What are Isotonic solutions and why are they used?
Concentrations match 275-295 mOsm, same tonicity as the blood serum
no net movement in or out of the intravascular space
may be used in low bp, hypotension, hypovolemia, dehydration, to keep vein open
lactated ringers may be used in metabolic acidosis because it breaks down bicarb
isotonic solution is choice for a "fluid challenge" when bp drops