Oxygen cage for the dyspnoeic cat: advantages and limits
12-year-old cat with severe dyspnoea, highly stressed, that struggles violently when an oxygen mask is applied.
Which statement about the oxygen cage is correct?
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A. It maintains a constant FiO2 even when the door is opened to examine the cat
Opening the door makes FiO2 fall rapidly towards 21% and it takes several minutes to recover; handling should be grouped together.
B. It reaches an FiO2 close to 100% and is the method of choice in refractory hypoxaemia
In practice the cage provides an FiO2 of about 40–60%; refractory hypoxaemia requires high-flow nasal oxygen or mechanical ventilation.
C. It needs no environmental control because oxygen is continuously renewed
Heat, humidity and CO2 build up inside the cage; temperature must be monitored and CO2 removal or adequate flows used, especially in hyperthermic cats.
D. It minimises handling and stress with an FiO2 of about 40–60%, but temperature, humidity and CO2 must be monitored
Correct. It is the most useful option for a dyspnoeic cat that will not tolerate restraint: it allows stress-free oxygenation while the breathing pattern is observed. Its limits are the FiO2 drop on opening and the build-up of heat and CO2.
lightbulb Key takeaway
Approximate FiO2: flow-by 25–40%, mask 35–60%, nasal cannula 30–50%, cage 40–60% and high-flow nasal oxygen up to nearly 100%. In cats, the stress of restraint can be fatal: oxygenate first, examine later.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.