously extract dynamic information and synthesize multiframe features. The LRR decomposition channel approach guarantees the fine reconstruction of both global features and local details. In addition, a novel ultrasound loss is added to the conventional mean square error (MSE) loss to acquire ultrasound-specific perceptual features. A comprehensive evaluation is conducted in the experiments, and the results confirm that the proposed method can effectively reconstruct high-quality ultrasound videos for handheld devices. With the aid of the proposed method, handheld ultrasound devices can be used to obtain convincing and convenient diagnoses.

Telemedicine for Patient Management on Expeditions in Remote and Austere Environments: A Systematic Review

Telemedicine potentially offers enormous value to expeditions to remote environments. For healthcare professionals, telemedicine can provide access to specialist advice. Where no healthcare professionals are present, telemedicine may be the sole source of expert care. This systematic review appraises and summarizes the current literature regarding telemedicine in patient management on expeditions to remote locations and identifies areas for future research. MEDLINE and EMBASE were systematically searched for relevant articles from 1980 through February 2018. Data were handled according to the PRISMA process and analyzed using type-specific critical appraisal checklists where possible. Two hundred twenty-five articles were identified, 33 of which were included in this systematic review. They encompassed a variety of remote environments, including maritime (13), polar (9), mountainous (5), jungle (1), and multiple austere environments (6). Although some environments were better reported than others, many overarching concepts were generalizable. Through channels of communication that included telephone, radio, videoconferencing, and email, telemedicine has been used effectively in a range of environments to initiate treatment, follow up with patients, and determine the appropriateness of evacuation. Telementoring, in which a remote expert guides a local care provider in performing a procedure or task, is a promising aspect of telemedicine that is currently being developed. As technology advances, the scope of telemedicine will continue to expand. However, each new telemedical development must be shown to do more than simply function in a remote environment. Instead, new technologies should be tested for improved patient, practitioner, or expedition outcomes, within a telemedical system.

Vertical displacement of pleura: a new method for bronchospasm evaluation?

Background

Lung ultrasonography has been increasingly recognized has a valuable diagnostic tool. In adult patients with asthma/chronic obstructive pulmonary disease and wheezing, LUS usually presents as an A/nude profile (normal profile, with sliding and A-lines, and without any abnormal findings) or at most reveals a decrease/absence of lung sliding. Therefore, until now simple point-of-care ultrasonography appeared to be unable to assess the severity of airflow limitation.

Case presentation

We report the case of a woman presenting to the emergency department with an asthma exacerbation. Bedside ultrasound showed the usual A/normal profile, but also an associated vertical pleural displacement, probably secondary to hyperinflation and accessory muscle recruitment. We evaluated the described movement with M-mode and established a comparison index between end-inspiration and end-expiration, using the skin as reference. This index showed improvement and complete normalization during treatment.

Conclusions

Pleural vertical displacement appears to be a sonographic alteration associated to bronchospasm and accessory muscle recruitment. It is easily identifiable and measurable on LUS, thus possibly representing a new method to evaluate bronchospasm and monitoring treatment response. Further research is needed to confirm or refute this finding.

Ultrasound Use in the Prehospital Setting for Trauma: A Systematic Review

BACKGROUND

Trauma is a leading cause of death in the United States. Ultrasound use in the prehospital environment has the potential to change trauma management. Although ultrasound use for prehospital trauma is increasing, the role of this modality is not clearly defined.

OBJECTIVES

We examined the use of prehospital ultrasound (PHUS) for trauma patients and the use by different provider types. Specific factors of interest were if prehospital ultrasound has been shown to improve providers' ability to recognize conditions that can be managed in the prehospital setting, treat these conditions, change transport destination, or improve overall mortality rates for trauma patients.

METHODS

We searched MEDLINE/PubMed, EBSCOhost, Cochrane Library, and Embase medical literature databases for articles that addressed our outcomes. Abstracts and articles were examined and studies that did not specifically evaluate ultrasound in the prehospital setting for trauma and duplicates were eliminated. Studies included in this comprehensive review were assessed for the use of ultrasound in the prehospital setting to aid in the diagnosis, treatment, and transport of trauma patients. We also conducted an analysis of bias in the included articles. Due to the large heterogeneity in the included studies, no meta-analysis could be performed.

RESULTS

Sixteen studies were identified comprising 3,317 patients. One study evaluated Emergency Medical Services (EMS) professionals as the ultrasound operator while five studies involved mixed practitioners and ten studies involved only physicians. Diagnostic accuracy was similar amongst physicians and mixed practitioners with no studies reporting PHUS accuracy for EMS providers alone. Seven studies evaluated treatment and transport impact of PHUS though the variables measured were inconsistent and results varied by protocol and outcomes measured. There were no studies that evaluated PHUS and its impact on patient mortality.

CONCLUSION

Ultrasound use in the prehospital setting for trauma is feasible and demonstrates potential. However, the evidence in the medical literature mainly consists of prospective observational studies of physicians utilizing ultrasound for trauma in a HEMS setting. Further scientific research must be undertaken to firmly establish the role of prehospital ultrasound in trauma management by all types of EMS providers.

Sonographic evaluation of chest wall thickness in Chinese adults in Hong Kong: Should the updated (10th edition) Advance Trauma Life Support guidelines on preferred site of needle thoracocentesis in tension pneumothorax be adopted in the Asian population?

Objective

To compare the anterior with lateral mean chest wall thickness measured by bedside ultrasound in Chinese adults in order to suggest a preferred site for needle decompression in tension pneumothorax.

Study design

This was an observational cross-sectional study conducted in a regional hospital over three months. Subjects were recruited by convenience sampling. Chest wall thickness at the second intercostal space, mid clavicular line, fifth intercostal space, anterior axillary line and fifth intercostal space and mid axillary line was measured using ultrasound on both sides. Range, mean values and confidence intervals were calculated.

Results

One-hundred and fourteen subjects were recruited. The mean anterior chest wall thickness was 2.62 cm (at second intercostal space, mid-clavicular line) and mean lateral chest wall was 2.68 cm (at fifth intercostal space, anterior axillary line) and 2.87 cm (at fifth intercostal space and mid-axillary line) respectively. Chest wall thickness at fifth intercostal space and mid-axillary line was significantly greater than second intercostal space, mid-clavicular line ( p < 0.01). Chest wall thickness was greater than 5 cm in 3.5% of the study population.

Conclusion

There is a need for population-based guidelines. We recommend needle decompression at the second intercostal space, mid-clavicular line with a 50-mm angiocath for Chinese patients with tension pneumothorax. A lateral approach at the fifth intercostal space, anterior axillary line may be considered as an alternative in case of failure. Prehospital point-of-care ultrasound may be a useful adjunct in managing such patients.

Offshore telementored ultrasound: a quality assessment study

Background

Telementored ultrasound (US) connects experts to novices through various types of communication and network technologies with the overall aim to bridge the medical imaging gap between patients’ diagnostic needs and on-site user experience. The recurrent theme in previous research on remote telementored US is the limited access to US machines and experienced users. This study was conducted to determine whether telementored US was feasible in a remote offshore setting. The aim was to assess if an onshore US expert can guide an offshore nurse through focused US scanning protocols by connecting an US machine to existing videoconference units at the offshore hospitals and to evaluate the diagnostic quality of the images and cineloops procured.

Results

The diagnostic quality of cineloops was scored on a five-point scale. The percentage of cineloops suitable for interpretation (score 3 ≥) for the FATE and e-FAST protocols was 96.4 and 79.1. Lung sliding and seashore sign could be identified in all volunteers. The scan time for the FAST protocol (n = four scanning positions), FATE protocol (n = six scanning positions) and both lungs (n = two scanning positions) was 1 min 20 s, 4 min 15 s and 32 s, respectively.

Conclusion

A novice US user can be guided by a remote expert through focused US protocols within an acceptable time frame and with good diagnostic quality using existing communication and network systems found onboard offshore oil rigs.

Point-of-care ultrasound (POCUS) in Norwegian general practice

Objective: To assess the use of point-of-care ultrasound (POCUS) in Norwegian general practice.Design: Retrospective register study based on general practitioners' (GPs') reimbursement claims.Setting: Norwegian general practice excluding out-of-hours clinics in 2009, 2012 and 2016.Subjects: GPs who scanned patients for a given set of symptoms and medical conditions.Main outcome measures: Number and characteristics of GPs performing POCUS. Number and type of scans carried out.Results: The number of scanning GPs increased from 479 in 2009 to 2078 in 2016. The number of registered scans increased from 8962 to 55921. In 2016, approximately 30% of Norwegian GPs sent at least one reimbursement claim for POCUS. Seven out of 10 GPs did not scan every month. The gender distribution of scanning GPs was equal to that of the total GP population. Male GPs scanned four times more frequent than female GPs. Specialist in family medicine scanned twice as much as non-specialist. The use of POCUS among GPs in different counties varied from 31.6 to 198.5 per 10,000 citizens.Conclusions: The number of Norwegian GPs using POCUS and the number of scans have increased substantially from 2009 to 2016. The use of the various scans, based on the use of reimbursement claims, have evolved differently. The reasons for this are not known. The low number of scans carried out by most GPs raises a concern when it comes to the quality of the performed scans.KEY POINTS30% of Norwegian general practitioners (GPs) used point-of-care ultrasound (POCUS) in 2016.The use of POCUS increased six-fold from 2009 to 2016.Three out of four scanning GPs performed less than 10 scans annually.Male GPs performed 80% of the claimed scans.

Strategic Undersampling and Recovery Using Compressed Sensing for Enhancing Ultrasound Image Quality

In conventional focused beamforming (CFB), there is a known tradeoff between the active aperture size of the ultrasound transducer array and the resulting image quality. Increasing the size of the active aperture leads to an increase in the image quality of the ultrasound system at the expense of increased system cost. An alternate approach is to get rid of the requirement of having consecutive active receive elements and instead place them in a random order in a larger aperture. This, in turn, creates an undersampled situation where there are only M active elements placed in a larger aperture, which can accommodate N consecutive receive elements (with ). It is possible to formulate and solve the above-mentioned undersampling situation using a compressed sensing (CS) approach. In our previous work, we had proposed Gaussian undersampling strategy for reducing the number of active receive elements. In this work, we introduce a novel framework, namely Gaussian undersampling-based CS framework (GAUCS) with wave atoms as a sparsifying basis for CFB imaging method. The performance of the proposed method is validated using simulation and in vitro phantom data. Without an increase in the active elements, it is found that the proposed GAUCS framework improved the lateral resolution (LR) and image contrast by 27% and 1.5 times, respectively, while using 16 active elements and by 39% and 1.1 times, respectively, while using 32 active elements. Thus, the GAUCS framework can play a significant role in improving the performance, especially, of affordable point-of-care ultrasound systems.

Application of Compressive Sensing to Ultrasound Images: A Review

Compressive sensing (CS) offers compression of data below the Nyquist rate, making it an attractive solution in the field of medical imaging, and has been extensively used for ultrasound (US) compression and sparse recovery. In practice, CS offers a reduction in data sensing, transmission, and storage. Compressive sensing relies on the sparsity of data; i.e., data should be sparse in original or in some transformed domain. A look at the literature reveals that rich variety of algorithms have been suggested to recover data using compressive sensing from far fewer samples accurately, but with tradeoffs for efficiency. This paper reviews a number of significant CS algorithms used to recover US images from the undersampled data along with the discussion of CS in 3D US images. In this paper, sparse recovery algorithms applied to US are classified in five groups. Algorithms in each group are discussed and summarized based on their unique technique, compression ratio, sparsifying transform, 3D ultrasound, and deep learning. Research gaps and future directions are also discussed in the conclusion of this paper. This study is aimed to be beneficial for young researchers intending to work in the area of CS and its applications, specifically to US.

Point-of-care blood analysis of hypotensive patients in the emergency department

OBJECTIVE

The aim of this study is to compare a point-of-care (POC) analysis, Enterprise POC (epoc), using the capillary blood obtained from skin puncture with conventional laboratory tests using arterial and venous blood in hypotensive patients.

METHODS

This study was conducted at the emergency department of a tertiary care hospital between June and November 2018. 231 hypotensive patients were enrolled. Three types of blood samples (capillary blood from skin puncture and arterial and venous blood from blood vessel puncture) were collected and analyzed. We compared a total of 13 parameters (pH, pCO2, pO2, HCO3-, Ca2+, lactate, Na+, K+, Cl-, glucose, Hb, Hct, and creatinine) between the POC analysis and reference analyzers by performing the equivalence test and Bland-Altman plot analysis.

RESULTS

In hypotensive patients, with the exception of two parameters (pCO2, pO2), the pH, HCO3-, Ca2+, lactate, Na+, K+, Cl-, glucose, Hb, Hct, and creatinine parameters measured by the POC analysis were equivalent to or correlated with the reference values. In the patients with cardiac arrest group, nine parameters (pH, HCO3-, Ca2+, Na+, K+, glucose, Hb, Hct, and creatinine) analyzed by the epoc system were equivalent to the reference values.

CONCLUSION

Most parameters, except pO2, measured by the epoc system using the capillary blood in hypotensive patients were equivalent to or correlated with those measured by the reference analyzers.

Compressed Sensing with Gaussian Sampling Kernel for Ultrasound Imaging

Recently, compressed sensing (CS) has been applied to ultrasound imaging for either data reduction or frame rate improvement. However, there are no detailed reports yet on strategies for lateral undersampling of channel data in conventional focused beamforming (CFB) and its recovery exploiting the CS approach. We propose a strategic lateral undersampling approach for channel data using the Gaussian sampling scheme and compare it with a direct extension of the often-used uniform undersampling reported for axial undersampling to the lateral direction and 2-D random sampling reported in the literature. As opposed to the reported 2-D random undersampling, we explore undersampling of channel data in the lateral direction by acquiring radiofrequency data from only a reduced number of chosen receive elements and subjecting these data to further undersampling in the axial direction. The effect of the sampling schemes on CS recovery was studied using data from simulations and experiments for various lateral and axial undersampling rates. The results suggest that CS-recovered data from the Gaussian distribution-based channel data subsampling yielded better recovery and contrast in comparison to those obtained from the often-used uniform distribution-based undersampling. Although 90% of the samples from the original data using the proposed sampling scheme were discarded, the contrast of the CS-recovered image was comparable to that of the reference image. Thus, CS with the proposed Gaussian sampling scheme for channel data subsampling not only reduces the data size significantly, but also strategically uses only a few active receive elements in the process; thus, it can provide an attractive option for the affordable point-of-care ultrasound system.

Image Quality Improvement of Hand-Held Ultrasound Devices With a Two-Stage Generative Adversarial Network

As a widely used imaging modality in the medical field, ultrasound has been applied in community medicine, rural medicine, and even telemedicine in recent years. Therefore, the development of portable ultrasound devices has become a popular research topic. However, the limited size of portable ultrasound devices usually degrades the imaging quality, which reduces the diagnostic reliability. To overcome hardware limitations and improve the image quality of portable ultrasound devices, we propose a novel generative adversarial network (GAN) model to achieve mapping between low-quality ultrasound images and corresponding high-quality images. In contrast to the traditional GAN method, our two-stage GAN that cascades a U-Net network prior to the generator as a front end is built to reconstruct the tissue structure, details, and speckle of the reconstructed image. In the training process, an ultrasound plane-wave imaging (PWI) data-based transfer learning method is introduced to facilitate convergence and to eliminate the influence of deformation caused by respiratory activities during data pair acquisition. A gradual tuning strategy is adopted to obtain better results by the PWI transfer learning process. In addition, a comprehensive loss function is presented to combine texture, structure, and perceptual features. Experiments are conducted using simulated, phantom, and clinical data. Our proposed method is compared to four other algorithms, including traditional gray-level-based methods and learning-based methods. The results confirm that the proposed approach obtains the optimum solution for improving quality and offering useful diagnostic information for portable ultrasound images. This technology is of great significance for providing universal medical care.

Diagnostic value of prehospital arterial blood gas measurements - a randomised controlled trial

Background

Arterial blood gas analysis is an important diagnostic tool in managing critically ill patients within the hospital. Whether prehospital application of this diagnostic modality contributes to more exact diagnoses and treatments in critically ill prehospital patients is unknown. The aim of this study was to establish whether access to arterial blood gas analysis increased the prehospital diagnostic accuracy of prehospital anaesthesiologists. Furthermore, we investigated whether prehospital blood gas analysis resulted in therapeutic interventions that would not have been carried out if the arterial blood gas analyser had not been available.

Methods

In a prospective randomised study, two groups of prehospital adult patients with acute critical illness were compared. All patients received standard prehospital care. In the intervention group, an arterial blood gas sample was analysed prehospitally. The primary outcome was the impact of blood gas analysis on the accuracy of prehospital diagnoses. Furthermore, we registered any therapeutic interventions that were carried out as a direct result of the blood gas analysis.

Results

A total of 310 patients were included in the study. Eighty-eight of these patients were subsequently excluded, primarily due to difficulties in obtaining post hoc consent or venous sampling or other technical difficulties. A total of 102 patients was analysed in the arterial blood gas group (ABG group), while 120 patients were analysed in the standard care group (noABG group). In 78 of the 102 patients in the ABG group, the prehospital physician reported that ABG analysis increased their perceived diagnostic precision. In 81 cases in the noABG group, the lack of arterial blood gas analysis was perceived to have decreased diagnostic accuracy. The claim that ABG analysis increased diagnostic accuracy could, however, not be substantiated as there was no difference in the number of un-specific diagnoses between the groups.

Blood gas analysis increased the probability of targeting specific prehospital therapeutic interventions and led to 159 interventions, including intubation, ventilation and/or upgrading the level of urgency, in 71 ABG-group patients (p < 0.001).

Conclusion

Although prehospital arterial blood gas analysis did not improve the accuracy of the prehospital diagnoses assigned to patients, it significantly increased the quality of treatment provided to patients with acute critical illness.

Trial registration

ClinicalTrials.gov, NCT03006692, retrospectively registered six months after first patient entry.

A real-time data-based scan conversion method for single element ultrasound transducers

The current work investigates the performance of a real-time scan conversion algorithm for generating a 2-D ultrasound image from a laterally scanned single-element ultrasound transducer, which has applications in point-of-care devices such as for skin imaging. The algorithm employs a fixed calibration curve to update a predefined image grid in real time. Simulations showed that the calibration curve (with a maximum of 1) is robust to changes in scatterer concentration (8.3×10^-3 mean absolute error), signal to noise ratio (1.0×10^-3 mean absolute error for -5 dB SNR), and can be accurately predicted from a small number (31) of point scatterers (6.9×10^-3 mean absolute error). Good agreement was also found between the calibration curves obtained from simulated and experimental data (1.19×10^-2 mean absolute error). The scan conversion algorithm was validated by evaluation of the position estimation errors on both simulations and experiments. Clinical images of skin lesions (N = 20) demonstrate the feasibility of the algorithm for real, non-homogeneous tissue. Use of a fixed calibration curve compared to an adaptive calibration curve gave similar accuracies in the scanning step size range of 150-350 μm (with an average overlap of the accuracy ranges of 92.94% for simulations and 42.83% for experiments), and a 350-fold improvement in computation time.

Evaluation of Noncommercial Ultrasound Gels for Use in Resource-Limited Settings

OBJECTIVES

Ultrasound (US) is increasingly used in settings where commercial US gel is unavailable. This study evaluated noncommercial gel recipes compared to commercial gel.

METHODS

A search for US gel formulations revealed 6 recipes. Half-strength commercial gel and a modified glucomannan recipe were also tested. Nine gels, including commercial gel, were tested in Liberia and the United States. In each session, 2 physician sonologists evaluated 9 gels on 2 models, obtaining videos from the hepatorenal space with a curvilinear transducer, the cardiac parasternal long view with a phased array transducer, and the left basilic vein with a linear transducer. The sonologists and models, who were blinded to gel identity, made independent quantitative and qualitative gel evaluations comparing the test gel to commercial gel. Two physician sonologists who were blinded to the gel identities and a US operator reviewed the images and rated their quality. An analysis of variance in repeated measures was performed to test for differences in the overall score, real-time quality, and other characteristics. Post hoc pairwise comparisons to commercial gel were performed with a Tukey-Kramer adjustment. Inter- and intra-rater reliability was calculated for the image review.

RESULTS

Commercial gel earned a perfect score. Compared to commercial gel, xanthine gum gel scored highest, followed by half-strength commercial gel. Hot concentrated glucomannan and cold glucomannan gel were found to be significantly worse than commercial gel. No significant difference was found between images based on the gel used on the image review.

CONCLUSIONS

No significant difference in image quality was found between commercial and noncommercial gels on US image review.

Usefulness of point-of-care ultrasound in military medical emergencies performed by young military medicine residents

INTRODUCTION

To evaluate the usefulness of point-of-care ultrasound (POCUS) performed by young military medicine residents after short training in the diagnosis of medical emergencies.

METHODS

A prospective study was performed in the emergency department of a French army teaching hospital. Two young military medicine residents received ultrasound training focused on gall bladder, kidneys and lower limb veins. After clinical examination, they assigned a 'clinical diagnostic probability' (CP) on a visual analogue scale from 0 (definitely not diagnosis) to 10 (definitive diagnosis). The same student performed ultrasound examination and assigned an 'ultrasound diagnostic probability' (UP) in the same way. The absolute difference between CP and UP was calculated. This result corresponded to the Ultrasound Diagnostic Index (UDI), which was positive if UP was closer to the final diagnosis than CP (POCUS improved the diagnostic accuracy), and negative conversely (POCUS decreased the diagnostic accuracy).

RESULTS

Forty-eight patients were included and 48 ultrasound examinations were performed. The present pathologies were found in 14 patients (29%). The mean UDI value was +3 (0-5). UDI was positive in 35 exams (73%), zero in 12 exams (25%) and negative in only one exam (2%).

CONCLUSION

POCUS performed after clinical examination increases the diagnostic accuracy of young military medicine residents.

Remote Mentoring of Point-of-Care Ultrasound Skills to Inexperienced Operators Using Multiple Telemedicine Platforms: Is a Cell Phone Good Enough?

OBJECTIVES

Telemedicine technology contributes to the teaching of point-of-care ultrasound (US); however, expensive equipment can limit its deployment in resource-challenged settings. We assessed 3 low-cost telemedicine solutions capable of supporting remote US training to determine feasibility, acceptability, and effectiveness. We also explored the value of instructional videos immediately before telementoring.

METHODS

Thirty-six participants were randomly assigned to receive US mentoring in 1 of 3 telemedicine conditions: multiple fixed cameras, a smartphone, and traditional audio with a live US stream. Participants were then asked to perform a standardized US examination of the right upper quadrant under remote guidance. We measured observer's global ratings of performance along with the mentor's and student's rating of effort and satisfaction to determine which of the 3 approaches was most feasible, acceptable, and effective. During the second phase, students were randomized to watch an instructional video or not before receiving remote coaching on how to complete a subxiphoid cardiac examination. Effort, satisfaction, and performance from the independent observer's and student's perspective were surveyed.

RESULTS

There was no significant difference between the different telemedicine setups from the observer's perspective; however, the mentor rated the smartphone significantly worse (P = .028-.04) than other technologies. Platforms were rated equivalent from the student's perspective. No benefit was detected for watching an instructional video before the mentored task.

CONCLUSIONS

Remote US skills can be taught equally effectively by using a variety of telemedicine technologies. Smartphones represent a viable option for US training in resource-challenged settings.

Use of Ultrasound for Joint Dislocation Reduction in an Austere Wilderness Setting: A Case Report

Point-of-care ultrasound has been shown to have a demonstrable impact in the austere/out-of-hospital environment. As ultrasounds become more affordable and portable, a myriad of uses in austere environments are becoming recognized. We present a case of a stranded hiker with an ultrasound-confirmed glenohumeral joint dislocation who underwent ultrasound-guided intra-articular lidocaine injection and ultrasound-confirmed reduction. This procedure allowed the patient to hike out under his own power, avoiding the potential dangers of extrication to both patient and rescuers. We believe this case demonstrates the feasibility and utility of ultrasound in the out-of-hospital environment both procedurally and diagnostically.

Evaluation of Glucomannan Powder as an Ultrasound Transmission Gel Alternative for Resource-Constrained Environments: A Prospective, Comparative Study

INTRODUCTION

Resource and logistical constraints may limit the availability of commercial ultrasound (US) transmission gel (USTG) in austere environments. Glucomannan powder, a dietary fiber supplement, can be mixed with tap water to form a gel that may be a field-expedient substitute for USTG. We compared glucomannan gel with a commercial USTG for US image adequacy and quality.

METHODS

A single clinician obtained 193 US video clips from 14 different examinations on live-tissue and simulation training models using both commercial and glucomannan USTGs. Four US fellowship-trained providers, blinded to type of gel used, independently reviewed the randomized US video clips. The primary outcome of US image adequacy was scored as "yes" or "no" and analyzed using Pearson χ² analysis. The secondary outcome of image quality was rated on a 0 to 5 Likert scale and analyzed with the independent t test.

RESULTS

For US image adequacy, commercial USTG was superior to glucomannan gel (P=0.042, 95% CI: 96.5-96.6%), with commercial USTG adequate in 96.6% of images (375 of 388 "yes"), whereas glucomannan USTG was adequate in 93.5% (359 of 384 "yes") of images. For US image quality there was no statistically significant difference between the 2 USTGs (P=0.176, 95% CI: 93.4-93.5%), with commercial USTG rated at 3.4±1.0 and glucomannan gel at 3.3±1.1.

CONCLUSION

Despite a high image adequacy rate, glucomannan gel proved inferior to commercial USTG for US image adequacy but produced equivalent image quality. Glucomannan USTG may be a reasonable substitute when commercial USTG is unavailable.

ABCDE of prehospital ultrasonography: a narrative review

Prehospital point-of-care ultrasound used by nonradiologists in emergency medicine is gaining ground. It is feasible on-scene and during aeromedical transport and allows health-care professionals to detect or rule out potential harmful conditions. Consequently, it impacts decision-making in prioritizing care, selecting the best treatment, and the most suitable transport mode and destination. This increasing relevance of prehospital ultrasonography is due to advancements in ultrasound devices and related technology, and to a growing number of applications. This narrative review aims to present an overview of prehospital ultrasonography literature. The focus is on civilian emergency (trauma and non-trauma) setting. Current and potential future applications are discussed, structured according to the airway, breathing, circulation, disability, and environment/exposure (ABCDE) approach. Aside from diagnostic implementation and specific protocols, procedural guidance, therapeutic ultrasound, and challenges are reviewed.

Recent Developments in Tele-Ultrasonography

A long-standing trend that will continue to grow in healthcare is providing high quality services for all the patient, no matter the distance and no matter the place. One approach currently being used to increase population access to healthcare services is telemedicine. This narrative review presents one branch of e-health, in particular the use of teleultrasonography (TUS) in clinical practice, the challenges and barriers encountered. Current advances in ultrasound technology, including the growth of portable and small ultrasound devices have increased the range of applications of TUS, from traumatic patients in emergency medicine, maternal ultrasound and even for monitoring and screening for chronic illnesses. Even though some barriers are still looking for a solution, like standardized training and protocols, errors in data acquisition, the lack of trained professionals to operate in remote areas, TUS has the potential to redesign future health care systems.

Elastography for portable ultrasound

Portable wireless ultrasound has been emerging as a new ultrasound device due to its unique advantages including small size, lightweight, wireless connectivity and affordability. Modern portable ultrasound devices can offer high quality sonogram images and even multiple ultrasound modes such as color Doppler, echocardiography, and endovaginal examination. However, none of them can provide elastography function yet due to the limitations in computational performance and data transfer speed of wireless communication. Also phase-based strain estimator (PSE) that is commonly used for conventional elastography cannot be adopted for portable ultrasound, because ultrasound parameters such as data dumping interval are varied significantly in the practice of portable ultrasound. Therefore, this research aims to propose a new elastography method suitable for portable ultrasound, called the robust phase-based strain estimator (RPSE), which is not only robust to the variation of ultrasound parameters but also computationally effective. Performance and suitability of RPSE were compared with other strain estimators including time-delay, displacement-gradient and phase-based strain estimators (TSE, DSE and PSE, respectively). Three types of raw RF data sets were used for validation tests: two numerical phantom data sets modeled by an open ultrasonic simulation code (Field II) and a commercial FEA (Abaqus), and the one experimentally acquired with a portable ultrasound device from a gelatin phantom. To assess image quality of elastograms, signal-to-noise (SNRe) and contrast-to-noise (CNRe) ratios were measured on the elastograms produced by each strain estimator. The computational efficiency was also estimated and compared. Results from the numerical phantom experiment showed that RPSE could achieve highest values of SNRe and CNRe (around 5.22 and 47.62 dB) among all strain estimators tested, and almost 10 times higher computational efficiency than TSE and DSE (around 0.06 vs. 5.76 s per frame for RPSE and TSE, respectively).

The reliability of carotid ultrasound in determining the return of pulsatile flow: A pilot study

Manual palpation of pulses is unreliable in detecting pulsatile flow in human participants, complicating the assessment of return of spontaneous circulation after cardiac arrest. Ultrasound may offer an alternative. This study's objective was to investigate whether return of pulsatile flow in humans can be reliably assessed by common carotid artery ultrasound. We conducted a single-blinded randomised study of common carotid artery ultrasound using 20 cardiopulmonary bypass patients to model the return of pulsatile flow. Synchronised time-stamped videos of radial artery invasive blood pressure and 10 two-dimensional or 10 colour Doppler ultrasounds were recorded. Three independent reviewers recorded the timestamp where they considered pulsatile flow was first visible on ultrasound. Ultrasound times were compared to the onset of arterial line pulsatile flow and reliability assessed by intraclass correlation coefficient. The median difference between radial artery and ultrasound flow time (interquartile range (range)) was 24 seconds (5-40 (0-93)) for two-dimensional and 5 seconds (2-17 (-28 to 188)) for colour Doppler. The intraclass correlation coefficient for two-dimensional ultrasound was 0.86 (95%CI 0.63-0.96) and 0.32 (95%CI -0.01 to 0.71) for colour Doppler. The median (interquartile range (range)) mean arterial pressure where ultrasound flow occurred for two-dimensional ultrasound was 62 mmHg (49-74 (33-82)) and 56 mmHg (52-73 (43-83)) for colour Doppler. In our pilot study, two-dimensional ultrasound was reliable in detecting the return of pulsatile flow. Colour Doppler detected pulsatile flow earlier and at lower mean arterial pressure but was not reliable, although a larger study is needed to determine colour Doppler's utility.

Prehospital Ultrasound in Trauma: A Review of Current and Potential Future Clinical Applications

Ultrasound (US) is an essential tool for evaluating trauma patients in the hospital setting. Many previous in-hospital studies have been extrapolated to out of hospital setting to improve diagnostic accuracy in prehospital and austere environments. This review article presents the role of prehospital US in blunt and penetrating trauma management with emphasis on its current clinical applications, challenges, and future implications of such use.

Emergency medical technician-performed point-of-care blood analysis using the capillary blood obtained from skin puncture

OBJECTIVE

Comparing a point-of-care (POC) test using the capillary blood obtained from skin puncture with conventional laboratory tests.

METHODS

In this study, which was conducted at the emergency department of a tertiary care hospital in April-July 2017, 232 patients were enrolled, and three types of blood samples (capillary blood from skin puncture, arterial and venous blood from blood vessel puncture) were simultaneously collected. Each blood sample was analyzed using a POC analyzer (epoc® system, USA), an arterial blood gas analyzer (pHOx®Ultra, Nova biomedical, USA) and venous blood analyzers (AU5800, DxH2401, Beckman Coulter, USA). Twelve parameters were compared between the epoc and reference analyzers, with an equivalence test, Bland-Altman plot analysis and linear regression employed to show the agreement or correlation between the two methods.

RESULTS

The pH, HCO₃, Ca²⁺, Na⁺, K⁺, Cl^-, glucose, Hb and Hct measured by the epoc were equivalent to the reference values (95% confidence interval of mean difference within the range of the agreement target) with clinically inconsequential mean differences and narrow limits of agreement. All of them, except pH, had clinically acceptable agreements between the two methods (results within target value ≥80%). Of the remaining three parameters (pCO_2, pO₂ and lactate), the epoc pCO₂ and lactate values were highly correlated with the reference device values, whereas pO₂ was not. (pCO₂: R²=0.824, y=-1.411+0.877·x; lactate: R²=0.902, y=-0.544+0.966·x; pO₂: R²=0.037, y=61.6+0.431·x).

CONCLUSION

Most parameters, except only pO₂, measured by the epoc were equivalent to or correlated with those from the reference method.

Compressed Sensing for Elastography in Portable Ultrasound

Portable ultrasound is recently emerging as a new medical imaging modality featuring high portability, easy connectivity, and real-time on-site diagnostic ability. However, it does not yet provide ultrasound elastography function that enables the diagnosis of malignant lesions using elastic properties. This is mainly due to the limitations of hardware performance and wireless data transfer speed for processing the large amount of data for elastography. Therefore, data transfer reduction is one of the feasible solutions to overcome these limitations. Recently, compressive sensing (CS) theory has been rigorously studied as a means to break the conventional Nyquist sampling rate and thus can significantly decrease the amount of measurement signals without sacrificing signal quality. In this research, we implemented various CS reconstruction frameworks and comparatively evaluated their reconstruction performance for realizing ultrasound elastography function on portable ultrasound. Combinations of three most common model bases (Fourier transform [FT], discrete cosine transform [DCT], and wave atom [WA]) and two reconstruction algorithms (L1 minimization and block sparse Bayesian learning [BSBL]) were considered for CS frameworks. Echoic and elastography phantoms, were developed to evaluate the performance of CS on B-mode images and elastograms. To assess the reconstruction quality, mean absolute error (MAE), signal-to-noise ratio (SNRe), and contrast-to-noise ratio (CNRe) were measured on the B-mode images and elastograms from CS reconstructions. Results suggest that CS reconstruction adopting BSBL algorithm with DCT model basis can yield the best results for all the measures tested, and the maximum data reduction rate for producing readily discernable elastograms is around 60%.

Application of compressive sensing to portable ultrasound elastography

Feasibility of applying compressive sensing (CS) to ultrasound radio-frequency (RF) data to produce elastography is investigated. The research also compares the performance of various CS frameworks associated with three common model bases (Fourier transform, discrete cosine transform (DCT), and wave atom (WA)) and two reconstruction algorithms (ℓ₁ minimization and block sparse Bayesian learning (BSBL)) using the quality of B-mode images and elastograms from the RF data subsampled and reconstructed by each framework. Results suggest that CS reconstruction adopting BSBL algorithm with DCT model basis can yield the best results for all the measures tested, and the maximum data reduction rate for producing readily discernable elastograms is around 60%.

Point-of-care ultrasonography in Norwegian out-of-hours primary health care

OBJECTIVE

The objective of this study is to determine the extent of ultrasound availability in Norwegian casualty clinics and estimate the prevalence of its use.

DESIGN

A retrospective study based on a national casualty clinic registry and data from reimbursement claims.

SETTING

Out-of-hours primary health care in Norway.

SUBJECTS

All Norwegian casualty clinics in 2016 and reimbursement claims from 2008 to 2015.

MAIN OUTCOME MEASURES

Percent of casualty clinics with ultrasound, types of ultrasound devices and probes, reasons for/against ultrasound access, characteristics of clinics with/without ultrasound, frequency of five ultrasound indications and characteristics of the physicians using/not using ultrasound.

RESULTS

Out of 182 casualty clinics, 41 (23%) reported access to ultrasound. Mobile (49%) and stationary (44%) devices were most frequent. Physician request was the most common cited reason for ultrasound access (66%). Neither population served by the casualty clinic nor distance to hospital showed any clear association with ultrasound access. All of the five ultrasound reimbursement codes showed a substantial increase from 2008 to 2015 with 14.1 ultrasound examinations being performed per 10,000 consultations in 2015. Only 6.5% of physicians performed ultrasound in 2015 and males were significantly more likely to use ultrasound than females (OR 1.85, 95% CI: 1.38-2.47, p < .001), even when adjusted for age, speciality status and geography.

CONCLUSIONS

Although the use of ultrasound is increasing in out-of-hours Norwegian primary health care, most casualty clinics do not have access and only a minority of physicians use ultrasound.

Implementation of the ABL-90 blood gas analyzer in a ground-based mobile emergency care unit

Point-of Care analysis is increasingly being applied in the prehospital scene. Arterial blood gas analysis is one of many new initiatives adding to the diagnostic tools of the prehospital physician. In this paper we present a study on the feasibility of the Radiometer ABL-90 in a ground-based Mobile Emergency Care Unit and report on some clinical situations in which the apparatus has proven beneficial.