Fluid and electrolytes....AHHH!!!

[dmfisher86]

For my med/surg class, we have a case study. I'm pretty sure the patient is hypovolemic with hyponatremia. I just want to make sure this is a possibility. And if so, would D5.45 NS be used to treat it because it's a hypertonic IV, so if I remember right, they are used to draw fluid out of the cells which would rehydrate the plasma, but I'm unsure how it would help to treat the hyponatremia. I thought I understood this in class, but apparently I was wrong. AHHH!!!!

[Daytonite, BSN, RN]

the reason for treating hyponatremia is to replace sodium. the dilemma of treatment is to replace sodium as quickly as possible without pulling the remaining water out of the cells while doing so. hypertonic solutions exert more osmotic pressure than the extracellular fluid so when these solutions are infused, fluid gets pulled into the vascular system. the higher solute concentration of the iv solutions used to treat hyponatremia also pulls water out of the surrounding cells. the iv solution used has to be done under close supervision since infusing higher concentrations of sodium at fast rates can result in the patient's death as a result of pulmonary edema and cardiovascular shock due to too much fluid being pulled out of the cells and into the vascular system.

see http://www.merck.com/mmpe/sec12/ch156/ch156d.html - hyponatremia

this chart includes all the major iv solutions and what they are used for: table of commonly used iv solutions.doc.

this thread includes a listing of the different iv solutions by category (hypotonic, isotonic and hypertonic) including why each is used: https://allnurses.com/nursing-student-assistance/iv-fluids-need-233712.html

here is the treatment for hyponatremia (from page 417 of nurse's 5-minute clinical consult: diseases):

• general: treatment of the underlying cause
  
• diet:
  
  • restricted fluid intake
    
  • high-sodium
    

  [*]medications:

  • administration of hypertonic saline solutions (3% or 5%) with serum sodium levels below 110 meq/l
    
  • administration of normal saline solutions (0.9%)
    
  • oral sodium supplements
    
  • demeclocycline or lithium
    

family practice notebook also gives the treatment for hyponatremia: http://www.fpnotebook.com/renal/sodium/hypntrmmngmnt.htm

• hypertonic saline (3%: 513 meq/l) (stating it is controversial) and normal saline (0.9%)
  
  
• it also mentions that potassium needs to be replaced
  

[dmfisher86]

THANK YOU SOOOOO MUCH!!! I was right in my thinking then.

I just want to make sure, but hypovolemia can lead to hyponatremia, correct?

[Daytonite, BSN, RN]

I just want to make sure, but hypovolemia can lead to hyponatremia, correct?

Yes. Hypovolemia, however, refers to diminished blood volume and is a term that is used when there has been hemorrhage and a large loss of blood. It includes the loss of a lot of other things that are contained within the blood. I think that perhaps you are meaning dehydration--the loss of body fluid. The loss of sodium occurs along with the loss of body fluid. Remember that "sodium follows water". They lose in an equal proportion all other factors being equal.