New article on the effects of filters on flow and FiO2 using venturi generators (Whisperflow and Harol 9293/D)
“The use of filters during H-CPAP reduces the flow delivered to the helmet and, consequently, modifies FiO2. If filters are applied, an adequate gas flow should be administered to guarantee a constant CPAP during the entire respiratory cycle and avoid CO2 rebreathing. Moreover, it might be important to measure the effective FiO2 delivered to the patient to guarantee a precise assessment of oxygenation.”