Questions to prepare for classes and examination
• Definition of hypoxia and its classification.
• Exogenous hypoxia: causes, types and typical changes of PaO2, PvO2, Pa-vO2, oxygen blood capacity, PaCO2 and pH in the given type of hypoxia.
• Respiratory hypoxia: causes, types and typical changes of PaO2, PvO2, Pa-vO2, oxygen blood capacity, PaCO2 and pH in the given type of hypoxia.
• Anemic hypoxia: causes, types and typical changes of PaO2, PvO2, Pa-vO2, oxygen blood capacity, PaCO2 and pH in the given type of hypoxia.
• Circulatory hypoxia: causes, types and typical changes of PaO2, PvO2, Pa-vO2, oxygen blood capacity, PaCO2 and pH in the given type of hypoxia.
• Histotoxic and substrate types of hypoxia: causes, types and typical changes of PaO2, PvO2, Pa-vO2, blood oxygen capacity, PaCO2 and pH in the given type of hypoxia.
• Overutilization hypoxia: causes, types and typical changes of PaO2, PvO2, Pa-vO2, oxygen blood capacity, PaCO2 and pH in the given type of hypoxia.
• Conditions that determine the susceptibility of cells to hypoxia.
• Signs of acute hypoxia.
• Adaptive reactions in acute hypoxia.
• Mechanisms of long-term adaptation to hypoxia.
N 42
In the study of various aspects of pathogenesis of hypoxia and edema a laboratory rat was intravenously injected a high dose of adrenaline. Immediately after the injection paws and ears of the rat turned pale; arterial blood pressure increased from 120/70 to 210/175 mm Hg; heart rate and respiration rate increased sharply. The level of PaO2 remained unchanged, but
the levels of PvO2 and PaCO2 decreased. Nine minutes after the adrenaline injection despite hyperventilation the rat developed acrocyanosis. The content of gases in the arterial blood remained normal, but a progressive decrease in the PvO2 level was noted. Four minutes later dyspnea and moist rales in the lungs developed; blood pressure decreased sharply; pulse pressure dropped, and heart beats became irregular. At the same time PaO2 started to decrease, and PaCO2 increased. By the end of the 18th minute the rat developed clonic and tonic seizures, agonal breathing (gasping) and foamy, reddish discharge from the respiratory tract. Soon it died.