Fluid balance
Body composition...
- 60% - 70% adult weight is water
- 67% water is intracellular
- 33% is extracellular (27% interstitial fluid, 6% plasma)
Decreased output can be due to...
- Diuretics
- Total urinary tract obstruction
- Severe infection
- Antimuscarinics
- Vomitting
- Fever
- Diarrhoea
Water level controlled by...
- Atrial naturetic peptide
- Antidiuretic hormone
- Aldosterone/renin/angiotensin
Post-op requirements...
- 30 ml/kg/24 hours
- 1 mmol/kg/day sodium
- 0.8 mmol/kg/day potassium
Fluid admin depends on...
- Deficit correction
- Basal needs
- Loss replacement
- Safest route is oral
Central Venous Pressure:
In unwell patients, there
is a poor correlation between fluid status and CVP, so only CVP trends
help in assessing fluid management.