Chloride - Fluid Balance

The Chloride Information
By: Dr. Obikoya

Chloride is one of the most important minerals in the blood, along with sodium, potassium, and calcium. Chloride helps keep the amount of fluid inside and outside of cells in balance. It also helps maintain proper blood volume, blood pressure, and pH of body fluids.

Chloride is a binary compound of chlorine; a salt of hydrochloric acid. In health, blood serum contains 100 to 110 mmol/L of chloride ions. Chloride is the major extracellular anion and contributes to many body functions including the maintenance of osmotic pressure, acid-base balance, muscular activity, and the movement of water between fluid compartments. It is associated with sodium in the blood and was the first electrolyte to be routinely measured in the blood. Chloride ions are secreted in the gastric juice as hydrochloric acid, which is essential for the digestion of food.

Most of the chloride in the body comes from table salt (sodium chloride) in the diet. Chloride is absorbed by the intestine during food digestion. Any excess chloride is passed out of the body through the urine. Chloride levels in the blood generally rise and fall along with sodium levels in the blood. The amount of chloride in the blood is indirectly regulated by the hormone aldosterone, which also regulates the amount of sodium in the blood.

The amount of chloride decreases when the amount of sodium in the blood decreases, and vice versa. The level of chloride in the blood is also related to the level of bicarbonate. When the amount of bicarbonate decreases, the amount of chloride normally increases, and vice versa. A test for chloride is usually done on a blood sample taken from a vein. Tests for sodium, potassium, and bicarbonate are usually done at the same time as a blood test for chloride. Occasionally, a test for chloride can be done on a sample of all the urine collected over a 24 hour period (called a 24-hour urine sample) to evaluate how much chloride is being released into the urine.

A test for chloride may be done to:

Evaluate the electrolyte balance in the body. Too little chloride can cause muscle twitching, muscle spasms, or shallow breathing. Too much chloride can be associated with rapid deep breathing, weakness, confusion, and coma.

Help determine whether a problem with the kidneys or adrenals is present.

Help determine the cause for high blood pH. A condition called metabolic alkalosis can be caused by a loss of acid from the body (for example, from a loss of electrolytes through prolonged vomiting or diarrhea). Metabolic alkalosis can also result when the body loses too much sodium or from eating excessive amounts of baking soda (sodium bicarbonate).

Chloride is an important component of salt, which is actually sodium chloride. People who have congestive heart failure, kidney disease, or high blood pressure would benefit from decreasing their salt consumption. Your body maintains a closely regulated concentration of sodium in your body. If you eat a lot of salt (sodium chloride), then the concentration of sodium increases. To bring it back to normal, your body has two options: excrete the excessive sodium in your urine, or hold onto more water so you can dilute the concentration of sodium in your blood. If you hold onto more water, then you may feel more bloated. Also, your blood pressure may increase, because you have more volume in a closed blood vessel system.

One of the consequences of high blood pressure is progressive kidney damage, as with every beat of your heart, your blood hits the kidney tubules with excessive force. As your kidneys become more damaged, they lose the ability to excrete salt into your urine, so you hold onto more water to dilute the concentration of sodium. This increased volume increases your blood pressure, causing more kidney damage, and this vicious cycle continues and gets progressively worse..

For people who need to restrict their intake of salt, you might also try substituting potassium chloride (available in most groceries) for sodium chloride. While it doesn't taste as good as regular salt to most people, some studies indicate that potassium may actually lower your blood pressure. Chloride is also used as Calcium chloride. Calcium chloride in water dissociates to provide calcium (Ca++) and chloride (Cl-) ions. Both are normal constituents of the body fluids and are dependent on various physiological mechanisms for maintenance of balance between intake and output.

Calcium Chloride, USP is indicated:
For the treatment of low blood calcium, for conditions that require a prompt increase in blood plasma calcium levels.
For the treatment of magnesium intoxification, due to overdosage of magnesium sulfate. To combat the deleterious effects of too much potassium in the body. as measured by electrocardiographic (ECG), pending correction of the increased potassium level in the extracellular fluid. Calcium Chloride Injection, USP also may be used in cardiac resuscitation when weak or inadequate contractions return following defibrillation or when epinephrine injection has failed to strengthen myocardial (heart) contractions.