![]() This change causes the diaphragm to be less efficient, requiring increased work of breathing and results in a decreased transdiaphragmatic pressure gradient. Loss of elastic recoil causes an enlargement (barrel shape) of the thorax, which pulls the diaphragm flatter.Calcification and kyphosis of the thoracic spine, osteoporosis, arthritis of the costovertebral joints, and structural changes to the intercostal muscles all contribute to increased chest wall rigidity.Memory aid: The pulmonary changes associated with aging are often described as “senile emphysema” due to its similarity with the pathologic condition.Consequently, PaO 2 decreases with age.Įstimated PaO 2 values for healthy adults is calculated with: PaO 2 = 110-(Age*0.4).The overall effect of these changes in elasticity is increased ventilation-perfusion (V/Q) mismatching.Age, Chronic bronchitis, LV failure, Smoking, Surgery Mnemonic for factors that increase closing capacity – ACLS-S.CC = FRC in the upright position at ~66 years old.CC = FRC in the supine position at ~44 years old.CC is the lung volume at which small airway closure begins.Closing capacity (CC) increases with age until it surpasses functional residual capacity (FRC), meaning that airway obstruction may occur during normal tidal breathing.Decreased alveolar surface area: loss of alveolar walls results in small alveoli coalescing to form larger sacs.Small airway collapse also is one of the causes of ↑ residual volume (RV). Airflow becomes limited during expiration due to the collapse of intrathoracic airways. Small airway collapse: elasticity and natural recoil are needed to hold small airways open during changes in lung volumes during respiration.Aging lungs develop decreased elastic recoil and increased compliance due to changes in the lung parenchyma.
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