Questions from sofa script

[tedinburgh]

In the ’concepts/severityscores/sofa.ipynb’ script:

1. Outliers for FiO2 values (>100) are discarded. Before converting to FiO2 %, there are also some entries that have a value between 1 and 20, which might also be outliers? Is it reasonable to assume this and discard them as well? (if not removed, it would give an artificially low PF ratio which is carried forward to the SOFA calculation).

2. In the SOFA bilirubin score, itemid 6813 (Bili Totaal, 2.7% of the entries) has units umol, while itemid 9945 (Bilirubine (bloed)) has units umol/l. We want the units of everything to be the latter. Is the umol unit in fact umol/l unit? If not, how would they be converted?

3. For the SOFA cardiovascular score, we retain cardiovascular drugs that are administered with rate >0.1. This excludes those with rate 0.1 (the minimum value). Why is this? Is it to exclude those with rate 0, and if so, should we change this to >=0.1?

[patrickthoral]

1. You are right that values between 1 and 20 are most likely data entry errors (might even be values that should have been entered as 'oxygen flow rate' instead of FiO2)
2. Yes, the original database should have used umol/l, so indeed they are the same
3. The main reason for excluding the 0.1 rate is by convention. In our unit some infusions are kept running 'as a convenience' at the lowest possible rate to allow 'restarting' (basically increasing the rate) if needed. So the 0.1 rate means that the infusion is not really required for that specific patient.