Air-Entrainment (Venturi) Quiz
Work the entrainment ratio and total flow from the formula — ten problems per round.
Problem 1 of 10
A Venturi mask is set to deliver FiO₂ 31% with the flowmeter set to 12 L/min of oxygen. What is the total delivered flow?
Set FiO₂
31%
O₂ flow
12 L/min
Written by Apex Respiratory Editorial Team
About this quiz
Each round draws ten Venturi (air-entrainment) problems and asks for either the air-to-oxygen entrainment ratio or the total delivered flow. Both come from one relationship: the ratio is (100 − FiO₂) ÷ (FiO₂ − 21), which gives the parts of room air entrained per part of oxygen, and the total flow is (air parts + 1) × the set oxygen flow. The lower the FiO₂, the more air is entrained — and the higher the total output flow, which is exactly what makes a low-FiO₂ Venturi a true fixed-performance device.
Educational use only. Ratios are rounded to the conventional whole-number bedside values; actual device output varies with the specific jet/entrainment port and any downstream flow resistance (e.g. added humidity), which lowers delivered FiO₂ and flow. This material supports respiratory therapy education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional protocols, or physician orders. Always follow facility policies and current provider orders, and verify calculations independently before clinical use.
Sources
- Kacmarek RM, Stoller JK, Heuer AJ. Egan's Fundamentals of Respiratory Care. 12th ed. Elsevier; 2021. Oxygen therapy / air-entrainment devices.
- Cairo JM. Mosby's Respiratory Care Equipment. 11th ed. Elsevier; 2022.