Hospitals & Services
Clinical assessment outweighs any "result" such as an ABG / CXR or other objective measurement (see below).
Consider institution of ventilation in the presence of:
Fatigue or imminent exhaustion
Inability to effectively cough or clear secretions
Respiratory failure, hypoxaemic or hypercaemic
In the appropriate clinical setting, and where time allows a combination of the following may assist your decision.
Resp rate > 30 breaths per minute
Abnormal oxygenation as indicated by:
PaO2 <75 mmHg on an FiO2 > 1.4 (40% O2)
PaO2 : FiO2 ratio < 150
Depressed minute ventilation as indicated by:
PaO2 > 60 mmHg