Acidosis
Alkalosis
Cardiovascular System
- Decreased cardiac output due to direct myocardial depression
- Particularly marked at pH <7.0 as compensatory effect of catecholamines overridden
- Predisposition to arrhythmias:
- Ventricular exotics and AF common
- Complex effects on vascular tone:
- Acidosis causes vasoconstriction
- Hypercapnia causes vasodilatation
- Increased myocardial contractility resulting in increased stroke volume
- Impaired myocardial oxygen delivery:
- Coronary vasoconstriction
- Impaired oxygen offloading due to left shift
Respiratory System
- Increased alveolar ventilation
- Right shift of the oxyhaemoglobin curve
- Complex effects on airway resistance
- Usually results in overall picture of bronchoconstriction and increased work of breathing
- Reduced alveolar ventilation
- Left shift of the oxyhaemoglobin curve
Renal System & Electrolytes
- Hyperkalaemia:
- Movement of potassium into extracellular fluid
- Effective hypercalcaemia (ionised Ca2+)
- Effective hypocalcaemia (ionised ca)
- Can lead to paraesthesia and tetany
Central Nervous System
- Hypercapnia causes cerebral vasodilatation:
- Can lead to headache, impaired consciousness and CO2 flap
- Hypocapnia causes cerebral vasoconstriction
- Cerebral alkalosis can alter neuronal RMP precipitating seizures
Musculoskeletal System
- Bone decalcification in chronic acidosis
- Contributes to the development of renal osteodystrophy