As we move into wearable technology I see the need for sensors built into an add-on platform to current body armor. The sensors would track 3 items and transmit it back to a decision maker / monitor. First: an officer's heart rate, above or below trigger points; Second, body core temp above or below a trigger point and Last, high impact or g loads indicating blunt force trauma (gunshot, impact weapon or stabbing weapon).
This information does not need to be transmitted continuously but when the trigger points are exceeded. Building the sensor package into a separate platform that could be placed inside the current body armor carrier would allow the system to be added to all existing armor.
Powering the system could be in the form of a bullet resistant battery, replacing the traditional soft trauma pack covering the heart. Another option is to harness the heat generated by the wearing the armor.
A forth sensor would be a GPS system to locate the officer when under duress or when the need to coordinate a large area response arises. A supervisor could monitor the location of all assigned officers on a wearable sleeve display and know where officers are located and see where they should be deployed or re-assigned.