At what left ventricular ejection fraction (LVEF) should I be cautious of administering intravenous (IV) fluids?

From the Guidelines

Be cautious when administering IV fluids to patients with an ejection fraction (EF) below 40%, particularly those with heart failure with reduced ejection fraction (HFrEF), as stated in the 2022 AHA/ACC/HFSA guideline for the management of heart failure 1. For patients with severely reduced EF (below 30%), IV fluids should be given with extreme caution and close monitoring. When fluid administration is necessary in these patients, consider using smaller boluses (250-500 mL rather than 1L), administering fluids at a slower rate, and reassessing frequently for signs of volume overload such as increasing dyspnea, crackles on lung examination, jugular venous distention, or worsening peripheral edema. The caution stems from the heart's limited ability to handle increased preload when contractility is impaired; excessive fluid can overwhelm the compromised left ventricle, leading to pulmonary edema and worsening heart failure. In these situations, consider alternative approaches such as vasopressors or inotropes if the clinical situation warrants, as suggested by the 2009 focused update incorporated into the ACC/AHA 2005 guidelines for the diagnosis and management of heart failure in adults 1. If you must give fluids, monitor vital signs, urine output, and respiratory status closely during and after administration. Some key points to consider when managing patients with heart failure include:

• Determining the adequacy of systemic perfusion, volume status, and the contribution of precipitating factors and/or comorbidities 1
• Using chest radiographs, electrocardiogram, and echocardiography as key tests in the assessment of heart failure 1
• Measuring concentrations of B-type natriuretic peptide (BNP) or N-terminal pro-B-type natriuretic peptide (NT-proBNP) in patients being evaluated for dyspnea 1
• Identifying common potential precipitating factors for acute heart failure, such as acute coronary syndromes, severe hypertension, and atrial and ventricular arrhythmias 1

From the Research

Ejection Fraction and IV Fluids

• The use of IV fluids in patients with heart failure should be cautious, especially in those with reduced ejection fraction (HFrEF) 2.
• HFrEF is defined as a left ventricular ejection fraction (LVEF) of 40% or less, and is often accompanied by progressive left ventricular dilatation and adverse cardiac remodeling 2.
• There is no specific ejection fraction threshold provided in the studies for caution with IV fluids, but patients with HFrEF should be treated with caution when administering IV fluids to avoid worsening heart failure symptoms 3.

Heart Failure Management

• The management of HFrEF involves the use of diuretics to relieve symptoms, and disease-modifying drug and device therapies 2.
• Patients with HFrEF should be treated with a β-blocker and one of an angiotensin receptor-neprilysin inhibitor, angiotensin-converting enzyme inhibitor, or angiotensin receptor blocker as foundational therapy 2.
• The use of IV fluids should be guided by the patient's volume status and clinical condition, rather than a specific ejection fraction threshold 4.

Clinical Considerations

• The assessment of LVEF is not required for the initiation of treatments like sodium-glucose cotransporter 2 inhibitors, mineralocorticoid receptor antagonists, and diuretics in patients with suspected de novo heart failure and elevated N-terminal pro-B-type natriuretic peptide levels 4.
• The reproducibility of LVEF measurement is poor, and its prognostic and diagnostic value lessens when it is above 45% 4.
• A more comprehensive approach to classify and assess heart failure is needed, focusing on the trajectory of LVEF rather than its absolute value 4.