[tz] Epic fail for DST fallback in hospital health records

Paul Eggert eggert at cs.ucla.edu
Sun Nov 4 07:28:13 UTC 2018

John Hawkinson wrote:

> This is confusing

Yes, unfortunately there's not much technical detail in Lupkin's article.

> Be afraid when drug delivery systems (e.g. IV pumps, etc.) decide they know what time it is and mess up dosages across time changes

I found a recent scholarly article by Ehlers et al (cited below) that covers DST 
problems in clinical laboratories. Although these labs don't do drug delivery, 
the article is illustrative nonetheless. Ehlers et al mention the following 
topics (I am in some cases making educated guesses about the real problems, as 
the authors wrote for an medical audience):

* The electronic health records (EHR) system may be from a different vendor than 
the laboratory information system (LIS), and the vendors may have different ways 
of dealing with DST issues and DST rule updates.

* Many hospitals and labs run older systems such as MS-Windows XP where the DST 
change rules may be wrong and the systems may be no longer supported.

* When a time server disagrees with the time settings on the local computer, the 
wrong side might win.

* Some devices update automatically and some don't, leading to time mismatches 
when output from one is fed as input to the other.

* The automatic clock-change procedure sometimes fails on some devices, and the 
manual process for fixing this can be quite involved and can require IT support.

* Some instruments require a pause in operation, then a manual time change, then 
a restart.

* Staffing issues for the missing or extra hour.

* Staff might not know manual clock-change procedures done only twice yearly.

* These problems surface on the third shift which has lower staffing; 
conversely, there tends to be less work during the third shift so staff has more 
time to fix DST-related problems.

Ehelers et al. give examples of extended downtime due to some of these issues 
and recommend having an IT expert available during DST changes. They summarize 
by saying that fallback is more of a pain than spring-forward, that the 
switchover isn't much of a problem for labs due to low volumes early Sunday, but 
that people should watch out for the rare problems that do occur.

Ehlers A, Dyson RL, Hodgson CK, Davis SR, Krasowski MD. Impact of Daylight 
Saving Time on the Clinical Laboratory. Acad Pathol. 2018 Jul 
11;5:2374289518784222. doi:10.1177/2374289518784222 

More information about the tz mailing list