sludged blood

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sludged blood

blood in which the corpuscles, as a result of some general abnormal state, for example, burns, traumatic shock, and similar stresses, become massed together in the capillaries, and thereby block the vessels or move slowly through them.


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BLOOD COMPOSITION: Components of blood and relationship to other body tissues
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BLOOD COMPOSITION: Cell types found in smears of peripheral blood from normal individuals.
The cell-containing fluid that circulates through the heart, arteries, veins, and capillaries, carrying nourishment, electrolytes, hormones, vitamins, antibodies, heat, and oxygen to the tissues and taking away waste matter and carbon dioxide. See: erythropoietin


Blood has a distinctive, somewhat metallic, odor. Arterial blood is bright red or scarlet and usually pulsates if the artery has been cut. Venous blood is dark red or crimson and flows steadily from a cut vein.


Human blood is about 52% to 62% plasma and 38% to 48% cells. The plasma is mostly water, ions, proteins, hormones, and lipids. The cellular components are the erythrocytes (red blood cells [RBCs]), leukocytes (white blood cells [WBCs]), and thrombocytes (platelets). The leukocytes comprise neutrophils, eosinophils, basophils, lymphocytes, and monocytes. See: illustration; buffy coat; plasma; serum

An adult weighing 70 kg has a blood volume of about 5 L or 70 ml/kg of body weight. Blood constitutes about 7% to 8% of the body weight. The pH of the blood is from 7.35 to 7.45. The specific gravity of blood varies from 1.048 to 1.066, the cells being heavier and plasma lighter than this. Blood is of slightly higher specific gravity in men than in women. Specific gravity is higher after exercise and at night. See: blood count; cell; erythrocyte; leukocyte; plasma; platelet


In passing through the lungs, the blood gives up carbon dioxide and absorbs oxygen; after leaving the heart, it is carried to the tissues as arterial blood and then returned to the heart in the venous system. It moves in the aorta at an average speed of 30 cm/sec, and it makes the circuit of the vascular system in about 60 seconds. RBCs carry oxygen; WBCs participate in the immune response to infection; platelets are important in blood clotting. The plasma transports nutrients, waste products, hormones, carbon dioxide, and other substances, and contributes to fluid-electrolyte balance and thermal regulation.


RBCs are produced in the red bone marrow at the rate of about 2,400,000/sec, and each RBC lives for about 120 days. In healthy individuals, the concentration of RBCs in the blood remains stable over time. Platelets and WBCs are also produced in the red bone marrow, and agranular WBCs are produced in lymphatic tissue.

clotting of blood

See: coagulation, blood

cord blood

The blood present in the umbilical vessels connecting the placenta to the fetus. Because cord blood is immunologically immature, it is esp. useful in transfusion therapy and hematological transplantation.

defibrinated blood

Whole blood from which fibrin has been removed. It does not clot.

formed elements of blood

Blood cells, as opposed to blood proteins or other chemical constituents of blood.

fresh blood

Blood that has been collected less than 48 hours prior to its use in a transfusion.

occult blood

See: occult

oxygenated blood

Blood that has been exposed to oxygen in the lung; sometimes referred to as arteriolized blood.

predonation of blood

autologous blood transfusion.

reconstituted blood

A blood product used in transfusion therapy composed of components of blood (packed red blood cells plus plasma), which have been recombined after their separation and storage.

sludged blood

Hemagglutinated blood.

unit of blood

Approx. 1 pint (473 ml) of blood, the usual amount used in adult transfusion.


the red fluid that circulates through the heart, arteries, capillaries and veins carrying nutrients and oxygen to the body tissues and metabolites away from them. It consists of a yellow, protein-rich fluid, the plasma, and the cellular elements including leukocytes, erythrocytes and platelets. It has a high viscosity and osmotic tension and clots on exposure to air and to damaged tissue. It has an essential role in the maintenance of fluid balance.
In an emergency, blood cells and antibodies carried in the blood are brought to a point of infection, or blood-clotting substances are carried to a break in a blood vessel. The blood carries hormones from the endocrine glands to the organs they influence. And it helps in the regulation of body temperature by carrying excess heat from the interior of the body to the surface layers of the skin, where the heat is dissipated to the surrounding air. See also bloody.

arterial blood
oxygenated blood in the arterial side of the circulation between the cardiac ventricles and the capillaries.
blood buffers
substances which enable the blood to absorb much acidity without significant change in pH. The principal ones are the bicarbonate and hemoglobin buffers.
central blood
blood from the pulmonary venous system; sometimes applied to splanchnic blood, or blood obtained from chambers of the heart or from bone marrow.
central venous blood
unoxygenated blood collected centrally from the right atrium or venae cavae.
citrated blood
blood treated with sodium citrate to prevent its coagulation.
blood clotting cascade
see coagulation cascade.
cord blood
that contained in the umbilical vessels at the time of delivery of the fetus.
defibrinated blood
whole blood from which fibrin has been separated during the clotting process.
extracorporeal blood flow
see extracorporeal circulation.
blood in feces
see melena.
blood islet
aggregates of splanchnic mesoderm on the surface of the yolk sac and allantois; the first blood cells in the embryo.
blood lactate
this estimation has good predictive value in a number of diseases, e.g. intestinal obstruction in horses.
blood in milk
appears as clots or as diffuse red tint. Common only in recently calved cows or after trauma. Of no disease significance but renders the milk unsuitable for sale.
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Blood clots in pink milk. By permission from Blowey RW, Weaver AD, Diseases and Disorders of Cattle, Mosby, 1997
occult blood
that present in such small amounts as to be detectable only by chemical tests or by spectroscopic or microscopic examination. See also occult blood test.
blood osmolality
see serum osmolality.
peripheral blood
that obtained from the circulation remote from the heart; the blood in the systemic circulation.
selective blood agar
see blood agar.
shunted blood
blood which is not oxygenated in the lung because it passes through unaerated tissue.
sludged blood
blood in which the red cells have become aggregated into clumps and is most marked where the flow rate is slowest, i.e. in the capillaries.
blood solutes
see individual elements, metabolic products, hormones and the like.
stiff blood agar
see blood agar.
blood substitutes
synthetic substances that may be used in place of blood or its components include dextran, hydroxyethyl starch, polyvinylpyrrolidone, gelatin and perfluorocarbon.
blood urea nitrogen (BUN)
see urea nitrogen.
blood urea test
see urea nitrogen.
blood in urine
venous blood
blood which has passed through the capillaries and discharged its oxygen load to tissues and relieved the tissue load of carbon dioxide by absorbing it, and is on its way to the lungs to reverse these processes; is dark red in color due to the high concentration of reduced hemoglobin.
blood volume expanders
are used in the treatment of shock to restore tissue perfusion. Various fluids including whole blood, plasma, crystalloids and colloids may be used.
blood in vomitus
whole blood
that from which none of the elements has been removed, especially that drawn from a selected donor under aseptic conditions, containing citrate ion or heparin, and used as a blood replenisher.