chartevents

The chartevents table

Table source: MetaVision ICU database.

Table purpose: Contains all charted data for all patients.

Number of rows: 313,645,063

Links to:

• patients on subject_id
• admissions on hadm_id
• icustays on stay_id
• d_items on itemid

Brief summary

chartevents contains all the charted data available for a patient. During their ICU stay, the primary repository of a patient’s information is their electronic chart. The electronic chart displays patients' routine vital signs and any additional information relevant to their care: ventilator settings, laboratory values, code status, mental status, and so on. As a result, the bulk of information about a patient’s stay is contained in chartevents. Furthermore, even though laboratory values are captured elsewhere (labevents), they are frequently repeated within chartevents. This occurs because it is desirable to display the laboratory values on the patient’s electronic chart, and so the values are copied from the database storing laboratory values to the database storing the chartevents.

Important considerations

• Some items are duplicated between the labevents and chartevents tables. In cases where there is disagreement between measurements, labevents should be taken as the ground truth.

Table columns

subject_id, hadm_id, stay_id

Identifiers which specify the patient: subject_id is unique to a patient, hadm_id is unique to a patient hospital stay and stay_id is unique to a patient ward stay. More information about these identifiers is available here.

caregiver_id

caregiver_id uniquely identifies a single caregiver who documented data in the ICU information system.

charttime, storetime

charttime records the time at which an observation was made, and is usually the closest proxy to the time the data was actually measured. storetime records the time at which an observation was manually input or manually validated by a member of the clinical staff.

itemid

Identifier for a single measurement type in the database. Each row associated with one itemid (e.g. 220045) corresponds to an instantiation of the same measurement (e.g. heart rate).

value, valuenum

value contains the value measured for the concept identified by the itemid. If this value is numeric, then valuenum contains the same data in a numeric format. If this data is not numeric, valuenum is null. In some cases (e.g. scores like Glasgow Coma Scale, Richmond Sedation Agitation Scale and Code Status), valuenum contains the score and value contains the score and text describing the meaning of the score.

valueuom

valueuom is the unit of measurement for the value, if appropriate.

warning

warning specifies if a warning for this observation was manually documented by the care provider.