CodeBlue
is a research program at Harvard that is exploring the application of
wireless sensor network technology to a range of medical applications.
Current applications include pre-hospital, in-hospital emergency care,
disaster response, and stroke patient rehabilitation. Lead by Professor
Matt Welsh, the team includes Boston Medical Center, Johns Hopkins Applied Physics Laboratory, 10Blade, Inc., and others.

The program has developed wearable pulse oximeter and ECG sensors based on Crossbow and Moteiv wireless sensor platforms. They've also designed their own wireless sensor platform called Pluto (pictured).

All of these sensors connect to the CodeBlue software infrastructure
designed to provide routing, naming, discover and security for wireless
sensors and gateways. The CodeBlue platform also includes Mote Track,
an RF based location tracking module - so that sensors connected to
patients (and thus the patients themselves) can be tracked through
indoor environments.

Very cool stuff.