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→What is the oxygen concentration in the diluted CPAP circuit?
=What is the oxygen concentration in the diluted CPAP circuit?=
The equation to calculate concentration from flow is:(oxygen flow rate (litres) at 100% O2 + air volume (litres) at 21% O2) / Total air volume = oxygen concentration %
therefore, at 1 litres/minute oxygen addition and assuming a total CPAP flow of 60 L/min:
(1L 1-L/min x 100) + (60L 60-L/min x 21) = 1360 /60 -L/min = 22.% Oxygen.
at 1 litre/minute oxygen
(3L 3-L/min x 100) + (60L 60-L/min x 21) = 1560 / 60 L/min = 26% oxygen.
Any variable can be changed based on available data. If the flow rate is 40 L/min from the CPAP, the oxygen concentrations will be higher. If leaks are present or pressure results in a higher average vent-rate, the oxygen concentrations will be lower.
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