Handheld Ultrasound at Remote Locations

Handheld focused cardiac ultrasound in diagnosis of suspected heart failure

Diagnostic ultrasound is more frequently used by clinicians in different scenarios. Echocardiography (cardiac ultrasound) is the most frequently method used when diagnosing heart failure (HF), cardiomyopathies, valvular pathology and cardiac tamponade, as well as other diseases affecting the heart, great vessels and pleural cavity. Ideally, the diagnostic workflow should conclude with a correct diagnosis as soon as possible, as this is important for preserving health and quality of life for the patients, as well as for total health care expenditure and the diagnostic workflow logistics.

For the last 6-7 years smaller and cheaper ultrasound scanners have become available. These pocket-sized (or handheld) imaging devices (PSIDs) have allowed for more inexperienced users, at locations outside the dedicated ultrasound laboratories, to perform ultrasound diagnostics. PSIDs fits in the "white coat" pocket and may be brought to the patient, and thus, allowing diagnostic imaging examinations to be performed at the patients' point-of-care. PSIDs from different vendors are available on the market. Large efforts are made in developing dedicated software helping the inexperienced users to maximize the diagnostic gain of including PSIDs in the diagnostic workflow. Experts have launched the PSIDs as the next generation stethoscope.

The cardiac research groups at Levanger Hospital and NTNU (Norway) have recently evaluated the PSID Vscan® from GE Ultrasound in several studies where the PSID has been tested on cardiac patients by different users. The PSID allow for improved diagnostics by both experts, residents, general practitioners (GPs), as well as medical students and dedicated nurses.

In the inpatients setting the population is selected and the prevalence of disease is high. Research has shown that by using the PSIDs the diagnosis was corrected in up to 1 of 5 medical inpatients. With less experienced users the diagnostic impact may be reduced. Studies from outpatient hospital settings have shown that the PSIDs may allow for diagnostic gain both in cardiac and non-cardiac care. Studies evaluating the influence of using PSIDs by GPs or other health care personnel outside the hospitals are scarce. Thus, there is a need for studies evaluating the use of PSIDs or other imaging modalities performed by the GPs in the outpatient setting.

Education

For all inexperienced users, that are non-experts, dedicated training and education is mandatory to optimize gain and minimize misdiagnosis and subsequent imaging procedures. The gain of including PSIDs in the diagnostic workflow largely depends on the population examined. In the latest recommendation from the European Association of Cardiovascular Imaging (EACVI) no specific numbers are given for the training program, neither regarding time nor number of examinations. However, it is stated that "since the competency in FoCUS (Focused Cardiac UltraSound) should be the minimal net result of the training process, the number of required hours/studies might be adjusted for each trainee according to the results of the competency evaluation incorporated into the ongoing training process". The training program should aim to educate the user in the specific use of the PSIDs relevant for the planned scenarios to "ensure that the operators are aware of their own capacity and limitations, given the specific equipment and different situations".

Telemedicine The health care system of today has implemented a variety of technical tools that are based on advanced technological innovations. Such advances usually require highly technical and medical skills of the users, for optimization of the use and outcome of the advances. The advances in information technology, communication bandwidth capacities of both wired and non-wired networks have made the basis for performing the diagnostics at one place and interpret the diagnostic tests at another location. According to the World Health Organization, telemedicine is defined as "the delivery of health care services, where distance is a critical factor, by all health care professionals using information and communication technologies for the exchange of valid information for diagnosis, treatment and prevention of disease and injuries, research and evaluation, and for the continuing education of health care providers, all in the interests of advancing the health of individuals and their communities".

Telemedicine has among others been implemented in radiology, where teleradiology is a common and accepted form in the diagnostic process. The methodology was first implemented in clinical scenarios where the need for a physical meeting between the patient and the physician was lower than the need for the specific tests. Traditionally, ultrasound examinations have been performed by highly specialized personnel and interpreted by the specialist more or less real time and at the same location.

User support Technological advances with the invention of easy-to-use, cheap and attainable ultrasound devices has allowed for a broader spectrum of users to implement ultrasound diagnostics. From the health care providers' point of view, this may allow for moving diagnostics to the patients' point-of-care, in contrast to moving the patients to the diagnostic laboratories. To implement ultrasound diagnostics outside the dedicated diagnostics laboratories, education and support of the users is mandatory. Even though inexperienced users easily can be trained to perform ultrasound images with indices, the interpretation of the images of anatomical structures and cardiac function indices requires experience.

The more inexperienced users can be supported in different ways. Beyond the obligatory theoretical support by literature and possibility to discuss findings with experts, there is need for qualitative feedback on the ultrasound recordings. Telemedicine may offer secure transmission of the ultrasound recordings for interpretation by experts and allowing for discussion as well. The outpatient ultrasound recordings may also be included in hospital referrals. In addition, our research group has been involved in development of an algorithm which can automatically interpret ultrasound recordings of the function of the left ventricle. Such software can give quick feedback which may be helpful for training and education of the user, as well its possibility to improve the diagnostic ability of the ultrasound examination performed by the inexperienced user.

Heart failure Heart failure (HF) affects 15 million Europeans; incidence in Norway is 11.000 per year. The prevalence is increasing due to improvements in diagnostics and therapy, not to mention the increased age of the population. Health care expenditure related to management of heart failure is significant, both with respect to the financial costs and patient burden. Thus, early and correct diagnosis is important to improve patient care and reduce the financial burden on the health care system. Heart failure patients often have comorbidities, and hospitalization is common if not optimally monitored and treated. Today approximately 50% of heart failure patients are readmitted within 6 months after hospitalization for decompensated heart failure.

Hyper- and hypovolemia can both lead to decompensated HF and secondary organ failure caused by inadequate perfusion. However, pleural effusion is easy assessable by ultrasound and in a recent study we found that pleural effusion was present in 42% of the patients. Non-cardiologists may have a growing role in diagnostics and follow-up of outpatient HF patients, and adding ultrasound diagnostics to the consultations may improve care.

Telemedicine in follow-up of patients with chronic heart failure The most advanced way of monitoring chronic HF patients by telemedicine is the use of implantable devices for haemodynamic monitoring, where invasive pressures were automatically uploaded from implanted devices through a patient home monitoring system and used to guide treatment. The Remote monitoring has become appealing, and is a potentially cost-effective method of home management and prevention of readmission.