Fluid, Electrolyte, and Acid-Base Balance

Characteristics of body fluids

Fluid amount (volume), concentration (osmolality), composition (electrolyte concentration), degree of acidity (pH)

Normal sodium (Na+) values

136-145 mEq/L (136-145 mmol/L)

Normal potassium (K+) values

3.5-5.0 mEq/L (3.5-5.0 mmol/L)

Normal chloride (Cl-) values

98-106 mEq/L (98-106 mmol/L)

Normal total CO2 values

22-30 mEq/L (22-30 mmol/L)

Normal arterial bicarbonate (HCO3-) values

21-28 mEq/L (21-28 mmol/L)

Normal venous bicarbonate (HCO3-) values

24-30 mEq/L (24-30 mmol/L)

Normal total calcium (Ca2+) values

9.0-10.5 mg/dL (2.25-2.6 mmol/L)

Normal magnesium (Mg2+) values

1.3-2.1 mEq/L (0.65-1.05 mmol/L)

Normal phosphate values

3.0-4.5 mg/dL (0.97-1.45 mmol/L)

Normal anion gap values

6+/ -4 mEq/L (6+/ -4 mmol/L)

Normal pH values

7.35-7.45

Normal PaCO2 values

35-45 mmHg (4.7-6.0 kPa)

Normal PaO2 values

80-100 mmHg (10.7-13.3 kPa)

Normal O2 saturation values

95%-100%

Movement of water and electrolytes

Active transport, diffusion, osmosis, filtration

Fluid balance

Fluid intake, distribution, output

Thirst mechanism

Increased plasma osmolality, decreased plasma volume, angiotensin I and III, psychological factors, dry pharyngeal mucous membranes

Fluid imbalances

Extracellular fluid volume imbalances, osmolality imbalances, clinical dehydration

Extracellular fluid volume imbalances

Hypovolemia, hypervolemia

Osmolality imbalances

Hypernatremia, hyponatremia

Electrolyte imbalances

Potassium, calcium, magnesium imbalances

Low potassium diet

Fruits, potatoes, molasses, brazil nuts, instant coffee

Low calcium diet

Dairy products, canned fish with bones, broccoli, oranges

Low magnesium diet

Dark green leafy vegetables, whole grains

Low phosphate diet

Milk, processed foods

Acid-base balance

Acid production, buffering, excretion

Acid-base imbalances

Respiratory acidosis, respiratory alkalosis, metabolic acidosis, metabolic alkalosis

Respiratory acidosis

Elevated carbon dioxide levels lead to increased acidity in blood

Respiratory alkalosis

Decreased carbon dioxide levels result in reduced acidity in blood

Metabolic acidosis

Decreased bicarbonate levels or increased acid production, leading to lower blood pH

Metabolic alkalosis

Increased bicarbonate levels or decreased acid production, resulting in higher blood pH

Nursing knowledge base

Formulate assessment questions to determine pt risk factors for fluid, electrolyte, and acid-base imbalances, assess for s/s of imbalances, implement nursing and collaborative interventions to maintain/restore fluid and electrolyte and acid-base balance

Nursing history

Age, environment, dietary intake, lifestyle, medications

Assessment

Medical history, physical assessment, lab values

Medical history assessment

Recent surgery, GI output, acute illness or trauma (respiratory disorders, burns, trauma), chronic illness (cancer, heart failure, oliguric renal disease)

Physical assessment

Daily weights and fluid intake and output measurement

Nursing diagnosis

Fluid imbalance, dehydration, electrolyte imbalance, acid base imbalance, lack of knowledge of fluid regimen

Implementation

Health promotion, acute care

Health promotion

Patient education

Acute care implementation

Enteral replacement of fluids, restriction of fluids, parenteral replacement of fluids and electrolytes, vascular access devices, inserting IV line, regulating infusion flow rate, changing IV fluid containers, tubing and dressings, helping pts protect IV integrity

Complications of IV therapy

Circulatory overload of IV solution, infiltration, extravasation, phlebitis, local infection, air embolism, bleeding at venipuncture site

Restorative care

Home IV therapy, nutritional support, medication safety