Fluid Balance

Identify risks for fluid volume deficits, excesses, and third spacing.
Interpret common lab tests for determining fluid imbalances.
Explain nursing considerations and management for fluid volume deficit and excess.
Identify common diuretic therapy medications, their classifications, therapeutic effects, nursing considerations, and patient education.
Text references: Lewis Chapter 17 (pp. 308-311), ATI Chapter 43 (pp. 277-281).
Interactive case study available through ATI on fluid volume management.

Definition: Fluid and electrolyte output exceeds intake and absorption. This is also termed hypovolemia.
Contrast with Dehydration: Dehydration refers to water loss without electrolyte loss (e.g., concentrated urine).

Diuretic Use: Medications like furosemide or hydrochlorothiazide can induce hypovolemia.
Diabetes: Increased urination leads to fluid loss.
Recent Surgery: Blood and fluid loss during procedure; patients may be NPO preoperatively.
Trauma: Accidents can lead to blood loss.
Dietary Changes: Can result in volume loss.

Intake and Output Monitoring: Strict I&O charting to determine the fluid balance.
Lab Values: Indicators of fluid deficit include:
- BUN/Creatinine: Elevated due to high solute concentration (normal BUN: 7-20 mg/dL, normal creatinine: 0.6-1.2 mg/dL).
- Urine Specific Gravity: Increased due to low urine volume.
- Hematocrit: Elevated (42-52% for males, 37-47% for females) indicating concentrated red blood cells because of low plasma levels.

Vital Signs:
- Decreased blood pressure due to low circulating volume.
- Increased heart rate as the body compensates for low volume.
Neuro: Headaches & confusion due to decreased blood flow.
Cardiac Assessment: Weak, thready pulse due to peripheral vasoconstriction.
Respiratory: Shortness of breath due to compromised perfusion.
GI: Constipation from insufficient fluid for bowel movements.
GU: Decreased urine output (typically less than 30 mL/hr).
Integumentary: Cold, clammy skin, dry mucous membranes, poor skin turgor (not a reliable measure in elderly).

Intake and Output: Close monitoring to assess fluid status.
Encourage Oral Intake: Promote oral hydration if possible.
IV Fluids: Administer isotonic fluids like Normal Saline or Lactated Ringer's as needed.
Monitor Weight: Significant weight loss is a crucial indicator of fluid deficit.
Vital Signs Monitoring: Observe for changes in pulse and BP during fluid therapy.
Fall Precautions: Due to potential for orthostatic hypotension.
Supplemental Oxygen: If dyspnea is present.
Lab Monitoring: Watch for improvements in lab values during intervention.

Kidney Disease: Impaired filtration results in fluid retention.
Heart Failure: Excess fluid due to backup in the vascular system.
Recent Trauma: Can result in fluid overload.
SIADH: Retention of water due to inappropriate antidiuretic hormone secretion.

Lab Values: Decreased BUN, creatinine, osmolality due to dilution; low sodium levels due to excess fluid.

Vital Signs:
- Increased blood pressure due to higher circulating volume.
- Increased heart rate from added cardiac workload.
Neuro: Anxiety and shortness of breath from fluid overload.
Cardiac: Possible presence of S3 heart sound; jugular venous distension.
Respiratory: Shortness of breath with potential crackles due to pulmonary congestion.
GI: Weight gain (>1 kg in 24 hours indicates fluid retention).
GU: Oliguria, with kidneys unable to excrete excess fluid.
Integumentary: Edema due to high capillary hydrostatic pressure.

Intake and Output: Close monitoring to identify fluid imbalance.
Head Elevation: To alleviate respiratory distress.
Fluid Restrictions: Set limits on fluid intake.
Dietary Considerations: Assist patients in selecting low-sodium meals to reduce fluid retention.
Lung Sounds Assessment: Monitor for changes in respiratory status.
Skin Assessment: Watch out for potential skin breakdown from edema.
Vital Signs & Labs Monitoring: Observe trends for improvement; adjust treatment accordingly.

Definition: Excess fluid collects in nonfunctional areas (e.g., pleura or gastrointestinal cavities) due to leaky capillaries from trauma or burns.
Phases:
- Loss Phase: Trauma leads to albumin loss and fluid leaks from vessels.
- Reabsorption Phase: Fluid returns to the vasculature depending on the healing of underlying issues.

Infections: Pancreatitis and systemic infections leading to third spacing.
Obstructions: Can cause failures in kidney perfusion.
Severe Allergic Reactions: Anaphylaxis and its inflammatory response can result in fluid shifts.

Thiazide Diuretics (Hydrochlorothiazide)
- Indication: Mild to moderate edema; can lead to dehydration and electrolyte loss.
- Nursing Considerations: Monitor potassium intake and blood pressure.
Potassium-Sparing Diuretics (Spironolactone)
- Mechanism: Blocks aldosterone, promoting sodium and fluid excretion while conserving potassium.
- Nursing Considerations: Avoid potassium supplements and monitor potassium levels.
Loop Diuretics (Furosemide/Lasix)
- Indication: Strong diuresis; monitor the rate of administration via IV for potency.
- Nursing Considerations: Observe for dehydration and electrolyte imbalances.

Postural Hypotension: Advise to get up slowly.
Weight Monitoring: Regular checks to prevent dehydration or fluid overload.
Dietary Instructions: Emphasize foods high in potassium for thiazides and loop diuretics, avoid potassium in potassium-sparing.

Fluid volume management is essential in patient care. Understanding deficits, excesses, and appropriate diuretic therapies aids in effective treatment and patient safety.