Hemorrhage is defined as excess loss of blood due to rupture of blood vessels.
HEMORRHAGE occurs due to various reasons. Based on the causes, hemorrhage is classified into five categories:
Accidental hemorrhage can occur in road accidents and industrial accidents, which are very common in the developed and developing countries.
Capillary hemorrhage is the bleeding due to the rupture of blood vessels, particularly capillaries. It is very common in brain (cerebral hemorrhage) and heart during cardiovascular disease. The rupture of the capillary is followed by spilling of blood in the surrounding area.
Internal hemorrhage is the bleeding in viscera. It is caused by rupture of blood vessels in the viscera. The blood accumulates in viscera.
Excess bleeding that occurs immediately after labor (delivery of baby) is called post-partum hemorrhage.
In some cases, it is very severe and leads to major complications.
In some cases, the placenta is detached from the uterus of mother before the due date of delivery causing severe hemorrhage.
Many effects are observed during and after the hemorrhage. Effects are different in acute and chronic hemorrhage.
Acute hemorrhage is sudden loss of large quantity of blood. It occurs in conditions like accidents. Decreased blood volume in acute hemorrhage causes hypovolemic shock.
Chronic hemorrhage is the loss of blood either by internal or external bleeding over a long period of time. Internal bleeding occurs in conditions like ulcers. External bleeding occurs in conditions like hemophilia and excess vaginal bleeding (menorrhagia). Chronic hemorrhage produces different types of effects such as anemia.
After hemorrhage, series of compensatory reactions develop in the body to cope up with the blood loss.
Compensatory effects of hemorrhage are of two types:
Reduced blood volume after hemorrhage decreases venous return, ventricular firing and cardiac output. In severe hemorrhage, there is fall in blood pressure also. However, when blood loss is slow or less, the arterial blood pressure is not affected much. If it is affected it is restored quickly.
During mild hemorrhage:
During slow or mild hemorrhage when there is loss of small amount of blood up to 350 to 500ml the blood pressure decreases slightly and soon it returns back to normal.
Mechanism involved in maintenance of blood pressure are:
During severe hemorrhage:
When hemorrhage is severe with loss of about 1500 to 2000ml of blood, the arterial blood pressure fails to a great extent. It is because of decreased venous return and stroke volume.
In the heart, the reflex tachycardia increases the quantity of metabolic products in myocardium.
Vasoconstriction in skin which occurs after hemorrhage decreases the cutaneous the cutaneous blood flow. It increases the deoxygenating of blood and large quantity of reduced hemoglobin is accumulated in cutaneous blood vessels.
If hemorrhage is not severe some delayed compensatory reactions occur. These reactions help the restore blood volume, blood pressure and blood flow to different regions of the body.
Delayed reactions are: