Fluid and Electrolyte Regulation in Health and Disease

Electrolytes

Minerals in the body that conduct electricity.

Basic metabolic panel (BMP)

A blood test that provides information on electrolytes and fluid balance, renal function, and glucose levels.

Complete metabolic panel (CMP)

Everything in a BMP + protein and liver function.

Serum Reference Range

285-295 mOsm/kg.

Urine Reference Range

50-1200 mOsm/kg.

Osmolality

A blood or urine test that can help monitor water and electrolyte balance.

Intracellular space

Space within a cell.

Extracellular space

Space outside the cell (interstitial + intravascular).

Interstitial space

Space outside of the cells.

Intravascular

Space within vasculature including chambers of the heart, arteries, and veins.

Osmosis

Movement of water across a semipermeable membrane.

Homeostatic mechanisms

Processes that help maintain stability in the body's internal environment.

Thirst response

Innate mechanism to promote water consumption.

Insensible fluid loss

Fluid loss that occurs without the person being aware, such as respiratory droplets and sweating.

Dehydration / Hypovolemia

A condition resulting from excessive fluid loss.

Overhydration / Hypervolemia

A condition resulting from excessive fluid intake.

Potassium (K+)

Electrolyte with a serum level reference range of 3.5 - 5.0 mEq/L.

Recommended dietary allowance (RDA) for Potassium

Adult Males: 3400 mg, Adult Females: 2600 mg.

Hypokalemia

Serum level <3.5 mEq/L, may present with fatigue, constipation, muscle weakness, and cardiac arrhythmias.

Critical lows for Hypokalemia

Critical lows: <3 mEq/L in adults; Severe life-threatening: <2.5 mEq/L.

Symptoms of Severe Hypokalemia

Respiratory paralysis/failure, paralytic ileus, hypotension, tetany, rhabdomyolysis.

Hypokalemia

A condition characterized by low potassium levels in the blood.

Hypokalemia: Treatment

Starts with identifying the underlying cause, which may include medications, diuretics, certain cardiac conditions, GI loss, metabolic alkalosis, decreased oral intake, excessive alcohol use, chronic kidney disease, diabetic ketoacidosis, excessive sweating, and folic acid deficiency.

Hypokalemia: Routine tests

CMP/BMP.

Hypokalemia: Replacement Options

Oral supplementation, IV supplementation, encourage high potassium foods, and changing to a potassium-sparing diuretic.

High Potassium Foods

cooked spinach, pumpkin seeds, black beans, cooked soybeans, cashews, dark chocolate, avocados, tofu, salmon, banana

IV Potassium - SAFETY

If given incorrectly, the patient can suffer GREAT HARM. Must be diluted in 100 - 1000ml compatible solution. Dose should not exceed 40 mEq/L unless treating severe hypokalemia. Rate of administration: 10-20 mEq/hour. Continuous ECG monitoring must be in place. Serum levels need to be rechecked periodically. NEVER EVER IV PUSH IV POTASSIUM.

Hyperkalemia

A condition characterized by high potassium levels in the blood.

Hyperkalemia: Serum Levels & Presentation

Serum level >5.0 mEq/L; critical high: >6 in adults. Mild hyperkalemia (5.1-5.9) is usually asymptomatic but increases the risk for life-threatening cardiac dysrhythmias, muscle weakness, and paralysis. Severe/life-threatening hyperkalemia (>7 mEq/L) can lead to paralysis, heart failure, and death.

Hyperkalemia: Treatment

Starts with identifying the underlying cause, which may include renal failure, dehydration, diabetes mellitus, medications, trauma, excess intake of this electrolyte, burns, transfusion of pRBCs, acidosis, and sepsis.

Hyperkalemia: Routine tests

CMP/BMP.

Hyperkalemia: Removing excess potassium

Hemodialysis if due to renal failure, loop and thiazide diuretics, resin medication: sodium polystyrene sulfonate, and insulin (must monitor glucose simultaneously).

Hyperkalemia: Stabilize the heart

Calcium gluconate or calcium chloride.

Sodium (Na+)

136-145 mEq/L; major electrolyte in ECF and present in most body fluids and secretions.

Functions of Sodium

Neurologic/neuromuscular function, fluid balance regulation, and maintaining blood pressure.

Sodium RDA

<2300 mg per day = approx. 1 teaspoon.

Hyponatremia

A condition characterized by low sodium levels in the blood.

Hyponatremia: Serum Levels & Presentation

Serum level <136 mEq/L; critical level: <120 mEq/L. Mild hyponatremia (130-134) presents as general unwellness; moderate (125-129) includes lethargy and confusion; severe (<125) can lead to muscle twitching, worsening LOC, seizures, coma, and possible death if untreated.

Hyponatremia: Treatment

Starts with identifying the underlying cause, which may include medications, chronic or severe vomiting or diarrhea, drinking excess amounts of water, excess alcohol intake, heart, kidney, and liver problems, and severe burns.

Hyponatremia: Raise sodium levels

Raise sodium levels slowly to avoid overcorrection and prevent further neurologic issues.

Hyponatremia: Routine tests

CMP/BMP and urinalysis - sodium level.

Hypernatremia

A condition characterized by high sodium levels in the blood.

Hypernatremia: Serum level

Serum level >145 mEq/L; critical level: >160 mEq/L.

Hypernatremia: Physiology

Body water loss > solute loss (leaving Na+ behind), too much sodium present in the body, or a combination of both.

Hypernatremia: Diagnosis

BMP / CMP; Plasma Osmolality >295 mOsm/kg

Hypernatremia: Treatment

Address the underlying cause; Initiate IVF replacement containing water and small amount of sodium; Possibly a low sodium diet; Decrease sodium levels slowly to reduce cerebral edema.

Hypernatremia: Patient Education

Avoiding high salt foods; Importance of adequate hydration.

Hypernatremia: Possible Causes

Loss of body water; Infants and older adults are at most risk; Medications; Gastroenteritis; Vomiting; Prolonged Suctioning; Burns; Excessive Sweating; CKD; DM; Impaired thirst response.

Calcium: Background

Most abundant mineral in the body; 99% found in bones and teeth; The rest: our blood and various other cells.

Calcium: Main Functions

Bone mineralization; Muscle contraction; Nerve transmission; Clotting time of blood; Hormone secretion; Normal heart function.

Calcium Absorption

Absorption into the body depends on adequate supply of Vitamin D.

RDA Vitamin D

600 IU (adults); 800 IU (elderly).

RDA Calcium

Depends on age; Young children; Teenagers; Older adults, especially women.

Calcium Excretion

Excreted through the kidneys which is signaled by the Parathyroid Gland.

Calcium: Serum Levels

Serum: 9-10.5 mg/dL; Ionized Calcium: 4.5-5.6 mg/dL.

Ionized Calcium

Represents active, unbound amounts of calcium in the blood; Generally estimated to be 50% of one's total calcium.

Hypocalcemia: Serum Levels

Serum: < 9 mg/dL; Ionized: <4.5 mg/dL; Critical values: Serum: < 6 mg/dL; Ionized: < 2.2 mg/dL.

Hypocalcemia: Multi-system Effects

Respiratory, Cardiac, Neuro, MSK, Integumentary.

Hypocalcemia: Presentation - CVD

Chest pain, dysrhythmias, heart failure, syncope.

Hypocalcemia: Presentation - Respiratory

Wheezing, larynx spasms, dysphagia, voice changes.

Hypocalcemia: Presentation - Neuro/MSK

Peripheral neuropathy, muscle cramping, spasms of back and lower extremities; Confusion, vision difficulties, depression, psychosis, dementia, lethargy, seizures, personality changes.

Hypocalcemia: Presentation - Integumentary

Course hair, alopecia, dry skin, itching; Dental problems.

Hypocalcemia: Treatment

Depends on severity; May self-resolve or may need supplementation, dietary changes, or injections of this electrolyte

Hypocalcemia: Patient Education

Instruct on high calcium foods; Limit calcium supplements to < 600 mg/day to promote absorption; Risks to health r/t hypocalcemia.

Hypercalcemia: Serum Levels

Serum: > 10.5 mg/dL; Ionized: >5.6 mg/dL; Critical levels: Serum: >13 mg/dL; Ionized: >7mg/dL.

Hypercalcemia: Complications

Kidney stones, weak bones, brain/heart functioning.

Hypercalcemia: Presentation - Mild

Asymptomatic.

Hypercalcemia: Presentation - Moderate

GI effects (constipation, abdominal pain, N/V, anorexia).

Hypercalcemia: Presentation - Severe

Neuro changes (confusion, behavioral change, increased thirst); polyuria; bone pain; muscle weakness.

Hypercalcemia

Can lead to arrhythmias, delirium, and renal failure.

Magnesium

Most common intracellular electrolyte; 50-60% in the bones; Reference range: 1.3-2.1 mEq/L; Intake: whole foods, supplements, medications; Output: urine/feces; Main Functions: Nerve/Muscle function, Maintain BP, Maintain serum glucose levels, Support bone/teeth health, Synthesize DNA and RNA; RDA: Adult male: 400-420 mg/day, Adult female: 310-320 mg/day.

Hypomagnesemia

Serum: <1.3 mEq/L; Critical low: <0.5 mEq/L; Clinical Signs: Moderate: Nausea, vomiting, decreased appetite, weakness; Severe: Neuro/MSK changes - muscle cramps, spasms, neuropathy, seizures, tetany, personality changes; Cardiac dysrhythmias (*along with other electrolyte disturbances).

Hypomagnesemia: Treatment

Address underlying cause: Medications (Thiazides, certain abx, PPIs), Decreased intake, Decreased absorption by intestines, Increased excretion by GI tract or kidneys, Excessive alcohol use, T2DM; Poor nutrition, Severe burns, Electrolyte imbalances; Therapies: PO magnesium replacement, IV magnesium replacement if needed, Increase magnesium via diet.

High-Alert Medications: IV Magnesium

Doses should be double-checked with another nurse; Concentration and rate must be validated; Risks: flushing, sweating, potentially respiratory depression if administered too quickly; Neuro risk: decrease LOC if concurrent with a CNS depressant; Monitor urine output!

Hypermagnesemia

Serum level: >2.1 mEq/L

Mildly high Hypermagnesemia

Levels: < 7 mgd/L; Symptoms: Nausea, dizziness, confusion, weakness

Moderately high Hypermagnesemia

Levels: 7-12 mgd/L; Symptoms: Increased neuro sxms: confusion, sleepiness, blurred vision, headaches, decreased reflexes, bladder paralysis, flushing, constipation

Severely high Hypermagnesemia

Levels: >12 mg/dL; Symptoms: Muscle flaccidity, paralysis, decreased RR, hypotension, bradycardia, dysrhythmias

Critical Hypermagnesemia

>15 mg/dL: Seizures, coma, cardiac arrest, and death

Hypermagnesemia Treatment

Address the underlying cause: Kidney disease (acute or chronic), Excessive intake, Decreased GI motility, Medication side effects (Opioids; Anticholinergics)

Hypermagnesemia Medications

Containing Mg: Laxatives, Antacids (Maalox, Mylanta), Lithium

Hypermagnesemia Therapies

Mild cases: Eliminating intake; Severe cases: IV calcium gluconate or calcium chloride, IV diuretics with IV saline, Hemodialysis (if needed)

Dehydration

A loss or lack of water intake without a concomitant loss of sodium

Dehydration Causes

Possible causes: vomiting, diarrhea, diaphoresis, polyuria, illness, fevers, insufficient of water/fluids, inadequate thirst response

Dehydration Presentation

Altered cognitive/neuro-MSK functions; thirst; dry mucosa; oliguria; tachycardia; hypotension; lactic acidosis; shock; coma/death

Dehydration Diagnosis

Lab tests: CMP / BMP = shows hypernatremia, Serum osmolality = elevated, Urine specific gravity = elevated

Dehydration Treatment

Restore water balance in the body; PO: if awake/alert/safe; IV: slow infusion of D5W

Hypovolemia

AKA "Fluid Volume Deficit" (FVD); Loss of BOTH fluid AND electrolytes

Hypovolemia Causes

Possible causes: blood loss, GI loss, severe burns, third spacing, excessive sweating, fever, medications trauma

Hypovolemia Early Signs

Thirst, dry mucous membranes, decreased skin turgor, decreased urine output

Hypovolemia Late Signs

Lethargy, muscle weakness, orthostatic hypotension, tachycardia, chest pain, tachypnea, palpitations, oliguria, hypotension

Hypovolemic Shock

>20% or 1/5 of total body fluid is lost; If not reversed: MULTIORGAN FAILURE

Hypovolemia Diagnosis

CMP/BMP: electrolyte imbalances, increased BUN and CR; CBC: Hct/Hb levels; Urine: highly concentrated with little sodium present

Hypovolemia Treatment

Depends on cause; Goal: control fluid/blood loss; Replace and restore circulation

Hypovolemia Nursing Interventions

Assess vital signs and changes in the physical exam; Monitor I&O; Notify provider of output <30 ml/hr

Hypervolemia

Body has too much water in the extracellular space, particularly the interstitial space

Hypervolemia Causes

Heart failure, Kidney failure, Nephrotic syndrome, Cirrhosis or end-stage liver disease, Pregnancy, Medications (Vasodilators, CCB, glitazones)

Hypervolemia Diagnosis

Physical Exam: weight, edema checks, full head-to-toe; Labs: Sodium levels can be low, high, or normal

Hypervolemia Treatment

Manage the root cause(s); Remove excess fluid; Diuretics; Fluid and sodium restrictions for intake

Gerontologic Considerations

Vulnerable to imbalances due to age-related changes: Less efficient cardiovascular and renal system, Decreased thirst sensation, Decline in total body fluid, Polypharmacy, Underlying health conditions