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(hī′ĕ-rar-kē) [Gr. hierarchia, power or rule of the (high) priest] The ordering or classification of things in ascending or descending order of importance or value. For example, the needs of a human being might be listed in order of theoretical importance, e.g., air, water, food, health, protection from the elements and predators, security, esteem, and love.


High-intensity focused ultrasound.

high colonic

(hī″ kō-lon′ik) Irrigation of the bowel with large volumes of fluid. It is promoted as a form of internal cleansing and detoxification.

image Colonic irrigation poses a potential risk of bowel perforation and electrolyte disturbances and other potential injuries to the patient.

high-dose-rate remote brachytherapy

Radiation treatment for an internal cancer, e.g., cancer of the prostate, in which a powerful source of radiation is placed inside the body for a specified time and then removed. It may be replaced several times over the course of a treatment to achieve the desired effect on the tumor.

high endothelial venule

ABBR: HEV. A postcapillary venule found in gut-associated lymphoid tissue, e.g., Peyer's patches, and in lymph nodes. It regulates the movement of lymphocytes in and out of the blood.

higher order aberration

SEE: under aberration.

high-frequency chest compressions

During emergency cardiac care, chest compressions that are given at a rate of more than 100 per minute.

high-grade squamous intraepithelial lesion

SEE: under lesion.

high-intensity focused ultrasound

SEE: under ultrasound.

highly active antiretroviral therapy

ABBR: HAART. The combination of antiviral agents from three or more classes of drugs to treat patients with HIV infection. HAART reduces the viral load (the number of viruses circulating in the blood), increases CD4 cell counts, reduces the incidence of opportunistic infections, and prolongs life and disease-free survival. Reverse transcriptase inhibitors, nonnucleoside reverse transcriptase inhibitors, and protease inhibitors are used in HAART.

image Although HAART when used in pregnancy prevents AIDS in newborns, it appears to increase the risks of preterm delivery, fetal growth restriction, and preeclampsia.

SYN: combination antiretroviral therapy; combined antiretroviral therapy. SEE: HIV/AIDS.

highly pathogenic avian influenza

SEE: under influenza.

highly reliable organization

ABBR: HRO. An institution that consistently makes fewer mistakes than others working in the same field despite conditions that are stressful, fast-paced, or full of risk. Health care institutions strive to be HROs, i.e., to copy the performance achieved by other industries such as airlines, power plants, and utilities. ...

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