An Integrated Analysis of Lung and Respiratory Muscle Dysfunction in the Pathogenesis of Hypercapnic Respiratory Failure

Abstract

We review the pathogenesis of hypercapnic respiratory failure, emphasizing the interrelationship between respiratory muscle dysfunction and abnormal pulmonary gas exchange. Although dysfunction in the gas-exchange region of the lungs (alveolar-capillary area) is commonly the initiating event of respiratory failure, failure of the respiratory muscles figures importantly in the final development of hypercapnic respiratory failure from ventilation-perfusion mismatch. Respiratory muscle dysfunction contributes to this failure when muscle fatigue occurs, which it can do as a result of a decrease in the maximum force the muscles are capable of generating or an increase in the force required to sustain ventilatory demands. Theoretically, there are two ways to treat hypercapnic respiratory failure: decrease the demand for ventilation, or increase the ventilation.