What does respiratory failure mean?

The term “respiratory insufficiency” can be translated as “inadequate breathing.” In ALS, inadequate respiratory function (respiratory insufficiency) can result either from weakness of the respiratory muscles (hypoventilation) or from narrowing of the airways (obstruction).

The primary function of respiration is to ensure an effective exchange of respiratory gases (gas exchange). All organs and structures of the human body require oxygen, which enters the bloodstream through inhalation (via the pharynx, larynx, trachea, bronchial system, and lung tissue) and is then transported to all tissues. The “consumption” of oxygen in the tissues produces carbon dioxide, which is expelled from the body via the reverse pathway during exhalation.

In cases of respiratory failure, oxygen uptake may be reduced and the elimination of carbon dioxide may be impaired—with the primary consequence being an accumulation of carbon dioxide (“hypercapnia”). Respiratory failure is a major symptom of ALS and the primary life-limiting factor. Preventing or delaying respiratory failure is the primary focus of ventilatory care.