Technical dependability of obstetric ultrasound transmission via ISDN

To evaluate the dependability of a live telemedicine link for the transmission of obstetric ultrasonograms using a commercial telephone network.

We established an integrated services digital network (ISDN), consisting of three dedicated telephone lines from three satellite offices, to our central prenatal diagnostic center. All patients had a sonographic evaluation recorded on videotape by a trained sonographer. A live interactive video telemedicine link was then established, and a perinatologist directed the sonographer through the scan. A report was issued on the basis of the telemedicine examination. The number of calls required to obtain satisfactory real-time images was recorded, as were the reasons for suboptimal transmissions. The first 150 transmissions were excluded from this study. The results in the subsequent 100 patients who agreed to participate were analyzed.

We were able to provide obstetric interpretations in all 100 patients scheduled to be examined using the telemedicine link. A single connection was required in 85 cases, two calls in 5 cases, three calls in 8 cases, four calls in 1 case, and five calls in another case. A repeat call was required in 20 cases because of poor image transmission; other repeat calls were caused by failure to connect (5 cases), calls disconnected (2 cases), and no image transmission (2 cases).

The provision of telemedicine services for obstetric ultrasonography in the community is feasible, but the need for repeat connections because of technical failures needs to be incorporated into cost and time analyses in order to provide a measure of the system's efficiency.