ELECTROLYTES
by Guiomar Goransson, RN, CHPN
©2008
FLUID/WATER - The body holds water/fluid in 2 basic areas or compartments --- inside cells and outside them. Sixty-five percent (65%) of body is water/fluid.
EXTRACELLULAR fluid -found OUTSIDE cells.
fluid - extracellular fluid that fills spaces between most of the cells of body and provides substantial portion of liquid of the body.
INTRAVASCULAR fluid - found INSIDE blood vessel (it’s blood)
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INTRACELLULAR fluid - found INSIDE cells. Cells are mostly water.
TRANSCELLULAR fluid comprises about 8% and includes:
- digestive juices
- intraocular fluid
- cerebrospinal fluid
- bladder and renal tubles
- synovial fluid
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FUNCTIONS OF WATER/FLUID
INTRACELLULAR FUNCTION OF WATER: it’s a medium for cellular chemical function. The main need for water is at a CELLULAR LEVEL - perfusion of tissue.
EXTRACELLULAR FUNCTION OF WATER: maintains blood volume, transports nutrients and wastes to and from cells, cushions and lubricates. Water also takes CO2 from cells.
TRANSCELLULAR FUNCTION OF WATER:
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hydrolyzes food in digestive system
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lubcates structures of eye & keeps configuration of eyeball
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medium for filtration, secretion, reabsorption & excretion of waste in renal system
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cushions and protects brain & spinal cord
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cushions & lubricates joints
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medium for nourishment of neurons
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ELECTROLYTES
ELECTROLYTES - are elements or compounds that when melted or dissolved in water or another solvent, dissociates into ions and is able to produce an electric current. Eg. tabled salt mixed in water are now sodium or chloride and carry an electrical charge.
MOST IMPORTANT POSITIVELY CHARGED ELECTROLYTES (cat-ions) are:
(controls ACID BASE - powerful!!!)
POTASSIUM (K+) (bananas a good source)
SODIUM (Na+)
MAGNESIUM (Mg++)
CALCIUM (Ca++)
POSITIVE: SO CALCulate the magnesium in the HY-PO
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MOST IMPORTANT NEGATIVELY CHARGED ELECTROLYTES (anions) are:
- CHLORIDE (CL-)
- BICARBONATE (HCO3-)
- PHOSPHATE (PO4) (important because of calcium)
- SULFATE *SO4-)
When water evaporates, sodium and chloride come together because of AFFINITY. NEED TO KNOW hydrogen and bicarbonate go together.
PRECISE CONCENTRATIONS of ELECTROLYTES are VITAL to BODY FUNCTION
MEASURE ELECTROLYTES by mEQ/L
MEASURE CALCIUM by mg/L
Concentration at neutral balance is maintained in all compartments.
Fluids contain equal quantities (mEqs) of anions and cations
LAB NORMS FOR ELECTROLYTES
- Na+ 135-145 mEq/L
- K+ 3.5-5.3 mEq/L
- Mg++ 1.3-2.1 mEq/L
- Ca++ 8.6-10 mg/L
- Cl- 98-106
mEq/L
- PO4- 2.5-4.5 mg/l
- HC03- 22-28
mEq/L
- H+ pH 7.35 - 7.45 (
arterial blood)
H+ controls acid base. This lab value does not vary much. Arterial blood needs to maintain this value for homeostasis.
FUNCTIONS OF ELECTROLYTES:
- promotes neuromuscular irritability.
maintain body fluid volume and osmolarity (osmolarity is concentration of particles in solution - osmosis/liter - of solution) The more concentrated a solution is, the more power it has to pull in water.
Regulates acid-base balance
plasma osmolarity regulates the release of ADH. *
OSMOSIS: only water moves from lower to high concentration to equalize concentration.
DIFFUSION moves in opposite direction.
*ADH (anti-diuretic) is a hormone that restores blood volume by reducing peeing and increasing water retention. Also called VASOPRESSIN.
WITH SEVERE FLUID & ELECTROLYTE IMBALANCE.....
- Changes in behavior with changes in electrolytes
- Operations & exchanges that are primary to life of cells can not take place
- Heart can’t beat
- Neurons can not fire or will fire uncontrollable
Digestion can not take place (hydrochloric acid aspiration can be lethal because acid of 2-3 is in lungs!)
Skeletal muscle can not contract
PREVENT IMBALANCE OF FLUIDS & ELECTROLYTES!
WHO IS AT RISK?
WHAT CONDITIONS ARE RISKS FOR IMBALANCE?
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- Burns (intra- and extracellular fluid loss)
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- Eating Disorder...
- anorexia, bulimia
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retains water by hoarding sugar)and diuretics
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- Gastrointestinal Surgery*
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*With GASTROINTESTINAL SURGERY, esp at risk are: Preps (laxatives & enemas); NPO status; Gastric suction; Delayed peristalsis. In hospital, esp. w/gastric suction of hydrochloric acid, pt at risk for alkalosis.
IF SUCTION TUBE IS IN INTESTINE, loss will be of HCO3- (bicarbonate) and risk will be acidosis.
NOTES: K+ (potassium) is MAJOR abundant intracellular electrolyte. Sodium is major extracellular. When K+ moves into a cell, sodium moves out (or vice versa). Electrical charge happens.
TPN - TOTAL PARENTAL NUTRITION or HYPERAILAMENTATION will increase osmolarity and will pull water from tissue.
TRANSFUSIONS - preserved with citrate which removes calcium from body.
CIRCULATORY OVERLOAD --- if pt already has heart problem and IV, they can overload on fluid. Forty year old man is not at risk like 90 y/o man. Need to watch infusion rate!
WHAT QUESTIONS TO ASK:
- Date of onset
- Duration
- Tx & meds taken
- Weight changes
- I&O
- Feet swelling?
- Can you put on rings?
- If vomiting and diarrhea, ask if pt is peeing
- Have you had this problem before?
WHAT ARE SIGNS & SYMPTOMS OF OVERHYDRATION?
- Changes in behavior: confusion, incoordination, convulsions
Hyperventilation
Sudden Weight gain
Warm, moist skin
Increased & bounding pulse w/increase in systolic & decrease in diastolic blood pressures
Peripheral edema, usually not marked
WHAT ARE SIGNS & SYMPTOMS OF DEHYDRATION?
Dry mouth, mucous membranes
Postural hypotension (early), low blood pressure, tachycardia, increased respiration, decreased vein filling
Weight loss
Urine output low, increased specific gravity
Increase in hematocrit, BUN, electrolytes
Infants; fontanel, esp for first 18 months
Infants; fontanel, esp for first 18 months
WHAT ARE SIGNS & SYMPTOMS OF CIRCULATORY OVERLOAD?
Venous distention
Hoarseness
Dyspnea
Cough
Pulmonary rales
Restlessness
ASSESSMENT: PALPATE for edema, peripheral pulses, fontanel (infants) When assessing for edema, take thumbs and push in along tibia around ankle bones. In ANASARCA you can actually see fluid seep out of tissue!
ASSESSMENT: AUSCULTATION for blood pressure, apical pulse rate and rhythm (high risk for dysrhythmias), lung sounds - be sure to listen to lungs sitting up.
DIAGNOSTIC DATA
changes
CBC: hemodilation or hemoconcentration - Hb may have lost or gained fluid
BUN: renal function - Urea waste from protein metabolism in kidney but could be off if pt has eaten much protein
CREATININE: MOST ACCURATE VALUE. Best way to check kidney function
PREVENTION, TREATMENT & EVALUATION
- If K+ levels are rising in ARF pt, he will be put on dialysis because of risk of heart arrhythmia.
- Tell pt not to stay in sun
- Recognize signs and symptoms of overhydration or dehydration + circulatory overload.
TO BE CONTINUED....
Electrolytes ©2008 Guiomar Goransson, RN, CHPN