Lactated Ringers vs. Normal Saline as IV Fluids

Medically Reviewed by Dan Brennan, MD on April 15, 2021
Written by WebMD Editorial Contributor
3 min read

Lactated ringers and normal saline are both types of intravenous (IV) fluids. IV fluids are given whenever there is a concern about maintaining fluid balance. Each type of IV fluid has different benefits and drawbacks. Your doctor will decide whether to use lactated ringers or normal saline based on your medical condition and other medications you may be taking. 

Your body is made up of about 60% water. About two-thirds of this fluid is stored in your cells. The rest is in your blood vessels and between your cells. Your brain and heart are 73% water. Your lungs are 83% water. Your muscles and kidneys are 69% water, and your skin is 64% water.

Because so much of your body is made of water, it is essential for the healthy function of every one of your cells. Some of the functions water performs in your body include: 

  • Helps your cells perform basic functions
  • Lubricates your joints
  • Regulates your internal body temperature
  • Transports protein and carbohydrates
  • Eliminates waste through urine and feces
  • Acts as a shock absorber for your brain and spinal cord

If you lose enough fluid for any reason, your electrolytes can become imbalanced. Your body systems get stressed, and your thinking process is impaired. When you're dehydrated your body decreases urine output, and your blood becomes thicker, which makes your heart work harder. Replacing lost fluids intravenously helps restore your body's normal functions. 

Lactated ringers and normal saline are two types of fluid-replacement products. They are both crystalloid solutions. This means that they have small molecules that can easily flow through membranes, such as the cell membranes in your body's tissues. Lactated ringers and normal saline are also both isotonic solutions. This means that they are similar to plasma in the number of dissolved particles they contain. 

Lactated ringers and normal saline contain different ingredients that affect how they work in your body. Each one also has different side effects that can cause problems. The risks of these are discussed below in the final section of this article. 

Lactated ringers contain:

  • Sodium chloride 
  • Sodium lactate 
  • Potassium chloride 
  • Calcium chloride dihydrate 
  • Water for injection

By contrast, normal saline is a mixture of water and sodium chloride.

Lactated ringers are more similar to your blood plasma than saline. Lactated ringers are used for:

  • Burn and trauma patients who need fluids
  • Acute blood loss 
  • Metabolic acidosis, which is an electrolyte disorder 
  • Electrolyte loss

Lactated ringers should not be used with people who have these issues:

Normal saline is the chemical name for salt. It is one of the most commonly used IV fluids and is used for most hydration needs, including: 

Normal saline should be used with caution or avoided by people who have the following issues: 

  • Heart disease
  • Kidney disease 
  • Prone to fluid volume overload, which is too much water in the body
  • Prone to hyperchloremia, which is too many chloride ions in the body

The risks associated with IV fluid replacement usually stem from receiving too much, too little, or the wrong type of fluid. 

The risks associated with receiving too much fluid include:

The risks associated with not receiving enough fluid include:

Finally, the risks associated with receiving the wrong type of fluid result from the wrong concentration of sodium in the blood. This can lead to changes in cell volume and function which may cause brain injury.