The American Telemedicine Association (ATA) defines telemedicine as “the use of medical information exchanged from one site to another via electronic communications to improve patients’ health status” (1). Telemedicine has been traditionally divided into three areas: Interactive Video Teleconferencing (VTC), Asynchronous Store-and-Forward (S&F), and Remote Patient Monitoring (RPM). While the distinction between these categories has begun to blur with advances in device technology and means of information transfer, it is worthwhile to review each as well their current usage in medicine.

The term “VTC” telemedicine applies to a medical encounter performed over a live teleconference link with video and audio and, in some instances, a live display of data from remote medical devices. As commonly practiced, a “presenting provider” is physically present with the patient to assist with the interview, conduct aspects of the examination, and operate devices to obtain parts of the examination to be transmitted. The presenting provider, for example, may operate an endoscope to provide live video of the examined body system. The “consulting provider” is located at a distance and receives the live video feed. There is synchronous communication between the providers and the patient; questions can be asked and immediately answered. The consulting provider may direct certain parts of the examination. The encounter may be recorded for future reference. Some of the advantages of VTC are that it is interactive, patient movement and affect can be assessed, and a “human” connection between the involved parties can be established. The consulting provider has the ability to conduct an interview similar to an in-person exam and can help direct the encounter. The disadvantages of VTC are that all involved parties must be available simultaneously for the encounter, technical and network support is needed to ensure full function at the time of the scheduled encounter, and sufficient bandwidth is required for adequate video quality. VTC has generally been most successful when used as part of an integrated health system where coordinated scheduling, technical support, training, and funding are provided (2). Examples of medical specialties
where VTC has been successfully used include psychiatry and mental health services, cardiology, and intensive care unit consultation (Tele-ICU) (3,4). VTC has also been used in the recent development of “telestroke” networks, where a remotely located neurologist assesses patients with evolving strokes and decides whether thrombolytic therapy should be administered (5).

“S&F” telemedicine involves the capture, storage, and transmission of data between providers for the purpose of obtaining medical advice and opinion. As commonly practiced, the “creator” is physically present when interviewing the patient, conducting an examination, capturing data, and documenting the encounter in a telemedicine case. The “consultant” at a remote location would then review the transmitted data after it was sent in its entirety. S&F is asynchronous; the providers need not be available at the same time, and the created “case” may be viewed minutes, hours, or days after it was created and transmitted. Typical data that are captured and utilized in S&F include clinical histories, vital signs, digital photos, radiology images, endoscopic images, scanned documents, audiograms, tympanograms, and heart and lung sounds. The advantages of S&F are that it does not require simultaneous availability of providers, thereby avoiding scheduling and logistic problems. It can be extremely time efficient for the consultant as complete data collection and organization of information have occurred during creation of the case, often along predetermined guidelines (Fig. 205.1). S&F can be used with low or interrupted bandwidth, enabling its use in very remote or infrastructure-deprived locations. Finally, once set up with the appropriate software, security, and operational standards, S&F “works like e-mail” requiring much less ongoing maintenance and support than VTC. Disadvantages of S&F are that real-time interaction between providers is not possible; the consulting provider cannot direct the exam (though they can asynchronously request additional information), and sustained movement, voice, and affect of the patient cannot be assessed (though short video files are now easily transferrable). S&F has long been successfully used in those specialties where the assessment or “read” of the consultant regarding static clinical data is the valued service. Well-established examples are teleradiology (6), teledermatology (7), and telepathology (8).

RMP technology enables the monitoring of patient health data originated from the patient’s home, nursing facility, place of employment, school, and other locations. It is most often employed in the patient’s home and, as such, is often called “home telehealth.” RPM almost always involves capture of data similar to S&F and sometimes includes video. To date, RPM has proven useful for the management of chronic disease states such as diabetes, congestive heart failure, and chronic pulmonary disease (9,10). Used appropriately, RPM facilitates access to care, patient and family involvement and education, and early identification and intervention for acute illness or health status decompensations. RPM holds tremendous promise for cost savings through improved chronic disease management, especially for integrated health systems (11). From a commercial standpoint, RPM represents a large potential market, and device manufacturers are rapidly adding new products to the field. For these reasons, this is the most rapidly growing field in telemedicine, and clinicians will likely have increasing opportunities to use home monitoring in the future.

A final category of telemedicine deserving mention relates to the use of telemedicine technologies in the performance of surgical procedures. In telementoring and teleproctoring, a distantly located “expert” surgeon monitors and assists a surgeon at a distant location performing a surgery. A typical current application would involve using a live VTC link used to mentor an endoscopic procedure (12). Telesurgery, the performance of a surgical procedure by a remotely located surgeon using robotic devices, is currently the subject of feasibility studies and demonstration projects (13).