Oxygen therapy & respiratory calculations worksheet with answers

Practice exercise (made-up values, not clinical guidance). A patient receives oxygen by nasal cannula at 4 L/min. Using FiO₂ ≈ 21% + 4% per L/min, estimate the inspired oxygen FiO₂ in percent.

Practice exercise (made-up values, not clinical guidance). A patient breathes 32 times a minute with a tidal volume of 350 mL. Find the minute ventilation V̇E in L/min.

Practice exercise (made-up values, not clinical guidance). A size E oxygen cylinder (factor 0.28 L/psi) reads 900 psi and runs at 6 L/min. Keeping a safe residual of 200 psi, how many minutes t will it last? Round down to a whole minute.

Practice exercise (made-up values, not clinical guidance). A patient has Hb 70 g/L, SaO₂ 97% and PaO₂ 88 mmHg (11.7 kPa). Find the arterial oxygen content CaO₂ = 1.34 × Hb (g/dL) × SaO₂ + 0.003 × PaO₂ (mmHg) in mL O₂/dL.

Practice exercise (made-up values, not clinical guidance). A patient with acute hypoxaemia and bilateral opacities, not explained by heart failure, has PaO₂ 12.6 kPa on 100% oxygen with a PEEP of 5 cmH₂O. Grade the ARDS severity with the Berlin definition. Click your answer.

1. 1above 300
2. 2mild
3. 3moderate
4. 4severe
5. 5not gradable: PEEP below 5

Practice exercise (made-up values, not clinical guidance). A cylinder with a water capacity of 2 L is filled to 163 bar and runs at 15 L/min. The gas volume is about the water capacity × the pressure. In this exercise the cylinder is changed at 20 bar. How many minutes t until it must be changed? Round down to a whole minute.