Following on from the Bluetooth Medical Devices SIG (special interest group) is this story about a new OEM Bluetooth module from Bluegigga Technologies. While the story leads with the advantages of eliminating the wires between sensors and devices or gateway devices, it quickly segues to Bluegigga's vision of networking medical devices using Bluetooth. They have a case study (PDF file) of a telemetry monitor using a Bluetooth radio and a "gateway to network" device (what everyone else calls an access point). The profiled company is Swedish firm Ortivus. Here's Bluegiga's description of their access point:

Bluegiga’s WRAP Access Server™ enables the deployment of Bluetooth connectivity as a new virtue in already existing networks without network reconfiguration. Bluegiga’s WRAP Access Server™ equipped with the multiradio feature is the first network device that combines multiple Bluetooth
radios with Wi-Fi, GSM data, GPRS, and Ethernet connectivity in one
integrated form factor. The product is capable of serving up to 21
simultaneous Bluetooth connections making it the ideal solution for
linking small battery operated mobile devices to a wide range of data
networks. Also configured to act as a Wi-Fi base station, the WRAP Access Server™ offers one integrated Hot Spot solution for serving Wi-Fi and Bluetooth access to cell phones, PDAs, and laptops as well as to special purpose hand-held devices.

Sounds like a pretty cool AP. I'm wondering where the market is for the use of Bluetooth as a wireless network. According to the 2006 HIMSS Leadership Survey, 32% of U.S. hospitals are implementing wireless systems, and 84% of U.S. hospitals have wireless networks deployed somewhere in their hospitals. The wireless technology that's been deployed is 802.11a/b/g, not Bluetooth. The Ortivus case study is not cable replacement, but LAN replacement (for a wireless LAN).

Bluetooth can of course serve as a WLAN - a class 1 Bluetooth radio has a range of 100 meters. The problem here is not a technical one, it's a marketing problem. Virtually all medical devices use some flavor of 802.11 for network connectivity. The wireless LANs deployed in hospitals are virtually all WiFi. I would hate to be the sales rep trying to convince a hospital they need to implement Bluetooth on top of their infrastructure WiFi if they buy my medical device - especially when everyone else (okay, everyone but Philips) is using WiFi.

Bluetooth makes a great radio for some sensor to gateway connections. The LifeSync wireless ECG uses Bluetooth, but only between the sensor and the gateway that resides at the patient monitor. A medical device is like a gateway where the sensors are connected by wires. Medical device connectivity needs the range of WiFi (or class 1 Bluetooth) and the low cost of a shared infrastructure - especially as devices become more pervasive outside of critical care areas.

Be sure to check out the Ortivus products. They focus more on the EMS market than hospitals, and their devices use Bluetooth to connect to a gateway in the ambulance that then connects to a wireless carrier's network. Pictured right is their SmartLead ECG system.