Usage of High Flow Nasal Cannula in Preventing Desaturations in Elderly Patients Going for Lower Limb Surgeries

high flow nasal cannula provides heated and humidified gas to the airways via nasal prongs at a prescribed accurate fraction of inspired oxygen (FiO2) ranging from 0.21 to 1.0 and with a higher flow rate of up to 60 litres per minute

nasoprong @L/min will deliver approximately a FiO2 of 0.3. subsequently, if incremental O2 is needed, patient will be provided with ventimask 40% and so forth