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12 Cards in this Set
- Front
- Back
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Mechanism of respiration
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principle mech is changing volume in the chest cavity - and thus change pressure
contraction of diaphragm - increase volume and decrease pressure -> air flows in from high to lower pressure Expiration, diaphragm relax and intercostal muscles relax -> chest cavity size will decrease -> increase in pressure |
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normal arterial blood gas
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pH: 7:35-7:45
pO2 - 100mm Hg pCO2 - 40mm Hg HCO3 - 24 mmol |
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respiratory failure
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due to increased Carbon Dioxide or decreased O2 or Both
hypoxic respirartory failure - due to low O2 Hypercapnic respiratory failure due to high CO2 other causes: post op period, shock |
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regulation of respiration - central chemoreceptors
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pons/medullar - chemoreceptors
pons - pneumotoxic center - swtich off for inspiration and apneustic center medulla - DRG: upper motor neurons for inspiration VRG: inspiration and expiration medulla/pons detect pH as CO2 is the only mediator that can pass through BBB into CSF - forms carbonic acid |
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regulation of respiration - peripheral chemoreceptors
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carotid bodies
aortic bodies detect decreases in pO2, increases in pCO2, and decrease in pH |
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hypoxic respiratory failure
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high altitude
dead space V/Q mismatch shunt |
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ventilatory failure/hypercapnic failure
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CNS depressions
spinal cord injury peripheral nerve injury NMJ disorders Respiratory muscles damage chest cage fractures airway disorders |
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hypercapnia
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increased CO2 or decreased elimination
fever diets rich in carbs hypoventilation |
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hypoxia
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deficient in O2 at tissue level
hypoxic hypoxia - most common - due to decreased arterial O2 anemic hypoxemia - less hemoglobin normal O2 stagnant hypoxia - perfusion or delivery to tissue is low histotoxic hypoxia - cells can't utilize O2 due to toxin |
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shunt vs V/Q mismatch
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if V/Q mismatch then patient should respond to 100% O2
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causes of hypoxemic hypoxia
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high alt
hypoventilation V/Q mismatch - most common obstructive lung disease, lung parenchyma disease, pulm embolism, pneumothorax shunts (V/Q = 0) |
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treatment of respiratory failure
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treat primary cause
then support with O2 and vent |
