Clinic of cerebral edema
Hypoxic cerebral edema. Clinic of cerebral edema
No less formidable and dangerous for the life of the patient complication in the postoperative period is hypoxic edema of the brain.
Clinical picture this formidable complication is formed unequally. There are 2 types of development of the clinical picture of cerebral edema with the imposition of cavapulmonary anastomosis: 1) ischemic, 2) hypoxic: a) on the basis of venous stasis and b) on the soil of arterial hypoxemia.
At the first ischemic type brain oscillations recorded atelectroencephalogram, completely disappear immediately after clamping the superior vena cava through 8-10 sec, the blood pressure decreases to 60 mm Hg. Art. and lower (up to 0). After switching on the anastomosis, the blood pressure rises to 90-100 mm Hg. Art. there are oscillations on the encephalogram, indicating a deep hypoxia of the brain, not recovering completely. After the narcosis is stopped, consciousness is not restored and the patient dies even before the end of the operation or in the next few hours (6-8) after surgery from a progressive drop in blood pressure and cardiac arrest.
On autopsy Discover the sharpest edema of the brain (L.D. Crimean). This type of clinical picture is most likely based on the necrosis of the cerebral cortex on the basis of its ischemia as a result of a sharp drop in blood pressure.
As is known, Bainbridge described a reflex, after which his name was established(Bainbridge reflex), which consists in that when the upper vena cava is clasped at the right atrium wall, the blood pressure drops deeply. We in the experiment (TM Darbinyan, 1957) and in clinical practice in the overwhelming majority of patients found that in response to clamping of the superior vena cava, BP immediately decreases by 15-20 mm Hg. then slightly increases and is set at a level somewhat lower than the initial (by 10-15 mm Hg).
We explained this not by the reflex Bainbridge. and a decrease in the flow of blood to the heart almost40% (40% of the minute volume of blood passes through the superior vena cava). But in some patients, blood pressure falls very deeply, and the patient dies. In 1 of our patients, death occurred precisely with such a picture: 10 seconds after the upper vena cava was clamped, the brain oscillations disappeared, but the upper vena cava was already crossed, there was only one way out - to speed up the anastomosis application.
After 17 minutes anastomosis was included, but the oscillations of the brain are notappeared and the patient died on the operating table. In this type, probably, it is a question of the death of the cortex and the higher parts of the brain on the basis of ischemia. To ischemic necrosis of the cerebral cortex may lead to a progressive fall in blood pressure due to terminal decompensation of the "painfully altered" heart.