Acid-Base Balance Overview
Your blood needs the right balance of acid and basic (alkaline) compounds to function properly.
This is called the acid-base balance. Your kidneys and lungs work to keep the acid-base balance.
Even slight variations from the normal range can have significant effects on your vital organs.
Acid and alkaline levels are measured on a pH scale. An increase in acidity causes pH levels to
fall. An increase in alkaline causes pH levels to rise.
When the levels of acid in your blood are too high, it is called acidosis. When your blood is too
alkaline, it is called alkalosis.
Respiratory acidosis and alkalosis are due to a problem with the lungs. Metabolic acidosis and
alkalosis are due to a problem with the kidneys.
Each of these conditions is caused by an underlying disease or disorder. Treatment depends on
the cause.
What is Acidosis?
When your body fluids contain too much acid, this is known as acidosis. Acidosis occurs when
your kidneys and lungs can’t keep your body’s pH in balance.
There are two types of acidosis--metabolic and respiratory. Metabolic acidosis occurs when your
kidneys can’t get rid of acid buildup or when your body gets rid of too much base. Bases
neutralize acids, and vice versa. Respiratory acidosis occurs when your lungs do not properly
eliminate the carbon dioxide (CO2). When CO2 builds up in your blood, it becomes more acidic.
Causes and Risk Factors for Acidosis
The acidity of your blood is measured by determining its pH. A lower pH means that your blood
is more acidic. A higher pH means that your blood is more basic. The pH of your blood should
be around 7.4.
Many of the body’s processes produce acid. Your lungs and kidneys can usually compensate for
slight pH imbalances. However, problems with these organs can lead to acidosis.
Respiratory Acidosis
Respiratory acidosis occurs when too much CO2 builds up in the body. Normally the lungs
remove CO2 while you breathe. However, sometimes your body can’t get rid of enough CO2.
This may happen because of:
 chronic airway conditions, like asthma
 injury to the chest
 obesity, which can make breathing difficult
 sedative misuse, including overuse of alcohol
 muscle weakness in the chest
 problems with the nervous system
 deformed chest structure
Metabolic Acidosis
Metabolic acidosis starts in the kidneys instead of the lungs. It occurs when they can’t eliminate
enough acid or when they get rid of too much base. There are three major forms of metabolic
acidosis:
 Diabetic acidosis occurs in people with poorly managed diabetes. Ketones build up in
the body and acidify the blood.
 Hyperchloremic acidosis results from a loss of sodium bicarbonate. This base helps to
keep the blood neutral. Both diarrhea and vomiting can cause this type of acidosis.
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Lactic acidosis occurs when there is too much lactic acid in your body. Many things can
cause a buildup of lactic acid. These include chronic alcohol use, heart failure, cancer,
seizures, liver failure, prolonged lack of oxygen, and low blood sugar. Even prolonged
exercise can lead to lactic acid buildup!
Other factors that can contribute to your risk of metabolic acidosis include:
 eating a high-fat, low-carbohydrate diet
 kidney failure
 dehydration
 aspirin or methanol poisoning
Symptoms of Acidosis
Both respiratory and metabolic acidosis share many symptoms. However, the symptoms of
acidosis do vary based on its cause. Some of the common symptoms include:
Respiratory Acidosis
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fatigue
becoming tired easily
confusion
shortness of breath
sleepiness
Metabolic Acidosis
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rapid and shallow breathing
confusion
fatigue
headache
sleepiness
lack of appetite
breath that smells fruity – this is a sign of diabetic acidosis/ketoacidosis
Tests and Diagnosis
If you think you may have acidosis, go to the doctor immediately. Early diagnosis can make a
big difference in your recovery.
Doctors diagnose acidosis with a series of blood tests. An arterial blood gas looks at the levels of
oxygen and carbon dioxide in your blood. It also reveals your blood pH. A basic metabolic panel
checks your kidney functioning and your pH balance. It also measures your calcium, protein,
blood sugar, and electrolyte levels. Taken together, these tests can identify the different types of
acidosis.
If you are diagnosed with respiratory acidosis, your doctor will want to check the health of your
lungs. This may involve a chest X-ray or a pulmonary function test. If metabolic acidosis is
suspected, you will need to provide a urine sample. Doctors will check the pH to see if you are
properly eliminating acids and bases. Additional tests may be needed to determine the cause of
your acidosis.
Part 5 of 7: Treatments
Treatments
Doctors usually need to know what is causing your acidosis in order to treat it. However, some
treatments can be used for any type of acidosis. For example, your doctor may give you sodium
bicarbonate (baking soda) to raise the pH of your blood. This can be done either by mouth or in
an intravenous (IV) drip. Other types of acidosis are often treated by treating their cause.
Respiratory Acidosis
Treatments for this condition are usually designed to help your lungs. For example, you may be
given drugs to dilate your airway. You might also be given oxygen or hooked up to a continuous
positive airway pressure (CPAP) device. The CPAP can help you breathe if you have an
obstructed airway or muscle weakness.
Metabolic Acidosis
The specific types of metabolic acidosis each have their own treatments. People with
hyperchloremic acidosis are given oral sodium bicarbonate. Acidosis from kidney failure can be
treated with sodium citrate. Diabetics with ketoacidosis receive IV fluids and insulin to balance
out their pH. Lactic acidosis treatment might include bicarbonate supplements, IV fluids,
oxygen, or, antibiotics, depending on the cause.
Part 6 of 7: Prognosis
Acidosis Prognosis
How well you recover from acidosis depends on its cause. Quick, correct treatment also has a
strong influence on your recovery.
Some individuals fully recover from acidosis. Others have problems with organ function,
respiratory failure, and kidney failure. Severe acidosis can cause shock or even death.
Part 7 of 7: Prevention
Acidosis Prevention
You can’t completely prevent acidosis. However, there are some things you can do to lower your
risk.
To Reduce The Risk of Respiratory Acidosis:
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Take sedatives as prescribed and never mix them with alcohol.
Stop smoking. Smoking can damage your lungs and make breathing less effective.
Maintain a healthy weight. Obesity can make it harder for you to breathe.
To Reduce The Risk of Metabolic Acidosis:
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Stay hydrated. Drink plenty of water and other fluids.
Keep control of your diabetes. If you manage your blood sugar levels well, you can avoid
ketoacidosis.
Stop drinking alcohol. Chronic drinking can increase lactic acid buildup.
What is Alkalosis?
Alkalosis is when alkaline levels are too high due to decreased carbon dioxide or increased
bicarbonate. There are five kinds of alkalosis.
Respiratory alkalosis is when your blood has low levels of carbon dioxide. This can be caused
by a number of factors, including:
 lack of oxygen
 high altitude
 fever
 lung disease
 liver disease
 salicylate poisoning
When you have alkalosis, your body works to get your acid levels back to normal. That can leave
carbon dioxide and bicarbonate levels at abnormal levels. This is called compensated alkalosis.
When your blood has too much bicarbonate, it is called metabolic alkalosis. This can happen
from prolonged vomiting. Prolonged vomiting can also make you lose too much chloride. This is
called hypochloremic alkalosis. Some diuretic medicines can cause you to lose too much
potassium. This is called hypokalemic alkalosis.
Symptoms
Symptoms of alkalosis may include:
 muscle twitching, hand tremor, muscle spasms
 numbness and tingling
 nausea, vomiting
 lightheadedness, confusion
Risks
In severe cases, alkalosis can lead to arrhythmias or coma.
Diagnosis
Along with a physical exam, diagnostic testing for alkalosis may include a metabolic panel,
blood gas analysis, urinalysis, and urine pH.
Treatment
Some medications can help correct chemical losses. Further treatment will depend on the cause.