Fluid Replacement Therapy Flashcards
What % of the total body weight is fluid in a newborn baby?
75%
What % of the total body weight is fluid in the eldery?
45%
Decreasing muscle mass
What % of the total body weight is fluid in a man?
60%
What % of the total body weight is fluid in a female?
55%
Why does fluid take up more of the total body weight in men than women?
Men have more muscle mass
Water is stored in the muscle
Why do patients need fluids?
Nil by mouth
Malfunction in GI tract
Dehydration
Fluid loss
Abnormal electrolyte levels
What are the three reasons for giving fluids?
Resuscitation
Replacement
Maintenance
How can you add K+ to fluids?
As KCl
As 20 or 40mmol
What fluid bag can you not modify?
Hartmann’s
What happens if you administer 5% dextrose in 1L bag?
- glucose taken up by cells rapidly
- H2O is left and distributed through all compartments
What happens if you administer 0.9% saline?
- osmolarity is similar to ICF so liquid says in ECF
- distributes proportionally between interstitium 75% and plasma 25%
- contains Na+ and Cl-
What happens when you administer Hartmann’s?
- osmolarity is similar to ICF so liquid says in ECF
- distributes proportionally between interstitium 75% and plasma 25%
- contains Na+, Cl-, K+, Ca+ and lactate (HCO3-)
What fluids are the first choice for resuscitation?
Hartmann’s
Saline
What happens when you administer 4% dextrose/0.18% saline in a 1000ml bag?
(200ml 0.9% saline + 800ml 5% dextrose)
- 800ml H2O reduces osmolarity across ALL compartments from 5% dextrose (+glucose taken up by cells)
- 200ml 0.9% saline remains in ECF + distributes proportionally across interstitium 75% + intravascular space 25%
When are maintenance fluids needed?
Patient is haemodynamically stable but unable to meet their daily fluid requirements via oral or enteral routes
e.g. Nil by mouth before surgery
