Core distinction
Oxygenation and ventilation are related but not interchangeable.
- Oxygenation: getting oxygen into blood.
- Ventilation: removing carbon dioxide and moving gas effectively.
A patient can have acceptable oxygen saturation while ventilation worsens.
Support ladder (conceptual)
- Low-burden oxygen support for mild hypoxemia.
- Higher concentration oxygen interfaces when demand rises.
- Positive-pressure support (noninvasive or invasive) when work of breathing or gas exchange failure escalates.
The operational goal is to match support level to physiology and trajectory, not to a fixed device preference.
Bedside reassessment signals
- Respiratory effort: accessory muscle use, fatigue, altered speech.
- Oxygen trend: persistent decline despite escalating oxygen suggests worsening pathology.
- Ventilation trend: rising carbon dioxide pattern, reduced tidal movement, or declining mental status.
- Hemodynamics and perfusion: instability can worsen respiratory failure and vice versa.
Safety points
- Treat rising support requirements as a warning signal.
- Avoid delayed escalation when trajectory is clearly deteriorating.
- Pair respiratory support changes with cause-directed therapy.
See airway treatment principles for integration with broader management.