N5315 Advanced Pathophysiology Pulmonary and Shock Module 6. Complete Solution Guide.

N5315 Advanced Pathophysiology Pulmonary and Shock Module 6 Age related Difference in pulmonary anatomy and physiology 1. Describe the age-related changes which occur in the alveoli, chest wall, and gas exchange. (pg 1244-45) ● Alveoli: During adulthood and as age advances, the alveoli tend to lose alveoli wall tissue and capillaries. This process diminishes alveolar surface area available for gas diffusion and decreases airway support provided by normal lung tissues. ● Chest Wall: Mechanical changes involve elastic properties of the lungs and chest wall. Chest wall compliance decreases with age, because the ribs become ossified (less flexible) and joints become stiffer. As a result, the chest wall loses some of its ability to expand. In addition, respiratory muscle strength and endurance decrease by up to 20% by age 70. These mechanical changes in the lung and chest wall, along with structural changes in the alveoli, reduce ventilatory capacity in older adults. Vital capacity decreases and residual volume increases, however, total lung capacity remains unchanged. These changes decrease ventilatory reserves and lead to decreased ventilation-perfusion ratios. With advancing age there is also increased immune dysregulation, asymptomatic low-grade inflammation, and increased risk of infection. ● Gas Exchange: Alterations in gas exchange are reflected by blood gas analysis. With advancing age, pH and Paco2 do not change much, even though it has been documented that the chemoreceptors become less sensitive to gas partial pressure with age. Older adults have a decreased compensatory response to hypercapnia and hypoxemia; however, the perception of dyspnea remains intact and is even enhanced. Pao2 declines with age as a result of structural and mechanical changes, such as loss of alveolar surface area and increased ventilation-perfusion mismatch. The maximum Pao2 in...

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