37. Embolism of pulmonary, systemic and portal circulation.

Pulmonary embolism

It has one of the first place among death reasons in modern people (especially if thromboembolism and especially if sudden death). Pulmonary vein thromboembolism according to WHO is the hardest haemostasis disorder with lethal result.

Arterial pressure in pulmonary vein is sharply increased (big circle unloading, heart contractile function decreasing, pressure gradient increasing on distance “pulmonary artery-capillary” due to reflectory spasm of pulmonary vessels).

Systemic arterial pressure decreasing.

Acute right-ventricular insufficiency (death reason).

CO2 tension increasing and O2 tension decreasing in blood.

Systemic embolism (of big circle)

Thromboendocarditis, myocardial infarction, left-ventricular insufficiency, thrombs in arteries of big circle with consequent thromboembolism, gas embolism or fatty embolism as reasons. The most often location places: coronary, intermediate brain, internal carotid, renal, splenic (lienal) and mesenterial arteries. Conditions influencing greatly on embol location: angle of lateral vessel, its diameter, organ blood filling intensivity. Predisposed factors are: big angle, big diameter, hyperemia. Nitrogen is well-dissolved in lipoid-rich tissues (gas embolism in brain and subcutaneous tissues vessels). Besides, all mentioned organs are rich vascularized. Collaterals development and refelctory vessels spasm degrees define gravity of pathological processe. Collaterals prevent necrosis of surrounding tissues.

Portal vein embolism

More seldom observation but very hard haemodynamical disorders. It leads to portal hypertension (pressure is increased from 0,78-0,98 to 3,92-5,88 kPa or from 8-10 to 40-60 cm of water col in portal veins). Ascitis, all features of portal hypertension (see below), heart return, shock and minute volumes decreasing, arterial hypotension, apnoe then hypopnoe and apnoe, consciousness loss, respiration paralysis. All blood (90%) is accumulated in portal veins that lead to such disorders. Such haemodynamics disorders are patients’ death direct reason. Correlation between mentioned features are absent.

38. Microcirculation disorders typical forms:

1. Intravascular:

   1. retardation, stoppage of blood or (and) lymph flow;

   2. blood (lymph) flow excessive acceleration;

   3. blood (lymph) laminarity disorder or turbulence;

   4. blood juxtacapillary flow excessive increasing.

2. Transmural:

   1. changing (increasing or decreasing) in blood plasma transport volume;

   2. blood formed elements transport volume changing:

• erythrocytes diapedesis increasing;

• leucocytes exit increasing from vessels into surrounding tissues;

• leucocytes exit decreasing from vessels into surrounding tissues.

3. Extravascular: intercellular liquid flow (outflow) retardation.

39. Intravascular circulation disorders: rheological changings and changings of blood flow.

Sluge-phenomen (from English word “viscous dirty, slime, mud, silt”) is characterized by blood formed elements adhesion, aggregation and agglutination (cells gluing with consequent membranes lysis) which determines its separation to more or less large conglomerates from erythrocytes, platelets, leucocytes and blood plasma.

Reasons:

1. central and regionary haemodyamics disorders (at cardiac insufficiency, venous stagnation, ishemia, pathological arterial hyperemia);

2. blood viscosity increasing (at haemoconcentration, hyperproteinemia, polycytemia);

3. microvessels walls injury.

Mechanisms:

1. blood cells activation with physiologically-active substances releasing from them particularly the ones which possess powerful proaggregant action (ADP, thromboxane A₂, kinines, histamine, some prostaglandines);

2. “removal” of negative (under norm) cellular superficial charge and (or) its “overshooting” to the positive one with cationes excess releasing from injured cells; also under these conditions normal negative charge can be decreased of blood coagulation factors;

3. cellular superficial negative charge decreasing on blood formed elements at proteins contact with them (hyperproteinemia) especially due to highly-molecular proteins (Ig, paraproteins, fibrinogen).

Results (capillary-trophyc insufficiency syndrom):

1. vasoconstriction;

2. blood stream retardation up to stoppage (stasis),

3. blood stream turbulence;

4. transcapillary exchange disorders;

5. hypoxy;

6. acidosis;

7. tissular metabolism disorders.

Blood flow changing – blood stream velocity decreasing.

Rheology:

1. the term is equal to the integrity of rheological indexes or parameters (erythrocytes membranes deformability, velocity sedimentation rate, acid resistance, haemolysis maximum time, blood viscosity, haematocrit);

2. physical science studying phenomena between elasticity theory and haemodynamics as well as assessing blood, liquor, sinovia and other liquids course in medical-biological aspects.

Haemorheology – is a science abut blood rheology and formed elements undergone tension during blood stream in cardiac-vascular system inducing their deformation and activation under physiological conditions.

Clinical haemorheology – haemorheology chapter studying haemorheological disorders and striving for studying of their connection with diseases as well as their diagnostic and treatment approach.

Rheometry – the integrity of measures which allows to assess blood rheological prophile indexes in theoretical and practical aims.