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Generalized hypoxia is a medical condition in which the tissues of the body are deprived of the necessary levels of oxygen due to an insufficient supply of oxygen, which may be due to the composition or pressure of the breathing gas, decreased lung ventilation, or respiratory disease, any of which may cause a lower than normal oxygen content in the arterial blood, and consequently a reduced ...
Key to understanding whether the lung is involved in a particular case of hypoxemia is the difference between the alveolar and the arterial oxygen levels; this A-a difference is often called the A-a gradient and is normally small. The arterial oxygen partial pressure is obtained directly from an arterial blood gas determination. The oxygen ...
In addition, gas transport is only diffusion limited in extreme cases, such as for oxygen uptake at very low ambient oxygen or very high pulmonary blood flow. [citation needed] The diffusing capacity does not directly measure the primary cause of hypoxemia, or low blood oxygen, namely mismatch of ventilation to perfusion: [2]
Hypoxia can be due to external causes, when the breathing gas is hypoxic, or internal causes, such as reduced effectiveness of gas transfer in the lungs, reduced capacity of the blood to carry oxygen, compromised general or local perfusion, or inability of the affected tissues to extract oxygen from, or metabolically process, an adequate supply ...
Cerebral hypoxia can also be classified by the cause of the reduced brain oxygen: [23] Hypoxic hypoxia – Limited oxygen in the environment causes reduced brain function. Divers, aviators, [24] Mountain climbers and firefighters are all at risk for this kind of cerebral hypoxia. The term also includes oxygen deprivation due to obstructions in ...
The process might initially seem counterintuitive, as low oxygen levels might theoretically stimulate increased blood flow to the lungs to increase gas exchange. However, the purpose of HPV is to distribute bloodflow regionally to increase the overall efficiency of gas exchange between air and blood.
Respiratory failure results from inadequate gas exchange by the respiratory system, meaning that the arterial oxygen, carbon dioxide, or both cannot be kept at normal levels. A drop in the oxygen carried in the blood is known as hypoxemia; a rise in arterial carbon dioxide levels is called hypercapnia. Respiratory failure is classified as ...
The main reason for the acute phase of ischemia-reperfusion injury is oxygen deprivation and, therefore, arrest of generation of ATP (cellular energy currency) by mitochondria oxidative phosphorylation. Tissue damage due to the general energy deficit during ischemia is followed by reperfusion (increase of oxygen level) when the injury is enhanced.