AID-N - Advanced Heath and Disaster Aid Network

Johns Hopkins University's Applied Physics Laboratory has developed an advanced high performance communication network to facilitate collaboration among local public health officials, first responders, disease surveillance systems, etc. to respond to public health emergencies. Steady advances in wireless networking, medical sensors, and interoperability software have created exciting possibilities for improving the way we provide emergency care. The Advanced Health and Disaster Aid Network (AID-N), developed at the Johns Hopkins University Applied Physics Laboratory, explores and showcases how these advances in technology can be employed to assist victims and responders in times of emergency.

Researchers have developed a system that facilitates collaborative and time-critical patient care in the emergency response community. During a mass casualty disaster, one of the most urgent problems at the scene is the overwhelming number of patients that must be monitored and tracked by each first responder. The ability to automate these tasks could greatly relieve the workload for each responder, increase the quality and quantity of patient care, and more efficiently deliver patients to the hospital. The AID-N system accomplishes this through the following technologies:

• Wearable sensors to sense and record vital signs into an electronic patient record database. This dramatically improves the current time-consuming process of manually recording vital signs onto paper pre-hospital care reports and then converting the reports into electronic form for the hospitals.
• Pre-hospital patient care software with algorithms to continuously monitor patients’ vital signs and alert the first responders of critical changes.
• A secure web portal that allows authenticated users to collaborate and share real-time patient information.

In order to understand user needs, researchers at JHU-APL collaborated with physicians and nurses at Suburban Hospital Emergency Department (Bethesda, Maryland), physicians and bioinformatics experts at the Johns Hopkins Pediatric Trauma Center (Baltimore, Maryland), and first responders in the local area. As indicated in the figure above, a wearable computer was attached to the patient's wrist and then formed an ad hoc wireless network with the portable tablet PC. A GPS device on the mote provided the patient's geolocation. A pulse oximeter sensor on the patient’s finger measured heart rate (HR) and blood oxygenation level (SpO2) of the patient. The tablet PC was harnessed to the first responder in a weatherproof and anti-glare casing. This packaging allowed it to be used during rainy days or under bright sunlight.

The mote on the patient's wrist regularly transmitted vitals in real-time to the first responder’s tablet device. The transmission used the TinyOS Active Message protocol, which is based on the IEEE 802.15.4 standard. The device used for this application implemented Crossbow's MICAz Mote platform. The system required little setup time. Each medic carried many mote packages and distributed them to the patients. Each mote came with a pre-attached paper triage tag. When the patient was first triaged, the medic would strap the mote wristband on the patient, place the finger sensor on the patient’s finger, and would tear the triage tag to patient’s triage category (red/yellow/green). The mote would automatically start transmitting data to the medic’s tablet PC.

These wearable sensors were integrated with a pre-hospital patient care software package (MICHAELS) created by the OPTIMUS Corporation. MICHAELS ran on the first responder’s tablet PC. MICHAELS was modified to automatically record and analyze the patients’ vital signs and alert the first responder of abnormal changes. It also transmitted the patient's information in real time to a central server that hosted the patient record database. The tablet PC required a network connection to communicate with the central server. In this implementation, researchers took advantage of Verizon’s EVDO coverage in the Washington, D.C., Metropolitan Area. The tablet PCs used EVDO wireless cards to attain network connectivity at high data rates from anywhere in the greater Washington area. The tablet PC regularly transmitted vitals data and alerts for multiple patients to the electronic patient record database via the wireless network. If network connectivity was unavailable, the patient monitor and alert system on the tablet PC continued to operate. When an anomaly was detected, the medic’s software application generated an alert in the user interface, and an LED on the patient’s mote turned on. The medic could then locate the patient by selecting to view a map of the disaster scene marked with the GPS location of each patient. The medic could also select a “sound alert” feature that will sound a buzzer and blink an LED on the mote.

The AID-N system has great potential in improving problems in today’s emergency response system, especially in plans to deal with mass casualty disasters. The team at Johns Hopkin's Applied Physics Lab collaborated extensively with medical professionals in the area to build a prototype that met their greatest needs when designing the system. The key activities which could be improved using AID-N are patient monitoring, record generation and remote record review. AID-N has constructed hardware and software prototypes to address these areas, and shows promise in improving the efficiency of emergency personnel for these activities.