The association of attentional foci and image interpretation accuracy in novices interpreting lung ultrasound images: an eye-tracking study.

It is unclear, where learners focus their attention when interpreting point-of-care ultrasound (POCUS) images. This study seeks to determine the relationship between attentional foci metrics with lung ultrasound (LUS) interpretation accuracy in novice medical learners. A convenience sample of 14 medical residents with minimal LUS training viewed 8 LUS cineloops, with their eye-tracking patterns recorded. Areas of interest (AOI) for each cineloop were mapped independently by two experts, and externally validated by a third expert. Primary outcome of interest was image interpretation accuracy, presented as a percentage. Eye tracking captured 10 of 14 participants (71%) who completed the study. Participants spent a mean total of 8 min 44 s ± standard deviation (SD) 3 min 8 s on the cineloops, with 1 min 14 s ± SD 34 s spent fixated in the AOI. Mean accuracy score was 54.0% ± SD 16.8%. In regression analyses, fixation duration within AOI was positively associated with accuracy [beta-coefficients 28.9 standardized error (SE) 6.42, P = 0.002). Total time spent viewing the videos was also significantly associated with accuracy (beta-coefficient 5.08, SE 0.59, P < 0.0001). For each additional minute spent fixating within the AOI, accuracy scores increased by 28.9%. For each additional minute spent viewing the video, accuracy scores increased only by 5.1%. Interpretation accuracy is strongly associated with time spent fixating within the AOI. Image interpretation training should consider targeting AOIs.

Lung ultrasound: A comparison of image interpretation accuracy between curvilinear and phased array transducers.

Introduction: Both curvilinear and phased array transducers are commonly used to perform lung ultrasound (LUS). This study seeks to compare LUS interpretation accuracy of images obtained using a curvilinear transducer with those obtained using a phased array transducer. Methods: We invited 166 internists and trainees to interpret 16 LUS images/cineloops of eight patients in an online survey: eight curvilinear and eight phased array, performed on the same lung location. Images depicted normal lung, pneumothorax, pleural irregularities, consolidation/hepatisation, pleural effusions and B-lines. Primary outcome for each participant is the difference in image interpretation accuracy scores between the two transducers. Results: A total of 112 (67%) participants completed the survey. The mean paired accuracy score difference between the curvilinear and phased array images was 3.0% (95% CI: 0.6 to 5.4%, P = 0.015). For novices, scores were higher on curvilinear images (mean difference: 5.4%, 95% CI: 0.9 to 9.9%, P = 0.020). For non-novices, there were no differences between the two transducers (mean difference: 1.4%, 95% CI: -1.1 to 3.9%, P = 0.263). For pleural-based findings, the mean of the paired differences between transducers was higher in the novice group (estimated mean difference-in-differences: 9.5%, 95% CI: 0.6 to 18.4%; P = 0.036). No difference in mean accuracies was noted between novices and non-novices for non-pleural-based pathologies (estimated mean difference-in-differences: 0.6%, 95% CI to 5.4-6.6%; P = 0.837). Conclusions: Lung ultrasound images obtained using the curvilinear transducer are associated with higher interpretation accuracy than the phased array transducer. This is especially true for novices interpreting pleural-based pathologies.

An overview of Internal Medicine Point-of-Care Ultrasound rotations in Canada.

BACKGROUND: Point-of-care ultrasound (POCUS) is a growing part of internal medicine training programs. Dedicated POCUS rotations are emerging as a particularly effective tool in POCUS training, allowing for longitudinal learning and emphasizing both psychomotor skills and the nuances of clinical integration. In this descriptive paper, we set out to review the state of POCUS rotations in Canadian Internal Medicine training programs. RESULTS: We identify five programs currently offering a POCUS rotation. These rotations are offered over two to thirteen blocks each year, run over one to four weeks and support one to four learners. Across all programs, these rotations are set up as a consultative service that offers POCUS consultation to general internal medicine inpatients, with some extension of scope to the hospitalist service or surgical subspecialties. The funding model for the preceptors of these rotations is predominantly fee-for-service using consultation codes, in addition to concomitant clinical work to supplement income. All but one program has access to hospital-based archiving of POCUS exams. Preceptors dedicate ten to fifty hours to the rotation each week and ensure that all trainee exams are reviewed and documented in the patient's medical records in the form of a consultation note. Two of the five programs also support a POCUS fellowship. Only two out of five programs have established learner policies. All programs rely on In-Training Evaluation Reports to provide trainee feedback on their performance during the rotation. CONCLUSIONS: We describe the different elements of the POCUS rotations currently offered in Canadian Internal Medicine training programs. We share some lessons learned around the elements necessary for a sustainable rotation that meets high educational standards. We also identify areas for future growth, which include the expansion of learner policies, as well as the evolution of trainee assessment in the era of competency-based medical education. Our results will help educators that are endeavoring setting up POCUS rotations achieve success.

Comparing accuracy of bedside ultrasound examination with physical examination for detection of pleural effusion.

BACKGROUND: In detecting pleural effusion, bedside ultrasound (US) has been shown to be more accurate than auscultation. However, US has not been previously compared to the comprehensive physical examination. This study seeks to compare the accuracy of physical examination with bedside US in detecting pleural effusion. METHODS: This study included a convenience sample of 34 medical inpatients from Calgary, Canada and Spokane, USA, with chest imaging performed within 24 h of recruitment. Imaging results served as the reference standard for pleural effusion. All patients underwent a comprehensive lung physical examination and a bedside US examination by two researchers blinded to the imaging results. RESULTS: Physical examination was less accurate than US (sensitivity of 44.0% [95% confidence interval (CI) 30.0-58.8%], specificity 88.9% (95% CI 65.3-98.6%), positive likelihood (LR) 3.96 (95% CI 1.03-15.18), negative LR 0.63 (95% CI 0.47-0.85) for physical examination; sensitivity 98% (95% CI 89.4-100%), specificity 94.4% (95% CI 72.7-99.9%), positive LR 17.6 (95% CI 2.6-118.6), negative LR 0.02 (95% CI 0.00-0.15) for US). The percentage of examinations rated with a confidence level of 4 or higher (out of 5) was higher for US (85% of the seated US examination and 94% of the supine US examination, compared to 35% of the PE, P < 0.001), and took less time to perform (P < 0.0001). CONCLUSIONS: US examination for pleural effusion was more accurate than the physical examination, conferred higher confidence, and required less time to complete.

Actions of adiponectin on the excitability of subfornical organ neurons are altered by food deprivation.

Adiponectin (ADP) is a peptide produced by adipose tissue, which acts as an insulin sensitizing hormone. Recent studies have shown that adiponectin receptors (AdipoR1 and AdipoR2) are present in the CNS, and although adiponectin does appear in both circulation and the cerebrospinal fluid there is still some debate as to whether or not ADP crosses the blood brain barrier (BBB). Circumventricular organs (CVO) are CNS sites which lack normal BBB, and thus represent sites at which circulating adiponectin may act to directly influence the CNS. The subfornical organ (SFO) is a CVO that has been implicated in the regulation of energy balance as a consequence of the ability of SFO neurons to respond to a number of different circulating satiety signals including amylin, CCK, PYY and ghrelin. Our recent microarray analysis suggested the presence of adiponectin receptors in the SFO. We report here that the SFO shows a high density of mRNA for both adiponectin receptors (AdipoR1 and AdipoR2), and that ADP influences the excitability of dissociated SFO neurons. Separate subpopulations of SFO neurons were either depolarized (8.9+/-0.9 mV, 21 of 97 cells), or hyperpolarized (-8.0+/-0.5 mV, 34 of 97 cells), by bath application of 10nM ADP, effects which were concentration dependent and reversible. Our microarray analysis also suggested that 48 h of food deprivation resulted in specific increases in AdipoR2 mRNA expression (no effect on AdipoR1 mRNA), observations which we confirm here using real-time PCR techniques. The effects of food deprivation also resulted in a change in the responsiveness of SFO neurons to adiponectin with 77% (8/11) of cells tested responding to adiponectin with depolarization, while no hyperpolarizations were observed. These observations support the concept that the SFO may be a key player in sensing circulating ADP and transmitting such information to critical CNS sites involved in the regulation of energy balance.