Fluids and Electrolytes

Understanding Fluids

• Fluids contain water and dissolved substances like glucose, mineral salts, and proteins.
• Fluids surround all cells and are inside cells.
• Fluids help maintain the health and function of bodily systems.
• Fluids contain electrolytes like Sodium (Na+) and Potassium (K+).
• Fluid characteristics include volume, osmolality, composition, and degree of acidity (pH).

Fluid Location

• Extracellular Fluid (ECF) makes up 1/3 of total body water.
  • Intravascular fluid is the liquid part of blood, also known as plasma.
  • Interstitial fluid is located between cells and outside of blood vessels.
  • Transcellular fluid includes cerebrospinal, pleural, peritoneal, and synovial fluids.
• Intracellular Fluid (ICF) accounts for 2/3 of total body water.

Fluid Movement - Osmosis

• Osmosis involves the movement of water against a concentration gradient.
• Water moves from an area of lower particle concentration to an area of higher particle concentration.

Fluid Movement - Filtration

• Filtration is the movement of fluid in and out of capillaries, specifically between vascular and interstitial compartments.
• It is influenced by four forces: Hydrostatic pressure in the capillary, hydrostatic pressure in the interstitium, osmotic pressure in the capillary, and osmotic pressure in the interstitium.

Electrolytes

• Electrolytes are substances that separate into ions when placed in water.
• Electrolytes move through active transport and diffusion
• Cations are positively charged ions, including sodium (Na+), potassium (K+), calcium (Ca2+), and magnesium (Mg2+).
• Anions are negatively charged ions, including bicarbonate (HCO3-), chloride (Cl-), and phosphate (PO43-).

Fluid Balance

• Fluid intake comes from drinking and foods, influenced by thirst and habit.
• Fluid distribution involves movement of fluid among compartments.
• Fluid output occurs through the skin, lungs, gastrointestinal tract, and kidneys.

Osmolality

• Osmolality is the number of particles per kilogram of water.
• Isotonic solutions have the same tonicity as normal blood.
• Hypotonic solutions are more dilute than blood.
• Hypertonic solutions are more concentrated than blood.

Fluid Imbalances

• Factors influencing fluid balance: age, medications, acute illness, surgery, burns, respiratory disorders, head injury, chronic illnesses, environmental factors, and diet.

Types of Fluid Imbalances

• Volume imbalances include isotonic imbalances in fluid volumes:
  • Hypovolemia is decreased blood volume.
  • Hypervolemia is increased blood volume.
• Osmolality imbalances involve sodium (Na+):
  • Hypertonic imbalances with hypernatremia from losing water or gaining sodium.
  • Hypotonic imbalances with hyponatremia from gaining water or losing sodium.

Hypovolemia

• Hypovolemia is volume fluid deficit

Hypovolemia Clinical Manifestations

• Weigh loss (overnight)
• Postural hypotension
• Tachycardia
• Dry mucous membranes
• Poor skin turgor
• Flat neck veins
• Dark yellow urine
• Restlessness
• Confusion
• Hypotension
• Oliguria (output <30 mL/hour)
• Cold and clammy skin
• Hypovolemic shock

Hypovolemia Treatment and Management

• Oral fluid replacement avoiding sugary beverages and caffeine.
• Parenteral replacements using isotonic fluids like D5W, 0.9%NaCl, NS, or LR.
• Assessment and monitoring includes mental status, vital signs, input and output, daily weights, controlling nausea/vomiting/diarrhea, and fever management.

Hypervolemia

• Hypervolemia refers to fluid volume excess.

Hypervolemia Cinical Manifestations

• Sudden weight gain (overnight)
• Edema in dependent areas
• Full neck veins when upright or semi-upright
• Crackles in lungs
• Confusion
• Pulmonary edema
• Anxious appearance with labored breathing
• Crackles on auscultation
• Productive cough

Hypervolemia Treatment and Management

• Restrict fluid intake and sodium.
• Promote excretion with diuretics and dialysis.
• Assessment and monitoring includes respiratory status (crackles in lungs, pulse oximetry), acute pulmonary edema, input and output, daily weights, and diet management.

Electrolyte Normal Ranges

• Sodium (Na+): 135-145 mEq/L
• Potassium (K+): 3.5 – 5.0 mEq/L
• Calcium (Ca 2+): 8.6 – 10.2 mEq/L
• Magnesium (Mg 2+): 1.5 – 2.5 mEq/L

Sodium (Na+)

• Sodium (Na+) is the most abundant cation, making up 90% of electrolyte fluid.
• The normal range is 135-145 mEq/L.
• Sodium functions include:
  • Maintains osmotic pressure.
  • Controls blood volume.
  • Works with sensors in the heart, blood vessels, and kidneys.
  • Aids in acid-base balance.
  • Transmits nerve impulses.
  • Facilitates muscle contractions.

Hypernatremia Imbalance

• High Concentration of Sodium
• Loses more water than sodium
  • Gaining more sodium than water

Hypernatremia Treatment and Monitoring

• Treat the underlying cause of hypernatremia.
• Involves sodium restriction and oral water intake.
• Administer hypotonic solutions (0.45% NaCl) and isotonic solutions (D5W) via IV therapy.
• Medications include diuretics and Desmopressin (DDAVP) for diabetes insipidus to promote excretion.
• Monitor electrolytes, input and output, daily weights, and neurological status to prevent cerebral edema.
• Prevent seizure related injuries, and note patient's thirst level.

Hyponatremia Imbalance

• Low concentration of sodium
• Losing more sodium than water
  • Gaining more water than sodium

Hyponatremia Treatment and Management

• Sodium administration: oral. NG, or IV
• Water restriction
• Hypertonic solution IV
  • 2% or 3% NaCl (Central line) Medications that are IV Conivaptan (Vaprisol)-- Vasopressor receptor antagonist
• Assessment and Monitoring
• Electrolytes
• Mental Status
• Vital signs
• Input and Output, daily weights
• Manage source of loss and manage
  • Medications
  • Prevent seizure related injuries and nurse station closer

Potassium (K+)

• Potassium (K+) is mostly inside cells
• It is essential for the function of exclitable tissues
• Normal Range 3.5-5.0 mEq/L Potassium (K+) functions include:
  • Osmotic Pressure
  • Acid Base balance
  • Nerve conduction
  • Muscle Function Controls the rate and force of heart contractility and cardiac output.

Hyperkalemia

• Hypokalemia- to little in blood
• Potassium movement into cells/Decreases in Blood

Hyperkalemia Treatment and Management

• Cardiac and Electrolyte Monitoring
• Increase K+ Restrictions (oral or parenteral)
  • Avoid - Fruits (bananas), potatoes, molasses, and brazil nuts
• Increase Elimination
  • Diuretics/Kayexalate
• Force K+ from ECF to ICF (Na/K pump)
• Insulin/Sodium Bicarbonate
• Intravenous Calcium Gluconate

Hypokalemia

• Decreased in Blood
• Increased Potassium Excretion

Hypokalemia Treatment and Management

• Cardiac and electrolytes monitoring
• Oral or IV K+ replacement
• K+ Rich Foods
• NEVER BOLUS POTASSIUM

Calcium

• Major cation form for structure of bones and teeth
• Normal Range
  • 8.6-10.2 mg/dL
  • 4.5-5.5 mEq/L (ionized level)
• Storage and Movement
• 99% of the skeleton and teeth
• 50% ionized (active form in the blood)
• 50% protein bound
• ECF>ICF

Hypercalcemia Treatment and Management

• Excretion of Ca 2+
  • Loop Diuretics
• IV Therapy
  • Isotonic Therapy LR, NS
• Restricting Ca 2+
• Avoid Dari, Canned fish with bones, broccoli, oranges, avoid vitamin D
• Mobilization and Exercise
• Calcitonin
• Bisphosphonate

Hypocalcemia Treatment and Management

• Cardiac and Electrolyte Monitor
• Monitor for Bleeding
• Oral Replacements
• Calcium Gluconate (IV)
• Calcium Chloride (IV)
• Calcium Carbonate (Oral)
• Increase Calcium Rich Foods
• Dairy, Broccoli, Vitamin D intake, canned fish with bones
• Treatment of Pain and Anxiety
  • Prevent respiratory alkalosis from hyperventilation

Magnesium (MG)

• Influence Neuromuscular Junctions
• Energy Production and ATP
• Aids in Regulation of NA+, K+, Ca++
• 50-60% stored in Muscle and Bone
• 30 in Cells
• Regulated by Intestines and Kidneys
• Normal Range 1.5-2.5 mEq/L

Hypermagnesemia Treatment and Management

• Cardiac and electrolyte monitoring
• Increase Mg 2+ Medications and Foods
• Dark Leafy Vegetables, and whole grains
• Increase Renal Excretions
• Dialysis and Diuretics' Admit the patient Calcium Gluconate (IV)

Hypomagnesemia Treatment and Management

• Cardiac and electrolytes monitoring
• Increase Mg + rich foods
• Administer oral or IV Mg 2+
  • Administer Mg 2+ before K+ replacements (if both hyplokalemia and hypomagnesemia), think N/K pump .
• Post K+ Follows MG 2+