Fluid management Flashcards
What is the ratio of fluid distribution in the body?
- 2/3 is intracellular
* 1/3 is extracellular
What is the main electrolyte in the intracellular fluid?
Potassium
What are the main ions in the extracellular fluid?
In the interstitium: sodium and chloride
What is the normal intake?
20-30ml/kg/day
What is the normal output?
Total loss approx 2l a day
What are the fluid intakes?
- Drinking - 1.5l
- Food -0.5l
- Metabolic - 0.5l
What are the fluid losses?
- Urine - 1.5l
- Respiration - 0.4l
- Sweating - 0.5l
- Faeces - 0.1l
What are the three broad categories of things that can go wrong with fluid balance?
- Imbalance between input and output
- Redistribution of fluid
- Osmolar problems
What are the things causing excess loss?
- Vomiting
- Diarrhoea
- Stoma
- Drains
- Fever
- Polyuria - diuretics, metabolic problem
What is the main electrolyte of the gastric fluid?
Cl
What is the main electrolyte of the bile?
Na
Which electrolytes are lost due to diarrhoea?
- Na
- K
- HCO3-
What electrolytes are lost via colostomy?
- Na
- K
- Cl
What is 3rd space loss?
Fluid is lost into the extracellular space
What is serum osmolarity a measure of?
- The concentration of small diffusible ions
* Na, K, glucose and urea
What is osmotic pressure?
Ions exert a pressure which causes water to move across the cell membrane from weaker to stronger solutions until the concentration of solutes is equal on both sides
What is the risk of osmolar problems?
- Cerebral oedema
- Water moves from ECF to ICF in acute hyponatraemia
- Water moves out of the brain if sodium is corrected too quickly
What are the 3 different aims of IV fluid management?
- Maintenance - daily fluid replacement i.e. If NBM
- Replacement - replace ongoing loss
- Resuscitation - to correct intravascular or extravascular volume deficit
What are the 5 questions you should ask yourself before prescribing fluid?
- Is the patient dry, wet or euvolaemic]
- Do they need IV fluid
- Why?
- how much?
- What type
What is a typical history of someone with fluid depletion?
- Abnormal losses
* Diuretic therapy
What is the typical history of someone with fluid overload?
- Heart failure
* Renal failure
What are the symptoms of fluid depletion?
- Thirst
- Dry mouth
- Dry skin
- Dark urine
- Postural dizziness
What are the signs of fluid overload?
- Hypertension
- Increased JVP
- 3rd heart sound
- Oedema
What are the symptoms of fluid overload?
- Breathlessness
* Swollen ankles
