Letter: h

Hertz – Unit of frequency; 1 Hz equals one cycle per second

The response of pulmonary arterioles to depressed alveolar oxygen tension. The vascular response shunts pulmonary blood flow away from alveoli that are under-ventilated, toward lung regions that are better ventilated, thus minimizing the effect of ventilation-perfusion inequalities in the lung.

Hypoxic hypoxia is commonly referred to as hypoxemic hypoxia (or relative deficiency in the bloodstream), but is described accurately as a condition of relative oxygen deficiency in the tissues caused by low arterial oxygen tension.

Increased oxygenation via ventilator or Ambu bag.

An increase in the depth of breathing, with or without an increase in the rate of breathing.

Term used to describe an exaggerated response to a foreign substance (i.e., an antigen), which causes tissue damage in a host after repeated challenges, causing the individual to become sensitized. Type I hypersensitivity mediated by IgE antibodies and produces an immediate (minutes to an hour) reaction; e.g. peanut, latex, penicillin allergy. Type IV hypersensitivity is cell mediated and response requires 24-72 hours for the rash-like symptoms to fully express, skin transplants to be rejected, etc.

Describes the production of a much higher number of spores per population of a specific spore-forming bacterium than is usually encountered. Hypersporulation increases the likelihood of successful dispersion and of being transmitted to a vulnerable host.

A much higher than normal core body temperature.

In digestive health, a property of a tube feeding formula where the osmolality (particles per volume of solute) is greater than 300 mOsm.

A term that refers to either the production of an extreme amount of toxin (poison) or a toxin that causes more harm than normally encountered. In either case, there is a more severe level of morbidity.