Oxygen therapy & respiratory calculations worksheet with answers

Free printable Oxygen therapy & respiratory calculations worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
0123456L/minQ = ? L/minFiO₂ ≈ 33%

Practice exercise (made-up values, not clinical guidance). The team wants an inspired oxygen of about 33% 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.)

FiO₂ 33%
Q = L/min
2.Easy
1550psiDf = 0.16 L/psiresidual 200 psiV = ? L

Practice exercise (made-up values, not clinical guidance). The gauge on a size D oxygen cylinder reads 1550 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?

1550 psif = 0.16 L/psi200 psi
V = L
3.Medium
60 s650 mLf = 25/min · V̇A = ?VD​ = 120 mL

Practice exercise (made-up values, not clinical guidance). A patient breathes 25 times a minute with a tidal volume of 650 mL. The anatomical dead space is 120 mL. Find the alveolar ventilation V̇A in L/min.

VT 650 mL25/minVD 120 mL
V̇A = L/min
4.Medium
PaO₂ 140 mmHg · FiO₂ 0.8 · PEEP 12 cmH₂O0100200300400500P/F (mmHg)above 300: no ARDS grademildmoderatesevere

Practice exercise (made-up values, not clinical guidance). A ventilated patient who meets the other Berlin criteria for ARDS has PaO₂ 140 mmHg (18.7 kPa) on 80% oxygen with a PEEP of 12 cmH₂O. Calculate the P/F ratio and click the ARDS severity.

PaO₂ 140 mmHg (18.7 kPa)FiO₂ 80%PEEP 12 cmH₂O
  1. 1above 300: no ARDS grade
  2. 2mild
  3. 3moderate
  4. 4severe
5.Hard
SpO₂ 96% · FiO₂ 0.7ROX = ?RR 32/minROX = (SpO₂/FiO₂)/RR

Practice exercise (made-up values, not clinical guidance). A patient on high-flow nasal oxygen has SpO₂ 96% on FiO₂ 0.7 and a respiratory rate of 32/min. Find the ROX index ROX = (SpO₂/FiO₂)/RR, with SpO₂ in percent and FiO₂ as a fraction. Round to two decimal places.

SpO₂ 96%FiO₂ 0.7RR 32/min
ROX =
6.Hard
SpO₂ 92% · FiO₂ 0.6ROX = ?RR 17/minROX = (SpO₂/FiO₂)/RR

Practice exercise (made-up values, not clinical guidance). A patient on high-flow nasal oxygen has SpO₂ 92% on FiO₂ 0.6 and a respiratory rate of 17/min. Find the ROX index ROX = (SpO₂/FiO₂)/RR, with SpO₂ in percent and FiO₂ as a fraction. Round to two decimal places.

SpO₂ 92%FiO₂ 0.6RR 17/min
ROX =

Answer key

  1. 1. Q = 3 L/min
  2. 2. V = 216 L
  3. 3. V̇A = 13.25 L/min
  4. 4. moderate
  5. 5. ROX = 4.29
  6. 6. ROX = 9.02

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