Dehydration & Overhydration Vocabulary

Dehydration (Fluid Volume Deficit)

• Dehydration means there is not enough fluid inside the vessels (vascular space).

Assessment Findings (Dehydration)

• Cardiovascular:

  • Tachycardia (increased heart rate)

  • Hypotension (low blood pressure) often with Orthostatic Hypotension

  • Thready, weak pulses, even in dependent positions (no visible veins)

  • Palpitations (patient complaint of feeling heart racing or pounding)

• Respiratory:

  • Tachypnea (increased respiratory rate)

  • Hypoxia (low oxygen levels)

  • Increased rate and depth of respirations

  • Crackles are typically associated with fluid volume overload. Therefore, the student should investigate if these crackles are dehydration-related.

• Skin:

  • Dry, scaly, flaky skin (geriatric snow, or Jerry glitter).

  • Poor skin turgor (tenting).

  • Dry oral cavities.

  • Best place to check skin turgor - clavicle.

• Renal:

  • Decreased urine output.

  • Concentrated, dark, and smelly urine; or no urine output at all (30-40% reduction).

• Neurological:

  • Confusion.

  • Lethargy and fatigue

  • Restlessness, irritability

  • May or may not have a fever, but dehydration can occur after breaking a fever due to sweating.

Pathophysiology Reminders (Dehydration)

• Everything is generally decreased due to lack of blood volume, except for compensatory mechanisms like tachycardia.

• Tachycardia leads to decreased cardiac output.

• Rapid respirations (tachypnea) are an attempt to compensate for hypoxia but may not be adequate.

Overhydration (Fluid Volume Overload, Hypervolemia)

• Excess of fluid volume in the extracellular fluid.

Causes of Overhydration

• Poor IV therapy control: Isotonic IV fluids (Normal Saline) given in excess may eventually cause fluid backup or shift fluid into the vascular space. Frequent monitoring is essential.

• Decreased cardiac output, heart failure: The heart muscle weakens over time when continually tachycardic, leading to decreased cardiac function and output. This leads to fluid backup.

• Renal failure or renal dysfunction: Inadequate kidney function leads to fluid retention.

• Corticosteroids: Long-term use leads to fluid retention, among other side effects like false hyperglycemia, and symptoms similar to Cushing's syndrome.

• Blood transfusion: Hypertonic nature can draw fluid into the vascular space if given too rapidly. Protocol is 2-4 hours, but can be faster in emergencies. Be cautious with older adults.

Fluid Volume Overload Leading to Circulatory Overload

• Too much fluid in the vascular space.

Edema Explained

• Edema is caused by Filtration: Fluid is pushed from the vascular space into the interstitial space.

• Excess fluid inside vessels has nowhere to go. Venous system returns blood to the heart, but the heart can't push it fast enough, causing venous retention.

• Venous system stretches out, pushing fluid into tissues, causing edema.

Pulmonary Edema

• Right-sided heart failure causes edema because blood returns to the right side of the heart.

• Left side of heart must be strong to push blood out, but it struggles against excess fluid (resistance), causing blood to back up into the lungs.

• Fluid is dumped into the lungs; both the heart and lungs are in distress.

Assessment Findings (Overhydration)

• Cardiovascular:

  • Increased heart rate (working harder).

  • Bounding pulses (so much fluid).

  • Increased blood pressure (hypertension).

  • Distended neck veins, even in upright position.

  • Weight gain (often attributed to fluid retention).

• Respiratory:

  • Increased rate.

  • Shallow respirations (panting).

  • Shortness of breath.

  • Crackles (moist crackles with auscultation).

  • Coarse crackles indicate significant fluid; sounds like air moving underwater (air hunger).

• Skin and Mucous Membranes:

  • Pitting edema in dependent areas: Gravitational pull causes fluid to accumulate in dependent areas. Example: A patient lying supine will develop wrinkles in their skin on their back with fluid accumulation. Turning the patient will reveal the fluid shifts to the new dependent side.

  • Pale and cool skin due to decreased cardiac output and circulation.

• Neuromuscular:

  • Changes in level of consciousness (LOC) due to cerebral edema: Fluid in the vessels of the brain swell, pushing fluid against the brain.

  • Headache, visual disturbances

  • Skeletal muscle weakness (electrolyte imbalances).

  • Paresthesia (numbness and tingling) from fluid pressing on nerves.

  • Potential brain bleed (hemorrhagic stroke).

• Gastrointestinal (GI):

  • Increased GI motility.

  • Enlarged liver.

  • Diarrhea.

  • Ascites (abdominal swelling from fluid accumulation).

    • Assessment of Ascites

      • Percussion to differentiate fluid from air.

      • Fluid sounds like a watermelon (full).

      • Air sounds hollow (like a bouncy ball).

Patient Safety (Overhydration)

• Crucial due to:

  • Excess fluid volume inside vascular space.

  • Cardiac issues (tachycardia, bounding pulses).

  • Lack of oxygen (fluid in the lungs)

• Patients become agitated due to hypoxia and changes in LOC, increasing risk of falls and injury.

• Skin safety:

  • Edema seeping into interstitial tissues causes swelling.

  • Skin stretches; fluid seeps out.

  • Risk for infection from moist skin.

  • Check pressure points.

  • Use air mattress.

Interventions (Overhydration)

• Turn patients every two hours.

• Drug therapy: Diuretics (to be discussed in detail later).

• Nutritional therapy:

  • Fluid restriction (e.g., 1500 cc per 24 hours broken up per shift, and monitor the tray contents to ensure no additional liquids).

  • Sodium restriction (be cautious when instructing Southern patients).

• Intake and output: Accuracy and consistency.

• Daily weight: Best indicator of fluid retention.

• Patient education:

  • Daily weights at home.

  • Keep a journal.

  • Notify provider if they gain 3 lbs in a week or 2 lbs in 24 hours.

Overhydration Assessment Cheat Sheet

• Cardiovascular:

  • Bounding pulses.

  • Tachycardia.

  • Hypertension.

  • JVD (Jugular Vein Distention).

• Respiratory:

  • Crackles (moist lung sounds).

  • Shortness of Breath (SOB).

  • Shallow respirations.

  • Hypoxia - Low pulse oximeter reading.

• Skin:

  • Skin is swollen.

  • Weeping from your skin.

  • May be moist.

  • Skin may crack, pore will be expanded.

  • Pitting edema.

  • Cool and pale skin.

• Neurological:

  • Cerebral edema.

  • Brain bleeds.

  • Changes in mental status.

  • Possible Seizures.

  • Neuromuscular weakness.

• Gastrointestinal:

  • Ascites.

  • Diarrhea.

  • Enlarged Liver - Hepatomegaly.

• Renal:

  • Decreased Urine Output.

Key to Understanding

• When you're studying, ask yourself why. Understand that WHY is happening. That's where the application comes in.