Why is Normal Saline (NS) most often used in a hospital setting?

From the Guidelines

Normal saline (NS) is most often used in hospital settings because it is an isotonic intravenous fluid that can be administered in severe dehydration, shock, or altered mental status, as recommended by the 2017 Infectious Diseases Society of America clinical practice guidelines 1. The use of NS in hospital settings is supported by its ability to remain in the intravascular space longer than other fluids due to its osmolarity similar to blood plasma. This makes it an excellent first-line intravenous fluid for volume resuscitation in hypovolemic patients, medication administration, and maintenance fluid therapy. Some of the key benefits of NS include:

• Its compatibility with most medications, making it an ideal carrier solution for drug delivery
• Its ability to provide electrolyte replacement, especially sodium and chloride, without causing significant fluid shifts in most patients
• Its widespread availability and relatively low cost, which contribute to its prevalence in hospital settings However, hospital practitioners should be aware that large volumes of NS can potentially cause hyperchloremic metabolic acidosis due to its high chloride content, and alternative balanced crystalloids like lactated Ringer's may be preferred for massive fluid resuscitation. In comparison to other fluids, NS has been shown to be a cost-effective option, with a lower financial barrier to implementation, as noted in the Canadian Society of Nephrology commentary on the 2012 KDIGO clinical practice guideline for acute kidney injury 1. Overall, the use of NS in hospital settings is supported by its effectiveness, safety, and cost-effectiveness, making it a versatile and widely used intravenous fluid.

From the Research

Reasons for NS Use in Hospital Settings

• Normal saline (NS) is widely used in medical settings due to its long history of use and perceived safety 2, 3.
• NS is often the crystalloid of choice in the United States, particularly in medical and pediatric care, as well as in hematology and transfusion medicine 2.
• Despite growing concerns about its potential toxicity, NS remains the most widely employed solution in these fields 2.

Comparison with Other Solutions

• Studies have compared NS with other crystalloid solutions, such as Lactated Ringer's (LR) and Plasma-Lyte A, in various clinical settings 4, 5.
• These studies have shown that LR may be superior to NS in certain situations, such as resuscitation of uncontrolled hemorrhagic shock 4, 5.
• However, NS is still widely used due to its familiarity and perceived effectiveness 3.

Historical Context

• The use of NS in hospital settings dates back to its introduction in the medical field, and it has remained a widely used agent despite ongoing debates about its safety and efficacy 3.
• Early studies examined the compatibility of NS with blood components, highlighting potential issues with its use in certain situations 6.

Current Status

• Recent evidence suggests that NS may cause metabolic acidosis, vascular and renal function changes, and abdominal pain compared to balanced crystalloids 2.
• Additionally, NS has been shown to cause substantially more in vitro hemolysis than Plasma-Lyte A and similar solutions during short-term storage 2.
• These findings have raised concerns about the safety of NS for various clinical uses, and some studies suggest that it may eventually be abandoned in favor of safer, more physiologic crystalloid solutions 2.