Dyspnea

Dyspnea is the patient's subjective experience of breathing discomfort: air hunger, chest tightness, an uncomfortable effort to breathe, or the fear that breathing will stop. It can occur with or without measurable hypoxemia and affects up to 80% of people with advanced illness. The sensation develops when the brain perceives a mismatch between the effort demanded for ventilation and what the respiratory system can deliver. Advanced heart or lung disease, pulmonary edema, pneumonia, pleural effusion, anemia, airway obstruction, weakness, and reduced respiratory muscle reserve can all widen that mismatch. Anxiety then adds another layer: fear increases sympathetic arousal and the sense of respiratory effort, which can produce faster, less efficient breathing. Anxiety may intensify dyspnea, but it should not be assumed to be the cause until physical contributors have been considered. The experienced nurse notices the patient's distress before focusing on the monitor. A person may be gasping and frightened with an SpO₂ above the hypoxemia threshold, while another person with severe chronic hypoxemia may report little discomfort. The number helps guide oxygen therapy; it does not measure the entire...