From the Guidelines
Management of Hypernatremia in the ICU
The primary goal in managing hypernatremia in the ICU is to correct the sodium imbalance gradually to prevent cerebral edema, with a recommended reduction rate of 10-15 mmol/L per 24 hours 1.
Approach to Correction
The approach to correcting hypernatremia involves using intravenous fluids to slowly lower the sodium level. For patients with severe hypernatremia, consider using 5% dextrose in water (D5W) to provide free water, as salt-containing solutions like 0.9% saline can exacerbate hypernatremia in conditions like nephrogenic diabetes insipidus 1. The initial rate of fluid administration can be based on physiological demand, with routine maintenance rates used as a starting point 1.
Medications and Monitoring
Medications such as desmopressin (DDAVP) may be considered for patients with central diabetes insipidus, while hydrochlorothiazide (HCTZ) may be used for those with nephrogenic diabetes insipidus 1. Close monitoring of serum sodium levels, urine output, and neurological status is crucial during the correction process. In patients with hypernatremia due to dehydration, enteral or parenteral nutrition may be necessary to provide additional free water and electrolytes 1.
Key Considerations
- Fluid Intake: Ad libitum access to fluid is recommended to prevent dehydration and hypernatremia, especially in patients who can self-regulate their fluid intake 1.
- Intravenous Fluids: 5% dextrose in water can be used for intravenous administration, especially in patients who cannot self-regulate their fluid intake, with close monitoring of weight, fluid balance, and biochemistry 1.
- Correction Rate: A maximum correction rate of 8-10 mmol/L per 24 hours is generally recommended to avoid cerebral edema, although specific guidelines may vary depending on the underlying cause and patient condition 1.
From the Research
Management of Hypernatremia in the ICU
The management of hypernatremia in the Intensive Care Unit (ICU) involves correcting the underlying cause of the disorder and replenishing free water deficit to restore normal plasma osmolality 2. The following are key aspects of hypernatremia management:
- Judicious replacement of free water deficit using electrolyte-free water or hypotonic fluids 2
- Identification and correction of underlying causes of hypernatremia 2, 3
- Assessment of free water requirements in ICU patients to prevent hypernatremia 2
- Frequent monitoring of plasma sodium levels to ensure appropriate response to treatment and adjust the rate of fluid replacement 2, 4
- Avoiding rapid correction of chronic hypernatremia to prevent cerebral edema 4, 5
Correction Rate of Hypernatremia
The optimal rate of hypernatremia correction is unclear, but some studies suggest a reduction rate not to exceed 0.5 mmol/L per hour 4. However, a study found no significant difference in mortality or neurologic outcomes between rapid and slow correction rates in critically ill patients with hypernatremia 4.
Consequences of Hypernatremia
Hypernatremia can lead to severe consequences, including:
- Abnormal cognitive and neuromuscular function 2
- Hemorrhagic complications or death from vascular stretching and rupture in advanced cases 2
- Increased mortality, length of stay, and postdischarge mortality in ICU patients 6
Prevention and Treatment
Prevention of hypernatremia is essential in the hospital, and its management consists of treating the underlying cause and correcting the hyperosmolarity by ensuring close monitoring of the sodium level 5. Physicians can apply a step-by-step approach to manage hypernatremia, including identifying underlying causes, distinguishing between acute and chronic hypernatremia, and determining the amount and rate of water administration 3.