What are the recommendations for postoperative (post-op) maintenance fluid management?

From the Guidelines

For postoperative maintenance fluid therapy, I recommend using isotonic crystalloid solutions such as 0.9% normal saline or lactated Ringer's solution at a rate of 1.5-2 mL/kg/hour for adult patients, as suggested by the most recent evidence-based consensus recommendations from the international multidisciplinary perioperative quality initiative 1. This approach is supported by the latest guidelines, which emphasize the importance of individualized fluid management, taking into account the type of surgery and important patient factors, including intravascular volume status and acute and chronic comorbidities 1. The goal of maintenance fluids is to replace insensible losses and maintain adequate hydration while avoiding fluid overload, which can lead to complications such as pulmonary edema or electrolyte disturbances. Some key points to consider in postoperative fluid management include:

• Monitoring fluid status by assessing vital signs, urine output (target >0.5 mL/kg/hour), and laboratory values including electrolytes, BUN, and creatinine every 6-12 hours 1
• Adjusting the rate based on the patient's clinical status, accounting for ongoing losses from drains, nasogastric tubes, or other sources 1
• Using the 4-2-1 rule for pediatric patients: 4 mL/kg/hour for the first 10 kg of weight, plus 2 mL/kg/hour for the next 10 kg, plus 1 mL/kg/hour for each additional kg
• Transitioning to oral intake as soon as the patient can tolerate it, typically within 24-48 hours postoperatively for uncomplicated cases It is also important to note that patients with cardiac, renal, or hepatic dysfunction require more careful fluid management, often at lower rates, and that the use of balanced crystalloids has been shown to be superior to 0.9% saline for the maintenance of electrolyte balance 1.

From the FDA Drug Label

During major surgery, patients can lose over half of their circulating albumin with the attendant complications of oncotic deficit.(2,4,5) A similar situation can occur in sepsis or intensive care patients. Treatment with Plasbumin-25 may be of value in such cases.

The recommendations for postoperative (post-op) maintenance fluid management are not explicitly stated in the provided drug label. However, it can be inferred that albumin replacement may be considered in cases of oncotic deficit or hypoproteinemia that may occur during major surgery.

• The use of Plasbumin-25 may be of value in such cases.
• Additionally, crystalloids may be required to support the blood volume, especially if the patient is dehydrated. However, the label does not provide specific guidelines for postoperative maintenance fluid management. 2

From the Research

Postoperative Maintenance Fluid Management

The following are recommendations for postoperative maintenance fluid management:

• Administration of post-operative intravenous fluids as boluses of balanced salt solution is feasible, safe, and results in significantly less fluid administered compared to a traditional continuous protocol 3.
• Balanced crystalloids are superior to normal saline in maintaining a stable acid-base balance 4, 5.
• The use of balanced crystalloids rather than isotonic saline is conditionally recommended for critically ill patients in general, patients with sepsis, and patients with kidney injury 6.
• Intermittent boluses of balanced salt solution can limit post-operative fluid volume and may lead to a faster time to regular diet and discharge 7.

Key Considerations

• The choice of crystalloid solution is important, with balanced crystalloids being preferred over normal saline due to their ability to maintain a stable acid-base balance 4, 5.
• The use of intermittent boluses rather than continuous infusion can reduce the volume of maintenance fluids administered and may lead to improved outcomes 3, 7.
• The European Society of Intensive Care Medicine provides conditional recommendations for the use of crystalloids, including balanced crystalloids, in critically ill patients 6.

Fluid Administration

• The administration of fluids as intermittent boluses can be an effective strategy for postoperative maintenance fluid management, resulting in significantly less fluid administered compared to traditional continuous protocols 3, 7.
• The use of balanced crystalloids, such as lactated Ringer's solution, is recommended due to their ability to maintain a stable acid-base balance 4, 5.