Concept: Intensive Care Unit (ICU) Days

Introduction

This concept describes two ways of calculating the number of days spent in the Intensive Care unit (ICU): Manitoba Health's definition , and MCHP's definition.

NB: There are over/under counting issues for both of these ICU calculations

1 - Manitoba Health Definition

Manitoba Health's definition for ICU days (algorithm given below) is:

• If Admit date = Discharge date
  
• If one service and is ICU, count 1 day
  
• If two services, if ICU is last occurring service, count 1 day
  
• If ICU is not last service, count 0 days.

TRANSLATION:


Service (one, two, two+) = up to six codes that describe the type of service that the patient underwent in one hospitalization.

ICU: If the 6 service codes = 'xx90' then this is a visit to the ICU.

• If Admit date < Discharge date
  
• If one service and is ICU, count should be = LOS
  
• If two+ services, for same day, if last service is ICU, count N days
  
• Where N = ([NEXT 1 to 6 SERVICE DATES or Discharge Date] - DATE(ICU))
  
• If ICU but not last service, count 0 days.
  
• (Same day means 1 or more services start on the same day).

TRANSLATION:


DATE(ICU) = Date of ICU visit, uses up to six dates associated with the service provided during the hospitalization.

• If one of six service codes= 'xx90' then one to six service dates associated with that service is the ICU date.
  
• LOS = Length of stay in hospital.

EFFECTS:

• counts services as of midnight on each day so ignores ICU care of less than 1 day if another service begins later that day.
  
• ICU count cannot be > LOS
  
• sum of service days (all units) cannot exceed LOS.
  
• undercounts ICU usage.

Programming Notes:

See the pseudo-SAS code below to find ICU DAYS (assumed to be Manitoba Health's method). See the SAS code link below to access Manitoba Health ICU SAS Code (internal access only).

|| Keep only inpatients;
|| Set up several arrays for converting service code dates into usable dates, and counting service codes initialize several counting variables.
|| Count services and put service dates into a SAS date keep only those claims which have ICU service codes *;
|| ICU counts Manitoba Health's method (according to Pat) & service if there is only one day in the claim, and the last service code is an ICU code;
|| Count 1 ICU day *;
|| If the stay is longer than one day then count the service codes *;
|| If the last service code is an ICU then count the days from the last service date to the date of separation as ICU days, this includes claims with only a single service code. *;
|| The following adds one day if the last service date is the same as the date of separation and the service is ICU *;
|| For longer stays count days in ICU units by checking the previous service code for an ICU marker.
|| Mark all claims with an ICU stay. This is not necessary in this case since all of the claims kept have ICU days. *;

2 - MCHP's Definition

To create the Number of Days in ICU variable on the hospital datasets:

• Every ICU service encountered (If 1 to 6 service code = 'xx90') counts as 1 or more days, depending on change in service date or discharge date. (i.e.: counts days (or portions thereof) in ICU).
  
• Intervening services (not ICU) which are followed by a return to ICU on the same date cause the algorithms to attribute the return to ICU to a new day (1 too many).

EFFECTS:

• In cases which have one or more dates on which ICU has been left and reentered, each such return increases the count by 1.
  
• We are counting days (or portions thereof) in ICU but due to the "same day" effects the ICU count can exceed LOS.

See the SAS code link below to access MCHP ICU Days SAS Macro Code (internal access only).

GENERAL NOTE (applies to both definitions)

Due to the limitation of having only 6 coded services/dates available, the ICU days may be:

• understated if ICU services occurred after the sixth service.
  
• overstated when the sixth service code is intensive care since the service code is assumed to be applicable to all days from the start of intensive care to the date of discharge. Without further service code/date info, it cannot be determined if the service level changed prior to the date of discharge.