[MIMIC-IV v3.1] 14 ICU stays in icustays have a null outtime and los

[Amorfati123]

• Checked the online documentation: https://mimic.mit.edu/
• Checked that this issue isn't already addressed: https://github.com/MIT-LCP/mimic-code/issues

Version: MIMIC-IV v3.1. All files match SHA256SUMS.txt and every table's row count matches mimic-iv/buildmimic/postgres/validate.sql.

What I found

14 of the 94,458 rows in icu/icustays have a valid intime but a null outtime and a null los. For every other stay, los matches outtime - intime exactly.

These look like real, completed ICU stays rather than stub rows:

• All 14 have a hospital dischtime on their admission: 7 in-hospital deaths and 7 discharged alive.
• All 14 have bedside charting in chartevents after intime, for example between 4 and 147 RASS values per stay.
• They are spread across units: MICU (4), CCU (4), MICU/SICU (2), CVICU (2), SICU (1), Neuro SICU (1).

I have not traced them back through transfers.

To reproduce

SELECT i.stay_id, i.first_careunit, i.intime, i.outtime, i.los,
       a.dischtime, a.hospital_expire_flag
FROM mimiciv_icu.icustays i
JOIN mimiciv_hosp.admissions a USING (hadm_id)
WHERE i.outtime IS NULL;

Questions

1. Is this expected, for example because the last ICU transfer has no out time in the source system?
2. Could outtime and los be filled from transfers in a future release? If not, could the icustays documentation note that outtime can be null?