Oxygen therapy & respiratory calculations worksheet with answers

Practice exercise (made-up values, not clinical guidance). The team wants an inspired oxygen of about 41% by nasal cannula. Using the rule of thumb FiO₂ ≈ 21% + 4% per L/min, what flow Q does it suggest? (Real FiO₂ varies with the patient's breathing.)

Practice exercise (made-up values, not clinical guidance). A patient breathes 24 times a minute with a tidal volume of 360 mL. Find the minute ventilation V̇E in L/min.

Practice exercise (made-up values, not clinical guidance). A patient breathes 28 times a minute with a tidal volume of 480 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 H oxygen cylinder (factor 3.14 L/psi) reads 800 psi and runs at 8 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 89% on FiO₂ 0.9 and a respiratory rate of 36/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 120 g/L, SaO₂ 92%, PaO₂ 63 mmHg (8.4 kPa) and a cardiac output of 4.6 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.