The sleep data transfer between remote and central sites.

: Sleep laboratory have long waiting lists due to the high prevalence of sleep disorders and the low availability of centers. One possibility for improving patient care is an ambulatory recording at home or in a distributed center. Then the data recorded must be transferred for analysis in the specialized center. Similarly, an application is needed for the transfer of raw data when the recordings are made by a health care provider sending sleep technologists to set-up the equipment in the patient's home. It is ethically preferable that the analysis be made by a physician from an independent organization from the provider to avoid any conflict of commercial interest with the provider whose main purpose is delivering therapeutic equipment (CPAP, oxygen...). The objectives were to set-up and test the transfer of sleep data files by ISDN lines between a health care provider and an expert sleep center. The application had to take into account a wide geographical dispersion of patients, general practitioners and medical experts. For that reason, it was decided to use existing Internet Web technology to facilitate portability and interoperability, reduce design time and costs and speed up deployment. The healthcare provider is the collecting site of ambulatory sleep recordings performed at the patient's home by the sleep technician of the provider. The raw data are sent to the sleep center for expert analysis. The methods used were: a PC set-up with a Gazel pro 2B PCI board, a commercially available file transfer software (DT Winstutel from ORSENNA) and an ISDN connection at 128 Kbps. The transfer security needs a set-up to maintain the confidentiality of the personal data transmitted: this is ensured through an identification sequence with several encrypted passwords. The duration of the transfer between Paris and Clamart has been tested for a 44 Moctets file: it took 66 min instead of a theoretical duration of 50 min. This difference was explained by a slower transfer rate (93 Kbps) instead of 128 Kbps. The cost of the transfer has been estimated at 5.4 Euro. This cost can be reduced by subscribing higher transfer tariffs. It amounts to 4.5% of the total cost of the ambulatory procedure at a value of 0.12 Euro per Moctet.