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). The gauge on a size D oxygen cylinder reads 1700 psi. Its cylinder factor is 0.16 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 ventilated patient who meets the other Berlin criteria for ARDS has PaO₂ 87 mmHg (11.6 kPa) on 70% oxygen with a PEEP of 14 cmH₂O. Calculate the P/F ratio and click the ARDS severity.

1. 1above 300: no ARDS grade
2. 2mild
3. 3moderate
4. 4severe

Practice exercise (made-up values, not clinical guidance). A size H oxygen cylinder (factor 3.14 L/psi) reads 1350 psi and runs at 15 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 has Hb 99 g/L, SaO₂ 94%, PaO₂ 72 mmHg (9.6 kPa) and a cardiac output of 3.8 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 ventilated woman is 172 cm tall and weighs 73 kg. Lung-protective ventilation is set at 6 mL per kg of predicted body weight. Using PBW = 45.5 + 0.91 × (height cm − 152.4) kg, find the tidal volume V_T to the nearest mL.