What is Acid – Base Balance?
The balance of the body between acidity and alkalinity is referred to as acid-base balance. In order to work properly, the blood requires the right combination of acidic and basic (alkaline) compounds. The kidneys and lungs are working to maintain the acid-base balance. Also minor differences in the standard range may have major effects on vital organs.
The levels of acid and alkaline are determined on a pH scale. The increase in acidity causes the pH to fall. Increase in alkaline triggers a rise in pH levels. When the amount of acid in the blood is too high, it is called acidosis. In the same vein, when blood is too alkaline, it is called alkalosis.
Acidosis
Acidosis is caused by an overproduction of acid that builds up in the blood or by an excessive loss of bicarbonate from the blood (metabolic acidosis) or by a build-up of carbon dioxide in the blood resulting from poor lung function or depressed breathing (respiratory acidosis).
If the increase in acid overwhelms the body’s acid-based control systems, the blood will become acidic. As the pH of the blood drops (becomes more acidic), the parts of the brain that regulate breathing are stimulated to produce faster and deeper breathing (respiratory compensation). Breathing faster and deeper increases the amount of carbon dioxide that’s been exhaled.
The kidneys are also trying to compensate for this by excreting more acid in the urine. However, both mechanisms can be overwhelmed if the body continues to produce too much acid, leading to severe acidosis and eventually heart and coma problems. The acidity or alkalinity of any solution, including blood, are shown on the pH scale.
Cause of Acidosis
Acidosis is known as metabolic or respiratory acidosis, depending on the primary cause.
Metabolic Acidosis
Metabolic acidosis occurs when the amount of acid in the body is increased by intake of a product that is or may be broken down (metabolised) to an acid—such as wood alcohol (methanol), antifreeze (ethylene glycol) or high doses of aspirin (acetylsalicylic acid). A number of other drugs and poisons can cause acidosis. Metabolic acidosis can also occur as a result of irregular metabolism. The body develops excess acid in advanced shock phases (lactic acidosis) and in poorly regulated type 1 diabetes mellitus (diabetic ketoacidosis).
Even the formation of normal amounts of acid can lead to acidosis when the kidneys do not function normally (kidney failure) and are therefore unable to excrete sufficient amounts of acid in the urine. Metabolic acidosis also happens when the body lacks too much base. For example, bicarbonate may be lost via the digestive tract due to diarrhoea or ileostomy.
Respiratory Acidosis
Respiratory acidosis occurs when the lungs do not sufficiently remove carbon dioxide (inadequate ventilation), an issue that may arise in disorders that have a significant impact on the lungs (such as chronic obstructive pulmonary disease, severe pneumonia, heart failure, and asthma).
Respiratory acidosis can often occur when brain or nervous disorders or chest muscle disorders (such as Guillain-Barré syndrome or amyotrophic lateral sclerosis) affect breathing. In addition, people can experience respiratory acidosis when their breathing is slowed down due to oversedation due to opioids (narcotics), alcohol, or strong drugs that cause sleep (sedatives). As a result of slower breathing, the oxygen level in the blood may be low.
Sleep-disordered breathing (e.g. sleep apnea) will regularly stop breathing long enough to cause temporary respiratory acidosis.
Signs and Symptoms of Acidosis
In mild metabolic acidosis, people may have no symptoms but typically experience nausea, vomiting and tiredness. Breathing becomes deeper and slightly quicker (as the body tries to correct the acidosis by expelling more carbon dioxide). As acidosis worsens, people begin to feel incredibly weak and tired, and may feel confused and gradually nauseated. Eventually, cardiac attacks may occur in extreme cases, and blood pressure may drops, leading to shock, coma, and death.
When in respiratory acidosis, headache and drowsiness are the first symptoms. Sleepiness can progress to stupor and coma as oxygen in the blood becomes insufficient. Stupor and coma can develop in moments when breathing stops or is severely impaired, or in hours when breathing is less severely impaired.
Treatment of Acidosis
Treatment of the trigger and often bicarbonate fluids is provided by the vein. The treatment of acidosis is almost always aimed at reversing the cause. Doctors seldom offer alkaline medications, such as bicarbonate, to reverse acidosis. Treatment depends mainly on the cause of metabolic acidosis. For example, medication may be required to regulate insulin diabetes or to eliminate the poisonous agent from the blood in cases of poisoning.
In respiratory acidosis, treatment is aimed at improving the function of the lungs. Drugs that open the airways (bronchodilators, such as albuterol) can help people with lung diseases such as asthma and chronic obstructive pulmonary disease. Sedation from medications and other substances may often be reversed by antidotes. People who have seriously impaired breathing or lung function, for whatever cause, may need artificial ventilation to support breathing.
Extreme acidosis can also be treated directly if it does not respond to attempts to treat the cause. In such cases, bicarbonate can be administered intravenously. However, bicarbonate offers only temporary relief and can cause harm—for example, by overloading the body with sodium and water.
Alkalosis
Alkalosis is an excessive alkalinity in the blood due to an overabundance of bicarbonate in the blood or to a lack of acid in the blood (metabolic alkalosis) or a reduced level of carbon dioxide in the blood resulting from fast or deep breathing (respiratory alkalosis).
Causes of Alkalosis
If there is too much bicarbonate in the blood, a lack of acid in the blood or a low amount of carbon dioxide in the blood overwhelms the body’s acid-based regulation mechanisms, the blood will become alkaline. Alkalosis is known as metabolic or respiratory alkalosis, depending on the primary cause.
Metabolic Alkalosis
Metabolic alkalosis occurs when the body loses too much acid or gets too much base. For example, stomach acid is lost during times of excessive vomiting or when stomach acids are suctioned with a gastric tube (as is sometimes done in hospitals). In rare cases, metabolic alkalosis occurs in a person who has consumed too much base from substances such as baking soda (bicarbonate of soda).
In addition, metabolic alkalosis can occur when excessive loss of fluids and electrolytes (such as sodium or potassium) affects the ability of the kidneys to maintain the acid-base balance of the blood. For example, potassium loss sufficient to cause metabolic alkalosis can result from overactive adrenal gland or diuretics (for example, thiazides, furosemide, or ethacrynic acid).
Respiratory Alkalosis
Respiratory alkalosis occurs when rapid, deep breathing (hyperventilation) allows too much carbon dioxide to be eliminated from the bloodstream. Anxiety is the most common cause of hyperventilation and hence respiratory alkalosis. Other causes of hyperventilation and subsequent respiratory alkalosis include pain, low blood oxygen levels, fever, and overdose of aspirin (which can also cause metabolic acidosis).
Signs and Symptoms of Alkalosis
Alkalosis can cause irritability, muscle twitching, cramping, tingling in the fingers and toes and around the lips. Tingling (paresthesia) is a common hyperventilation complaint due to anxiety. Often alkalosis does not cause symptoms at all. If alkalosis is serious, painful muscle spasms (tetany) can develop.
Treatment of Alkalosis
The treatment of alkalosis is almost always aimed at reversing the cause. Doctors rarely literally give acids, such as hydrochloric acid, to reverse alkalosis. Metabolic alkalosis is typically treated by replacing water and electrolytes (sodium and potassium) while the cause is being treated. Rarely, when metabolic alkalosis is very severe, dilute acid is administered intravenously.
The first step, when in respiratory alkalosis, is to ensure that the person has enough oxygen. The doctor would then check for a serious cause, such as infection. If the pain allows a person to breathe quickly, it is generally enough to alleviate the pain.
When respiratory alkalosis is caused by anxiety or a panic attack, a deliberate effort to relax and slow breathing can cause the condition to disappear. Calming reassurance and emotional encouragement can help, and breathing in a paper bag (not a plastic bag) can help increase the level of carbon dioxide in the blood when a person breathes carbon dioxide back in after breathing.
