Q: What is the formula to convert S/F ratio to P/F ratio? 

 - PaO2/FiO2 and SpO2/FiO2 ratio 


Answer: S/F = 64 + 0.84*(P/F) 

 An S/F value of 235 corresponded with P/F ratio of 200 while S/F value of 315 corresponded with P/F ratio of 300. Study shows that validation database from 2031 measurements produced a linear relationship.