From the Guidelines
Assessing volume status in a patient involves a comprehensive approach that includes a thorough history, physical examination, laboratory tests, and point-of-care ultrasound, with a focus on integrating these parameters to guide clinical decision-making. The most recent and highest quality study, 1, published in 2013, emphasizes the importance of a thorough history and physical examination in patients presenting with heart failure, including the assessment of volume status and vital signs at each patient encounter.
Key Components of Volume Status Assessment
- A thorough history focusing on fluid intake/output, recent weight changes, and symptoms like thirst, dizziness, or edema
- Physical examination including:
- Vital signs (heart rate, blood pressure including orthostatic measurements)
- Skin turgor
- Mucous membrane moisture
- Jugular venous pressure
- Presence of edema
- Lung auscultation for crackles
- Laboratory tests providing additional information:
- BUN/creatinine ratio
- Electrolytes
- Hematocrit
- Urine specific gravity
- Point-of-care ultrasound to assess inferior vena cava diameter and collapsibility
- Dynamic tests like passive leg raise (PLR) or fluid challenge to determine fluid responsiveness
Integration of Parameters
These assessments should be integrated rather than relied upon individually, as each has limitations and can be affected by comorbidities or medications. Daily weight measurements provide objective tracking of fluid status, with 1 kg roughly equivalent to 1 liter of fluid, as highlighted in the management guidelines for heart failure 1. The 2013 ACCF/AHA guideline for the management of heart failure 1 supports the use of a thorough history and physical examination, including the assessment of volume status, with a Level of Evidence: B, underscoring the importance of these assessments in clinical practice.
From the FDA Drug Label
As with any effective diuretic, electrolyte depletion may occur during Furosemide tablets therapy, especially in patients receiving higher doses and a restricted salt intake All patients receiving Furosemide tablets 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. Serum electrolytes (particularly potassium), CO2, creatinine and BUN should be determined frequently during the first few months of Furosemide tablets therapy and periodically thereafter.
To assess volume status in a patient, 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, including nausea and vomiting Regularly check serum electrolytes, particularly potassium, as well as CO2, creatinine, and BUN levels 2.
From the Research
Assessing Volume Status
To assess volume status in a patient, the following methods can be used:
- Medical history and physical examination, which are readily available, cost-effective, and non-invasive 3
- Point-of-care ultrasound (POCUS), which is a valuable adjunct to physical examination and can help assess hemodynamic parameters related to volume status, fluid responsiveness, and fluid tolerance 3, 4, 5
- Evaluation of central venous pressure, right heart function, left heart assessment, extravascular volume, and venous congestion using POCUS 4
- Assessment of skin turgor, axillary sweat, peripheral edema, pulmonary crackles, orthostatic vital signs, and jugular venous distension 5
- Invasive assessments of volume status, including direct measurement of central venous pressure and pulmonary artery pressures 5
Using POCUS for Volume Status Assessment
POCUS can be used to assess volume status by evaluating the following:
- Collapse point of the internal jugular vein 3
- Diameter of the inferior vena cava 3
- Presence of pulmonary B-lines 3
- Central venous pressure, right heart function, left heart assessment, extravascular volume, and venous congestion 4
Clinical Decision-Making
When assessing volume status, it is essential to combine medical history, physical examination, and POCUS findings to enhance diagnostic certainty 3. Clinicians must be aware of the strengths and weaknesses of findings in different physiologic states and potential pitfalls of image acquisition and interpretation 4. The use of POCUS should complement clinical assessment and not replace it, guiding providers to give thorough and accurate clinical care to their patients 5.