Water, Electrolyte, And Acid Base Balance Flashcards
TBW =
Total Body Water
What is total body water (TBW)?
TBW content averages 50-70% of body weight
What does the total body water depend on?
- age
- sex
- fatty mass per cent (fat tissue has a lower water content)
How is the total body water (TBW) distributed?
- 2/3 of TBW is intracellular
- 1/3 of TBW is extracellular
LOOK AT THE TABLE “water balance”
On the first page of this PP
Dehydration def:
Dehydration is not having enough water in the body
How does the body try to deal with dehydration?
- the body tries to keep blood pressure from falling by moving water from cells and the spaces around the cells into blood vessels
- tissues dry out
- the kidneys try to conserve water by concenrating urine
Conditions that make dehydration more likely include the following: (I have not included everything that is on this list becaseu some are logical)
- kidney disorders, because kidneys are less able to concentrate urine as needed
- problem with walking, because getting water is difficult
- dementia, because the sense of thirst is reduced and the ability to get water when needed is impaired
- use of diuretics, because these drugs increased the amount of water (and salt) excreted by kidneys
Isotonic dehydration:
- Na loss in the isolsmolalic solution form
- Body fluid loss by digestive track (vomiting, diarrhea)
- Loss of sodium and water by kidneys
- Blood loss
- Intestinal obstruction
What are the main symptomps of isotonic dehydration?
- hypovolemia
- circulatory disturbances
- collapse
- pressure fall
- kidney function disturbances (prerenal failure) with oliguria and uremia
What does the laboratory test of somebidy with isotonic dehydration show?
- increase: Hb, Ht, Total protein, RBC
- Na-0
Hypertonic dehydration:
- Free water loss: more water is lost than sodium
Wyat causes hypertonic dehydration?
- high loss of body fluids by: kidney (renal diabetes insioidus, osmotic diuresis in diabetes), lungs (hyperventilation), skin
- low water inntake: young children, senseless people, old people
What does the laboratory test of those who have hypertonic dehydration show?
Increase: Ht (0), Hb, Osm, Na, RBC
Hypotonic dehydration:
Loss sodium syndrome
What is loss sodium syndrome?
- hypotonic dehydration
- loss of sodium by kidneys: chronic renal failure, Addison disease, organic lesion of CNS
What will the laboratory findings of somebody with hypotonic dehydration show?
- Increase: Ht, Hb, Osm, RBC
- Decrease: Na
Overhydration def;
Overhydration is having too much water in the body
How does the body react to overhydration?
The blodd vessels overfill and fluid moves from the blood vessels into the spaces around the cells, causing swelling (edema)
What can the examinations, for an overhydrated patient, show?
- blood test may be done to measure levels of electrolytes or other substances that indicate how well the kidneys are functioning
- a chest x-ray can show the back of fluid in the lungs
- test may be needed to determine whether heart failure is present
- for people who are overhydrated, treatment involves helping the body excrete the excess waater. Diuretics are drugs that help the kidneys do just that.
What causes overhydration?
- heart failure
- kidney disorders
- when the body produces too much antidiuretic hormone (may be caused by pneumonia, stroke, and by drugs like carbamazepine and sertraline)
- too rapid intravenous fluid infusion pr blood tansfusions or blood transfusion
Isotonic overhydration def:
Excessive retention of body water and Na
