Oxygen therapy & respiratory calculations worksheet with answers

Practice exercise (made-up values, not clinical guidance). A patient receives oxygen by nasal cannula at 2 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 750 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 21 times a minute with a tidal volume of 560 mL. The anatomical dead space is 120 mL. Find the alveolar ventilation V̇A in L/min.

Practice exercise (made-up values, not clinical guidance). A size H oxygen cylinder (factor 3.14 L/psi) reads 1050 psi and runs at 4 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 on high-flow nasal oxygen has SpO₂ 91% on FiO₂ 0.3 and a respiratory rate of 24/min. Find the ROX index ROX = (SpO₂/FiO₂)/RR, with SpO₂ in percent and FiO₂ as a fraction. Round to two decimal places.

Practice exercise (made-up values, not clinical guidance). A patient has Hb 141 g/L, SaO₂ 96%, PaO₂ 80 mmHg (10.7 kPa) and a cardiac output of 3.6 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.