New Date/Time Extension for VistA
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Author:  rcr [ Thu Nov 11, 2010 5:54 am ]
Post subject:  New Date/Time Extension for VistA

We recently had a time switch from daylight savings time to standard time. The VA has addressed this problem for decades by turning off the machines for 1 hour to keep from experiencing the same hour twice and providing an ambiguity in the medical care. The time signature in VistA is 3101107.01

There are some extensions to this representations which will be able to represent these hickups in the time swaps and the resolve the transfer of patients from one time zone to another seamlessly. The solution revolves around two representations of time, one military and one UTC. The military is compact, but the UTC reference is more exact for odd time zones (of which there are many surprising ones.

The military representations are defined here; ... time_zones
or ... /military/
and the UTC exceptions (half hour/quarter/20 minute/45 minute/etc) are listed at the bottom of the page for the first URL.

The military extension is the addition of a single Upper-case Alpha to the date/time signature, 3101107.010001U becomes 3101107.000001T and there is no ambiguity with the date/time signature and the computer does not need to be shut down for an hour. These all resolve to ZULU (UTC) time exactly without loss or ambiguity.

The alternate rarer means of time representation might be for the odd case where the patient is being transported from a foreign country which does not break the hour at 00, but does it on the half/quarter/or 20 minute boundary. The time signature would be 3101107-1045 or 3101107+0315.

These two solutions are not ambiguous but can be used to make patient medication time records as the patient is being transported across timezones, or projected to the time frame of the observer.

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