Low-flow systems:oxygen flows at less than inspiratory demand, actual FiO2 is highly dependent upon ptís minute ventilation and pattern.

1.†† nasal canulae: FiO2 24-50%, max flow rate 6L/min

2.†† simple mask: FiO2 35-50%, min flow rate 5L/min to allow mask washout.

3.†† mask with reservoir bag (partial or non-rebreather): capable of FiO2>90%, but practically only about 60%.


High-flow systems:oxygen flows fast enough to completely satisfy inspiratory demand

1.†† Venturi mask: max FiO2 50%

2.†† high-flow mask: max FiO2 60-70%