Pathophysiology

Pathophysiology Study Guide

©2018 of 131 Pulmonary Hypertension Pulmonary hypertension is a kind of hypertension that attacks the arteries of the lungs and the right side of the heart. This situation is characterized by the narrowing, blocking, and destroying of the tiny pulmonary arteries of the lungs and capillaries. Due to this, the flow of blood through the lungs becomes harder, raising the pressure in the arteries of the lungs. The consequence of this high blood pressure causes the tight ventricle to exert more pumping, thereby making the heart muscles weak and eventually causing heart failure. There is no definite known cause, however some of the causes of secondary pulmonary hypertension involve pulmonary emboli, COPD, connective tissue disorders, sleep apnea, congenital heart defects like Eisenmenger syndrome, sickle cell anemia, cirrhosis, AIDS, left-side heart failure, use of stimulant drugs like cocaine, and lung diseases like pulmonary fibrosis. The main symptoms are shortness of breath, fatigue, syncope, pressure and pain in the chest, cyanosis, tachycardia, and swelling in the ankles, legs, and abdomen. Cor Pulmonale Cor pulmonale is generally caused due to high blood pressure in the arteries of the lungs and right ventricle of the heart. It is characterized by the enlargement of the right ventricle of the heart due to the pumping mechanism of the heart losing its efficiency, and ultimately failing. The causes of cor pulmonale include emboli in the lungs, chronic obstructive pulmonary disease, damage or destruction of lung tissues, sleep apnea, and cystic fibrosis. Signs and symptoms of this disorder are chest pain, swelling in the legs or feet, fainting, excessive coughing, wheezing, and extreme fatigue. 4.4 Alterations in Gas Exchange The main function of the gas exchange system is oxygenation and elimination of carbon dioxide. Impaired gas exchange is the situation in which the alveolar-capillary membrane of the lungs receives inadequate levels of oxygen and carbon dioxide. In normal situations, oxygen and carbon dioxide travel through the alveolar capillary membrane such that blood is exchanged with gas in the ratio of 1:1, known as the ventilation perfusion ratio. When this ratio gets impaired, it leads to impairment in the gas exchange. Some diseases disorders due to alterations in the gas exchange are studied below. Hypoxemia Hypoxemia is the situation in which the blood arteries carry below the normal level of oxygen. Normal oxygen in arteries varies between 75 to 100 millimeters of mercury and in hypoxemia, it falls below 60mm Hg. This leads to trouble breathing and insufficient blood circulation in the body. It is also calculated using pulse oximeter readings, which are normally between 95 and 100 percent, but when it falls below 90 percent, it is considered low and signifies hypoxemia. Causes include anemia, acute respiratory distress syndrome, asthma, congenital heart defects, chronic obstructive pulmonary diseases, emphysema, interstitial lung disease, pneumonia, collapsed lungs due to pneumothorax, pulmonary edema, pulmonary embolism, pulmonary fibrosis, and sleep apnea. The major symptom is shortness of breath. Achieve Page 70

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