• Fluid, Electrolyte, Acid/Base Balances are necessary to maintain health and function in all body systems
• The balance is maintained by:
• Distribution of fluids in the body
• Intake and Output of fluids and electrolytes
• Acid/Base regulation by the renal, vascular, and pulmonary organs

• Fluid makes up approximately 60% of an average adult's body weight
• Water contains
• Gases
• Solutes
• Electrolytes
• Non-electrolytes
• Body fluids perform several important functions
• When the body is in a healthy state, fluid losses are equivalent to fluid intake

• Intracellular (ICF)
• Within the cells
• Extracellular (ECF)
• Intravascular
• Interstitial
• Transcellular
• Third Spacing: ascites, pleural effusion (fluid is in the wrong space)

• Osmosis
• Diffusion
• Filtration
• Active Transport
• Hydrostatic Pressure (the force created by fluid within a closed system)
• Osmotic Pressure (the power of a solution to draw water)

• Minerals that are present in all body fluids
• When dissolved in water, electrolytes separate into ions and conduct either a positive or negative electrical current
• Responsible for regulation of fluid balance, skeletal strength, catalysts in nerve responses and muscle contraction, and acid/base balance
• Electrolytes are distributed between the ICF and ECF
• Can be measured in serum (can't measure in tissues)
• (Electrolyte imbalances cause illness, Illnesses cause electrolyte imbalances)

Osmolarity of serum and IV solutions is primarily determined by the amount of Na⁺ (Sodium) 

• Isotonic Solutions
• The same solute concentration as blood
• Normal saline (0.9%) is the IV solution with the same amount of saline as serum
• Hypotonic Solutions
• Lower solute concentration than blood (½NS or D5W)
• Hypertonic Solutions
• Higher solute concentration than blood

• Kidneys
• Hormones
• Antidiuretic Hormone (ADH) (retain fluid)
• Aldosterone (retain sodium)
• Renin-Angiotensin System
• ACE Inhibitors (Lisinopril)
• Thirst Mechanisms
• Fluid Intake and Output

• Subjective Data concerns past medical history of cardiovascular, liver, or kidney disease; hormonal imbalances; medications
• Food and Fluid Intake
• Reports of thirst; color, amount and frequency of urine; weight gain; excessive perspiration; swelling; dyspnea; n/v/d; confusion; disorientation

• Daily Weights (1 gm = 1 mL)
• Intake & Output (I&O)
• Laboratory & Diagnostic Values
• BUN, Hematocrit, Sodium, Creatinine
• Serum Osmolarity (<300 mOsm/kg)
• Urine Specific Gravity (1.001 - 1.029)
• Brain Natriuretic Peptide (BNP) Test - CHF
• Chest or Abdominal X-Ray, CAT Scan

• Recommendation is an intake of 2700 mL per day for women and 3700 mL per day for men
• 80% from drinking and 20% from food and cellular metabolism of food
• Sources
• Oral (PO)
• Enteral
• Parenteral
• Irrigations

• Sensible
• Urine
• Vomitus
• Perspiration
• Feces
• Blood
• Drains
• Insensible
• Wounds, Burns, Breaks in Skin
• Exhalation

• Skin Moisture or Turgor
• Edema
• Mucous Membranes
• Tongue
• Vital Signs
• Capillary Refill
• Jugular Vein
• Breath Sounds
• Level of Consciousness

• May be ordered q shift, q hour, Strict I&O
• Evaluate trends over 24-48 hours unless otherwise indicated
• Measure in mL using a graduated container and hold at eye level
• Enlist patient's help in keeping track if they are able
• Call MD if output <30 mL/h or <240 mL in an 8 hour period
• You may delegate recording I&O to unlicensed personnel

• Oral
• Beverages
• Soups
• Anything that melts into liquid at room temperature (ice cream, jello, sherbet, ice, milk)
• Liquid medications and fluids used to take pills
• Parenteral
• Enteral
• Rectal and Bladder instillation/irrigation

• Measure urine, watery stool, vomitus, wound drainage, surgical drains, NG tubes, chest tubes, and any fluid aspirated from a body cavity
• Teach patient to keep toilet paper out of the urine
• If irrigating NG tube or the bladder, measure the amount instilled and subtract it from the total output
• Weigh Attends and saturated dressing if needed
• Insensible losses: noted saturated linens, gowns, excessive perspiration, burns, rapid breathing

• Hypovolemia
• Loss of blood volume
• Dehydration
• Insufficient intake of fluids
• Excessive fluid loss
• Fluid shifts

• Dry skin, mucous membranes, sunken eyeballs
• Non-elastic Skin Turgor/Flattened Neck Veins
• Decreased Urine Output
• Drop in Blood Pressure/Weak Rapid Pulse
• Rise in Temperature
• Increased Hematocrit/Increased BUN
• Rise in Urine Specific Gravity
• Confusion, Weakness, Fatigue

• Monitor weight and VS, including temperature
• I&O, laboratory findings
• Encourage PO intake, administer intravenous fluids, blood products, enteral feedings
• Provide mouth care
• Implement measure to prevent skin breakdown
• Safety measures (i.e. assist out of bed)

• Typically people drink more during the day and early evening when they are most active
• Offer a variety of fluids both in flavor, texture, and temperature. Remind patient to drink every time you are at the bedside. Keep drink within reach.
• Set goals with patient and have them record progress

• Hypervolemia/Overhydration
• Disease affecting kidney or liver function, or poor pumping action of the heart
• Administering intravenous solutions too rapidly
• Excessive sodium intake (not to be confused with hypernatremia)
• Overzealous plain water intake without replacing electrolytes (athletes drink water instead of Gatorade)

• Elevated blood pressure
• Bounding pulse, distended neck veins
• Pale, cool skin
• Edema, Ascites
• Crackles, Dyspnea
• Weight Gain
• Confusion and Weakness
• Decreased BUN, Hematocrit, Electrolytes, and Urine Specific Gravity

• Semi-Fowlers
• Administer diuretics as ordered
• Restrict fluid intake as ordered
• Measures to prevent skin breakdown
• Monitor weight and VS
• Assess breath sounds
• I&O, laboratory findings

• Educate as to reason to restriction and how much
• Provide liquids in small containers
• Avoid liquids with meals
• Include IV fluids in daily intake
• Kitchen provides a certain amount and rest is at bedside
• Avoid salty foods
• Give Ice Chips
• Provide oral care

• Excessive Interstitial Fluid
• Most apparent around the eyes or dependent tissues
• Several mechanisms
• Pitting edema
• Pitting (1+, 2+, 3+, 4+)
• Non-pitting (mild, moderate, severe)

• Potassium wasting diuretics: Lasix (furosemide): block Cl- thus Na+ resorption but secretes K+ (watch for hypokalemia)
• K+ sparing diuretics: Aldactone (spironolactone): blocks Aldosterone so Na+ and water go out/K+ stays in (watch for hyperkalemia)
• Thiazides (hydrochlorothiazide): causes fluid loss and relaxation of vessels. Used in combination with HTN medications (sodium and potassium loss)
• Osmotic diuretics: Mannitol

• Cations
• Potassium - K⁺
• Magnesium - Mg⁺⁺
• Sodium - Na⁺
• Calcium - Ca⁺⁺
• Anions
• Phosphate - PO₄
• Chloride - Cl^-
• Bicarbonate - HCO₃

• Most abundant ECF cation
• Regulates fluid volume
• Helps maintain blood volume
• Activates nerve/muscle cells
• Regulated by dietary intake, kidneys, hormones
• Normal ECF concentration 135 - 145 mEq/L

• Lethargy, Weakness, Confusion
• Nausea and Vomiting
• Muscle cramps, twitching, seizures
• Serum Sodium < 135 mEq/L

• Thirst
• Dry, Sticky Mucous Membranes
• Fever
• Agitation and Irritability
• Hallucinations and Convulsions
• Serum Sodium > 145 mEq/L

• Most abundant ICF cation
• Regulates normal cardiac rhythm
• Transmission and conduction of nerve impulses
• Assists with Acid/Base Balance
• Normal serum concentration 3.5 - 5.0 mEq/L
• Regulated by dietary intake and renal excretion

• Muscle weakness, paresthesia
• Anorexia, N/V
• Decreased bowel motility (constipation)
• EKG Changes
• Serum Potassium < 3.5 mEq/L

• Gastrointestinal hyperactivity, diarrhea
• Cardiac dysrythmias or arrest
• Muscle weakness, absence of reflexes
• Serum K+ > 5 mEq/L

• Most abundant electrolyte in the body
• Normal serum calcium: 8.9 - 10.1 mg/dL
• Responsible for teeth and bone formation, blood clotting, muscle contraction, transmission of nerve impulses and cardiac automaticity

• Numbness and tingling of fingers and around mouth
• Muscle tremors and cramps progressing to tetany, laryngeal spasms, and convulsions
• Positive Trousseau's and Chvostek signs
• Diarrhea
• Cardiac Dysrhythmias
• Pathological fractures/Osteoporosis
• Serum calcium < 8.5 mg/dL

• Lethargy, weakness
• Depressed deep-tendon reflexes
• Constipation
• Decreased LOC
• Bradycardia
• Low back pain from kidney stones
• Serum calcium >10.5 mg/dL 

• Acidity or alkalinity is determined by hydrogen ion concentration (H+)
• The amount of acid or base in a solution is measured in pH
• Normal pH is 7.35 - 7.45
• Acidosis <7.35: too much acid
• Alkalosis >7.45: too much base
• Three mechanisms maintain acid/base balance:
• Chemical buffers
• Respiratory Regulation
• Renal Regulation

• A buffer prevents major changes by releasing or accepting hydrogen ions
• Carbonic acid - Sodium Bicarbonate System
• Phosphate buffer
• Protein buffer

• The lungs help regulate acid-base balance by eliminating or retaining carbon dioxide (CO2), a potential acid
• The lungs regulate acid-base balance by altering the rate and depth of respirations
• The response of the respiratory to changes in pH is rapid, occuring within minutes
• Respiratory disorders can cause acidosis or alkalosis

• The kidneys selectively excrete or conserve bicarbonate ions (HCO₃^-) in order to neutralize acids or bases in body fluids
• Slower to respond to changes, requiring hours to days, but response is more permanent

Key diagnostic test for acid/base balance

• Serum pH level (7.35 - 7.45)
• Serum pCO₂ (35 mmHg - 45 mmHg)
• pCO₂ = partial pressure of carbon dioxide in blood
• Serum HCO₃ (22 mmHg - 26 mmHg)
• Bicarbonate level in blood
• Serum O₂ (85-95 mmHg)
• pO₂ = partial pressure of oxygen in blood

• Respiratory Acidosis
• Respiratory Alkalosis
• Metabolic Acidosis
• Metabolic Alkalosis

• Diagnostic ABG
• pH < 7.35
• pCO2 > 45 mmHg
• HCO3 = 26 mEq/L

(COPD, pneumonia - retain CO2)

• Diagnostic ABG
• pH > 7.45
• pCO₂ < 35 mmHg
• HCO₃ = 22 mEq/L

(hyperventilation, blowing off too much CO₂)

• ABGs
• pH < 7.35
• pCO₂ = 35 mmHg
• HCO₃ < 22 mEq/L

(diarrhea can cause to lose base)

• ABGs
• pH > 7.45
• pCO₂ = 35 mmHg
• HCO₃ > 26 mEq/L

(too much base possible from too much antacid, or vomiting - lose acid)

• Give or restrict fluids as appropriate
• Maintain accurate intake and output record
• Monitor respiratory, GI and cardiac function. Weigh daily and monitor trends
• Obtain laboratory specimens (CMP, CBC, Urine, Mg++, BNP)
• Administer diuretics as ordered
• Administer mineral replacements as ordered