Fluid and Electrolyte Balance

Dehydration (Fluid Volume Deficit)

• Definition: Insufficient fluid in the vascular space.
• Assessment Findings:
  • Cardiovascular:
    • Tachycardia (increased heart rate)
    • Hypotension (low blood pressure), potentially leading to orthostatic hypotension.
    • Thready, weak pulses, even in dependent positions (where veins should normally engorge).
    • Palpitations (patient complaint of feeling heart racing).
  • Respiratory:
    • Tachypnea (increased respiratory rate).
    • Hypoxia (low oxygen levels).
    • Increased depth of respirations (body attempting to compensate).
  • Skin:
    • Dry, scaly, flaky skin (described as "geriatric snow").
    • Poor skin turgor (tenting).
    • Dry oral cavities.
  • Renal:
    • Decreased urine output.
    • Concentrated, dark, and potentially smelly urine.
    • In severe cases, no urine output (34%).
  • Neurological:
    • Confusion.
    • Lethargy.
    • Fatigue.
    • Restlessness.
    • Irritability.
    • Fever (can exacerbate dehydration due to sweating).
• Important Note: Decreased blood volume leads to decreased cardiac output, resulting in weak pulses and tachypnea to compensate for hypoxia; however, this compensation is often inadequate.

Overhydration (Fluid Volume Overload, Hypervolemia)

• Definition: Excess fluid volume in the extracellular fluid.
• Causes:
  • Poor IV therapy control (e.g., excessive or incorrect IV fluid administration).
    • Normal saline is the only true isotonic IV fluid. Other fluids may initially act one way but shift and cause fluid shifts if administered over prolonged periods.
  • Decreased cardiac output or heart failure.
    • The heart, being a muscle, can weaken from prolonged tachycardia, leading to decreased cardiac function and output.
    • Depending on whether it's left- or right-sided heart failure, fluid will back up differently.
  • Renal failure or dysfunction.
    • Kidneys are unable to produce urine adequately, leading to fluid retention.
  • Corticosteroids.
    • While beneficial short-term, long-term use can cause:
      • Fluid retention.
      • False hyperglycemia.
  • Blood transfusions.
    • Hypertonic nature can draw fluid into the vascular space, especially if administered too quickly. Protocol: Administer slowly (2-4 hours), but in emergencies, it may be given rapidly.
    • Old folks in particular, you gotta be careful giving blood transfusions, causes them to go into heart failure real quick.
• Complications:
  • Circulatory overload: Too much fluid in the vascular space.
  • Edema: Caused by filtration – fluid pushes from the vascular space to the interstitial space.
  • Pulmonary edema: Fluid backs up into the lungs.
    • Right-sided heart failure causes edema.
    • Left-sided heart failure causes fluid backup into the lungs, leading to pulmonary edema.
• Assessment Findings:
  • Cardiovascular:
    • Increased heart rate (heart working harder to pump excess fluid).
    • Bounding pulses (due to increased fluid volume).
    • Increased blood pressure (hypertension).
    • Distended neck veins, even in upright position.
    • Weight gain (fluid retention).
  • Respiratory:
    • Increased respiratory rate (tachypnea) but shallow respirations.
    • Shortness of breath.
    • Crackles (moist crackles upon auscultation), sometimes coarse enough to hear without a stethoscope.
  • Skin & Mucous Membranes:
    • Pitting edema in dependent areas (areas affected by gravitational pull).
    • Skin may be pale and cool.
    • Skin may be moist from weeping (fluid leaking through pores).
  • Neurological:
    • Changes in level of consciousness.
    • Headache.
    • Visual disturbances.
    • Skeletal muscle weakness.
    • Paresthesia (numbness and tingling due to fluid pressing on nerves).
    • In severe cases, cerebral edema (fluid around the brain).
  • Gastrointestinal:
    • Increased GI motility, potentially leading to diarrhea.
    • Enlarged liver (hepatomegaly).
    • Ascites (fluid accumulation in the abdominal cavity).
• Patient Safety Concerns:
  • Hypoxia and altered mental status increase the risk of falls and injuries.
  • Skin breakdown due to edema increases risk of infection.
• Nursing Interventions:
  • Ensure patient safety due to potential agitation and confusion from hypoxia.
  • Protect skin integrity; use air mattresses and turn patients every two hours to prevent dependent edema.
    • Dependent edema occurs when fluid accumulates in areas affected by gravity, creating skin wrinkles and increased edema on the dependent side.
• Medical Management:
  • Drug therapy: Diuretics to remove excess fluid (specific types to be discussed later).
  • Nutritional therapy: Fluid restriction and sodium restriction.
    • Fluid restriction example: 1500 cc restriction divided into shifts (e.g., 700 cc for 7-3 shift, 500 cc for 3-11 shift, 300 cc for 11-7 shift).
    • Strict I&O monitoring is essential.
• Patient Education:
  • Daily weights: Take weight at the same time each day, after voiding. Keep a journal.
  • Notify healthcare provider for weight gain of 3 pounds in a week or 2 pounds in 24 hours (2.2 pounds is approximately 1 liter of fluid).

Assessing Ascites

• Percussion Technique: Place three fingers on the abdomen and tap the middle finger firmly.
  • Fluid-filled abdomen (ascites) will sound like a watermelon when tapped.
  • Air-filled abdomen will resonate and sound hollow (like a bouncy ball).

Differentiating Fluid vs. Air in Tissue

• Subcutaneous Emphysema: Air escapes from the lungs into subcutaneous tissue; palpation feels like Rice Krispies (crackling).