Medical definitions - H

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Hemodialysis – the use of a special machine (a dialysis machine) to filter waste products from the blood and to restore normal constituents to it; most often used for chronic renal disease.

Hemofilter – a part of the ECMO machine that makes hemodialysis possible to help with renal function.

Hematocrit - the proportion of the blood that consists of packed red blood cells; expressed as a percentage by volume.

Hematoma - an abnormal localized collection of blood in which the blood is usually clotted or partially clotted and is usually situated within an organ or a soft tissue space, such as within a muscle. A hematoma is caused by a break in the wall of a blood vessel. The break may be spontaneous, as in the case of an aneurysm, or caused by trauma.

Heparin - an anticoagulant (anti-clotting) medication; a blood thinner.

Hernia - an opening or weakness in the muscular structure of the wall of the abdomen.

High frequency oscillatory ventilation (HFOV) – also known as the oscillator or oscillating vent; a method of mechanical ventilation that employs many short, fast puffs of air to inflate the lungs.

Hydrops – gross edema (swelling), usually with anemia, of the fetus.

Hyperal – nutritional substance delivered via IV.