Why is half normal saline (0.45% sodium chloride solution) used in sickle cell crisis?

From the Guidelines

Half normal saline (0.45% sodium chloride) is used in sickle cell crisis to help with hydration while avoiding excessive sodium intake. During a sickle cell crisis, patients require aggressive hydration to improve blood flow, reduce blood viscosity, and help prevent further sickling of red blood cells. Half normal saline provides necessary fluid volume while delivering less sodium than normal saline (0.9%), which is important because excessive sodium can potentially worsen dehydration through osmotic effects. The typical administration rate is 1.5 times maintenance fluid requirements, often starting at 10-15 mL/kg/hour for the first 1-2 hours, then adjusting to 1.5 times maintenance based on the patient's clinical status. This approach helps expand plasma volume, improve microcirculation, and dilute the concentration of sickled cells. Additionally, adequate hydration supports kidney function, which is particularly important as sickle cell patients are at risk for renal complications, as noted in the guidelines for peri-operative management of patients with sickle cell disease 1. The lower sodium content also helps minimize the risk of fluid overload while still providing effective hydration to address the underlying pathophysiology of the crisis. Key considerations in the management of sickle cell crisis include:

• Aggressive hydration to improve blood flow and reduce blood viscosity
• Avoiding excessive sodium intake to prevent worsening dehydration
• Providing adequate fluid volume to expand plasma volume and improve microcirculation
• Supporting kidney function to minimize the risk of renal complications
• Minimizing the risk of fluid overload while providing effective hydration. It is essential to note that while the provided evidence does not directly address the use of half normal saline in sickle cell crisis, the principles of hydration and fluid management in sickle cell disease are well-established, and half normal saline is a common choice for hydration in these patients, as it provides necessary fluid volume while minimizing the risk of excessive sodium intake 1.

From the Research

Use of Half Normal Saline in Sickle Cell Crisis

• Half normal saline (0.45% sodium chloride solution) is used in sickle cell crisis due to the patient's reduced ability to excrete sodium load in normal saline, as stated in the study 2.
• The use of normal saline may lead to hyposthenuria, and therefore, a 5% dextrose solution or 5% dextrose in 25% normal saline is recommended for intravenous hydration 2.
• However, there is no direct evidence in the provided studies that specifically addresses the use of half normal saline in sickle cell crisis.
• The studies discuss the importance of intravenous hydration in managing sickle cell crisis, but they do not provide clear guidelines on the type of fluid to be used 3, 4.
• Other studies focus on the management of sickle cell disease, including transfusion therapy, red blood cell exchange transfusion, and treatment of complications, but they do not mention the use of half normal saline 5, 6.