Noninvasive intermittent self ventilation in chronic respiratory insufficiency

Corresponding to the two compartments of the respiratory system (lungs and ventilatory pump), two different forms of respiratory insufficiency can be distinguished on a pathophysiologic basis: disturbances of gas exchange with primary oxygenation failure (hypoxemia) due to pulmonary diseases and reduced ventilation of the lungs (hypoventilation) with primary elevated arterial carbon dioxide partial pressure (hypercapnia) and secondary hypoxemia due to disorders of the ventilatory pump. Different methods can be employed in the diagnosis of respiratory insufficiency, e.g., spirometry, blood gas analysis, nocturnal monitoring with capnography, or transcutaneous pCO2 registration and measurement of mouth occluding pressure. Therapeutic measures for respiratory insufficiency are based on two treatment principles: long-term oxygen therapy to improve hypoxemia and noninvasive ventilation therapy to improve hypercapnia and concomitant hypoxemia. The indication for long term ventilation depends on subjective complaints, objective measurement parameters, disease course, and other disease symptoms. The most frequent indications for home mechanical ventilation are diseases with restrictive ventilatory defects, especially chest wall disorders and neuromuscular disorders.