Two Forms of Telemedicine: Synchronous vs. Asynchronous
What is Synchronous Telemedicine?
The Office of the National Coordinator for Health Information Technology (ONC) defines synchronous telemedicine as "live video-conferencing," which is a "two-way audiovisual link between a patient and a care provider."
The U.S. Department of Veterans Affairs (VA) states, "Synchronous telemedicine requires the presence of both parties at the same time and a communication link between them that allows a real-time interaction to take place."
The American Telemedicine Association (ATA) defines synchronous telemedicine as follows: "Interactive video connections that transmit information in both directions during the same time period."
The University of Miami (UM) Miller School of Medicine states, "Real-time telehealth sessions are live and interactive, and frequently use video-conferencing technologies. Often, special telehealth-enabled instruments, such as a video otoscope or an electronic stethoscope, are operated by a nurse or technician at the consulting provider's direction to remotely perform a physical examination."
What is Asynchronous Telemedicine?
ONC defines asynchronous telemedicine as "store-and-forward video-conferencing," which is the "transmission of a recorded health history to a health practitioner, usually a specialist."
VA states, "Asynchronous telemedicine involves acquiring medical data, then transmitting this data to a doctor or medical specialist at a convenient time for assessment offline."
ATA defines asynchronous telemedicine as follows: "Term describing store-and-forward transmission of medical images and/or data because the data transfer takes place over a period of time, and typically in separate time frames. The transmission typically does not take place simultaneously."
UM states, "In store-and-forward telehealth, data are captured locally, then temporarily stored for transfer at a later time, either via a secure web server, encrypted e-mail, specially-designed store-and-forward software, or electronic health record. The consulting provider then reviews the stored data and makes diagnosis, treatment, and planning recommendations that are electronically transferred or faxed back to the referring provider."
Benefits of Synchronous Telemedicine
An article in Healthcare Informatics Research (HIR) states, "The major advantage of a synchronous approach is the efficiencies gained by having the opportunity to refine details pertinent to the care episode during the session, by seeking additional information or data, and in many cases providing a clinical decision or advice within the session."
An mHealth Intelligence article notes, "Real-time telehealth provides timely care, especially in emergencies or urgent situations, and maintains the concept of the doctor-patient relationship by enabling a face-to-face analysis and treatment. The doctor is able to see the patient, conduct, and examination and engage in conversation, much as he or she would in an office visit."
A study published in the American Journal of Emergency Medicine concludes, "Synchronous audio-video telemedicine consults resulted in short-term cost savings by diverting patients from more expensive care settings."
An American Psychiatric Association report on synchronous video-conferencing in psychiatry found that, based on a review of more than 30 adequately powered randomized controlled trials, "… treatment intervention outcomes using synchronous video-conferencing was comparable to in-person care outcomes. With the exception of one study, the review found no statistical difference in clinical outcomes for pharmacotherapy or psychotherapy delivered by synchronous video-conferencing treatment and in-person treatment."
Finally, an article in The Online Journal of Issues in Nursing includes the following sentiments:
"Synchronous visits enable assessment, diagnosis, and treatment in hospital or clinic settings, and facilitate nurse-to patient-education."
"Critical access hospitals with limited resources can benefit from prompt, synchronous consultation by a neurologist, in the event a stroke is clinically suspected, and timely treatment with thrombolysis is critical."
"Synchronous telehealth models improve convenience, access, and efficiency of care by offering walk-in telehealth services."
Benefits of Asynchronous Telemedicine
The HIR article previously referenced states that asynchronous systems "… decouple the components of the interaction so that they can occur at different times at the convenience of the participating parties. This model still allows for multiple component interactions to occur, but the effect of the time separation may add overhead of required refreshing of the episode context during this process. An efficiency gain may nevertheless be obtained in asynchronous services when the telemedicine task does not require to-and-from interactions, and especially when it does not rely on direct interaction with the patient throughout."
The Center for Connected Health Policy (CCHP) shares several asynchronous telemedicine benefits, including the following:
"Patients can get timely specialty care without needing to travel beyond the location of their primary care providers."
"Wait times for specialty care are lessened, especially in areas with shortages of medical specialists."
"The store-and-forward process can overcome language and cultural barriers."
A study published in the Journal of General Internal Medicine that compared blood pressure control and healthcare use between patients who received "virtual visits" structured as asynchronous online interactions and typical hypertension care concludes, "Among patients with reasonably well-controlled hypertension, virtual visit participation was associated with equivalent blood pressure control and reduced in-office primary care utilization."
Finally, the previously cited mHealth Intelligence article notes, "… proponents of store-and-forward technology say the platform is ideal for evidence-based care in which providers are able to gather all the information on a patient, analyze that data, match it to evidence-based care and make a diagnosis. While perhaps not suitable for emergency care, it gives providers the leeway to add clinical decision support to the process and eliminates the sometimes-inconvenient requirement of having both patient and doctor available at the same time."
Synchronous Telemedicine Applications
While our discussion up to this point has touched on various synchronous telemedicine applications, CCHP provides several examples of other ways organizations can leverage synchronous telemedicine, including the following:
"Video conferencing connects emergency providers with medical specialists who otherwise would not be available for consults."
"Primary care providers can consult with medical specialists who are not available locally."
"Medical specialists can examine patients in remote locations when distance is a barrier, as is the case when patients live in rural and underserved urban areas. This includes situations where the physician needs to directly observe the patient."
"Language translators can provide video interpretation services to multiple locations, a cost-effective expansion of these programs."
A study published in the Journal of Medical Internet Research on synchronous telehealth services for patients with cardiovascular diseases notes that such services include "… instant transmission of blood pressure, pulse rate, electrocardiography, oximetry, and glucometry for analysis; mutual telephone communication and health promotion; and continuous analytical and decision-making support."
A recent FierceHealthcare article notes that real-time video conferencing is leading to a resurgence of "house calls," albeit virtual ones.
As a final application example, synchronous telemedicine is helping improve medication management. As a U.S. Pharmacist article states, "Essentially, telepharmacy leverages technology to allow one pharmacist to provide supervision and review prescriptions at multiple locations. Patients pick up medications from a nearby licensed location staffed by pharmacy technicians and have access to the same counseling with a pharmacist at the remote location as they would at the home pharmacy, only it is done via a screen rather than in person."
Asynchronous Telemedicine Applications
CCHP also provides the following examples of how organizations can use asynchronous telemedicine:
"In radiology, physicians at small rural hospitals can forward X-rays or MRIs to specialists at major medical centers for review."
"In dermatology, primary care providers can take digital photos of their patients' skin conditions and forward the images to dermatologists for review and determination of treatment if needed."
"In ophthalmology, eye screenings for diabetic retinopathy, a disease that is a major cause of blindness among individuals with diabetes, can be captured digitally by retinal cameras and transmitted to a specialist for review."
A Urology Times article notes, "In our specialty, a relevant example might involve receiving a computed tomography image or a photo of a genital lesion for expert opinion. Obtaining CME hours via a downloadable course is another example of asynchronous telehealth services."
Finally, an article in The Lancet Oncology states, "Store-and-forward communication is practical in fields that require imaging. As an example, the nonprofit organization ORBIS links clinicians in developing countries with mentors in developed countries to improve the diagnosis and management of ocular diseases, including cancer."