Self-powered wireless sensor networks for remote patient monitoring in hospitals

Patient vital sign monitoring within hospitals requires the use of non-invasive sensors that are hardwired to bedside monitors. This set-up is cumbersome, forcing the patient to be confined to his hospital bed thereby not allowing him to move around freely within the hospital premises. This paper addresses the use of wireless sensor networks for monitoring patient vital sign data in a hospital setting. Crossbow MICAz motes have been used to design a robust mesh network that routes patient data to a remote base station within the hospital premises. A hospital care giver can have access to this data at any point in time and doesn't have to be physically present in the patient's room to review the readings. The network infrastructure nodes are self-powered and draw energy from overhead 34W fluorescent lights via solar panels. The sensor nodes can be interfaced to a variety of vital sign sensors such as electrocardiograms (ECGs), pulse-oximeters and blood pressure (BP) sensors. In order to verify a completely functioning system, a commercial BP/heart-rate monitor (BPM) was interfaced to a wireless sensor node. The sensor node controls the BPM to initiate a reading, then collects the data and forwards it to the base station. An attractive graphical user interface (GUI) was designed to store and display patient data on the base station PC. The set-up was found to be extremely robust with low power consumption.