What to know about respiratory alkalosis
A person may breathe too fast due to anxiety, overdosing on certain medications, or using a ventilator.
Symptoms of respiratory alkalosis may include muscle spasms, irritability, dizziness, and nausea.
Respiratory alkalosis is one possible classification of an acid-alkaline imbalance in the body. The human body normally works to maintain a pH level of around 7.35–7.45.
Treating the underlying cause with medications or making changes to ventilator settings, if applicable, can help treat this condition.
Symptoms of respiratory alkalosis include anxiety and lightheadedness.
At its simplest definition, respiratory alkalosis almost always means that a person is breathing so fast that they are getting rid of carbon dioxide in excess. Carbon dioxide is an acid.
As a result of this carbon dioxide loss, the body's pH becomes more alkaline, the opposite of acidic.
Because some of the body's processes work in a tightly controlled range of pH levels, it is important that people maintain a pH balance that is close to normal.
In some cases, a doctor may consider having a more alkaline pH less dangerous than having an acidic one. However, some causes of respiratory alkalosis can be high-risk and require more urgent medical attention.
Doctors will usually divide the potential causes of respiratory alkalosis into three categories. All of these causes result in hyperventilation, or breathing too fast.
These three categories are:
1. Related to a medical condition
Numerous medical conditions can cause respiratory alkalosis. Some of these include:
- atrial flutter
- panic disorder
- liver disease
- pneumothorax, which occurs when air in the pleural cavity causes a collapsed lung
- pulmonary embolism
- overdose of salicylate medications, such as aspirin
Pregnancy can also cause respiratory alkalosis. This is because a woman tends to breathe faster during the third trimester due to the metabolic demands of the growing fetus.
2. Accidentally induced
Sometimes, a person receiving breathing support via a ventilator may show signs of respiratory alkalosis.
This means that the ventilator is providing too many breaths, or breaths that are too large, and the person breathes off extra carbon dioxide. This results in respiratory alkalosis.
3. Purposefully induced for therapy
If a person has a condition that causes acidosis, a doctor may make changes to their ventilator settings to try to help them breathe off excess carbon dioxide.
This can help bring a person's pH levels back to normal. An example of a time when a doctor may do this is after a head injury. Respiratory alkalosis may be protective to the brain if a person's body cannot maintain a normal breathing pattern.
The rate of respiration can be one of the most apparent symptoms of respiratory alkalosis.
Most people will breathe around 12–20 times per minute when not performing physical activity. An adult breathing faster than this at rest can experience respiratory alkalosis.
Symptoms of respiratory alkalosis may include:
- chest pain
- muscle stiffness
- numbness around the mouth
Sometimes, however, there may be no visible symptoms other than a faster-than-normal respiratory rate.
Some people, such as those with chronic obstructive pulmonary disease, may experience chronic respiratory alkalosis due to continuing hyperventilation. This is because these people frequently breathe faster than normal when trying to get more oxygen into the body.
A doctor can diagnose respiratory alkalosis using a blood test called an arterial blood gas test. They will take blood from an artery, and a special machine will then interpret the acid-alkaline content of the blood.
A person with respiratory alkalosis will have a pH higher than 7.45 and a lower arterial carbon dioxide level because they are breathing off excess carbon dioxide.
Doctors will base treatment on what is causing the underlying illness.
Doctors recommend treatment for respiratory alkalosis based on what is causing the underlying illness.
If the cause is related to a ventilator setting, such as it being too fast, having too high a supplemental oxygen setting, or giving too large a volume in each breath, the doctor may modify the settings so that the person can breathe more suitably.
This can help correct respiratory alkalosis quickly.
Other treatments may include:
- administering an opioid pain reliever or anti-anxiety medication to reduce hyperventilation
- providing oxygen to help keep a person from hyperventilating
- correcting any heart rhythm abnormalities by using medications or direct current cardioversion, which delivers an electric shock to reset the heart's rhythm
Because respiratory alkalosis is not usually life-threatening and the body often works to correct the imbalance, a doctor may not treat the higher-than-normal pH level aggressively.
Instead, they will treat the underlying condition to help a person's pH achieve a more normal value with time.
While respiratory alkalosis is not life-threatening, the underlying cause might be. The condition will likely resolve if a person or doctor corrects the underlying cause.
The body may try to self-correct the pH imbalance that comes with respiratory alkalosis, such as by having the kidneys increase excretion of alkaline and reduce excretion of acid.