Glossary of Children's Hospital Terms
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z
H & P or History and Physical: The initial medical history and clinical physical examination of the patient. A "focused" H and P means that the doctor focuses upon the patient's present problem.
High blood pressure: A blood pressure that is abnormally high for age. See chart in the attachment sections that gives "normal" BP ranges.
Head circumference: The measurement of the size of the head usually obtained in children less than 2 years old to track growth.
Heart murmur: A murmur is a sound made by blood moving round the heart. It could be caused by a heart defect, but is usually a normal finding.
Hemoglobin: The oxygen-carrying protein pigment in red blood cells. Hemoglobin forms an unstable, reversible bond with oxygen allowing for its easy release to cells. In its oxygenated state it is called oxyhemoglobin and is bright red. In the reduced or used state it is called deoxyhemoglobin and is purple-blue.
Hematocrit: The proportion of the blood that consists of packed red blood cells. The hematocrit is expressed as a percentage by volume. A normal hematocrit (Hct) is between 32-60, depending on age and health status. A low Hct (for example <20) may result in the need for a red blood cell transfusion.
Hematoma: An abnormal localized collection of clotted or partially clotted blood 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.
Hemorrhage: Bleeding or blood loss. This could require transfusions to prevent shock.
Hemothorax: An abnormal collection of blood surrounding the lung.
Heparin lock (hep lock): An intravenous catheter that is kept from clotting by Heparin a blood-thinning drug that is injected into the catheter between uses. This avoids the need for continuous IV fluid and allows the patient to be mobile between medications.
HICKMAN® catherter: A thin long tube made of flexible silicone rubber that is surgically inserted into the vena cava, one of the main blood vessels leading to the heart. Depending on the therapy needs, the catheter may have either a single, double, or triple lumen (opening) at the tip. The catheter can be used for drawing blood samples and for giving intravenous fluids, blood, medication, or nutrition and avoids many needle sticks.
High Frequency Ventilation: A technique of positive pressure ventilation that uses very high rates (over 150 breaths per minute) and small volumes. It is used to lower pressures applied to the lung by the ventilator, thus decreasing the risk of "barotrauma" or damage to the lung tissue while improving oxygenation.
Hormone: A chemical substance produced in the body that controls and regulates the activity of certain cells or organs. Specialized glands such as the thyroid secrete many hormones. Hormones are essential for every activity of daily living, including the processes of digestion, metabolism, growth, reproduction, and mood control. Many hormones, such as the neurotransmitters, are active in more than one physical process.
Hydrocephalus: Sometimes called water on the brain, is an abnormal buildup of cerebrospinal fluid (CSF) in the ventricles of the brain. The fluid often results in increased intra-cranial pressure (ICP) and can compress and damage the brain.
Hyperalimentation or Hyperal: see TPN.
Hypertonia: Increased tightness of muscle tone also known as spasticity. Untreated it can lead to loss of function and deformity. Treatment is by physical and/or occupational therapy, and sometimes muscle relaxant medication. Injections of botulism toxin (botox) are a recent treatment for chronic hypertonia in cerebral palsy and other disorders.
Hypoplasia: Underdevelopment or incomplete development of a tissue or organ. For example, there can be hypoplasia (underdevelopment) of the enamel of the teeth. Hypoplasia is less drastic than aplasia (where there is no development at all).
Hypoplastic Right or Left Ventricle: The right or left ventricle of the heart has not developed properly so it is small.
Hypotension: Any blood pressure that is below the normal expected for an individual in a given environment. Hypotension is the opposite of hypertension (high blood pressure). Hypotension is a relative term because the blood pressure normally varies greatly.
Hypothermia: Abnormally low body temperature. Hypothermia becomes life threatening below body temperatures of 32.2 C (90 F).
Hypotonia: Decreased tone of skeletal muscles. In a word, floppiness.
Hypoxia: Concentration of oxygen in arterial blood that is less than normal. Anoxia refers to complete lack of oxygen.