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What is involved in a chem 7?
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What are normals for the BMP?
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What are normals for the CMP?
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Know where the electrolytes are found in quantity (ie in cells or in BS)
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Potassium (K+)
- Major cation of the ICF
- Necessary for:
- Transmission & conduction of nerve impulses
- Maintenance of normal cardiac rhythms
- Skeletal muscle contraction
- Acid-base balance
- Normal 3.5.5.0 mEq/L
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K+ and pH
- Alkalosis:
- Decreased H+ ions
- H+ leaves the cell
- K+ is drawn into the cell-->HYPOkalemia
- Normal pH 7.35-7.45
- Acidosis:
- Increased H+ ions
- H+ pushed into the cell
- K+ pushed out of cell= HYPERkalemia
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Functions and sources of K+
- Critical to action membrane potential
- Kidneys are major route for K+ loss. (Minor loss of K+ via stool & sweat).
- Sources of K+:
- --Fruits & vegetables (e.g. bananas, oranges)
- --Salt substitutes
- --K+ medications (PO, IV)
- --Stored blood
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Hyperkalemia pathophys
- Renal failure
- Increased cellular destruction
- Excessive administration/ingestion of K+
- K+ sparing diuretics
- Low cardiac output or sodium depletion
- Acidosis
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SnSs of Hyperkalemia
- EKG – Tall, peaked T-waves, widening QRS, bradycardia, VT, VF, asystole (potentially lethal)
- Abdominal cramps, diarrhea, hyperirritable BS
- Lethargy, muscle weakness
- Myocardial depression – contractility & conduction
- Oliguria (low pee)/anuria (no pee) (if renal insufficiency or failure)
Nursing intervension: get pt on a heart monitor!
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Nursing care for pt with hyperkalemia
- Administer Ca++ chloride or gluconate IV-->Decreases cardiac irritability
- Monitor serum K+
- Frequent cardiac, GI, renal assessments
- Avoid K+ in diet
- Avoid K+ sparing diuretics
- Treat underlying problem
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Rx involved in hyperkalemia Tx
- May anticipate/administer:
- Kayexelate PO or PR (exchanges K+ for Na+ in gut-->diarrhea)
- Diuretic (non-K+ sparing)
- ½ or 1 amp Dexterose 50% IVP followed by regular insulin IV
- NaHCO3 w/confirmed acidosis
- Dialysis
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Pathyophys of hypokalemia
- K+ loss exceeding intake due to...
- Elevated aldosterone levels
- Loop diuretics
- GI losses
- Movement into cells
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SnSs of Hypokalemia
- Ventricular dysrhythmias (potentially lethal)
- Impaired repolarization
- Increased digoxin toxicity (in those taking dig)
- Muscle cell breakdown (leads to myoglobin in plasma & urine)
- Decreased GI motility
- Altered airway responsiveness
- Impaired regulation of arterial blood flow
- Diuresis
- Hyperglycemia
Nursing intervension: get pt on a heart monitor. Sound familiar?
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Hypokalemia nursing care
- Administer K+ as indicated
- *NEVER GIVE POTASSIUM IVP
- *Consider renal function when giving K+. If impared, give less.
Standard of care: KCl 10mEq/100mL IV over one hour
- K+ is very irritating to peripheral veins. May be painful & not tolerated by pt.
- Some facilities add Lidocaine … but consider …not feeling the pain does not necessarily mean the damage isn’t happening…
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Function of sodium (Na+)
- Major cation of the ECF - imbalances change ECF osmolality
- “Serum sodium” = Na+ + H2O
- Major role in:
- --ECF volume & concentration
- --Generation & transmission of nerve impulses
- --Acid-base balance
- --Normal 135-145
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Hypernatremia Pathophys
- Elevated Na+ occurs w/water loss OR Na+ gain
- Hyperosmolality leads to cellular dehydration
- Protected by hypothalamus because it will trigger thirst to dilute [Na+]
- Hyperosmolar tube feedings
- Osmotic diuretics (ie, mannitol)
- Sensible losses (sweating to the point of losing electrolytes including Na+)
- Na+ gain/intake
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Hypernatremia labs
- (not normals. values indicate hypernatremia)
- Serum Na+ > 145 mEq/L
- Serum osmolality > 300 mOsm/L
- Normal to high Hct (consider concentration vs. dilution)
- Urine specific gravity > 1.030
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SnSs of hypernatremia with Hypervolemia
- Na+ Gain
- Edema, weight gain
- Bounding pulses
- Distended neck veins
- Crackles in lungs
- Dyspnea, orthopnea
- Possibly low Hct
- Tachycardia
- Hypertension
- Restlessness, lethargy, agitation, sz, coma
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Hypernatremia with hypovolemia
- H2O Loss due to a variety of reasons including diaphoretic-- ^ [Na+] in BS-->water drawn from cells-->SnSs below:
- Dry skin & mucous membranes
- Tenting skin
- Warm, flushed, dry skin
- Initial elevated temp
- Hypotension (esp orthostatic)
- Tachycardia
- Thirst
- Oliguria
- Restlessness, lethargy, agitation, sz, coma
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Nursing care for Na+ gain with hypervolemia
- Na+ restriced diet
- Avoid over-infusion w/saline
- Diuretics
- Frequent Assessments – neuro, renal, cardiac, respiratory
- Monitor labs
- Treat underlying cause
In both hyper/hyponatermic cases, pt will get confused and will be high risk for falls.
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Nursing care for Na+ game with hypovolemia
- Water (esp if pt needs volume)
- IVF – consider Na+ content (e.g. ½, ¼ NaCl; D5W)
- Frequent Assessments – neuro, renal, cardiac
- Monitor labs
- Treat underlying cause
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pathophys of Hyponatremia
- Results from loss of sodium-containing fluids OR from excessive water intake
- Causes hypoosmolality leading to cellular swelling and explosion
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Pathophys of hyponatremia with Na+ depletion
- NaCl loss > H2O loss (usually w/FVD)
- Diuretics
- Diarrhea, fistula drainage
- NG suction
- Diaphoresis
- Hyperglycemia (glucose-induced diuresis)
- Adrenal insufficiency
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Hyponatremia pathophys due to Excessive H2O
- Water intoxication (dilutional effect; usually w/FVE)
- SIADH
- Overhydration w/dextrose
- Tap water enema
- Hypotonic irrigating solutions (CBI)
- HF, cirrhosis
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SnSs of hyponatremia due to v Na+
- CNS – HA, malaise, muscle weakness, confusion/coma
- FVD effects (hypotension, decrease BP/JVD, tenting, low U/O
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SnSs of hyponatremia due to ^H2O.
- CNS – LOC, HA, delirium, sz
- FVE effects (weight gain, taut skin turgor, JVD/elev CVP, hypertension, risk for pulmonary edema
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Nursing care for hyponatremia due to v Na+
- Neuro checks!
- SZ precautions
- Diet high in sodium w/adequate fluid
- Fluid resuscitation w/NS
- Monitor labs
- Frequent cardiac & renal assessments
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Nursing care for hyponatremia due to ^ H2O.
- Neuro checks! w/ SZ precautions
- Fluid restriction
- Diuretics
- Monitor labs
- Frequent assessments – respiratory, renal, cardiac
- 3% NaCl very slowly
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