Receiving fluids through a vein can be a life-saving treatment. Intravenous (IV) fluids are necessary in many circumstances, such as when a person is unable to consume fluids by mouth, is very dehydrated or requires medications that can only be given through a vein.
But like all treatments, IV fluids can have side effects, particularly if the body receives more than it needs. Excess fluids in the body produce hypervolemia, which can cause swelling and other potentially harmful effects. Depending on the type of fluid, changes in electrolytes in the blood may also occur, leading to additional side effects.
Nasal Congestion and Peripheral Edema
Fluid accumulation in tissues lining the nose is one of the earliest indicators of hypervolemia. These tissues become swollen, causing the nose to feel congested. According to an article published in the "The Medical Journal of Australia" in November 2008, healthy individuals can receive as much as 2 to 3 quarts of IV fluid in a short period of time before they notice nasal congestion.
One of the most obvious signs of IV fluid overinfusion is the accumulation of fluid under the skin, known as peripheral edema. This produces swelling that is usually most noticeable in the feet, ankles, fingers and hands and around the eyes. When severe, the whole body can appear swollen, and fluid may leak out of holes in the skin produced by previous needle punctures.
Excessive fluid can also accumulate in or around organs inside the body. Fluid can collect, for example, in the walls of the intestines, producing bowel edema that interferes with normal bowel function. When fluid accumulates in the space surrounding the abdominal organs -- a condition called ascites -- the whole abdomen will appear swollen.
Fluid can also collect in the chest, either in the lungs themselves or in the pleural space surrounding the lungs. Shortness of breath will occur as fluid in either location interferes with breathing and the movement of oxygen from lungs into the bloodstream.
Blood Pressure and Heart Effects
As overinfusion of IV fluids increases the amount of fluid in the bloodstream, the blood pressure usually increases. This is an early sign of hypervolemia, according to Brenner and Rector's the Kidney E-book.
The heart is also affected, as it must work harder to pump the extra blood around the body. Although a healthy heart can handle a large increase in fluid, when heart disease is present, the heart may be unable to do so, leading to heart failure. Weakness and dizziness are common with heart failure, and the blood pressure may fall. As well, blood that cannot be pumped out of the heart will back up into the lungs, increasing the amount of fluid in the lungs and worsening shortness of breath.
Although IV fluids are all clear liquids that look the same, they contain different amounts and types of electrolytes. When large amounts of IV fluids are given, they may alter the concentration of electrolytes in the blood. Fluids, such as normal saline or hypertonic saline, contain more sodium and chloride than blood, so overinfusion of these fluids can raise blood sodium and chloride levels. By contrast, fluids containing low or no sodium and chloride, will lower blood levels.
Changes in blood sodium are particularly serious. The brain is very susceptible to changes in sodium, so symptoms are primarily neurologic. Both abnormally low and high sodium levels can produce headaches, confusion, muscle twitching, seizures and even coma.
Talk to your doctor if you think you may be receiving too much IV fluid. Simply reducing the amount of fluid you are being given is sometimes all that is needed. If your kidneys are normal, the excess fluid will eventually be removed through your urine.
If you have shortness of breath or other symptoms that require prompt removal of excess fluid, you will likely be given diuretic medications through an IV to increase the amount of urine your body produces. Treatment of electrolyte changes will depend on the specific abnormalities noted on blood tests.
Reviewed and revised by Mary D. Daley, M.D.
Is This an Emergency?
- The Medical Journal of Australia: Avoiding Common Problems Associated with Intravenous Therapy
- Merck Manual Professional Version: Hyponatremia
- Merck Manual Professional Version: Hypernatremia
- William's Textbook of Endocrinology E-book: Shlomo Melmed, et al.
- Brenner and Rector's the Kidney E-book; Maarten W. Taal, et al.