Under which condition should mechanical ventilation be started or continued?

Under which condition should mechanical ventilation be started or continued?

• A. When assisted ventilation is insufficient to support gas exchange.
• B. Immediately after intubation even if patient is breathing adequately.
• C. Only if SpO2 is above 95%.
• D. After patient breathes on their own for 5 minutes.

Answer: (A)

Mechanical ventilation should be started or continued whenever assisted ventilation cannot maintain adequate gas exchange. This means the patient’s oxygen delivery and carbon dioxide removal are not being supported well enough by their own efforts or by basic support alone. You look at the overall gas exchange: oxygen saturation and PaO2, CO2 levels and pH, the work of breathing, and the patient’s mental status and fatigue. A target like SpO2 above 95% isn’t by itself enough to decide to start or stop ventilation, because CO2 retention and respiratory muscle fatigue can occur even if SpO2 looks acceptable. Likewise, waiting for a fixed period of spontaneous breathing before starting ventilation isn’t appropriate when gas exchange is falling short. Immediate ventilation after intubation is only necessary if the patient cannot maintain gas exchange once secured, not simply because intubation occurred. The question hinges on whether the patient’s gas exchange can be supported adequately without ventilatory assistance; if not, mechanical ventilation should be started or continued.

Mechanical ventilation should be started or continued whenever assisted ventilation cannot maintain adequate gas exchange. This means the patient’s oxygen delivery and carbon dioxide removal are not being supported well enough by their own efforts or by basic support alone. You look at the overall gas exchange: oxygen saturation and PaO2, CO2 levels and pH, the work of breathing, and the patient’s mental status and fatigue. A target like SpO2 above 95% isn’t by itself enough to decide to start or stop ventilation, because CO2 retention and respiratory muscle fatigue can occur even if SpO2 looks acceptable. Likewise, waiting for a fixed period of spontaneous breathing before starting ventilation isn’t appropriate when gas exchange is falling short. Immediate ventilation after intubation is only necessary if the patient cannot maintain gas exchange once secured, not simply because intubation occurred. The question hinges on whether the patient’s gas exchange can be supported adequately without ventilatory assistance; if not, mechanical ventilation should be started or continued.