Oxygen therapy & respiratory calculations worksheet with answers

Practice exercise (made-up values, not clinical guidance). A patient receives oxygen by nasal cannula at 6 L/min. Using FiO₂ ≈ 21% + 4% per L/min, estimate the inspired oxygen FiO₂ in percent.

Practice exercise (made-up values, not clinical guidance). The gauge on a size H oxygen cylinder reads 1500 psi. Its cylinder factor is 3.14 L/psi. How many litres V can be used before the safe residual of 200 psi is reached?

Practice exercise (made-up values, not clinical guidance). A patient breathes 17 times a minute with a tidal volume of 300 mL. The anatomical dead space is 160 mL. Find the alveolar ventilation V̇A in L/min.

Practice exercise (made-up values, not clinical guidance). A patient has Hb 140 g/L, SaO₂ 93% and PaO₂ 68 mmHg (9.1 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 has Hb 125 g/L, SaO₂ 97%, PaO₂ 86 mmHg (11.5 kPa) and a cardiac output of 3.4 L/min. With CaO₂ = 1.34 × Hb (g/dL) × SaO₂ + 0.003 × PaO₂ (mmHg), find the oxygen delivery DO₂ = CaO₂ × CO × 10 in mL/min.

Practice exercise (made-up values, not clinical guidance). A transfer will take 120 minutes. The size E cylinder (factor 0.28 L/psi) reads 1650 psi. Keeping a safe residual of 200 psi, what is the highest whole-number flow Q in L/min that lasts the whole transfer?