How to assess a patient's fluid status?

From the Guidelines

To assess a patient's fluid status, a comprehensive evaluation including clinical examination and laboratory tests is essential, with a focus on signs of volume overload such as peripheral edema, rales, hepatomegaly, ascites, jugular venous pressure, S3 gallop, and S4 gallop, as recommended by the American College of Cardiology/American Heart Association task force on performance measures 1. When evaluating fluid status, it is crucial to consider both the clinical context and the patient's overall condition.

• Begin by reviewing the patient's vital signs, including blood pressure, heart rate, and orthostatic changes.
• Examine for physical signs of volume status, such as skin turgor, mucous membrane moisture, jugular venous distension, peripheral edema, and capillary refill time.
• Auscultate the lungs for crackles suggesting fluid overload and assess for the presence of a third heart sound.
• Ask about symptoms like thirst, dizziness, or shortness of breath.
• Laboratory evaluation should include serum electrolytes, BUN, creatinine, and urine specific gravity. In hospitalized patients, daily weights, strict intake and output monitoring, and fluid balance calculations provide valuable information, as emphasized in the 2013 ACCF/AHA guideline for the management of heart failure 1. For more precise assessment in critically ill patients, consider central venous pressure monitoring, ultrasound evaluation of the inferior vena cava, or more advanced hemodynamic monitoring. The assessment should be tailored to the clinical context, as fluid status evaluation differs between acute care settings and outpatient environments. Understanding a patient's fluid status is essential for appropriate management of conditions ranging from dehydration to heart failure and guides decisions about fluid administration or restriction. In patients with heart failure, careful evaluation of all physical findings, laboratory parameters, weight change, and net fluid change should be considered before discharge, as suggested by the 2013 ACCF/AHA guideline 1.

From the FDA Drug Label

As with any effective diuretic, electrolyte depletion may occur during furosemide therapy, especially in patients receiving higher doses and a restricted salt intake All patients receiving furosemide therapy should be observed for these signs or symptoms of fluid or electrolyte imbalance (hyponatremia, hypochloremic alkalosis, hypokalemia, hypomagnesemia or hypocalcemia): dryness of mouth, thirst, weakness, lethargy, drowsiness, restlessness, muscle pains or cramps, muscular fatigue, hypotension, oliguria, tachycardia, arrhythmia or gastrointestinal disturbances such as nausea and vomiting. Laboratory Tests: Serum electrolytes, (particularly potassium), CO 2, creatinine and BUN should be determined frequently during the first few months of furosemide therapy and periodically thereafter.

To assess a patient's fluid status, monitor for signs and symptoms of fluid or electrolyte imbalance, such as:

• Dryness of mouth
• Thirst
• Weakness
• Lethargy
• Drowsiness
• Restlessness
• Muscle pains or cramps
• Muscular fatigue
• Hypotension
• Oliguria
• Tachycardia
• Arrhythmia
• Gastrointestinal disturbances Laboratory tests should be performed, including:
• Serum electrolytes (particularly potassium)
• CO2
• Creatinine
• BUN These tests should be done frequently during the first few months of furosemide therapy and periodically thereafter 2.

From the Research

Assessing Patient's Fluid Status

To assess a patient's fluid status, several methods can be employed, including:

• Evaluation of hydration state or water homeostasis, which is an important component in the assessment and treatment of critically ill patients in the emergency department (ED) 3
• Distinguishing between normal hydrated, dehydrated, and hyperhydrated states, as fluid depletion may result from renal losses and extrarenal losses, while total body fluid increase can result from heart failure, kidney disease, liver disease, malignant lymphoedema, or thyroid disease 3
• Using noninvasive techniques such as bioelectrical impedance vector analysis (BIVA) to estimate body mass and water composition by bioelectrical impedance measurements, resistance, and reactance 3

Methods of Assessment

Some methods of assessing fluid status include:

• Bioelectrical impedance vector analysis (BIVA), which has been shown to be related to BNP values and the NYHA functional classes in patients with hyperhydration state due to heart failure 3
• Correlation between impedance and central venous pressure in critically ill patients 3
• Analysis of hydration state at admission to the ED, 24,72 h after admission, and at discharge, which can show a significant and indirectly proportional correlation between BIVA hydration and the Caval index 3
• Monitoring of urine output, which can be inversely related to BIVA hydration at admission and directly proportional at 72 h 3

Nursing Practice

In nursing practice, assessing fluid status is crucial, and nurses should be aware of:

• The role of water in the body and the balance of fluids in the body 4
• The provision of intravenous (IV) fluids to patients who are dehydrated, including the types of fluids used, their indications, administration, and potential side effects 4
• The importance of maintaining the balance of fluid and electrolytes, and key monitoring and assessment parameters, such as key electrolytes, their function, normal values, signs and symptoms of imbalances, and treatment modalities 5