The d_items table

Table source: CareVue and Metavision ICU databases.

Table purpose: Definition table for all items in the ICU databases.

Number of rows: 12,487

Links to:

  • CHARTEVENTS on ITEMID
  • DATETIMEEVENTS on ITEMID
  • INPUTEVENTS_CV on ITEMID
  • INPUTEVENTS_MV on ITEMID
  • MICROBIOLOGYEVENTS on ITEMID
  • OUTPUTEVENTS on ITEMID
  • PROCEDUREEVENTS_MV on ITEMID

Important considerations

  • D_ITEMS is sourced from two distinct ICU databases. The main consequence is that there are duplicate ITEMID for each concept. For example, heart rate is captured both as an ITEMID of 212 (CareVue) and as an ITEMID of 220045 (Metavision). As a result, it is necessary to search for multiple ITEMID to capture a single concept across the entire database. This can be tedious, and it is an active project to coalesce these ITEMID - one which welcomes any and all help provided by the community!
  • Another source of duplicate ITEMID is due to the free text nature of data entry in CareVue - as a result there are additional ITEMID which correspond to misspellings or synonymous descriptions of a single concept. It is important to search for all possible abbreviations and descriptions of a concept to capture all associated ITEMID.
  • If the LINKSTO column is null, then the data is currently unavailable, but planned for a future release.

Table columns

Name Postgres data type
ROW_ID INT
ITEMID INT
LABEL VARCHAR(200)
ABBREVIATION VARCHAR(100)
DBSOURCE VARCHAR(20)
LINKSTO VARCHAR(50)
CATEGORY VARCHAR(100)
UNITNAME VARCHAR(100)
PARAM_TYPE VARCHAR(30)
CONCEPTID INT

Detailed Description

The D_ITEMS table defines ITEMID, which represents measurements in the database. Measurements of the same type (e.g. heart rate) will have the same ITEMID (e.g. 211). The ITEMID column is an alternate primary key to this table: it is unique to each row.

Note that the D_ITEMS table is sourced from two ICU databases: Metavision and CareVue. Each system had its own set of ITEMID to identify concepts. As a result, there are multiple ITEMID which correspond to the same concept. For CareVue data, ITEMID = 211 is used to identify heart rates, whereas for Metavision data, ITEMID = 220045 is used. All Metavision ITEMIDs will have a value > 220000.

Note that the D_ITEMS table does not link to the LABEVENTS table, as this data was acquired separately from the hospital database. The D_ITEMS table was acquired from the ICU databases.

ITEMID

As an alternate primary key to the table, ITEMID is unique to each row.

LABEL, ABBREVIATION

The LABEL column describes the concept which is represented by the ITEMID. The ABBREVIATION column, only available in Metavision, lists a common abbreviation for the label.

DBSOURCE

The DBSOURCE column was generated to clarify which database the given ITEMID was sourced from: ‘carevue’ indicates the ITEMID was sourced from CareVue, while ‘metavision’ indicated the ITEMID was sourced from Metavision.

LINKSTO

LINKSTO provides the table name which the data links to. For example, a value of ‘chartevents’ indicates that the ITEMID of the given row is contained in CHARTEVENTS. A single ITEMID is only used in one event table, that is, if an ITEMID is contained in CHARTEVENTS it will not be contained in any other event table (e.g. IOEVENTS, CHARTEVENTS, etc).

CATEGORY

CATEGORY provides some information of the type of data the ITEMID corresponds to. Examples include ‘ABG’, which indicates the measurement is sourced from an arterial blood gas, ‘IV Medication’, which indicates that the medication is administered through an intravenous line, and so on.

UNITNAME

UNITNAME specifies the unit of measurement used for the ITEMID. This column is not always available, and this may be because the unit of measurement varies, a unit of measurement does not make sense for the given data type, or the unit of measurement is simply missing. Note that there is sometimes additional information on the unit of measurement in the associated event table, e.g. the VALUEUOM column in CHARTEVENTS.

PARAM_TYPE

PARAM_TYPE describes the type of data which is recorded: a date, a number or a text field.

MIMIC-III v1.4 documentation