Week 10: RN Fluid and Electrolyte Balance

Regulating Fluid and Electrolyte Balance

• Fluid and electrolyte balance is maintained through the thirst mechanism, antidiuretic hormone (ADH), and renal regulation.
• The hypothalamus controls the thirst mechanism, detecting high osmolality and signaling thirst to increase fluid intake.
• ADH is released from the posterior pituitary when osmolality is high, telling the kidneys to reabsorb water into the bloodstream, which reduces urine output and increases fluid volume.
• The kidneys filter blood and selectively reabsorb water and electrolytes based on the body's needs, regulating sodium, potassium, calcium, and magnesium.

Rehydration

• Rehydration can be administered through oral or intravenous (IV) methods.
• Oral rehydration is suitable for clients who can swallow and have mild to moderate dehydration using water, electrolyte solutions (e.g., Pedialyte), or sports drinks.
• IV rehydration is necessary for severe dehydration or when the client cannot tolerate oral intake.
• IV fluids like D5W or normal saline are used to restore volume.

Complications of Rehydration

• Overhydration, caused by administering fluids too quickly, can lead to fluid overload, especially in older adults or clients with heart failure, potentially causing pulmonary edema.
• Electrolyte imbalances can occur if too much hypotonic or hypertonic fluid is given, shifting electrolytes dangerously.

Blood Transfusions

• Blood transfusions are used for blood loss, anemia, or clotting issues, involving various blood components.
• Packed Red Blood Cells (PRBCs) restore oxygen-carrying capacity.
• Platelets help stop bleeding.
• Plasma replaces volume and clotting factors.

Complications of Blood Transfusions

• Transfusion reactions can occur, presenting as fever, chills, or back pain.
• Repeated transfusions may lead to iron overload.
• There is a risk of infection if blood is not screened properly.

Nursing Role in Fluid or Electrolyte Imbalance

• Nurses should monitor labs (BMP, CMP, ABGs).
• Assess signs and symptoms such as edema, muscle cramps, irregular heartbeat, confusion, dry mucosa, and hypotension.
• Administer prescribed fluids or electrolytes (e.g., potassium supplements, sodium restrictions).
• They should also educate clients about dietary changes (low sodium, high potassium foods).
• Accurate documentation of intake and output is essential.

Regulating Acid-Base Balance

• The body regulates pH between 7.35 and 7.45 using three systems: buffer systems, the respiratory system, and the renal system.
• Buffer systems use bicarbonate (HCO3-) to bind or release hydrogen ions, adjusting pH.
• The respiratory system removes CO2 (acid) through the lungs; faster breathing removes more acid.
• The renal system excretes or retains hydrogen ions and bicarbonate to balance pH. It is slower but more powerful.

Nursing Role in Acid-Base Imbalance

• Nurses should assess for symptoms such as confusion, deep or shallow breathing, fatigue, and cardiac arrhythmias.
• Review ABG results for pH, PaCO2, and HCO3 levels.
• Administer ordered treatments like oxygen, IV fluids, and sodium bicarbonate.
• Continuously monitor responses and lab results.
• Educate clients on prevention, including managing diabetes and avoiding antacid overuse.

Physiology Related to Fluid and Electrolytes

• Electrolytes are minerals like sodium, potassium, calcium, and magnesium that carry electrical charges and are found in blood, inside cells, and fluids between cells.
• Electrolytes help move nutrients into cells, remove waste, keep the heart beating, help muscles work, and support brain and nerve function.
• Water helps move electrolytes, maintain blood pressure, and regulate temperature.

Important Tests for Fluid and Electrolytes

• BMP and CMP are blood tests to check electrolyte levels.
• Serum Osmolality indicates blood concentration, with a normal range of 285-295 mOsm/kg.
• Urine Osmolality assesses hydration and kidney function, with a normal range of 50-1,200 mOsm/kg.

Water Compartments

• Intracellular: Inside cells, holding ~67% of water
• Extracellular: Outside cells
  • Interstitial: Space between cells, holding ~25% of water
  • Intravascular: In blood, holding ~8% of water

How Water Balance is Achieved

• Water moves via osmosis from areas of low solute concentration to areas of high solute concentration.
• Hormones such as ADH and the thirst mechanism in the hypothalamus help balance water levels.
• The kidneys reabsorb needed water and electrolytes and remove waste.

Causes of Fluid and Electrolyte Imbalances

• Fluid loss from diarrhea, vomiting, sweating, or bleeding
• Overhydration from excessive water or IV fluids
• Kidney, liver, or heart disease affecting fluid handling
• Medications like diuretics or steroids
• Inappropriate IV fluids or feeding solutions

Normal Electrolyte Ranges (Adults)

• Potassium (K+): 3.5–5 mEq/L
• Sodium (Na+): 136–145 mEq/L
• Calcium (Ca2+): 9–10.5 mg/dL
• Magnesium (Mg2+): 1.3-2.1 mEq/L

Nursing Considerations for Imbalances

• Electrolyte imbalances can affect muscle function, heart rhythm, and cognitive processes.
• Nurses must review lab values, recognize changes, and alert providers.

Potassium Imbalances (Hypokalemia & Hyperkalemia)

• Potassium (K+) is vital for muscle and nerve function, especially heart rhythm, with normal blood levels at 3.5 to 5 mEq/L.

Hypokalemia

• Low potassium (K+ < 3.5 mEq/L) causes by diuretics, vomiting, diarrhea, poor potassium intake, alcohol abuse, kidney disease, and insulin treatment.
• Symptoms: Muscle weakness, cramps, constipation, irregular heartbeats, and in severe cases, paralysis or cardiac arrest.
• Nursing: Report lab findings <3.5 mEq/L, monitor ECG, administer oral or IV potassium as ordered and offer high potassium foods

Hyperkalemia

• High potassium (K+ > 5.0 mEq/L) can result from kidney failure, high potassium intake, potassium-sparing diuretics, ACE inhibitors, NSAIDs, or tissue damage.
• Symptoms include fatigue, weakness, irregular heartbeat, and in severe cases, muscle paralysis or heart stoppage.
• Nursing: Report levels >5.0 mEq/L, monitor heart rhythm, and use insulin with glucose, diuretics, or resin binders, while advising against high-K+ foods and salt substitutes.

Sodium Imbalances (Hyponatremia & Hypernatremia)

• Sodium (Na+) helps with muscle contraction, nerve signals, fluid balance, and blood pressure regulation, primarily found outside the cells, having a normal range of 136-145 mEq/L.

Hyponatremia

• Low sodium (Na+ < 136 mEq/L) is due to drinking too much water, caused by diuretics, heart failure, liver or kidney problems, vomiting, diarrhea, or SIADH.
• Symptoms are nausea, headache, lethargy, confusion, seizures, muscle cramps, and severe cerebral edema.
• Nursing: Monitor CNS, check serum sodium and urine sodium, administer IV fluids if severe, teach fluid restrictions, and caution against overhydration during physical activity.

Hypernatremia

• High sodium (Na+ > 145 mEq/L) arises from water loss (fever, diarrhea, sweating, diabetes insipidus), too little water intake, tube feedings without water, or corticosteroids.
• Symptoms: Thirst, dry mouth, confusion, restlessness, muscle twitching, and severe seizures or coma.
• Nursing: Track sodium levels, neuro changes, provide PO/IV fluids, and educate about fluid intake.

Calcium Imbalances (Hypocalcemia & Hypercalcemia)

• Calcium (Ca2+) is crucial for strong bones and teeth, muscle movement, nerve signals, blood clotting, and heart function, with 99% stored in bones and normal serum levels between 9–10.5 mg/dL.

Hypocalcemia

• Low calcium (Ca2+ < 9 mg/dL) results from inadequate vitamin D, hypoparathyroidism, kidney disease, diuretics, multiple transfusions, or electrolyte imbalances.
• Symptoms exhibited are tingling around mouth, muscle spasms, seizures, a positive Chvostek's sign (cheek twitch), and a positive Trousseau's sign (hand spasm with BP cuff).
• Nursing: Check serum an urine calcium levels and Chvostek's / Trosseaus's signs and administer prescribed calcium plus advise eating a high calcium diet along side vitamin D diet.

Hypercalcemia

• High calcium (Ca2+ > 10.5 mg/dL) causes can be cancer, hyperparathyroidism, excess vitamin D or calcium supplements, prolonged bed rest, or thiazide diuretics.
• Symptoms include fatigue, weakness, constipation, abdominal pain, nausea, vomiting, confusion, and heart arrhythmias.
• Remember as "groans, bones, stones, and moans".
• Nursing: Monitor serum and kidney labs, administer antiemetics diuretics and fluids, and encouarge exercise/daily activity.

Magnesium Imbalances (Hypomagnesemia & Hypermagnesemia)

• Magnesium (Mg2+) regulates nerve and muscle function, blood sugar, blood pressure, protein synthesis, bone health, and heart rhythm, with 50-60% stored in bones with normal levels being 1.3-2.1 mEq/L.

Hypomagnesemia

• Low magnesium (Mg2+ < 1.3 mEq/L) stems from poor diet, alcoholism, GI disorders, diuretics, diabetes, or prolonged vomiting.
• Symptoms exhibited are muscle cramps, tremors, tingling, seizures, Chvostek's and Trousseau signs, irregular heartbeat, and personality changes.
• Nursing: Check Mg with potassium, and calcium. Provide oral/IV magnesium alongside a magnesium rich diet such as spinach!

Hypermagnesemia

• High magnesium (Mg2+ > 2.1 mEq/L) can be a result of kidney failure, overuse of antacids/laxatives, hypothyroidism, or bowel disorders.
• Results in: Nausea, flushing, dizziness, muscle weakness.
• Nursing: Administer calcium gluconate or diuretic medicine based on function of kidneys plus monitor heart and reflexes.

Fluid Imbalances

• Fluid balance needs a certain amount of water both outside/inside cells, if this balance is not met the body can have serious issues
• Dehydration = Loss of water AND Sodium

Dehydration (Fluid Imbalance)

• Loss of water leads to more sodium
• Caused by lack of drinking, fever or diarrhea, diabetes etc.
• Results in thirst, confusion and lethargy and less or dark urine. Very bad cases can result in shock
• Nursing: Intake and output and administering fluids either PO/IV

Hypovolemia (Fluid Imbalance)

• Loss of fluids and electrolyte (ESPECIALLY sodium)
• results as a loss to blood volume
• Cause is bleeding, surgery, or diuretics
• Symptoms are mucous membrane dryness (dry) and decreased pee
• Severe cases could result in shock as well

Hyperovolemia (Fluid Imbalance)

• High extra-cellular fluids
• Defined as more water and sodium outside of the cells
• Results of Kidney Failure, Liver Failure or Sodium Intake with Medications
• Symptoms of more fluids = Edema, High Pulse/BP, and Jugular Vin Distension

Age-Related - Fluid

• Older Adults more likely to be dehydrated due to reduced kidney functions
• Infants have more water!
• Rehydration is best to do orally through pedialyte
• IV rehydration is for serve dehydration

IV Therapy - Fluid

• Helps to deliver medication, etc and when PO isnt a option
• Isotonic have no Fluid Change, 0.9% (normal Saline), Lactated Ringers (LR)
• Hypertonic, greater concentration, causes cells to leave, for edema
• D5% NS

4 Sections Acid-Base Balance

• Understand 7.35 = 7.45 = ph Blood
• lungs, kidney and buffers
• Assesses ABG, vital signs
• 4 types of Disturbance
• 1 is respiratory
• 2 is metabolic

Respiratory Disturbance

• Too much C02

Metabolic Disturbance

• Not enough Bicarbonate

Review for Lungs

• C02

Kidney Reminder

• Metabolic!