Left Ventricular Longitudinal Function Assessed by Speckle Tracking Ultrasound from a Single Apical Imaging Plane

Background. Transthoracic ultrasonography of the heart is valuable in monitoring and treatment of critically ill patients. Speckle tracking ultrasound (STU) has proven valid in estimating left ventricular systolic deformation. The aims of the study were to compare conventional and automated STU and to determine whether left ventricular systolic deformation could be estimated from one single imaging plane. Methods. 2D-echocardiography cine-loops were obtained from 20 patients for off-line speckle tracking analysis, consisting of manually tracing of the endocardial border (conventional method) or automatically drawn boundaries (automated method). Results. We found a bias of 0,6 (95% CI −2.2−3.3) for global peak systolic strain comparing the automated and the conventional method. Comparing global peak systolic strain of apical 4-chamber cine-loops with averaged Global Peak Strain obtained from apical 4, 2 and long axis cine-loops, showed a bias of 0.1 (95% CI −3.9−4.0). The agreement between subcostal 4-chamber and apical 4-chamber global peak systolic strain was 4.4 (95% CI −3.7−12.5). Conclusion. We found good agreement between the conventional and the automated method. STU applied to single apical 4-chamber cine-loops is in excellent agreement with overall averaged global peak systolic strain, while subcostal 4-chamber cine-loops proved less compliant with speckle tracking ultrasound

Point-of-care ultrasound induced changes in management of unselected patients in the emergency department - a prospective single-blinded observational trial

Background Point-of-Care ultrasound (POCUS) changes the management in specific groups of patients in the Emergency Department (ED). It seems intuitive that POCUS holds an unexploited potential on a wide variety of patients. However, little is known about the effect of ultrasound on the broad spectrum of unselected patients in the ED. This study aimed to identify the effect on the clinical management if POCUS was applied on unselected patients. Secondarily the study aimed to identify predictors of ultrasound changing management. Methods This study was a blinded observational single center trial. A basic whole body POCUS protocol was performed in extension to the physical examination. The blinded treating physicians were interviewed about the presumptive diagnosis and plan for the patient. Subsequently the physicians were unblinded to the POCUS results and asked to choose between five options regarding the benefit from POCUS results. Results A total of 403 patients were enrolled in this study. The treating physicians regarded POCUS examinations influence on the diagnostic workup or treatment as following: 1) No new information: 249 (61.8%), 2) No further action: 45 (11.2%), 3) Further diagnostic workup needed: 52 (12.9%), 4) Presumptive diagnosis confirmed 38 (9.4%), and 5) Immediate treatment needed: 19 (4.7%). Predictors of beneficial ultrasound were: (a) triage > 1, (b) patient comorbidities (cardiac disease, hypertension or lung disease), or (c) patients presenting with abdominal pain, dyspnea, or syncope. Conclusion POCUS was found to be potentially beneficial in 27.0% of all patients. High triage score, known cardiac disease, hypertension, pulmonary diseases, a clinical presentation with abdominal pain, dyspnea, or syncope are predictors of this. Future research should focus on patient-important outcomes when applying POCUS on these patients. Trial registration The trail was registered prior to patient inclusion with the Danish Data Protection Agency (https://www.datatilsynet.dk/ Case no: 1–16–02-603-14) and Clinical Trials (www.clinicaltrials.gov/ Protocol ID: DNVK1305018)

Using Thoracic Ultrasonography to Accurately Assess Pneumothorax Progression During Positive Pressure Ventilation

Background: Although thoracic ultrasonography accurately determines the size and extent of occult pneumothoraces (PTXs) in spontaneously breathing patients, there is uncertainty about patients receiving positive pressure ventilation. We compared the lung point (ie, the area where the collapsed lung still adheres to the inside of the chest wall) using the two modalities ultrasonography and CT scanning to determine whether ultrasonography can be used reliably to assess PTX progression in a positive-pressure-ventilated porcine model. Methods: Air was introduced in incremental steps into fi ve hemithoraces in three intubated porcine models. The lung point was identifi ed on ultrasound imaging and referenced against the lateral limit of the intrapleural air space identifi ed on the CT scans. The distance from the sternum to the lung point (S-LP) was measured on the CT scans and correlated to the insuffl ated air volume. Results: The mean total difference between the 131 ultrasound and CT scan lung points was 6.8 mm (SD, 7.1 mm; range, 0.0-29.3 mm). A mixed-model regression analysis showed a linear relationship between the S-LP distances and the PTX volume ( P < .001). Conclusions: In an experimental porcine model, we found a linear relation between the PTX size and the lateral position of the lung point. The accuracy of thoracic ultrasonography for identifying the lung point (and, thus, the PTX extent) was comparable to that of CT imaging. These clinically relevant results suggest that ultrasonography may be safe and accurate in monitoring PTX progression during positive pressure ventilation

Building focused cardiac ultrasound capacity in a lower middle-income country: A single centre study to assess training impact

Background: In low- and middle-income countries (LMICs) where echocardiography experts are in short supply, training non-cardiologists to perform Focused Cardiac Ultrasound (FoCUS) could minimise diagnostic delays in time-critical emergencies. Despite advocacy for FoCUS training however, opportunities in LMICs are limited, and the impact of existing curricula uncertain. The aim of this study was to assess the impact of FoCUS training based on the Focus Assessed Transthoracic Echocardiography (FATE) curriculum. Our primary objective was to assess knowledge gain. Secondary objectives were to evaluate novice FoCUS image quality, assess inter-rater agreement between expert and novice FoCUS and identify barriers to the establishment of a FoCUS training programme locally. Methods: This was a pre-post quasi-experimental study at a tertiary hospital in Nairobi, Kenya. Twelve novices without prior echocardiography training underwent FATE training, and their knowledge and skills were assessed. Pre- and post-test scores were compared using the Wilcoxon signed-rank test to establish whether the median of the difference was different than zero. Inter-rater agreement between expert and novice scans was assessed, with a Cohen\u27s kappa \u3e0.6 indicative of good inter-rater agreement. Results: Knowledge gain was 37.7%, with a statistically significant difference between pre-and post-test scores (z = 2.934, p = 0.001). Specificity of novice FoCUS was higher than sensitivity, with substantial agreement between novice and expert scans for most FoCUS target conditions. Overall, 65.4% of novice images were of poor quality. Post-workshop supervised practice was limited due to scheduling difficulties. Conclusions: Although knowledge gain is high following a brief training in FoCUS, image quality is poor and sensitivity low without adequate supervised practice. Substantial agreement between novice and expert scans occurs even with insufficient practice when the prevalence of pathology is low. Supervised FoCUS practice is challenging to achieve in a real-world setting in LMICs, undermining the effectiveness of training initiatives

Clinical Study Echocardiographic Measures of Diastolic Function Are Preload Dependent during Triggered Positive Pressure Ventilation: A Controlled Crossover Study in Healthy Subjects

Background. The use of echocardiography in intensive care settings impacts decision making. A prerequisite for the use of echocardiography is relative resistance to changes in volume status and levels of positive pressure ventilation (PPV). Studies on indices of diastolic function report conflicting results with regard to dependence on volume status. Evidence is scarce on PPV. Methods. Ten healthy subjects were exposed to 6 levels of positive end-expiratory pressure (PEEP) and pressure support (PS) following a baseline reading. All ventilator settings were performed at three positions: horizontal, reverse-Trendelenburg, and Trendelenburg. Echocardiography was performed throughout. Results. During spontaneous breathing, early diastolic transmitral velocity (E) changed with positioning (P &lt; 0.001), whereas early diastolic velocity of the mitral annulus (e ) was independent (P = 0.263). With PPV, E and e proved preload dependent (P values &lt; 0.001). Increases in PEEP, PS, or a combination influenced E and e in reverse-Trendelenburg-and horizontal positions, but not in the Trendelenburg position. Discussion. The change towards preload dependency of e with PPV suggests that PPV increases myocardial preload sensitivity. The susceptibility of E and e to preload changes during PPV discourages their use in settings of volume shifts or during changes in ventilator settings. Conclusion. Positioning and PPV affect E and e