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 team wants an inspired oxygen of about 29% 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 ventilated patient who meets the other Berlin criteria for ARDS has PaO₂ 83 mmHg (11.1 kPa) on 100% oxygen with a PEEP of 12 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 patient has Hb 130 g/L, SaO₂ 98% and PaO₂ 106 mmHg (14.1 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 on high-flow nasal oxygen has SpO₂ 86% on FiO₂ 0.35 and a respiratory rate of 16/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 transfer will take 75 minutes. The size D cylinder (factor 0.16 L/psi) reads 700 psi. Keeping a safe residual of 200 psi, what is the highest whole-number flow Q in L/min that lasts the whole transfer?