Point-of-Care Ultrasound Transmission for Remote Interpretation in Austere Environments.

Introduction: Point-of-care ultrasound (POCUS) is used in wilderness medicine and could potentially be the only imaging modality available. Cellular and data coverage is often lacking in remote areas, limiting image transmission. This study evaluates the viability of transmitting POCUS images from austere environments using slow-scan television (SSTV) image transmission methods over very-high-frequency (VHF) hand-held radio units for remote interpretation.

Methods: Fifteen deidentified POCUS images were selected and encoded into an SSTV audio stream by a smartphone and transmitted over a VHF radio. A second radio and smartphone 1 to 5 mi away received and decoded the signals back into images. The original images and transmitted images were randomized into a survey graded by emergency medicine physicians using a standardized ultrasound quality assurance scoring scale (1-5 points).

Results: The difference in mean scores between the original image and transmitted image showed a 3.9% decrease in transmitted image scores, with P <0.05 on a paired t test; however, this is not likely a clinically significant decrease. Comparing transmitted images using different SSTV encodings and distances ranging up to 5 mi, 100% of survey respondents determined the images to be clinically usable. This dropped to 75% when significant artifacts were introduced.

Conclusions: Slow-scan television image transmission is a viable option for transmitting ultrasound images in remote areas where more modern forms of communication are unavailable or not practical. Slow-scan television may have potential as another data transmission option in the wilderness, such as electrocardiogram tracings.