Oxygen therapy & respiratory calculations worksheet with answers

Practice exercise (made-up values, not clinical guidance). The team wants an inspired oxygen of about 25% 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). The gauge on a size E oxygen cylinder reads 1600 psi. Its cylinder factor is 0.28 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 22 times a minute with a tidal volume of 350 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 E oxygen cylinder (factor 0.28 L/psi) reads 1900 psi and runs at 10 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 ventilated man is 162 cm tall and weighs 88 kg. Lung-protective ventilation is set at 6 mL per kg of predicted body weight. Using PBW = 50 + 0.91 × (height cm − 152.4) kg, find the tidal volume V_T to the nearest mL.

Practice exercise (made-up values, not clinical guidance). A patient has Hb 103 g/L, SaO₂ 95%, PaO₂ 76 mmHg (10.1 kPa) and a cardiac output of 3.7 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.