Oxygen therapy & respiratory calculations worksheet with answers

Practice exercise (made-up values, not clinical guidance). A patient breathes 24 times a minute with a tidal volume of 670 mL. Find the minute ventilation V̇E in L/min.

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 20 times a minute with a tidal volume of 360 mL. The anatomical dead space is 150 mL. Find the alveolar ventilation V̇A in L/min.

Practice exercise (made-up values, not clinical guidance). A size D oxygen cylinder (factor 0.16 L/psi) reads 550 psi and runs at 3 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 with acute hypoxaemia and bilateral opacities, not explained by heart failure, has PaO₂ 15.7 kPa on 45% oxygen with a PEEP of 12 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 transfer will take 120 minutes. The size E cylinder (factor 0.28 L/psi) reads 850 psi. Keeping a safe residual of 200 psi, what is the highest whole-number flow Q in L/min that lasts the whole transfer?