Expansion
A WET BED: Acid-base, Water, Electrolytes, Toxins, Blood pressure, Erythropoietin, vitamin D
Expansion
A WET BED:
- A - Acid-base balance, by excreting hydrogen ions and regenerating bicarbonate
- W - Water balance and osmolality
- E - Electrolyte balance: sodium, potassium, calcium, phosphate, magnesium
- T - Toxin and waste removal: urea, creatinine, drugs
- B - Blood pressure control, through renin and sodium handling
- E - Erythropoietin production
- D - vitamin D activation, by 1-alpha hydroxylation to calcitriol
The kidneys receive about 20 to 25 per cent of cardiac output for only 0.5 per cent of body weight, reflecting the fact that they process plasma rather than simply receiving a nutritive supply.
The endocrine functions explain the non-excretory features of chronic kidney disease: anaemia from erythropoietin deficiency, renal bone disease from failed vitamin D activation, and hypertension from sodium retention and renin activation.