Physiologic Effects of Acidosis
| Respiratory Effects |
- Hyperventilation ( Kussmaul respirations)
- Shift of oxyhaemoglobin dissociation curve to the right
- Decreases 2,3 DPG levels in red cells, which opposes the effect above. (shifts the ODC back to the left) This effect occurs after 6 hours of acidemia.
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| Cardiovascular Effects |
- Depression of myocardial contractility (this effect predominates at pH < 7.2 )
- Sympathetic over-activity ( tachycardia, vasoconstriction, decreased arrhythmia threshold)
- Resistance to the effects of catecholamines (occur when acidemia very severe)
- Peripheral arteriolar vasodilatation
- Venoconstriction of peripheral veins
- Vasoconstriction of pulmonary arteries
- Effects of hyperkalemia on heart
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| Central Nervous System Effects |
- Cerebral vasodilation leads to an increase in cerebral blood flow and intracranial pressure (occur in acute respiratory acidosis)
- Very high pCo2 levels will cause central depression
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| Other Effects |
- Increased bone resorption (chronic metabolic acidosis only)
- Shift of K+ out of cells causing hyperkalemia (an effect seen particularly in metabolic acidosis and only when caused by non organic acids)
- Increase in extracellular phosphate concentration
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