Pathophysiology

Pathophysiology Study Guide

©2018 of 131 Hypoxia Hypoxia is another consequence of the impairment of the gas exchange chamber. It occurs when the tissues are not adequately oxygenated. The compensatory mechanism for hypoxia includes tachycardia, myocardial contractility, and cardiac output. It can be caused by a variety of factors including anemia, monoxide poisoning, heart failure, cardiac arrest, heart attack, and high-altitude travel. Hypercapnia Hypercapnia is the disorder in which the blood stream and arteries get filled with excessive amounts of carbon dioxide. The causes of hypercapnia include drug overdose, seizures, brainstem lesions, lung diseases, hyperventilation, skeletal weakness in the muscles, asthma, chronic obstructive pulmonary disease, and sleep apnea. Signs and symptoms of hypercapnia are feeling drowsy, sleepiness, headaches, confusion, dizziness, flushed skin, tachycardia, hypertension, muscle spasm, shortness of breath, and twitches. Ventilation-Perfusion Mismatch Ventilation-perfusion (V/Q) disorder is a defect in the ratio between the amount of air and blood that reaches the alveoli. In the case of a V/Q defect, either the lungs receive oxygen but no flow of the blood, or they get blood without oxygen. The ideal ratio is measured at 0.8. If a person is detected with a low ratio, it causes low arterial partial pressure of oxygen and can lead to diseases like chronic bronchitis, asthma, acute pulmonary edema, and hepatopulmonary syndrome. In contrast, if the ratio becomes high, then it would signify a fall in arterial partial pressure of carbon dioxide and a rise in the arterial partial pressure of oxygen. This situation generally leads to pulmonary embolism and emphysema. 4.5 Respiratory Failure Respiratory failure is characterized by the occurrence of diseases or disorders associated with heart or lungs such that the adequate amount of oxygen is not maintained or higher levels of carbon dioxide are experienced. Some disorders related to respiratory failure are discussed below. Acute Respiratory Failure Acute respiratory failure is the situation in which excess fluid gets accumulated in the air sacs of the lungs, which leads to an inadequate amount of oxygen being released in the bloodstream. It is also possible that the lungs fail to remove excess carbon dioxide from the blood. Both these situations independently or jointly lead to respiratory failure. In this case, the organs are deprived of adequate oxygen rich blood and this makes them unable to function well. Acute respiratory failure can be caused due to a variety of reasons including obstruction in the throat, injury impacting the respiratory system, acute respiratory distress syndrome, drug or alcohol abuse, chemical inhalation, and stroke. Signs and symptoms of acute respiratory failure include difficulty breathing, cyanosis, restlessness, Achieve Page 71