Consider the need for blood gases in any patient with a change in their oxygen requirement, but especially in patients at risk of T2RF.
It is best practice to get an ABG in all patients on oxygen but consider whether it will change your management.
pH < 7.35 or [H+] > 45nmol/L and PCO2 > 6.0kPa = Respiratory Acidosis
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Immediately review the patient and consider getting help
PCO2 <= 6.0kPa = normal or low
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Titrate oxygen to maintain 94 - 98% and consider if repeat blood gases in 30 - 60min would be helpful
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Risk of T2RF:If PCO2 rises above 6.0kPa - reset target range to 88 - 92%
Risk of T2RF
pH >= 7.35 or [H+] <= 45nmol/L and PCO2 > 6.0kPa = Hypercapnia
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Continue with 24 - 28% venturi mask or 1 - 2L nasal cannula to maintain SpO2 in the target range.
Repeat blood gases in 30 - 60 minutes