The need for speed
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In Richmond, EMS vehicles are equipped with InMotion mobile gateways that send data over the Verizon Wireless or Sprint wireless networks, Overton said. Subscribing to both services doubles the cost but results in increased coverage, capacity and reliability.
Currently, patient electrocardiogram information is sent to a CAD system, but work is under way to develop a method to transmit the data directly to hospitals, Overton said. Meanwhile, using the vehicle-location function enabled with the network has enabled more efficient dispatching
“Our data shows that we're saving 20 to 30 seconds per call in response time,” Overton said. “That may not sound like much, but we're required by the city to be on the scene within eight minutes and 59 seconds on all life-threatening calls, so 20 to 30 seconds is notable in that context.”
Many in the public-safety arena have expressed concern about the reliability of commercial networks, but Overton said he does not see a problem.
“People get freaked out about all kinds of stuff,” he said. “We've had no reliability problems, so far, and we just had Tropical Storm Hanna come through.”
In terms of public-safety-grade reliability, McGinnis — who also is vice president of the Public Safety Spectrum Trust — said he believes the only options available to public safety are 4.9 GHz networks, which have such poor propagation that they are only economically feasible in urban areas, and the proposed 700 MHz broadband network that the FCC hopes will be available nationwide. (See story, page 7.)
“If we don't have a 700 MHz system, we have no rural or suburban solution for bringing EMS into the 21st century and being able to use data communications,” he said.
Converged Network Needs and Capabilties
+Consultation/instructions between physician, medic and patient.
+911 incoming calls.
+Communication within hospital enterprise and with public.
+Public and 911
+911 dispatch and EMS
+EMS and public safety
+EMS and hospital
+Hospital to hospital
+Hospital and public
+Network must support bidirectional, full duplex voice (voice over IP)
+Network needs quality of service to support real-time communication (low latency and jitter)
+Perceived voice delay must be minimized
Store and forward video/images, streaming biometric data, medical history and patient tracking.
+Electronic medical records
+Connecting with regional health information networks
+EMS transmission of real-time, multi-vital-sign telemetry
+Hospital/lab transmission of high-definition test results
+Communicating with providers, patients and insurers
+Biometric monitoring devices
|File transfer can tolerate longer latency/jitter. In general, data that can be passed tolerating delay or buffer time has less stringent requirements for the network.|
Video for observing an accident scene, patient or for physician — patient/medic interaction.
|Video resolution, frame rate and quality are linked to available bandwidth, latency and jitter. High-resolution video/images may be sent as “store and forward” (not real time).|
Source: Joint Advisory Committee on Communications Capabilities of Emergency Medical and Public Health Care Facilities