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Many people with chronic obstructive pulmonary disease have a low partial pressure of oxygen in the blood and high partial pressure of carbon dioxide.Treatment with supplemental oxygen may improve their well-being; alternatively, in some this can lead to the adverse effect of elevating the carbon dioxide content in the blood (hypercapnia) to levels that may become toxic.
High-altitude mountaineering can induce pulmonary hypoxia due to decreased atmospheric pressure. This hypoxia causes vasoconstriction that ultimately leads to high altitude pulmonary edema (HAPE). For this reason, some climbers carry supplemental oxygen to prevent hypoxia, edema, and HAPE.
Acute hypocapnia causes hypocapnic alkalosis, which causes cerebral vasoconstriction leading to cerebral hypoxia, and this can cause transient dizziness, fainting, and anxiety. [3] A low partial pressure of carbon dioxide in the blood also causes alkalosis (because CO 2 is acidic in solution), leading to lowered plasma calcium ions ...
Factors that may induce or sustain [2] hyperventilation include: physiological stress, anxiety or panic disorder, high altitude, head injury, stroke, respiratory disorders such as asthma, pneumonia, or hyperventilation syndrome, [5] cardiovascular problems such as pulmonary embolisms, anemia, an incorrectly calibrated medical respirator, [1] [3 ...
In the central nervous system, high levels of oxygen can cause seizures, which are a significant risk in hyperbaric oxygen therapy if not carefully monitored. [3] Besides, hyperoxia can result in vasoconstriction , particularly affecting cerebral and coronary circulation, potentially leading to adverse outcomes, including increased mortality in ...
The increased respiratory and cardiac workload causes increased blood flow to the cardiac and respiratory muscles. Stroke volume is not greatly affected by immersion or variation in ambient pressure , but bradycardia reduces the overall cardiac output, particularly due to the diving reflex in breath-hold diving .
Breathing is normally an unconscious, involuntary, automatic process. The pattern of motor stimuli during breathing can be divided into an inhalation stage and an exhalation stage. Inhalation shows a sudden, ramped increase in motor discharge to the respiratory muscles (and the pharyngeal constrictor muscles). [5]
Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation , the widening of blood vessels.