1. How is the content of a cylinder of N2O (nitrous oxide) measured?

2. A patient comes into the emergency department with obvious signs of upper airway obstruction. The physician agrees to deliver an 80/20 helium-oxygen mixture. The flowmeter reads 16 l/m. What is the true flow being delivered?

3. You are giving 70/30 Heliox to a patient with severe asthma. The oxygen flow meter is reading 8 l/m - what is the true flow of Heliox being delivered to the patient?

4. A patient has a respiratory rate of 15 and an average tidal volume of 400 ml. What is the patient's approximate inspiratory demand?

5. A patient is receiving Heliox therapy (70/30) for an acute asthma episode - the flowmeter reads 10 l/m, what is the true flow going to the patient?

6. A physician writes an order for a 80/20 Heliox blend to be delivered to a patient at 10 l/m. What setting would you use for the oxygen flowmeter used to administer the gas?