Task 3. Case study

Case 1

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 mm Hg to 210/175 mm Hg; heart rate and respiration rate increased sharply. The level of P_a remained unchanged, but the levels of P_vand P_aCO₂ decreased. Nine minutes after the adrenaline injection when hyperventilation still persisted the rat developed acrocyanosis. The content of gases in the arterial blood remained normal, but a progressive decrease in the P_vO₂ level was noted. Four minutes later dyspnea developed, and moist rales appeared; the blood pressure decreased dramatically; the pulse pressure lowered, and heart beats became irregular. At the same time, P_aO₂ started to decrease, and P_aCO₂ increased. By the end of the 18th minute clonic and tonic seizures developed, agonal breathing (gasping) and foamy, reddish secretions from the respiratory tract appeared, and the rat died.

Questions:

Can we state that despite activation of the heart function, increased vascular tone, and high blood pressure the rat suffered from hypoxia immediately after the adrenaline injection? If you think so, substantiate your opinion. If you do not agree, name the time point by which hypoxia has developed.

What are the type(s) and pathogenesis of such hypoxia?

Did the rat develop edema? If you think so, name the organs where it occurred and the time point after the adrenaline infusion when the edema became evident?

If, in your opinion, edema developed in the rat, what forms of pathology in humans may lead to edema with similar localization?

Case 2

An accident occurred in the aircraft during a flight on the height of 10,000 m. The cabin of the aircraft lost its hermetic state, and in the course of several seconds the barometric pressure inside fell down to atmospheric level at this altitude 170 mm Hg. The crew failed to make an urgent lowering maneuver, and the aircraft continued the flight at the same height for several minutes.

Questions:

What pathologic processes developed in the body of passengers during the aircraft accident? Which of them were the most dangerous for their well-being and can lead to death?

What are the likely causes and mechanisms of these pathologic processes?

What types of preexisting pathology could include the highest risk for life in this situation?

Case 3