The ability of emergency nurses to detect simulated long bone fractures with portable ultrasound

Kirschner Wire Fixation in Dorsally Displaced Distal Radius Fractures: A Biomechanical Evaluation

Background  There is currently no consensus for the optimum configuration and number of Kirschner wires (K-wires) to use for the stabilization of dorsally displaced distal radius fractures. In this biomechanical study, we compared the load to failure and stiffness of four common K-wire configurations to identify the strongest construct for use in extra-articular dorsally displaced distal radius fractures. Case Description  We created a standard distal radius fracture model in turkey tarsometatarsi which was stabilized using two or three K-wires (1.6 mm) in four different configurations. Following a power calculation, 10 fracture models of each configuration underwent testing in cantilever bending and axial compression. Literature Review  Recent randomized trials have shown no evidence that volar locking plates are superior to K-wires for the treatment of dorsally displaced distal radius fractures. This has led to an increase in the popularity of much cheaper K-wires. Several different K-wire techniques have been described but there is no strong evidence to determine which is the optimal configuration and number of wires. Clinical Relevance  The three-wire interfragmentary configuration was stiffer than the three-wire Kapandji in axial compression and cantilever bending. There was no difference in load to failure in cantilever bending or axial compression. The three-wire interfragmentary technique is the stiffest configuration of K-wires for dorsally displaced distal radius fractures. The two-wire Kapandji technique was significantly weaker than the other configurations, especially in cantilever bending. Conclusion  The authors recommend to always use three wires for percutaneous pinning and never to use two intrafocal wires alone.

Nurse Performed Ultrasonography in Confirming the Position of Nasogastric Tube in the Emergency Department: A Prospective Single Group Diagnostic Test Study

Introduction

Emergency nurses often encounter patients with nasogastric tube (NGT) dislodgements who require reinsertion. Empirical evidence supporting the use of ultrasonography in verifying the position of NGT in local accident and emergency departments (AED) is scanty. There is also a lack of validation of nurse performed ultrasonography in Hong Kong. With the support from hospitals and medical personnel, a prospective, single group diagnostic test study was conducted to review the possibility of nurse performed ultrasonography in verifying the position of NGT in AED.

Methods

This study was conducted in the AED of three local hospitals. Investigators with specific ultrasound training performed ultrasonography scans to the subjects in addition to conventional pH test and “whoosh” test. Results were compared with chest or abdominal X-ray for evaluation of accuracies.

Results

This study confirmed a high sensitivity and specificity of nurse performed ultrasonography in confirming the position of NGT in the AED. The high positive predictive value and positive likelihood ratio supported the confirmation of NGT position by bedside ultrasound. The high specificities and minimal negative likelihood ratios of ultrasonography tests also suggested the application of bedside ultrasound in ruling out patients with misplaced NGTs.

Conclusions

Nurse performed ultrasonography allows immediate bedside confirmation of the position of NGT in the overcrowded AED. Considered the limitations of conventional methods, nurse performed ultrasonography can be incorporated into daily practice for providing extra evidence for the confirmation of NGT position.

Pilot Educational Intervention and Feasibility Assessment of Breast Ultrasound in Rural South Africa

PURPOSE

Breast cancer is the leading cause of cancer death in women worldwide, with high mortality in low- and middle-income countries because of a lack of detection, diagnosis, and treatment. With mammography unavailable, ultrasound offers an alternative for downstaging. The literature reports successful training in various domains, but a focus on the breast is novel. We assessed the feasibility (knowledge acquisition, perceived usefulness, and self-efficacy) of breast ultrasound training for nonphysician providers.

METHODS

Training was implemented for 12 providers at Hlokomela Clinic in Hoedspruit, South Africa, over 3 weeks. Didactic presentations and example cases were followed by a presurvey and test (n = 12). All providers received hands-on training with nurses as models; five providers trained with patients. A post-test (n = 12) assessed knowledge acquisition and a postsurvey (n = 10) assessed perceived program usefulness and provider self-efficacy.

RESULTS

The pre- to post-test averages improved by 68% in total and in four competencies (foundational knowledge, descriptive categories, benign v malignant, and lesion identification). On the postsurvey, providers expressed that ultrasound could significantly influence breast cancer detection (9.1 out of 10), treatment (7.9 out of 10), and survival (8.7 out of 10) in their community and endorsed moderate confidence in their scanning (6.3 out of 10) and interpreting abilities (5.6 out of 10).

CONCLUSION

Our research supports the feasibility of breast ultrasound training as part of a breast education program in low- and middle-income countries. Pre- and post-test results and observed proficiency indicate that training nonphysician providers is achievable; postsurvey responses indicate program acceptance, community-based ownership, and provider self-efficacy with ultrasound. Future work may show that breast ultrasound is viable for early detection where mammography is unavailable.

Ultrasound for Distal Forearm Fracture: A Systematic Review and Diagnostic Meta-Analysis

Study Objective

To determine the diagnostic accuracy of ultrasound for detecting distal forearm fractures.

Methods

A systematic review and diagnostic meta-analysis was performed according to the PRISMA statement. We searched MEDLINE, Web of Science and the Cochrane Library from inception to September 2015. All prospective studies of the diagnostic accuracy of ultrasound versus radiography as the reference standard were included. We excluded studies with a retrospective design and those with evidence of verification bias. We assessed the methodological quality of the included studies with the QUADAS-2 tool. We performed a meta-analysis of studies evaluating ultrasound to calculate the pooled sensitivity and specificity with 95% confidence intervals (CI95%) using a bivariate model with random effects. Subgroup and sensitivity analysis were used to examine the effect of methodological differences and other study characteristics.

Results

Out of 867 publications we included 16 studies with 1,204 patients and 641 fractures. The pooled test characteristics for ultrasound were: sensitivity 97% (CI95% 93–99%), specificity 95% (CI95% 89–98%), positive likelihood ratio (LR) 20.0 (8.5–47.2) and negative LR 0.03 (0.01–0.08). The corresponding pooled diagnostic odds ratio (DOR) was 667 (142–3,133). Apparent differences were shown for method of viewing, with the 6-view method showing higher specificity, positive LR, and DOR, compared to the 4-view method.

Conclusion

The present meta-analysis showed that ultrasound has a high accuracy for the diagnosis of distal forearm fractures in children when used by proper viewing method. Based on this, ultrasound should be considered a reliable alternative, which has the advantages of being radiation free.

Diagnostic accuracy of history, physical examination, and bedside ultrasound for diagnosis of extremity fractures in the emergency department: a systematic review

OBJECTIVES

Understanding history, physical examination, and ultrasonography (US) to diagnose extremity fractures compared with radiography has potential benefits of decreasing radiation exposure, costs, and pain and improving emergency department (ED) resource management and triage time.

METHODS

The authors performed two electronic searches using PubMed and EMBASE databases for studies published between 1965 to 2012 using a strategy based on the inclusion of any patient presenting with extremity injuries suspicious for fracture who had history and physical examination and a separate search for US performed by an emergency physician (EP) with subsequent radiography. The primary outcome was operating characteristics of ED history, physical examination, and US in diagnosing radiologically proven extremity fractures. The methodologic quality of the studies was assessed using the quality assessment of studies of diagnostic accuracy tool (QUADAS-2).

RESULTS

Nine studies met the inclusion criteria for history and physical examination, while eight studies met the inclusion criteria for US. There was significant heterogeneity in the studies that prevented data pooling. Data were organized into subgroups based on anatomic fracture locations, but heterogeneity within the subgroups also prevented data pooling. The prevalence of fracture varied among the studies from 22% to 70%. Upper extremity physical examination tests have positive likelihood ratios (LRs) ranging from 1.2 to infinity and negative LRs ranging from 0 to 0.8. US sensitivities varied between 85% and 100%, specificities varied between 73% and 100%, positive LRs varied between 3.2 and 56.1, and negative LRs varied between 0 and 0.2.

CONCLUSIONS

Compared with radiography, EP US is an accurate diagnostic test to rule in or rule out extremity fractures. The diagnostic accuracy for history and physical examination are inconclusive. Future research is needed to understand the accuracy of ED US when combined with history and physical examination for upper and lower extremity fractures.

The effects of transducer geometry on artifacts common to diagnostic bone imaging with conventional medical ultrasound

The portability, low cost, and non-ionizing radiation associated with medical ultrasound suggest that it has potential as a superior alternative to X-ray for bone imaging. However, when conventional ultrasound imaging systems are used for bone imaging, clinical acceptance is frequently limited by artifacts derived from reflections occurring away from the main axis of the acoustic beam. In this paper, the physical source of off-axis artifacts and the effect of transducer geometry on these artifacts are investigated in simulation and experimental studies. In agreement with diffraction theory, the sampled linear-array geometry possessed increased off-axis energy compared with single-element piston geometry, and therefore, exhibited greater levels of artifact signal. Simulation and experimental results demonstrated that the linear-array geometry exhibited increased artifact signal when the center frequency increased, when energy off-axis to the main acoustic beam (i.e., grating lobes) was perpendicularly incident upon off-axis surfaces, and when off-axis surfaces were specular rather than diffusive. The simulation model used to simulate specular reflections was validated experimentally and a correlation coefficient of 0.97 between experimental and simulated peak reflection contrast was observed. In ex vivo experiments, the piston geometry yielded 4 and 6.2 dB average contrast improvement compared with the linear array when imaging the spinous process and interlaminar space of an animal spine, respectively. This work indicates that off-axis reflections are a major source of ultrasound image artifacts, particularly in environments comprising specular reflecting (i.e., bone or bone-like) objects. Transducer geometries with reduced sensitivity to off-axis surface reflections, such as a piston transducer geometry, yield significant reductions in image artifact.