An easy way to clarify times and dates when Daylight Savings time is starting/stopping is to format the date field to INCLUDE the designators EST, CST, MST, and PST for standard time, and EDT, CDT, MDT, and PDT whenever Daylight Savings Time is in force.

03/11/18 01:59 PST —>  03/11/18 02:00 PDT
11/14/18 01:59 PDT —> 11/14/18 02:00 PST

Note that in the fall, an event may occur at both 11/14/18 01:30 PDT and 11/14/18 01:30 PST and actually be 1 hour apart.  It is important for legal purposes to clarify exactly what time system is in force when events are recorded in the medical record.

Adding the time zone designator to the date/time stamp is compact enough to not interfere with the current formatting of most medical records.

It is also useful to also have a script added to each medical record on the dates a time change will occur, to remind those reviewing the records that a time change is occurring.

Time will change from Daylight Savings to Standard at 2:00 am
03/11/18 01:59 PST 

These recommendations minimize confusion regarding the time of events for someone reading the record and establishes the time unambiguously for legal purposes.