Ole Christian Mjølstad

Feasibility and reliability of point-of-care pocket-sized echocardiography

Aims To study the reliability and feasibility of point-of-care pocket-sized echocardiography (POCKET) at the bedside in patients admitted to a medical department at a non-university hospital. Methods and results One hundred and eight patients were randomized to bedside POCKET examination shortly after admission and later high-end echocardiography (HIGH) in the echo-lab. The POCKET examinations were done by cardiologists on their ward rounds. Assessments of global and regional left ventricular (LV) function, right ventricular (RV) function, valvular function, left atrial (LA) size, the pericardium and pleura were done with respect to effusion and measurements of inferior vena cava (IVC) and abdominal aorta (AA) were performed. Correlations between POCKET and HIGH/appropriate radiological technique for LV function, AA size and presence of pericardial effusion were almost perfect, with r ≥ 0.92. Strong correlation (r ≥ 0.81) was shown for RV and valvular function, except for grading of aortic stenosis (r = 0.62). The correlations were substantial for IVC and LA dimensions. Median time used for bedside screening with POCKET was 4.2 min (range: 2.3–13.0). There was excellent feasibility for cardiac structures and pleura, which was assessed to satisfaction in ≥94% of patients. Lower feasibility (71–79%) was seen for the abdominal great vessels. Conclusion Point-of-care semi-quantitative evaluation of cardiac anatomy and function showed high feasibility and correlation with the reference method for most indices. Pocket-sized echocardiographic examinations of ∼4 min length, performed at the bedside by experts, offers reliable assessment of cardiac structures, the pleural space and the large abdominal vessels. Clinical trial registration: http://www.clinicaltrials.gov; unique ID: NCT01081210.

Routinely adding ultrasound examinations by pocket-sized ultrasound devices improves inpatient diagnostics in a medical department.

BACKGROUND We aimed to investigate the potential benefit of adding a routine cardiac and abdominal diagnostic examination by pocket-sized ultrasound device in patients admitted to a medical department. METHODS A random sample of 196 patients admitted to the medical department at a non-university hospital in Norway between March and September 2010 was studied. The patients underwent cardiac and abdominal screening with a pocket-sized ultrasound device with B-mode and color flow imaging after a principal diagnosis was set. Three internists/cardiologists experienced in ultrasonography performed the examinations. Diagnostic corrections were made and findings were confirmed by high-end echocardiography and examinations at the radiologic department. RESULTS 196 patients were included (male=56.6%, mean±SD; 68.1±15.0 years old). The time spent doing the ultrasound screening was mean±SD 4.3±1.6 min for the cardiac screening and 2.5±1.1 min for the abdominal screening. In 36 (18.4%) patients this examination resulted in a major change in the primary diagnosis. In 38 (19.4%) patients the diagnosis was verified and in 18 (9.2%) patients an important additional diagnosis was made. CONCLUSION By adding a pocket-sized ultrasound examination of <10 min to usual care, we corrected the diagnosis in almost 1 of 5 patients admitted to a medical department, resulting in a completely different treatment strategy without delay in many of the patients. Routinely adding a cardiac and abdominal ultrasound screening has the potential to rearrange inpatients workflow and diagnosis.

Feasibility and reliability of point-of-care pocket-size echocardiography performed by medical residents

Aims To study the feasibility and reliability of pocket-size hand-held echocardiography (PHHE) by medical residents with limited experience in ultrasound. Methods and results A total of 199 patients admitted to a non-university medical department were examined with PHHE. Six out of 14 medical residents were randomized to use a focused protocol and examine the heart, pericardium, pleural space, and abdominal large vessels. Diagnostic corrections were made and findings were confirmed by standard diagnostics. The median time consumption for the examination was 5.7 min. Each resident performed a median of 27 examinations. The left ventricle was assessed to satisfaction in 97% and the pericardium in all patients. The aortic and atrioventricular valves were assessed in at least 76% and the abdominal aorta in 50%, respectively. Global left-ventricular function, pleural, and pericardial effusion showed very strong correlation with reference method (Spearmans r ≥ 0.8). Quantification of aortic stenosis and regurgitation showed strong correlation with r = 0.7. Regurgitations in the atrioventricular valves showed moderate correlations, r = 0.5 and r = 0.6 for mitral and tricuspid regurgitation, respectively, similar to dilatation of the left atrium (r = 0.6) and detection of regional dysfunction (r = 0.6). Quantification of the abdominal aorta (aneurysmatic or not) showed strong correlation, r = 0.7, while the inferior vena cava diameter correlated moderately, r = 0.5. Conclusion By adding a PHHE examination to standard care, medical residents were able to obtain reliable information of important cardiovascular structures in patients admitted to a medical department. Thus, focused examinations with PHHE performed by residents after a training period have the potential to improve in-hospital diagnostic procedures.

Causes of in-hospital cardiac arrest – Incidences and rate of recognition ☆

BACKGROUND AND METHODS Do emergency teams (ETs) consider the underlying causes of in-hospital cardiac arrest (IHCA) during advanced life support (ALS)? In a 4.5-year prospective observational study, an aetiology study group examined 302 episodes of IHCA. The purpose was to investigate the causes and cause-related survival and to evaluate whether these causes were recognised by the ETs. RESULTS In 258 (85%) episodes, the cause of IHCA was reliably determined. The cause was correctly recognised by the ET in 198 of 302 episodes (66%). In the majority of episodes, cardiac causes (156, 60%) or hypoxic causes (51, 20%) were present. The cause-related survival was 30% for cardiac aetiology and 37% for hypoxic aetiology. The initial cardiac rhythm was pulseless electrical activity (PEA) in 144 episodes (48%) followed by asystole in 70 episodes (23%) and combined ventricular fibrillation/ventricular tachycardia (VF/VT) in 83 episodes (27%). Seventy-one patients (25%) survived to hospital discharge. The median delay to cardiopulmonary resuscitation (CPR) was 1min (inter-quartile range 0-1min). CONCLUSIONS Various cardiac and hypoxic aetiologies dominated. In two-thirds of IHCA episodes, the underlying cause was correctly identified by the ET, i.e. according to the findings of the aetiology study group.

Assessment of left ventricular function by GPs using pocket-sized ultrasound

Background Assessment of left ventricular (LV) function with echocardiography is mandatory in patients with suspected heart failure (HF). Objectives To investigate if GPs were able to evaluate the LV function in patients at risk of developing or with established HF by using pocket-sized ultrasound (pUS). Methods Feasibility study in general practice, seven GPs in three different Norwegian primary care centres participated. Ninety-two patients with reduced or at risk of developing reduced LV function were examined by their own GP using pUS. The scan (<5 minute) was done as part of a routine appointment. A cardiologist examined the patients <30 minutes afterwards with both a laptop scanner and pUS. Measurements of the septal mitral annular excursion (sMAE) were compared. Results In 87% of the patients, the GPs were able to obtain a standard view and measure the sMAE. There was a non-significant mean difference in sMAE between GP pUS and cardiologist laptop scanner of −0.15 mm 95% confidence interval (−0.60 to 0.30) mm. A comparison of the pUS recordings and measurements of sMAE made by GP versus cardiologist revealed a non-significant mean difference with acceptable 95% limits of agreement (−0.26 ± 3.02 mm). Conclusions With tailored training, GPs were able to assess LV function with sMAE and pUS. pUS, as a supplement to the physical examination, may become an important tool in general practice.

Diagnostic Influence of Routine Point-of-Care Pocket-size Ultrasound Examinations Performed by Medical Residents

We aimed to investigate the potential benefit of adding goal‐directed ultrasound examinations performed by on‐call medical residents using a pocket‐size imaging device in patients admitted to a medical department.

Recognizing the causes of in-hospital cardiac arrest — A survival benefit

BACKGROUND The in-hospital emergency team (ET) may or may not recognize the causes of in-hospital cardiac arrest (IHCA) during the provision of cardiopulmonary resuscitation (CPR). In a previous 4.5-year prospective study, this rate of recognition was found to be 66%. The aim of this study was to investigate whether survival improved if the cause of arrest was recognized by the ET. METHODS The difference in survival if the causes were recognized versus not recognized was estimated after propensity score matching patients from these two groups. RESULTS Overall survival to hospital discharge was 25%. After propensity score matching, the benefit of recognizing the cause regarding 1-hour survival of the episode was 29% (p<0.01), and 19% regarding hospital discharge, respectively. Variables commonly known to affect the outcome after cardiac arrest were found to be balanced between the two groups. The largest difference was found in patients with non-cardiac causes and non-shockable presenting rhythms. Patient records and pre-arrest clinical symptoms were the information sources most frequently utilized by the ET to establish the causes of arrest. CONCLUSIONS Patients suffering an IHCA showed a substantial survival benefit if the causes of arrest were recognized by the ET. Patient records and pre-arrest clinical symptoms were the sources of information most frequently utilized in these instances.

Fast automatic measurement of mitral annulus excursion using a pocket-sized ultrasound system.

We present a fast, automatic method for mitral annulus excursion measurement using pocket-sized ultrasound (PSU). The motivation is to provide PSU users with a rapid measurement of cardiac systolic function. The algorithm combines low-frame-rate tolerance, computational efficiency and automation in a novel way. The method uses a speckle-tracking scheme, initialized and constrained by a deformable model. A feasibility study using 30 apical four-chamber PSU recordings from an unselected patient population revealed an error of (mean ± SD) -1.80 ± 1.96 mm, p < 0.001, when compared with manual anatomic m-mode analysis using laptop scanner data. When only septal side excursion was measured, the mean error was -0.27 ± 1.89 mm, p < 0.001. The accuracy is comparable with previously reported results using semiautomatic methods and full-size scanners. The computation time of 3.7 ms/frame on a laptop computer suggests that a real-time implementation on a PSU device is feasible.

Automatic real-time view detection

This work presents an algorithm capable of classifying an echocardiographic view as either an apical two chamber view, four chamber view or long axis view. It also provides a score on the overall image quality. The algorithm is based on a deformable non uniform rational B-spline (NURBS) model updated in an extended Kalman filter framework. Models are constructed for each of the three standard views. Each model is updated using a combination of edge and speckle-tracking measurements, where weak edges and edges strongly deviating from their neighbor edges are discarded. The most probable standard view is found using feature detection and general successfulness in detecting edges. This is also used as a measure of overall view quality. The algorithm was trained and validated using 68 recordings from the Norwegian HUNT database. An echocardiographer classified each recording as one of three standard views. 33 randomly chosen recordings, with approximately 10 of each view, were used for training. The other 35 recordings were used for validation. The algorithm successfully classified the view in 32 of 37 cases (86.5%). Each classification is accompanied by a score, which can be used to assess image quality.

Automated septum thickness measurement-A Kalman filter approach

Interventricular septum thickness in end-diastole (IVSd) is one of the key parameters in cardiology. This paper presents a fast algorithm, suitable for pocket-sized ultrasound devices, for measurement of IVSd using 2D B-mode parasternal long axis images. The algorithm is based on a deformable model of the septum and the mitral valve. The model shape is estimated using an extended Kalman filter. A feasibility study using 32 unselected recordings is presented. The recordings originate from a database consisting of subjects from a normal healthy population. Five patients with suspected hypertrophy were included in the study. Reference B-mode measurements were made by two cardiologists. A paired t-test revealed a non-significant mean difference, compared to the B-mode reference, of (mean±SD) 0.14±1.36 mm (p=0.532). Pearsons correlation coefficient was 0.79 (p<0.001). The results are comparable to the variability between the two cardiologists, which was found to be 1.29±1.23 mm (p<0.001). The results indicate that the method has potential as a tool for rapid assessment of IVSd.