FLUID, ELECTROLYTE, AND ACID-BASE
IMBALANCES 2026
I. FLUID IMBALANCES
A. Fluid Volume Deficit (Hypovolemia/Dehydration)
Pathophysiology:
Loss of extracellular fluid (ECF) volume
Can be isotonic (water and electrolytes lost proportionally), hypertonic (more water lost), or hypotonic
(more electrolytes lost)
Common causes: hemorrhage, vomiting, diarrhea, excessive diuretic use, burns, fever, decreased fluid
intake
Clinical Manifestations:
Early signs: Thirst, restlessness, decreased urine output
Vital signs: Tachycardia, hypotension (orthostatic), tachypnea, decreased pulse pressure
Physical exam:
Poor skin turgor (tenting)
Dry mucous membranes
Sunken eyes
Flat neck veins
Delayed capillary refill (>3 seconds)
Weight loss (1 liter fluid = 1 kg weight loss)
Lab findings:
Increased BUN and creatinine
Increased hematocrit (hemoconcentration)
Increased serum osmolality
Increased urine specific gravity (>1.030)
,Nursing Interventions:
Assess: Monitor vital signs q1-4h, daily weights, I&O, skin turgor, mucous membranes
Fluid replacement:
Oral rehydration if mild and patient can tolerate
IV fluids for moderate to severe (typically isotonic solutions: 0.9% NaCl or Lactated Ringer's)
Monitor: Urine output (goal: ≥30 mL/hr), electrolyte levels, lung sounds (for fluid overload)
Safety: Fall precautions (orthostatic hypotension), seizure precautions (if severe electrolyte imbalance)
Treat underlying cause: Antiemetics for vomiting, antidiarrheals, control bleeding
Patient Education:
Drink 8-10 glasses of water daily (unless contraindicated)
Recognize early signs of dehydration
Increase fluids during illness, hot weather, exercise
Weigh daily at same time
B. Fluid Volume Excess (Hypervolemia)
Pathophysiology:
Excess ECF volume
Common causes: Heart failure, renal failure, cirrhosis, excessive IV fluid administration, corticosteroid
therapy
Clinical Manifestations:
Vital signs: Hypertension, bounding pulse, tachycardia, tachypnea
Physical exam:
Peripheral edema (dependent areas)
Jugular venous distension (JVD)
Crackles in lungs (pulmonary edema)
Ascites
Weight gain (rapid)
S3 heart sound
Lab findings:
Decreased hematocrit (hemodilution)
, Decreased serum osmolality
Decreased BUN
Hyponatremia (dilutional)
Nursing Interventions:
Assess: Daily weights (same time, same scale), I&O, lung sounds q2-4h, edema assessment
Fluid restriction: Typically 1000-1500 mL/day as ordered
Sodium restriction: 2-3 g/day or as ordered
Medications:
Diuretics (loop diuretics like furosemide)
Monitor potassium (diuretics cause K+ loss)
Positioning: Semi-Fowler's or High Fowler's for respiratory distress
Skin care: Edematous skin is fragile; turn q2h, protect from pressure
Monitor: Electrolytes, BUN, creatinine, oxygen saturation
Patient Education:
Daily weight monitoring (report gain of 2-3 lbs in 24 hrs or 5 lbs in week)
Fluid and sodium restriction compliance
Read food labels for sodium content
Elevate edematous extremities
Take diuretics in morning to avoid nocturia
II. ELECTROLYTE IMBALANCES
A. SODIUM (Na+) IMBALANCES
Normal range: 135-145 mEq/L
1. Hyponatremia (<135 mEq/L)
Pathophysiology:
Can be hypovolemic (loss of Na+), hypervolemic (dilutional), or euvolemic (SIADH)
Causes: Excessive water intake, diuretics, heart failure, SIADH, vomiting/diarrhea, adrenal insufficiency
Clinical Manifestations:
Mild (130-135): Nausea, headache, lethargy, muscle cramps
Moderate (120-130): Confusion, irritability, decreased reflexes
IMBALANCES 2026
I. FLUID IMBALANCES
A. Fluid Volume Deficit (Hypovolemia/Dehydration)
Pathophysiology:
Loss of extracellular fluid (ECF) volume
Can be isotonic (water and electrolytes lost proportionally), hypertonic (more water lost), or hypotonic
(more electrolytes lost)
Common causes: hemorrhage, vomiting, diarrhea, excessive diuretic use, burns, fever, decreased fluid
intake
Clinical Manifestations:
Early signs: Thirst, restlessness, decreased urine output
Vital signs: Tachycardia, hypotension (orthostatic), tachypnea, decreased pulse pressure
Physical exam:
Poor skin turgor (tenting)
Dry mucous membranes
Sunken eyes
Flat neck veins
Delayed capillary refill (>3 seconds)
Weight loss (1 liter fluid = 1 kg weight loss)
Lab findings:
Increased BUN and creatinine
Increased hematocrit (hemoconcentration)
Increased serum osmolality
Increased urine specific gravity (>1.030)
,Nursing Interventions:
Assess: Monitor vital signs q1-4h, daily weights, I&O, skin turgor, mucous membranes
Fluid replacement:
Oral rehydration if mild and patient can tolerate
IV fluids for moderate to severe (typically isotonic solutions: 0.9% NaCl or Lactated Ringer's)
Monitor: Urine output (goal: ≥30 mL/hr), electrolyte levels, lung sounds (for fluid overload)
Safety: Fall precautions (orthostatic hypotension), seizure precautions (if severe electrolyte imbalance)
Treat underlying cause: Antiemetics for vomiting, antidiarrheals, control bleeding
Patient Education:
Drink 8-10 glasses of water daily (unless contraindicated)
Recognize early signs of dehydration
Increase fluids during illness, hot weather, exercise
Weigh daily at same time
B. Fluid Volume Excess (Hypervolemia)
Pathophysiology:
Excess ECF volume
Common causes: Heart failure, renal failure, cirrhosis, excessive IV fluid administration, corticosteroid
therapy
Clinical Manifestations:
Vital signs: Hypertension, bounding pulse, tachycardia, tachypnea
Physical exam:
Peripheral edema (dependent areas)
Jugular venous distension (JVD)
Crackles in lungs (pulmonary edema)
Ascites
Weight gain (rapid)
S3 heart sound
Lab findings:
Decreased hematocrit (hemodilution)
, Decreased serum osmolality
Decreased BUN
Hyponatremia (dilutional)
Nursing Interventions:
Assess: Daily weights (same time, same scale), I&O, lung sounds q2-4h, edema assessment
Fluid restriction: Typically 1000-1500 mL/day as ordered
Sodium restriction: 2-3 g/day or as ordered
Medications:
Diuretics (loop diuretics like furosemide)
Monitor potassium (diuretics cause K+ loss)
Positioning: Semi-Fowler's or High Fowler's for respiratory distress
Skin care: Edematous skin is fragile; turn q2h, protect from pressure
Monitor: Electrolytes, BUN, creatinine, oxygen saturation
Patient Education:
Daily weight monitoring (report gain of 2-3 lbs in 24 hrs or 5 lbs in week)
Fluid and sodium restriction compliance
Read food labels for sodium content
Elevate edematous extremities
Take diuretics in morning to avoid nocturia
II. ELECTROLYTE IMBALANCES
A. SODIUM (Na+) IMBALANCES
Normal range: 135-145 mEq/L
1. Hyponatremia (<135 mEq/L)
Pathophysiology:
Can be hypovolemic (loss of Na+), hypervolemic (dilutional), or euvolemic (SIADH)
Causes: Excessive water intake, diuretics, heart failure, SIADH, vomiting/diarrhea, adrenal insufficiency
Clinical Manifestations:
Mild (130-135): Nausea, headache, lethargy, muscle cramps
Moderate (120-130): Confusion, irritability, decreased reflexes
