Influence of FiO2 on PaCO2 in Chronic Obstructive Pulmonary Disease Patients with Chronic Carbon Dioxide Retention

Abstract

The respiratory system is comprised of several elements including the central nervous system, the chest wall, the pulmonary circulation, and the respiratory tract. The physiological action of the lungs maintains the delicate balance between these disparate anatomic entities. Total lung capacity is defined as the volume of gas in the lungs following maximal inspiration. Functional residual capacity is the volume of gas in the lungs at the end of normal expiration. The three main physiological functions of the respiratory tract are ventilation, perfusion, and diffusion. Ventilation is the process of procuring air from the external environment via inspiration to supply the alveolus, after which it is subsequently returned to the outside of the body through expiration. Chronic Obstructive Pulmonary Disease (COPD) is chronic bronchitis and emphysema, a pair of commonly co-existing diseases of the lungs in which the airways narrow over time. This limits airflow to and from the lungs, causing shortness of breath (dyspnea). COPD is defined by its characteristically low airflow on lung function tests. In