RESUMO
OBJECTIVES: Ultrasound (US) is an essential component of emergency department patient care. US machines have become smaller and more affordable. Handheld ultrasound (HUS) machines are even more portable and easy to use at the patient's bedside. However, miniaturization may come with consequences. The ability to accurately interpret ultrasound on a smaller screen is unknown. This pilot study aims to assess how screen size affects the ability of emergency medicine clinicians to accurately interpret US videos. METHODS: This pilot study enrolled a prospective convenience sample of emergency medicine physicians. Participants completed a survey and were randomized to interpret US videos starting with either a phone-sized screen or a laptop-sized screen, switching to the other device at the halfway point. 50 unique US videos depicting right upper quadrant (RUQ) views of the Focused Assessment with Sonography in Trauma (FAST) examination were chosen for inclusion in the study. There were 25 US videos per device. All of the images were previously obtained on a cart-based machine (Mindray M9) and preselected by the study authors. Participants answered "Yes" or "No" in response to whether they identified free fluid. The time that each participant took to interpret each video was also recorded. Following the assessment, participants completed a post-interpretation survey. The goal of the pilot was to determine the accuracy of image interpretation on a small screen as compared to a laptop-sized screen. Statistical analyses were performed using MATLAB (The MathWorks, Inc., Natick, MA). Nonparametric statistical tests were utilized to compare subgroups, with a Wilcoxon signed rank test used for paired data and a Wilcoxon rank sum test for unpaired data. RESULTS: 52 emergency medicine physicians were enrolled in the study. The median accuracy of US interpretation for phone versus laptop image screen was 88.0% and 87.6% (p = 0.67). The mean time to interpret with phone versus laptop screen was 293 and 290 s (p = 0.66). CONCLUSIONS: The study found no statistically significant difference in the accuracy of US interpretation nor time spent interpreting when the pre-selected RUQ videos generated on a cart-based ultrasound machine were reviewed on a phone-sized versus a laptop-sized screen. This pilot study suggests that the accuracy of US interpretation may not be dependent upon the size of the screen utilized.
Assuntos
Medicina de Emergência/instrumentação , Avaliação Sonográfica Focada no Trauma/instrumentação , Telemedicina/instrumentação , Gravação em Vídeo , Ferimentos e Lesões/diagnóstico por imagem , Telefone Celular , Competência Clínica , Computadores , Serviço Hospitalar de Emergência , Humanos , Simulação de Paciente , Projetos Piloto , Estudos ProspectivosRESUMO
Neurons in the brainstem nucleus locus ceruleus (LC) often exhibit phasic activation in the context of simple sensory-motor tasks. The functional role of this activation, which leads to the release of norepinephrine throughout the brain, is not yet understood in part because the conditions under which it occurs remain in question. Early studies focused on the relationship of LC phasic activation to salient sensory events, whereas more recent work has emphasized its timing relative to goal-directed behavioral responses, possibly representing the end of a sensory-motor decision process. To better understand the relationship between LC phasic activation and sensory, motor, and decision processing, we recorded spiking activity of neurons in the LC+ (LC and the adjacent, norepinephrine-containing subceruleus nucleus) of monkeys performing a countermanding task. The task required the monkeys to occasionally withhold planned, saccadic eye movements to a visual target. We found that many well isolated LC+ units responded to both the onset of the visual cue instructing the monkey to initiate the saccade and again after saccade onset, even when it was initiated erroneously in the presence of a stop signal. Many of these neurons did not respond to saccades made outside of the task context. In contrast, neither the appearance of the stop signal nor the successful withholding of the saccade elicited an LC+ response. Therefore, LC+ phasic activation encodes sensory and motor events related to decisions to execute, but not withhold, movements, implying a functional role in goal-directed actions, but not necessarily more covert forms of processing.
Assuntos
Tomada de Decisões/fisiologia , Locus Cerúleo/fisiologia , Neurônios/fisiologia , Recompensa , Animais , Locus Cerúleo/citologia , Macaca mulatta , Masculino , Movimento/fisiologia , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Sensação/fisiologiaRESUMO
BACKGROUND: Ultrasound (U/S) guided peripheral IV catheter (PIV) placement is often needed after unsuccessful traditional IV attempts. Commercial U/S PIV training phantoms are expensive and difficult to alter. Non-commercial phantoms have been described; however, there has been no comparison of these models. The primary objectives of this study were to compare the echogenic and haptic properties of various non-commercial phantoms. Secondary objectives were to characterize the cost and ease of making the phantoms. METHODS: This prospective observational study trialed six unique phantom models: Amini Ballistics; Morrow Ballistics; University of California San Diego (UCSD) gelatin; Rippey Chicken; Nolting Spam; and Johnson Tofu. Total cost and creation time were noted. Emergency Ultrasound Fellowship trained physicians performed U/S guided PIV placement on each model to evaluate their resemblance to human tissue haptic and echogenicity properties, utility for training, and comparability to commercial phantoms (Likert scale 1-5; higher performance = 5). RESULTS: The Rippey model scored highest for each primary objective with an aggregate score of 4.8/5. UCSD ranked second and Nolting last for all primary objectives, with aggregate scores 3.7/5 and 1.3/5 respectively. Cost of production ranged from $4.39 (Johnson) to $29.76 (UCSD). Creation times ranged from 10 min (Johnson) to 120 min (UCSD). CONCLUSION: In our study the Rippey model performed best and offered a mid-level cost and creation time. Non-commercial U/S phantoms may represent cost-effective and useful PIV practice tools. Future studies should investigate the utility of these phantoms in teaching U/S guided PIV to novices and compare non-commercial to commercial phantoms.
Assuntos
Cateterismo Periférico , Ultrassonografia de Intervenção , Cateterismo Periférico/efeitos adversos , Catéteres , Humanos , Imagens de Fantasmas , UltrassonografiaRESUMO
Magnetic resonance imaging (MRI) is often used by electrophysiologists to target specific brain regions for placement of microelectrodes. However, the effectiveness of this technique has been limited by few methods to quantify in three dimensions the relative locations of brain structures, recording chambers and microelectrode trajectories. Here we present such a method. After surgical implantation, recording chambers are fitted with a plastic cylinder that is filled with a high-contrast agent to aid in the segmentation of the cylinder from brain matter in an MRI volume. The resulting images of the filled cylinder correspond to a virtual cylinder that is projected along its long axis - parallel to the trajectories of microelectrodes advanced through the recording chamber - through the three-dimensional image of the brain. This technique, which does not require a stereotaxic coordinate system, can be used to quantify the coverage of an implanted recording chamber relative to anatomical landmarks at any depth or orientation. We have used this technique in conjunction with Caret [Van Essen DC, Drury HA, Dickson J, Harwell J, Hanlon D, Anderson CH. An integrated software suite for surface-based analyses of cerebral cortex. J Am Med Inform Assoc 2001;8:443-59] and AFNI [Cox RW. AFNI: software for analysis and visualization of functional magnetic resonance neuroimages. Comput Biomed Res 1996;29:162-73] brain-mapping software to successfully localize several regions of macaque cortex, including the middle temporal area, the lateral intraparietal area and the frontal eye field, and one subcortical structure, the locus coeruleus, for electrophysiological recordings.
Assuntos
Encéfalo/anatomia & histologia , Eletrofisiologia/instrumentação , Eletrofisiologia/métodos , Imageamento por Ressonância Magnética/métodos , Microeletrodos , Animais , Encéfalo/fisiologia , Encéfalo/cirurgia , Mapeamento Encefálico , Feminino , Imageamento Tridimensional/métodos , Macaca mulatta , MasculinoRESUMO
Midbrain dopamine neurons are thought to encode the difference between predicted and actual reward on conditioning tasks. Successful models assumed a simple form of prediction that depended only on currently available information. In this issue of Neuron, Nakahara and colleagues record from dopamine neurons in alert monkeys and show that the neurons can encode predictions that are not so restricted, taking into account the context of past trends.
Assuntos
Dopamina/fisiologia , Mesencéfalo/fisiologia , Recompensa , Animais , Haplorrinos/fisiologia , Mesencéfalo/citologia , Modelos Neurológicos , Estimulação LuminosaRESUMO
Changes in pupil diameter that reflect effort and other cognitive factors are often interpreted in terms of the activity of norepinephrine-containing neurons in the brainstem nucleus locus coeruleus (LC), but there is little direct evidence for such a relationship. Here, we show that LC activation reliably anticipates changes in pupil diameter that either fluctuate naturally or are driven by external events during near fixation, as in many psychophysical tasks. This relationship occurs on as fine a temporal and spatial scale as single spikes from single units. However, this relationship is not specific to the LC. Similar relationships, albeit with delayed timing and different reliabilities across sites, are evident in the inferior and superior colliculus and anterior and posterior cingulate cortex. Because these regions are interconnected with the LC, the results suggest that non-luminance-mediated changes in pupil diameter might reflect LC-mediated coordination of neuronal activity throughout some parts of the brain.