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Hypoxic ventilatory response (HVR) is the increase in ventilation induced by hypoxia that allows the body to take in and transport lower concentrations of oxygen at higher rates. It is initially elevated in lowlanders who travel to high altitude, but reduces significantly over time as people acclimatize .
The control of ventilation is the physiological mechanisms involved in the control of breathing, which is the movement of air into and out of the lungs. Ventilation facilitates respiration. Respiration refers to the utilization of oxygen and balancing of carbon dioxide by the body as a whole, or by individual cells in cellular respiration. [1]
A controlled F I O 2 is particularly important for patients whose ventilation is dependent on hypoxic drive, [5] as may be seen in patients with chronic obstructive pulmonary disease. Administration of too much oxygen may lead to a reduction in their respiratory rate and retention of carbon dioxide, and ultimately to reduced consciousness or ...
Serious signs/symptoms of hypoxia: 0.14-0.16: Initial signs/symptoms of hypoxia (normal environment oxygen in some very high altitude areas) 0.21: Normal environment oxygen (sea level air) 0.35–0.40: Normal saturation dive PO 2 level 0.50: Threshold for whole-body effects; maximum saturation dive exposure 1.0–1.20
While the maintenance of ventilation/perfusion ratio during regional obstruction of airflow is beneficial, HPV can be detrimental during global alveolar hypoxia which occurs with exposure to high altitude, where HPV causes a significant increase in total pulmonary vascular resistance, and pulmonary arterial pressure, potentially leading to ...
The capnogram is a direct monitor of the inhaled and exhaled concentration or partial pressure of CO 2, and an indirect monitor of the CO 2 partial pressure in the arterial blood. In healthy individuals, the difference between arterial blood and expired gas CO 2 partial pressures is very small (normal difference 4-5 mmHg).
For HVAC applications, CO 2 sensors can be used to monitor the quality of air and the tailored need for fresh air, respectively. Measuring CO 2 levels indirectly determines how many people are in a room, and ventilation can be adjusted accordingly. See demand controlled ventilation (DCV). [14]
Demand control ventilation is an attractive alternative to standard design in these situations because DCV systems only supply the outdoor airflow necessary to serve the occupants in a space. Therefore, the above-described energy is not wasted in this system type.