Respiratory Failure Health Article

Definition

Respiratory failure occurs when the lungs' ability to either add oxygen to the bloodstream or remove carbon dioxide from it is impaired. Respiratory failure can have any one of several causes, such as lung disease or infection, electrolyte imbalance, interruption of the nerve signals that regulate breathing or nervous system damage, structural (rib cage) collapse, or airway obstruction.

Description

During respiration, the lungs extract oxygen from inhaled air, oxygenate the bloodstream, and eliminate carbon dioxide (CO₂) from the blood into exhaled air. In respiratory failure, the level of oxygen in the blood becomes dangerously low, and/or the level of CO₂ becomes dangerously high. This result can happen if the gas-exchange process breaks down or if ventilation is inhibited.

There are two main types of respiratory failure. Hypoxemic failure occurs when normal gas exchange is interrupted, causing a condition called hypoxemia. When this happens, there is too little oxygen in the blood, and all of the body's organs and tissues suffer as a result. One common type of hypoxemic respiratory failure, which occurs in both adults and premature infants, is respiratory distress syndrome, a condition in which fluid or tissue changes or physical immaturity prevent oxygen from passing out of the lungs' air sacs into the circulating blood. Hypoxemia is also caused by exposure to high altitudes, where there is less oxygen in the air; lung diseases that impair the transfer of oxygen into the blood through the alveolar capillaries; severe anemia; and blood vessel disorders that shunt blood away from the lungs, thus preventing the lungs from picking up oxygen.

Ventilatory failure occurs when the body cannot exhale CO₂ properly. The resulting buildup in the blood is called hypercapnia. Ventilatory failure can result when the respiratory center in the brainstem fails to drive breathing, when muscle disease prevents the chest wall from expanding during inhalation, or when a patient has chronic obstructive pulmonary disease that impairs exhalation. Many of the diseases and conditions that produce respiratory failure can cause both hypoxemia and hypercapnia simultaneously.