Communicating Within Medical Facility
Many modern hospitals rely heavily on their paging systems; these systems generally depend on the telephone system and on the normal power supply When backup generators kick in, these systems may fail. Prepare for this by keeping up-to-date contact lists, in paper and electronic forms. (Paper lists are important, since computers may not be operational.) Telephone numbers for vital sites within the facility (especially the radio or telephone hubs) as well as contact information for physicians and other hospital staff should be listed here.
Many hospitals plan to use walkie-talkies (low-wattage radios) for post-disaster internal communication. Except for line-of-sight (straight line without obstructions) communication, they are ineffective in modern buildings, such as hospitals.
Our tests have demonstrated that walkie-talkies and handheld radios (even up to 5 megawatts and with antenna repeaters placed) failed to transmit signals in any consistent manner in a modern hospital. The tests included checking transmission vertically and horizontally in the building. The only way these radios function in modern buildings is to use a "trunk" repeater (essentially, a giant antenna) running through the core of the building. Even then, experience shows that transmission is not consistent, and that there are numerous "dead" spots from which messages cannot be heard. These dead spots change daily, depending on atmospheric and other conditions.
When communication options are not available, it usually means there is (a) no electricity, (b) no Internet, and (c) no working land or cellular phones. To construct a runner system, remember that the goals of a runner system are to transmit messages between specific points ("nodes" or "hubs") within an institution or a local area in a manner that maximizes efficiency, that is, that uses the fewest runners (messengers) and has the fastest transmission times. Using set nodes or hubs is the efficient model that FedEx employs. [Alan Reeter, MSEE, Tucson, Ariz., in a conversation with the author, March 26, 2008.]
The types of messages transmitted between sites typically vary in volume and urgency. System efficiency can be increased if the senders designate each message as "1" urgent/stat, "2" important, or "3" routine or delay-tolerant. Category 1 messages are urgent requests for help, equipment, or supplies; critical lab reports; or urgent security warnings. Most clinical messages fall into category 2, while category 3 messages are administrative information, general announcements, and so forth. All level 3 messages can be routed to the central node, where they may be stored until several messages are collected to send to the same location. This "store-and-forward" technique conserves resources and decreases runners' frustrations from continually delivering status 3 messages.
Assuming that the message volume between different nodes (sites) varies and no mechanism exists to signal runners at different nodes that they are needed elsewhere to carry a message, the following method is a way to determine how many runners are needed.
The general scheme is to position the "command center" so that there is minimal distance between the command center and the nodes. With the normal scarcity of runners, base most runners at busiest nodes, with a minimum of one runner at every node. Have runners go in only one direction; let another runner return to the original node. (This system generally provides a rest period for the runners.)
The number of runners based at a node also depends upon the distance they need to travel (and the time it takes to do so) to reach the most distant or difficult-to-get-to site. In a hospital, this may mean running between a node in the basement and one in the 12th floor ICU. If the lab and pharmacy (two frequent-message sites) have satellite facilities near the busiest clinical nodes, this limits the number of messages (and runners) required.
The following formula helps to determine how many runners are needed. With a runner dedicated to each pair of nodes, the total number of runners will be N × (N − 1), where N = the number of message nodes. For example, 3 nodes require 6 runners, 4 nodes require 12 runners, and 6 nodes require 30 runners. Optimally, the number of runners at each node would be N minus 1, with each of 6 nodes having 5 runners (Fig. 3-4). Since this number is too large for most situations, either decrease the number of nodes or assign more runners to the high-priority nodes. (Be aware that doing so may decrease the system's efficiency.)
Runners need to work in shifts. Assuming that they work 12-hour shifts, the total number of runners required will be double the number for each shift (plus extras for illnesses and time off).
Typical hospital nodes may include the command center/central administration, emergency department, ICU 1, ICU 2, ward 1, ward 2, ward 3, OR, pharmacy, laboratory, personnel pool, security, food services, and ambulance bay/helipad. Adjacent areas (e.g., two wards next to each other) can share one communication node.
The idea of using mobile radios is appealing. However, several problems exist. The first is that they can be very expensive, although the basic models cost only about $100 each. Next, there is the question of compatibility with other radios in use, concerns about message security, and the fact that the transmitting range diminishes depending on terrain, weather, buildings, body mass, and so forth. The range can be extended with one or more repeaters that rebroadcast the signals and thus increase their range.6
Despite these problems, consider using low-cost Family Radio Service radios to keep in touch with neighbors and family members. The range is 1 to 2 miles, and no license is required. Set up a network of these radios in your neighborhood to help each other in a disaster.7
Amateur Radio Operators (Hams)
Groups of amateur radio operators exist in many areas of the world to help with communications in disaster situations. In the United States, these groups are ARES and RACES. They generally have preset and tested equipment and can be activated in crises. This is an excellent method, even under austere circumstances, to communicate with others with similar amateur radio (not necessarily just ARES or RACES) capabilities.