Six main extrapulmonary causes of Acute Respiratory Failure are:

✓ Breath by a atmospheric gas mixture with the low percent of oxygen. Concentration of oxygen in an inhaled mixture <17% (for an unexercised organism) leads to clinical demonstration of Acute Respiratory Failure. A typical example is lifting on the big heights (> 3 km) without pre-award acclimatisation and additional oxygen supply

✓ Heavy anaemia (НЬ <65-70 g/l). Falloff of the haemoglobin concentration in blood, especially in the condition of accompanying hypovolemia (!) leads to dramatical reduction of blood oxygen saturation and a hypoxia of peripheric tissues.

✓ Hemodynamic violations. Low arterial pressure (systolic pressure less than 80-85 mm Hg) of any aetiology conducts to decrease in oxygen delivery and a histic hypoxia though SaO₂ may be in normal range.

✓ Poisoning with carbonic oxide. Haemoglobin is firmly bonded with the formation of carboxyhemoglobin (HbCO). Carboxyhemoglobin isn't able to participate in the process of tissue breathing, so oxygen transport function of blood becomes broken. It's possible to transform carboxyhemoglobin into haemoglobin with the help of vacuum chamber, considerably increasing quantity of the oxygen dissolved in blood. At poisoning with carbonic oxide PaO₂ is sharply reduced, however SaO₂ may be in normal range (because of red blood colouring by HbCO).

✓ Poisoning with cyanides. Cyanides cause a blockage of a special enzyme cytochrome oxidase, participating in molecular oxygen transmitting.

✓ Metabolic Acute Respiratory Failure. It is connected with to hyperproduction of CO₂ by tissues at some pathological conditions (hyperthermia, sepsis, thyrotoxicosis).

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  Low Compliance?
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  The Work Of Breathing
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  Neuromuscular Acute Respiratory Failure
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  Central Acute Respiratory Failure
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  Obstructive Acute Respiratory Failure
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  Restrictive Acute Respiratory Failure
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  Perfusive Acute Respiratory Failure
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