The transfers table

Table source: Hospital database.

Table purpose: Physical locations for patients throughout their hospital stay.

Number of rows: 261,897

Links to:

  • PATIENTS on SUBJECT_ID
  • ADMISSIONS on HADM_ID
  • ICUSTAYS on ICUSTAY_ID

Important considerations

  • The ICUSTAYS table is derived from this table.
  • Care units are defined based off the WARDID being associated with an ICU cost center.
  • ICUs in the Beth Israel have moved throughout the years, and consequently the same WARDID may be considered as an ICU for patient A but not an ICU for patient B.

Table columns

Name Postgres data type
ROW_ID INT
SUBJECT_ID INT
HADM_ID INT
ICUSTAY_ID INT
DBSOURCE VARCHAR(20)
EVENTTYPE VARCHAR(20)
PREV_CAREUNIT VARCHAR(20)
CURR_CAREUNIT VARCHAR(20)
PREV_WARDID SMALLINT
CURR_WARDID SMALLINT
INTIME TIMESTAMP(0)
OUTTIME TIMESTAMP(0)
LOS INT

Detailed Description

SUBJECT_ID, HADM_ID, ICUSTAY_ID

Identifiers which specify the patient: SUBJECT_ID is unique to a patient, HADM_ID is unique to a patient hospital stay and ICUSTAY_ID is unique to a patient ICU stay.

DBSOURCE

DBSOURCE contains the original ICU database the data was sourced from. Patients admitted between 2001 - 2008 had their data managed by the CareVue information system, represented in this column as ‘carevue’. Patients admitted between 2008 - 2012 had their data managed by the Metavision system, represented in this column as ‘metavision’. Knowing the database source is important as the data archiving for these two databases differs in some cases.

EVENTTYPE

EVENTTYPE describes what transfer event occurred: ‘admit’ for an admission, ‘transfer’ for an inter-hospital transfer and ‘discharge’ for a discharge from the hospital.

PREV_CAREUNIT, CURR_CAREUNIT

PREV_CAREUNIT contains the care unit in which the patient previously resided. CURR_CAREUNIT contains the care unit in which the patient currently resides. The care unit is defined based upon the ward: if the ward is an ICU cost center, then the care unit defines the type of ICU. If the ward is not an ICU then in most cases the care unit is null. There are one or two exceptions to this rule. For example, NWARD is a ward for newborns.

The INTIME and OUTTIME of the transfer event correspond to the CURR_CAREUNIT. The PREV_CAREUNIT for each row is provided for convenience, and is identical to the CURR_CAREUNIT of the previous row (assuming the event is not an admission).

Care units include the following:

Care unit Description
CCU Coronary care unit
CSRU Cardiac surgery recovery unit
MICU Medical intensive care unit
NICU Neonatal intensive care unit
NWARD Neonatal ward
SICU Surgical intensive care unit
TSICU Trauma/surgical intensive care unit

PREV_WARDID, CURR_WARDID

PREV_WARDID and CURR_WARDID contain the previous and current ward in which the patient stayed. Note that the grouping of physical locations in the hospital database is referred to as a ward. Though in practice ICUs are not referred to as wards, the hospital database technically tracks ICUs as “wards with an ICU cost center”. As a result, each ICU is associated with a WARDID, but not every WARDID is an ICU.

INTIME, OUTTIME

INTIME provides the date and time the patient was transferred into the current care unit from the previous care unit. OUTTIME provides the date and time the patient was transferred out of the current care unit.

LOS

LOS is the length of stay for the patient for the given ward stay, which may be within or outside of the ICU.

MIMIC-III v1.4 documentation