Why are maintenance Intravenous (IV) fluids and tube feeds not administered concurrently in Intensive Care Unit (ICU) patients?

From the Guidelines

Maintenance IV fluids and tube feeds should not be administered simultaneously in ICU patients to avoid fluid overload and optimize nutritional management. When a patient is receiving adequate enteral nutrition via tube feeds, the fluid component of the nutrition typically provides sufficient hydration, making additional maintenance IV fluids unnecessary and potentially harmful 1. Tube feeds contain water along with nutrients, electrolytes, and calories, often providing 70-80% of a patient's daily fluid requirements. Adding maintenance IV fluids could lead to iatrogenic fluid overload, which is particularly concerning in critically ill patients who may have compromised cardiac, renal, or pulmonary function. Fluid overload in ICU patients is associated with increased morbidity, including prolonged mechanical ventilation, pulmonary edema, and impaired wound healing 1.

Key Considerations

• The fluid component of tube feeds provides sufficient hydration, making additional maintenance IV fluids unnecessary in most cases.
• Adding maintenance IV fluids to tube feeds can lead to fluid overload, which is associated with increased morbidity in ICU patients.
• Managing fluid balance becomes more precise when the clinician accounts for the fluid content in tube feeds rather than simultaneously managing two separate fluid sources.
• In cases where additional hydration is needed beyond what tube feeds provide, it's preferable to calculate the deficit and administer targeted fluid boluses rather than continuous maintenance fluids.

Recommendations

• Avoid simultaneous administration of maintenance IV fluids and tube feeds in ICU patients.
• Calculate the patient's daily fluid requirements and adjust tube feed rates accordingly.
• Use targeted fluid boluses to address any additional hydration needs beyond what tube feeds provide.
• Monitor patients closely for signs of fluid overload and adjust fluid management strategies as needed 1.

From the Research

Fluid Management in ICU Patients

• The administration of intravenous fluids (IVF) and tube feeds simultaneously in ICU patients is not recommended due to the risk of fluid overload and its associated complications 2, 3.
• Fluid overload can lead to organ failure and increased mortality, highlighting the importance of careful fluid management in ICU patients 2.
• The type of fluid used for resuscitation also impacts patient outcomes, with different fluids having varying effects on intravascular volume expansion and potential adverse effects 2, 4.

Risks of Fluid Overload

• Maintenance fluids and fluid creep can impose significant fluid, sodium, and chloride burdens on critically ill patients, exceeding the amounts administered through resuscitation fluids 5.
• Inadvertent daily volume, sodium, and chloride loading should be avoided when prescribing maintenance fluids, especially when adopting an isotonic maintenance strategy 5.
• The choice of fluid can affect patient outcomes, with some fluids having a survival benefit over others in specific patient populations, such as those with acute pancreatitis 6.

Strategies for Fluid Management

• Clinicians should weigh the risks and benefits of giving fluid and consider the advantages and side effects of each fluid type to optimize patient outcomes 2.
• Proactive strategies should be implemented to establish negative fluid balance as soon as the clinical conditions are considered stable and the risk of deterioration is low 3.
• The use of hypotonic maintenance strategies can help reduce chloride levels and minimize the risk of fluid overload 5.