How do you manage fluid balance in patients?

From the Guidelines

Managing fluid balance in patients requires careful assessment, monitoring, and intervention, with the goal of maintaining euvolemia, and the most recent evidence suggests aiming for a mildly positive fluid balance (+1-2 L) by the end of the case to protect kidney function. Start by evaluating the patient's fluid status through physical examination (checking for edema, skin turgor, mucous membrane moisture), vital signs (blood pressure, heart rate), and laboratory values (electrolytes, BUN/creatinine ratio) 1. Daily weight measurements provide valuable information, with a 1 kg change roughly equivalent to 1 liter of fluid. For fluid administration, crystalloids like normal saline (0.9% NaCl) or lactated Ringer's are commonly used at maintenance rates of approximately 30-35 mL/kg/day for adults, adjusted based on clinical needs.

Some key points to consider in fluid management include:

• Avoiding the use of 0.9% saline due to the risk of salt and fluid overload 1
• Not using oliguria as a trigger for fluid therapy, but rather investigating and establishing the cause of low urine output before additional fluid therapy 1
• Discontinuing IVF at the latest during day 1 postoperatively and encouraging patients to drink when fully recovered 1
• Using a hypotonic crystalloid with 70–100 mmol/day of sodium and up to 1 mmol/kg/day of potassium if IVF needs to be continued postoperatively 1
• Replacing ongoing losses (diarrhea, vomiting) with a balanced solution (e.g., Ringer’s lactate) as required, while avoiding 0.9% saline solutions 1

In cases of dehydration, fluid replacement should address both deficit and ongoing losses, while fluid overload may require restriction (typically 1-1.5 L/day) and possibly diuretics such as furosemide (20-40 mg IV/PO). Continuous monitoring of intake and output is essential, with documentation of all fluid sources including IV medications, oral intake, and tube feedings, balanced against urine output, drainage, and insensible losses. Special consideration is needed for patients with heart failure, kidney disease, or liver disease, who may require stricter fluid management protocols, as evidenced by the need for careful management of fluid retention in heart failure patients 1. The goal is to maintain euvolemia—a balanced fluid state that supports organ perfusion while preventing complications of both overhydration and dehydration.

From the FDA Drug Label

In patients with hepatic cirrhosis and ascites, Furosemide tablets therapy is best initiated in the hospital. In hepatic coma and in states of electrolyte depletion, therapy should not be instituted until the basic condition is improved Sudden alterations of fluid and electrolyte balance in patients with cirrhosis may precipitate hepatic coma; therefore, strict observation is necessary during the period of diuresis. Supplemental potassium chloride and, if required, an aldosterone antagonist are helpful in preventing hypokalemia and metabolic alkalosis

To manage fluid balance in patients, strict observation is necessary during the period of diuresis, especially in patients with hepatic cirrhosis and ascites.

• Supplemental potassium chloride and, if required, an aldosterone antagonist can be helpful in preventing hypokalemia and metabolic alkalosis.
• Therapy should not be instituted until the basic condition is improved in cases of hepatic coma and electrolyte depletion 2, 3.

From the Research

Managing Fluid Balance

To manage fluid balance in patients, it is essential to understand the pathophysiology of fluid imbalance, which can arise due to hypovolemia, normovolemia with maldistribution of fluid, and hypervolemia 4. The following are key points to consider:

• Hypovolemia can lead to reduction in circulating blood volume, lower venous return, and arterial hypotension, which can result in myocardial failure and multi-organ failure 4.
• Normovolemia with maldistribution of fluid can cause localized perfusion deficits, contributing to multi-organ failure 4.
• Excessive volume administration can lead to fluid overload, impairing pulmonary function 4.
• The choice of resuscitation fluid is crucial, as some colloids may help diminish post-ischemic microvascular leukocyte adherence 4.

Fluid and Electrolyte Balance

Fluid and electrolyte balance is vital in patient care, particularly in surgical and critically-ill patients 5. Key considerations include:

• The efficiency of physiological responses to salt or water deficits and excesses 5.
• The use of saline versus more physiological solutions like Hartmann's solution to avoid hyperchloraemic acidosis and renal vasoconstriction 5.
• The importance of avoiding unnecessary additional fluid overload after resuscitation 5.
• The need for careful monitoring of fluid balance, especially in patients with congestive heart failure, to prevent fluid overload and associated adverse outcomes 6.

Monitoring and Management

Effective monitoring and management of fluid balance involve:

• Maintaining accurate records of fluid intake and output (I&O) to assess hydration status 6.
• Utilizing fluid balance charts in conjunction with physical assessment and electrolyte monitoring to assess hydration status 6.
• Involving patients in accurate documentation and providing staff education on fluid balance monitoring and documentation 6.
• Managing fluid and electrolyte disorders in renal failure, which requires careful assessment of hydration, personalized fluid treatment plans, and frequent reassessment of fluid and electrolyte balance 7.

Specific Considerations

In specific patient populations, such as children with severe head injury, it is essential to consider the release of antidiuretic hormone (ADH) in response to hypovolemia and/or sodium administration 8. Key points include:

• The appropriateness of ADH release in response to hypovolemia and/or sodium administration 8.
• The correlation of ADH levels with sodium intake, volume of fluids given IV, and plasma osmolality 8.
• The importance of fluid restriction to avoid inappropriate secretion of ADH in head-injured patients 8.