If the device isn't able to get a reading (for example, the fingertip sensor comes off), it records empty data fields. A simplified case of this is:
Date,Time,SpO2(%),PR(bpm)
3/3/2024,12:07:00 AM,90,71
3/3/2024,12:07:01 AM,,
3/3/2024,12:07:02 AM,92,87
00000000: 0003 0000 0000 1803 0300 0700 5a47 0000 ............ZG..
^^^^
00000010: 0018 0303 0007 0100 0000 0000 1803 0300 ................
^^^^^^^^^^^^^^^^^^^^^^-----------------
00000020: 0702 5c57 ..\W
---------
00000000: 0002 0000 0000 1803 0300 0700 5a47 0000 ............ZG..
----
00000010: 0018 0303 0007 025c 57 .......\W
----------------------