The Food and Drug Administration (FDA) has issued an advisory to alert hospital officials, healthcare workers, people who rely on medical devices and their caregivers about possible adverse affects of the new Daylight Savings Time (DST) change on some medical equipment and suggestions on how to prevent them.
It’s unknown if any problems will develop or what specific devices may be affected. The FDA is concerned about medical devices or medical device networks that operate together with other networked devices, e.g. where a synchronization of clocks may be necessary.
If a medical device or medical device network is adversely affected by the new DST date changes, a patient treatment or diagnostic result could be:
Any of these unpredictable events could harm patients and not be obvious to clinicians responsible for their care.
DST now starts three weeks earlier and ends one week later than in previous years as a result of the Energy Policy Act of 2005, which extended DST in the U.S. to conserve energy. Beginning in 2007, DST will start at 2:00 a.m. on the second Sunday of March (instead of the first Sunday of April) and end at 2:00 a.m. on the first Sunday of November (instead of the last Sunday of October). This means that DST will begin on March 11, 2007 (instead of April 1, 2007) and end on November 4, 2007 (instead of October 28, 2007).
As usual, at the beginning of DST, one hour effectively disappears as 1:59 a.m. is followed by 3 a.m. At the end of DST, a duplicate hour appears as 2:59 a.m. is followed by 2:00 a.m., meaning that the 2:00 a.m. hour happens twice.
There are many types of medical devices and systems with clocks and clock-related features such as timers that were sold before the DST rule changes, e.g. they were designed with the old start and end DST dates, it is unknown whether these devices and systems will operate correctly with the new 2007 DST start and end dates.
Internal clocks in devices and systems usually change automatically for DST based on values set internally or interactions with other devices, e.g., servers. Some devices and systems may rely on incorrect values for DST starting and ending dates if the device manufacturers have not patched or fixed their devices to use the new dates.
Patients who use medical devices in their homes are being advised to check with the manufacturers to see if any patches or fixes are available for their devices.
More information about medical devices and the DST change can be found in the ECRI (formerly the Emergency Care Research Institute) Health Device Alerts publication entitled “Medical Devices and the 2007 DST Changes” (PDF) at the ECRI web site.