Impute FiO2 with oxygen supply. If FiO2 is missing, replace with FiO2 calculated from oxygen supply. If still missing, impute with 21% (ambient air).
Details
FiO2 is missing in many cases. To fill those gaps, this function
converts the oxygen supply (L/min) to FiO2 based on the oxygen delivery device
in case the FiO2 is missing in the dataset. When also the
oxygen supply is missing, the FiO2 is imputed with 21%,
the ambient air oxygen percentage. This functions uses o2supply_to_fio2()
See also
Other respiration:
clean_fio2(),
clean_spo2(),
impute_pao2(),
o2supply_to_fio2(),
pfratio_imputed(),
spo2_to_pao2()