Week 1: Fluid Balance & Electrolytes

ADH and vasopressin

-The collecting ducts of the nephrons respond to ADH by increasing the reabsorption of water

-decrease excretion of urine

Potassium expected range:

3.5-5 mEq/L

Sodium expected range:

136-145 mEq/L

Calcium expected range:

9-10.5 mEq/L

Magnesium expected range:

1.3-2.1 mEq/L

Potassium functions:

-intracellular electrolyte

-support the transmission of electrical impulses of the body's nerves and muscles

-conduction of nerve cells within the heart

Hypokalemia

-muscle weakness/cramping, cardiac arrhythmias, respiratory weakness/paralysis

-never give IV push K

-put patient on cardiac monitoring

Hyperkalemia

-most common cause is renal failure

-paralysis, dysrhythmias or palpitations

-place on cardiac monitor/ECG

-decrease K intake

-remove K via dialysis or kayexalate (BMs)

-treated with dextrose

Sodium functions:

-extracellular electrolyte

-supports proper neurologic and neuromuscular function

-seizure precautions

Hyponatremia

-Neuro symptoms: loss of consciousness, seizures, and coma, headache due to swelling in brain

-rapid increase in fluids/fluid retention

--think kidney or heart failure

-focus on I and O and seizure precautions

Hypernatremia

-causes by dehydration or increase in sodium intake

-extreme thirst, some neuro, restlessness

-seizure precautions

-treat w/hypotonic fluids

Hypocalcemia

-numbness and tingling, muscle spasms, hyperactive deep tendon reflexes

-positive Chovostek and Trousseau sign

-causes by hypoparathyroidism after surgery or excess diarrhea or laxative misuse

-keep emergency tracheostomy equipment standby

Chvostek sign

Test which may indicate low calcium or magnesium levels. A positive result results in a twitching response of the side of the face when facial nerves are tapped

Trousseau sign

Test that can indicate low calcium or magnesium levels and spasms in the wrist and hand when a blood pressure cuff is inflated above the systolic blood pressure

-more specific to hypocalcemia

Hypercalcemia

-kidney stones, bone pain, dysrthmias

-most common causes are hyperparathyroidism/thyroidism and cancer

-monitor for bone fractures/restrict Ca, increase fluids

Magnesium function:

-intracellular electrolyte, 50% to 60%, is located in the bones

-regulation of nerve and muscle function, maintain blood pressure and serum glucose levels, support bone and teeth health, and synthesize protein, DNA, and RNA

-social butterfly

Hypomagnesemia

-nausea, vomiting, decreased appetite, fatigue, and weakness

-severe are neuromuscular changes, muscle cramps, spasticity, numbness, seizures, tetany, personality changes, cardiac dysrhythmias

-IV mg is high alert med

Hypermagnesemia

-most common cause is kidney disease

-nausea, dizziness, weakness, and confusion, confusion, sleepiness, blurred vision, headache, hypotension, bradycardia, dysrhythmias, decreased reflexes

-check patellar reflex if suspected

-long half life

-overuse of laxatives can cause this

Dehydration

-there is a loss of water or lack of water intake without a concomitant loss of sodium

-increased osmolality

-body water shifts from the inside of the cell to the extracellular space= cell shrink

-thirst, lethargy, dry mucosa, and oliguria

-severe is tachycardia, hypotension, lactic acidosis, shock

-increased urine specific gravity level, and all other labs!!

Fluid volume deficit (hypovolemia)

-thirst, dryness of mucosa, decreased skin turger, flat neck veins, dark urine, sudden weight loss, orthostatic hypotension, increased HR

-all labs go up EXCEPT FOR NA+

-similar to dehydration, but decrease in fluid AND electrolytes

-treat w/isotonic solutions

Fluid volume excess/overload (hypervolemia)

-sudden weight gain, edema, full neck veins, crackles in lungs, bounding pulse, pulmonary edema, increase in RR, decrease 02

-all labs go down

Interventions for fluid excess:

-weigh daily in the morning, same clothing (get patient to void)

-edema in legs--> elevate legs

-edema in lungs--> elevate HOB, possible IV diuretics, dialysis, supplemental 02

Interventions for fluid deficit:

-treat with isotonic solutions

-mild: oral rehydration w/electrolytes

-moderate to severe: isotonic, 0.9 or lactated ringers

Hematocrit (Hct)

-proportion of RBC in the blood

-males: 42-52%

-females: 37-47%

Importance of thyroid:

-controls Ca+ homeostasis via Calcitonin and PTH

Do we administer IV push potassium?

NO NEVER

-only use IVPB or oral routes (no crushing)

How to treat hyperkalemia?

-remove K via dialysis or kayexalate (BMs)

-treated with dextrose

BUN reference range:

10-20 mg/dL

Creatinine reference range:

0.5-1.1 mg/dL

Urine specific gravity:

1.005-1.030

Dextrose/insulin is used to treat which imbalance?

Hyperkalemia

-insulin increases re uptake

Phosphorus reference range

3.0-4.5 mg/dL

S/S of hypophosphatemia

-respiratory muscle weakness

-hypotension, arrhythmias

-bone pain, bone fractures

-bleeding, thrombocytopenia

S/s of hyperphosphatemia

same as hypocalcemia

-fatigue, anxiety

-hyperrelexia, tetany

-seizure

-positive Chvostek's sign, positive Trosseua's sign

Nursing considerations for hypophosphatemia:

-monitor cardiac rhythm and BP

-place patient on seizure and fall precautions

-administer oral replacement

Nursing considerations for hyperphosphatemia:

-ASSESS FOR HYPOCALCEMIA (tetany, twitching, seizures)

-place patient on cardiac monitoring

-administer phosphate binders

Fluid distribution in body

Intracellular fluid- inside the cell, 2/3 of body water; contains potassium, magnesium, phosphates, and proteins.

Extracellular fluid- outside of the cell, 1/3 of body water

Crystalloids

water and electrolytes (water soluble molecules)

-simple

-cost effective

-no immune response

Colloids

large insoluble molecules

-higher osmotic pressure

-more expensive

-immune response

Isotonic

-wont shift between ECF and ICF

-normal saline, lactated ringers, PlasmaLyte, D5W

Hypertonic

greater amount of solutes--> greater osmotic concentrate

-results in fluids pulled from ICF to ECF (dehydrates cells)

-3% normal saline

Hypotonic

less amounts of solutes--> less osmotic concentration

-fluid moves ECF to ICF (cells swell)

-0.5 normal saline--> (dont use w/head injuries or admin fast)