From the Guidelines
Isotonic fluids are generally contraindicated in congestive heart failure (CHF) as they can worsen fluid retention, increase preload, and exacerbate pulmonary edema and peripheral edema in these patients. Patients with CHF already have fluid overload and compromised cardiac function, making them particularly vulnerable to volume expansion. Administration of isotonic fluids like normal saline (0.9% NaCl) or lactated Ringer's solution can further compromise cardiac function and worsen symptoms and outcomes, as noted in the 2022 AHA/ACC/HFSA guideline for the management of heart failure 1.
When fluid administration is necessary in CHF patients, it should be done cautiously with close monitoring of vital signs, fluid status, and cardiac function. Small boluses rather than continuous infusions are preferred when absolutely needed. In cases where CHF patients require hydration or medication administration, alternatives such as hypotonic solutions in small volumes or concentrated medications may be considered. The underlying pathophysiology explains this contraindication: in heart failure, the heart cannot effectively pump blood forward, leading to backward pressure and fluid accumulation in the lungs and periphery. Adding more fluid to this system through isotonic fluid administration can overwhelm the already compromised cardiac function and worsen symptoms and outcomes.
Key considerations in managing CHF include:
- Prompt treatment with intravenous loop diuretics to reduce morbidity in patients admitted with evidence of significant fluid overload, as recommended in the 2013 ACCF/AHA guideline for the management of heart failure 1
- Use of diuretics to eliminate clinical evidence of fluid retention, using the lowest dose possible to maintain euvolemia, as noted in the 2022 AHA/ACC/HFSA guideline for the management of heart failure 1
- Avoidance of drugs known to adversely affect the clinical status of patients with CHF, such as nonsteroidal anti-inflammatory drugs and most calcium channel blocking drugs, as recommended in the 2009 focused update incorporated into the ACC/AHA 2005 guidelines for the diagnosis and management of heart failure in adults 1.
From the Research
Isotonic Fluids in CHF
- The use of isotonic fluids in patients with congestive heart failure (CHF) is a topic of interest, as fluid overload is a major determinant of symptoms in these patients 2.
- According to a study published in 2020, removal of isotonic fluid via hemofiltration and peritoneal dialysis is an understudied but promising therapy that enables decongestion without maladaptive stimulation of fluid retention pathways 3.
- However, there is no direct evidence to suggest that isotonic fluids are contraindicated in CHF, but rather that their removal can be beneficial in managing fluid overload 3.
- Diuretic therapy is the first-line treatment for fluid overload in CHF, and the choice of diuretic is guided by patient clinical situations and the presence of other co-morbidities 4, 5.
- The management of fluid balance in CHF is complex and involves the interplay between the heart, kidney, and lung, and therefore, requires a comprehensive approach 2, 6.
Fluid Management in CHF
- Fluid overload is a classic clinical feature of CHF, and its presence is associated with adverse outcomes 6.
- Diuretics are the mainstay of treatment for congestion, but no randomized trials have shown their effects on mortality in chronic heart failure patients 6.
- Research is required to determine whether a robust method of detecting and then treating subclinical congestion improves outcomes 6.
- The use of ultrafiltration, including hemofiltration and peritoneal dialysis, may be a useful adjunct to diuretic therapy in managing fluid overload in CHF 3.