In table Chartevents, there is a attribute named warning. What does it represent? for example if there is a data entry with ITEMID 220046 which represents Heart rate Alarm - High, what does warning value 1 means for that entry?
The chartevents table of MIMIC-III is populated with data that has been archived by Metavision ICU, a clinical information system that integrates charted data from various sources, for example heart rates from bedside monitors. Data from the bedside monitors must be validated by a caregiver in order for it to be stored as part of a patient record.
If a caregiver wishes to draw attention to a clinical event, he or she may label it with a 'warning'. Doing this makes the value or values appear in the patient chart in a bold red font. In the chartevents table, the warning is given the binary value of 1 to indicate a warning was logged. The following screenshot from a training video shows a warning being added against a heart rate of 140 beats per minute:
After the warning has been added, the value now appears in a bold red font: