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Compute Length of Stay in Intensive Care Unit

icu_los.Rd

Calculates the total duration in Intensive Care Unit (ICU) that an encounter spent during a hospital stay using CIHI Discharge Abstract Database (DAD) fields

Usage

icu_los(cohort, ipscu)

Arguments

cohort

(data.table or data.frame)
Table with all relevant encounters of interest, where each row corresponds to a single encounter. Must contain GEMINI Encounter ID (genc_id).

ipscu

(data.table or data.frame)
Table equivalent to the ipscu table defined in the GEMINI Data Repository Dictionary. Table must contain fields: GEMINI Encounter ID (genc_id), SCU admission time (scu_admit_date_time in "yyyy-mm-dd hh:mm" format), SCU discharge time (scu_discharge_date_time in "yyyy-mm-dd hh:mm" format), and SCU number (scu_unit_number).

Value

(data.table)
By default, for each encounter in input "cohort" returns the corresponding derived numeric fields "icu_los_hrs_derived" and "icu_los_days_derived".

Details

This function calculates the length of stay (LoS) in hours and days that an encounter spent in the ICU during a hospital stay.

It uses DAD fields SCU Admit date-time (Group 13, Field 03/04) and SCU Discharge date-time (Group 13, Field 05/06) to derive these numeric fields.

Rows with either of SCU Admit/Discharge date-time fields missing, will not be counted in calculation.

For encounters with multiple ICU visits, the function returns the sum of the duration of each visit.

By definition in DAD (Group 13, Field 02), SCUs include ICUs and Step-Down Units. Step-Down Units are not considered as ICUs.

Therefore, this function excludes below CIHI defined Step-Down Units numbers from calculation:

  • 90 : Step-Down Medical Unit

  • 93 : Combined Medical/Surgical Step-Down Unit

  • 95 : Step-Down Surgical Unit

  • 99 : No SCU

Please refer to the CIHI DAD abstracting manual for more details.

Note

: Encounter IDs in the cohort table that are not present in the ipscu table are assumed to have no visits to ICU. For these encounters, a value of 0 will be assigned to the derived fields. Encounter IDs in the ipscu table that have any missing/invalid scu_admit_date_time or scu_discharge_date_time will be returned with icu_los = NA. Some of those entries have valid date information (but no timestamp). Users may choose to impute missing timestamps prior to running this function. When one tries to left-join the output of this function to another table, make sure the list of encounters aligns in both tables.

Examples

# Compute ICU LoS for all encounters in ipadmdad:
if (FALSE) { # \dontrun{
icu_los (cohort=ipadmdad, ipscu=ipscu)
} # }