Is 0.45% normal saline (NS) / glucose 5% with potassium suitable for a patient with hypernatremia and hypokalemia?

From the Guidelines

For a patient with sodium 150 mEq/L and potassium 2.7 mEq/L, 0.45% normal saline with 5% glucose and potassium supplementation is an appropriate fluid choice. This recommendation is based on the need to address both hypernatremia and hypokalemia simultaneously. The use of a hypotonic solution like 0.45% normal saline helps in providing free water to correct the elevated sodium level, while the addition of glucose facilitates the entry of potassium into cells, which is crucial for correcting hypokalemia 1. Key considerations in managing these electrolyte imbalances include:

• Adding potassium to the fluid at a concentration of 20-40 mEq/L, depending on the severity of hypokalemia and renal function, as suggested by guidelines for managing hyperglycemic crises and electrolyte imbalances 1.
• Ensuring gradual correction of sodium levels, not exceeding 8-10 mEq/L per 24 hours, to prevent neurological complications.
• Regular monitoring of electrolytes every 4-6 hours to adjust the therapy as needed.
• Investigating the underlying cause of these electrolyte abnormalities while providing supportive treatment. The goal is to normalize both sodium and potassium levels while preventing further complications, thus prioritizing morbidity, mortality, and quality of life outcomes.

From the FDA Drug Label

The dose and rate of administration are dependent upon the specific condition of each patient. Recommended administration rates should not usually exceed 10 mEq/hour or 200 mEq for a 24-hour period if the serum potassium level is greater than 2.5 mEq/liter

The patient has a serum potassium level of 2.7 mEq/liter, which is greater than 2.5 mEq/liter.

• The use of 0.45% normal saline / glucose 5% with potassium is not directly addressed in the provided drug label.
• However, the label does provide guidance on the administration of potassium chloride (IV) solution, which should be administered at a slow, controlled rate, with recommended administration rates not usually exceeding 10 mEq/hour. Given the patient's serum potassium level and the lack of direct information on the use of 0.45% normal saline / glucose 5% with potassium, it is not possible to determine if this fluid is ok 2.

From the Research

Fluid Management for Sodium and Potassium Imbalance

• The patient's sodium level is 150 mmol/L and potassium level is 2.7 mmol/L, indicating hypernatremia and hypokalemia, respectively.
• According to the study 3, for hypovolemic patients, an infusion of isotonic sodium chloride solution (0.9%) is the method of choice.
• However, for patients with hypernatremia, the study 4 suggests that the corrected serum sodium concentration should be estimated to guide the tonicity of replacement solutions.
• The study 5 recommends that hypokalemia be treated by addressing the underlying cause and replenishing potassium levels, with an oral route preferred if the patient has a functioning gastrointestinal tract and a serum potassium level greater than 2.5 mEq per L.
• Regarding the use of 0.45% normal saline / glucose 5% with potassium, there is no direct evidence to support its use in this specific scenario.
• However, the study 3 mentions that administration of glucose with insulin can be used to rapidly drop potassium levels by shifting potassium to the intracellular space.

Considerations for Fluid Choice

• The study 6 highlights the importance of monitoring sodium and potassium levels in patients with subarachnoid hemorrhage, as both electrolyte imbalances can lead to dangerous outcomes.
• The study 7 found that abnormal sodium levels are an important risk factor for mortality in heart failure patients, independent of potassium levels.
• When choosing a fluid, it is essential to consider the patient's volume status, underlying cause of electrolyte imbalance, and potential risks associated with rapid correction of sodium and potassium levels.