I have a question about "ventilation.sql"

[hidoyebi]

Prerequisites

• [O ] Put an X between the brackets on this line if you have done all of the following:
  • Checked the online documentation: https://mimic.mit.edu/
  • Checked that your issue isn't already addressed: https://github.com/MIT-LCP/mimic-code/issues?utf8=%E2%9C%93&q=

Description

Hello, I have a question about "mimic-code/mimic-iv/concepts postgres/treatment/ventilation.sql" on github.

https://github.com/MIT-LCP/mimic-code/blob/main/mimic-iv/concepts_postgres/treatment/ventilation.sql

There is "Having MIN(charttime) <> MAX(charttime)" at the end of this code. Using the condition, number 3 of seq_num in the image below will be excluded. I am curious about why the "having" condition is used and whether this case corresponds to weaning failure.

[alistairewj]

Oh does it remove that case? It shouldn't. having MIN(charttime) <> MAX(charttime) is equivalent to not-equal, so it should only filter out rows where the start time is equal to the end time. It might be that these are weaning failures, would be very interested in investigation there. I added it because there were a ton of 0 length events, and the goal of the duration query is to get durations not point estimates.

[hidoyebi]

Thank you for your reply. In vd2(temporary table), number 3 of seq_num exists only one row, so min(charttime) and max(charttime) are excluded because they are the same time.

Number 3 of seq_num case, it seems that the process was to test whether the patient could breathe spontaneously.

I will take your advice into consideration. Thank you :)