A wireless tracking system for at-home medical equipment during natural disasters

Electricity-operated durable medical equipment (DME), such as ventilators, dialysis machines, and patient monitoring devices, are life-supporting machines used extensively by patients at home. While convenient and economical, at-home use of DME is susceptible to power outages, especially the ones caused by natural disasters that often occur in large area and for a long duration. There is little existing technology allowing hospitals to monitor DME-dependent patients without using the current infrastructure, such as the landlines, the cell towers, Ethernet cable or the Internet. Reported herein is a novel wireless system that utilizes a radio ad hoc network to automatically report the patient´s information and location, and the DME information and status to a nearby hospital when a power outage is detected. This system consists of two parts: a hospital-based receiving device, called the Base Station node, and multiple transmitting devices, called User Nodes, each connected to the DME at patients´ homes. The Base Station and User Nodes is each built with a Teensy® microcontroller, a GPS receiver module, and an Xbee® radio implementing the Zigbee® protocol. Additionally, each User Node contains a status LED and an internal lithium-ion battery connected by a charge controller. User Nodes are programmed to obtain the GPS location of the patient, monitor the DME status, communicate with nearby nodes, transmit the data and relay information to the Base Station through the radio ad hoc network the nodes form in the case of a power outage. The Base Station device is programmed to receive and convey the information transmitted from the User Nodes to a nearby hospital´s patient monitoring computer through a USB connection. This system works without relying on the infrastructure, and allows hospital staff to know the information and locations of DME and their users and provide help needed during power outages.