Fluid Balance & Electrolytes Flashcards
What is osmosis
Movement of WATER down a concentration gradient
From region of low SOLUTE concentration to one of high solute concentration across a SEMIPERMEABLE MEMBRANE
When does osmosis stop
Stops when concentration differences disappear OR when hydrostatic pressure builds and opposes further movement
what is diffusion
Movement of molecules from an area of high concentration to a lower concentration
when does diffusion stop
Movement stops when concentrations are equal in both areas
What 2 electrolytes are outside the cell
sodium and chloride
what 4 electrolytes are primarily inside the cell
potassium, magnesium, phosphate, and sulfer
what is osmotic pressure
the amt of pressure needed to prevent the movement of water across a cell membrane
What are the 3 Primary colloids
albumin, globulin, fibrinogen
how are colloids measured
Total protein level
What do colloids do?
move fluid from interstitial compartment to plasma (blood) compartment
what is hydostatic pressure
Force of fluid in compartment pushing AGAINST A CELL MEMBRANE (or vessel wall)
what generates hydrostatic pressure
Generated by blood pressure
what does hydrostatic pressure do at the capillary level
major force that pushes water OUT of the vascular system into interstitial space
Oncotic pressure
Caused by plasma colloids (large molecules) in solution
Major colloids in vascular system= albumin
T/F colloids are abundant in plasma and fewer in interstitial space
True, Plasma proteins attract water, pulling fluid from tissue space into vascular space
What does hydrostatic pressure do?
pushes fluid out of the capillary
what does oncotic pressure do
pulls fluid INTO the capillary
What 5 things do electrolytes influence
Fluid balance acid base balance nerve impulses muscle contraction heart rhythm other cell functions
what are electrolytes
substances that are ELECTRICALLY charged when in solution
what 4 things are concentrations of electrolytes dependent on
intake
absorption
distribution
excretion
What electrolytes have the highest INTRACELLULAR concentration
Potassium (+)
Magnesium (+)
Phosphorous (-)
What electrolytes have the highest EXTRACELLULAR concentration
Sodium (+)
Chloride (-)
Bicarbonate(-)
Normal range of sodium
136-145 meq/L
normal range of potassium
3.5-5.0meq/L
normal range of magnesium
1.7-2.2 mg/dl
normal range of calcium
9-11 mg/dl
normal range of phosphate
3.2-4.3 mg/dl
What does Na+ activate
muscle and nerve cells. ion movement important in action potentials
4 characteristics of Na+
main ECF cation
Governs osmolality
influences water distribution
aids in acid-base balance
5 Causes of hyponatremia
Na < 136
GI loss Renal loss Skin loss Fasting diets Excess hypotonic fluid
S/S of hyponatremia
CONFUSION/ ALTERED LOC
anorexia
muscle weekness
can lead to seizures/coma
Dilutional hyponatremia =
Hypervolemic
depletional hyponatremia =
hypovolemic
5 characteristics of dilutional hyponatremia
hypervolemia increase BP weight gain bounding rapid pulse increae urine sp gravity
6 characteristics of depletional hyponatremia
hypovolemia decrease BP tachy pulse dry skin weight loss decrease sp gravity
5 characteristics for treatments for hyponatremia
sodium replacement (slowly) PO/IV IV - normal saline Fluid restriction Treat underlying problems
Sodium Bicarbonate MOA
Dissociates to provide bicarbonate ion which neutralizes ion concentration and raises blood and urinary pH
Increases concentration of sodium in plasma
Sodium Bicarbonate Indication
metabolic acidosis
Adverse effects of Sodium Bicarbonate
edema,
cerebral hemorrhage, hypernatremia,
lots of electrolyte abnormalities, metabolic alkalosis, flatulence with PO, tetany,
pulmonary edema, heart failure exacerbation
4 nursing considerations for Sodium Bicarbonate
Do not give IV for hyponatremia- VESICANT at high concentrations
If IV, monitor patency thoroughly!
Lots of drug interactions if the drug mixing with is diluted with sodium solutions
PO- give 1-3 after or before meals
3 causes of Hypernatremia
>145
IV fluids, tube feeds, near drowning in salt water = excess sodium intake
Not enough water intake or too much water loss = cognitively impaired, diarrhea, high fever, heatstroke
Profound diuresis
S/S of Hypernatremia
>145
Alter LOC/Confusion, seizure, coma
Extreme thirst (hyperosmolality)
Dry, sticky mucous membranes
Muscle cramps
Hypernatremia treatment
If H20 loss is cause_ ADD WATER
If sodium excess is cause_ REMOVE SODIUM
T/F you should quickly correct sodium levels
False, GRADUALLY achieve normal sodium level over a 48 hours period to avoid edema of cerebral cells
6 characteristics of potassium
Intracellular cation
Helps regulate cell excitability and electrical status
Helps control intracellular osmolality
Diet is main source
Kidneys main source of potassium loss Pee out Potassium
Normal Values: 3.5-5 mEq/L
2 causes of Hypokalemia <3.5
Renal or GI losses
DIURESIS
Acid base disorders (potassium in ECF goes into ICF)
S/S of hypokalemia
Cardiac rhythm disturbances can be lethal
Muscle weakness, leg cramps
Decreased bowel motility- constipation, nausea, ileus
Potassium chloride (KCl) indications
Treat/prevent K+ depletions when dietary measures prove inadequate
4 nursing implications for KCl (PO)
DILUTE with water/juice to ↓ GI distress tastes awful! powder/tablets may cause GI ulcers/bleeding assess for N/V Critical Point: IV MUST ALWAYS be diluted; NEVER IV Push!!
4 nursing indications for KCl (IV)
IV: MUST BE DILUTED!!! and ADMINISTERED SLOWLY
Give only to clients with documented urine output
May cause phlebitis/pain
IV solutions should not contain more than 40 mEq/L of K+; rate should not exceed 10-20 mEq/hr
2 Contraindications for KCl
Renal Failure
Dialysis
what can undiluted potassium cause
ventricular fibrillation
Should you give K+ IV push?
NEVER
3 Causes of hyperkalemia
Decreased potassium OUTPUT (renal failure, not peeing)
Burns, crush injuries, sepsis anything with massive cell injury
Drugs– potassium sparing diuretics, ACE, ARBs NSAIDs
S/S of Hyperkalemia
CARDIAC RHYTHM DISTURBANCES
Muscle weakness, cramps
Abdominal cramping, diarrhea, vomiting
Kayexalate/sodium polystyrene sulfonate class
cation exchange resins
Kayexalate/sodium polystyrene sulfonate route
available as oral suspension, oral and rectal powder, oral and rectal suspension, rectal enema
Kayexalate/sodium polystyrene sulfonate Indication
To treat high levels of potassium in the blood (hyperkalemia
Kayexalate/sodium polystyrene sulfonate MOA
kayexalate binds to potassium in the digestive tract replacing potassium ions for sodium ions. Potential to drop K by 0.5-1.0 meq/L in 4-6H
Adverse Reactions to kayexalate
Constipation, diarrhea, N/V, hypokalemia
Serious: intestinal obstruction and intestinal necrosis
precaution of kayexalate
use only in patient with normal bowel function
MOA of D50/Insulin
combo shifts potassium into cell temporarily (10units of regular insulin to 1 ampule of D50)
Lytic Cocktail
Reduces potassium level
- 10% 10cc calcium gluconate - protects heart by stabilize myocardium
- dextrose 50 - 500cc - counteract effect of insulin
- insulin - iv actrapid 10 unit - drive K+ into cells
3 charateristics of magnesium
Helps to stabilize cardiac muscle cells
Blocks/controls movement of K+ out of cardiac cells
Helps to stabilize smooth muscle
causes of hypomagnesium
diuresis, GI or renal losses, limited intake (fasting or starvation), alcohol abuse, pancreatitis, hyperglycemia
S/S of hypomagnesium
S/S: hyperactive reflexes, confusion, cramps, tremors, seizures
Nystagmus
oral treatment of hypomagnesium
Mylanta
Magnesium sulfate
IV treatment of hypomagnesium
IV Magnesium sulfate
Replace over several days
Can give IV push if necessary
Hypermagnesemia causes
increased intake accompanied by renal failure
Chronic renal failure who take milk of mag
OB patients
S/S of hypermagnesium
lethargy, floppiness, muscle weakness, decreased reflexes, flushed/warm skin, decreased pulse/BP
Treatment of hypermagnesemia
Treatment: stop replacement, if chronic decrease intake = dialysis
Mag Sulfate and Mag Oxide MOA
replaces magnesium
Mag Sulfate and Mag Oxide indication
hypomag, prevent/treat seizures in pre-eclampsia, treat cardiac rhythm disturbances [constipation PO]
Mag Sulfate and Mag Oxide adverse effects
hypermag confusion, sluggish, slow movements, SOB, nausea, dizzy [low calcium], abnormal heart rhythm
What is calcium
Hormones released by the thyroid and parathyroid glands are controllers for the amount of calcium that is released from and absorbed into the bone
5 characteristics of calcium
Enzyme reactions
Effects membrane potentials and nerve excitability
Necessary for contraction of skeletal, cardiac and smooth muscle
Helps in release of hormones, neurotransmitters and chemical mediators
Influences cardiac contractility and automaticity
Necessary for blood clotting (part of the clotting cascade)
treatment of hypocalcemia (IV)
IV calcium Calcium Chloride (ionized form and preferred) = given through central only at UK Calcium Gluconate = prefer to give through central line
Oral treatment of hypocalcemia
Elemental calcium, calcium carbonate (Tums)
May also need Vit D
Active form in impaired liver &/or kidney function
causes of hypercalcemia
hyperparathyroidism, cancers
S/S of hypercalcemia
calcium acts like a sedative, fatigue, lethargy, confusion, weakness, leading to seizures, coma
Kidney stones
4 treatments of hypercalcemia
Adequate hydration
Increased urine output
Diuretics and NaCl (sodium excretion is accompanied by calcium excretion)
Dialysis in renal failure
T/F low calcium = high phosphate
True
5 MOAs of phosphorus
Role in bone formation Essential for ATP formation and enzymes needed for glucose, protein and fat metabolism Part of DNA and RNA Acid-base buffer Normal function of WBCs and platelets
percentage of phosphorus found in bone
85%
percentage of phosphorus found intracellular
14%
causes of Hypophosphatemia
Decreased absorption Antacids overdose Severe diarrhea Increased kidney elimination Malnutrition Alcoholism TPN Recovery from malnutrition
manifestations of hypophosphatemia
mild-moderate few, severe: Tremor Paresthesia Confusion to coma Seizure Muscle weakness Joint stiffness Bone pain Hemolytic anemia Plt dysfunction Impaired WBC function
causes of Hyperphosphatemia
Kidney failure Laxatives/enemas with phosphorus Shift from intra- to extracellular compartment Massive trauma Heat stroke Hypoparathyroidism
manifestations of Hyperphosphatemia
Usually asymptomatic Typically only symptoms of hypocalcemia: Muscle spasms Paresthesia Tetany
treatment for Hypophosphatemia
IV or oral replacement Given IV over a LONG period of time Increase oral intake Take care with CKD or hypercalcemia Increased risk of calcifications
treatment for Hyperphosphatemia
Treat the cause
Calcium-based phosphate binders
Hemodialysis – Renal failure
Chvostek’s sign
ipsilateral twitching of the circumoral muscles in response to gentle tapping of the facial nerve just anterior to the ear
Trousseau’s sign
carpal spasm upon inflation of a BP cuff to 20 mmHg above the patient’s systolic blood pressure for three minutes
T/F Low Mag= Low calcium
True
Causes of Hypocalcemia
Unable to mobilize bone increased renal loss increased binding decreased intake of absorption (Decreased vitamin D) Acute pancreatitis thyroid and parathyroid surgery increased neuromuscular excitability cardiac insufficiency positive chvosteks sign positive trousseaus sign