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| Henderson-Hasselbalch
equation |
Relation among pH, bicarbonate
ion concentration and free CO2 in a solution. (See Henderson-Hasselbalch
Equation in "Tools
of the Trade" under "Resources") |
| HFJV |
High Frequency Jet Ventilation
- A type of high-frequency ventilation in which gas is
delivered into the airway as a pulsating stream from a
small diameter catheter passed through the endotracheal
tube. |
| HFOV |
High Frequency Oscillatory
Ventilation - A type of high-frequency ventilation in
which the applied high frequency expiratory pressure and
delivered volume are negative relative to their base line
values. |
| HFV |
High Frequency Ventilation
- A form of ventilatory support characterized by breathing
frequencies in excess of 80 breaths per minute and tidal
volumes on the order of the anatomical dead space. |
| High Pressure Relief
Valve (safety valve) |
A device that prevents the
pressure in the patient circuit from exceeding a preset
limit by venting excess flow to the atmosphere. |
| High Priority Alarm |
A combination of audible
and visual signals indicating that immediate operator
response is required. |
| HME |
Heat and Moisture Exchanger
- A passive device designed to collect and hold some of
the heat and moisture from the patient's exhaled breath,
and to return them to the inspired gas mixture during
inspiration. |
| Humidifier |
A device that adds water
in the form of vapor to a gas mixture. |
| Humidity |
The amount of water vapor
contained in a given volume of air. |
| Hz |
Hertz - Unit of frequency
, cycles per second (cps). |
