Hypocarbia

What is Hypocarbia?

Hypocarbia, also known as hypocapnia, is a condition where the levels of carbon dioxide (CO2) in your lung’s air sac (alveoli) and blood are lower than the usual range. The normal range is 35 millimeters of mercury (mmHg). CO2 is a waste product produced by your cells when they process fats, sugars, and proteins. The lungs and kidneys are the main systems in the body that keep CO2 levels stable.

Additionally, CO2 levels are also managed through a system that balances CO2 and bicarbonate (HCO3), a chemical that helps regulate pH, which is a measure of how acidic or alkaline a substance is. When levels of CO2 drop too low, it generally results in a condition termed ‘respiratory alkalosis’, which makes your blood more alkaline or basic. Understanding these conditions is key to managing the balance of substances in the body.

What Causes Hypocarbia?

Hypocarbia, a condition where there’s too little carbon dioxide (CO2) in the blood, happens either when the body makes less CO2 or loses too much. Since our bodies rarely make less CO2, the main way we experience hypocarbia is by losing CO2. This can happen through bodily systems that help balance our pH levels or changes in the lungs, which are very efficient at removing CO2 from the body.

The process of removing CO2 from the body using the lungs involves moving the gas from areas in the body where it’s highly concentrated, like the blood, to the air outside our bodies where there’s less CO2. To maintain this transfer, the lungs regularly clear away CO2, regardless of how much there is in the blood. The rate at which the body produces CO2 and the speed at which the lungs remove it determine the amount of CO2 in the blood.

The flow of air from the lungs to the outside environment, called alveolar ventilation, is crucial to this process. It’s determined by the total ventilation (air movement in and out of the lungs) and the ratio of “dead space” – areas in the lungs where no gas exchange takes place – to the volume of air we inhale and exhale with each breath (tidal volume).

To mathematical relationships permit us to predict how the body produces and removes CO2:

* PaCO2 = 0.863 x CO2 production / alveolar ventilation
* Alveolar ventilation = total ventilation – dead space ventilation
* Total ventilation = respiratory rate x tidal volume
* Tidal volume = respiratory rate x dead-space volume

In simple terms, PaCO2 is the level of CO2 in our blood. VCO2 is the amount of CO2 our body produces. VA is the amount of air we exhale from our lungs into the environment. VE is the total amount of air we inhale and exhale. VD is the amount of air that stays in the ‘dead space’ in our lungs. RR is the speed at which we breathe, and TV is the amount of air we inhale and exhale with each breath.

This allows us to see that the rate of breathing and the volume of air we inhale and exhale with each breath controls how much CO2 we eliminate from our body. Any illness that makes us breathe faster or deeper can lead to hypocarbia. Quite often, breathing faster is the main cause. A variety of illnesses can cause this change.

Hypocarbia is often associated with a condition called respiratory alkalosis because both are typically caused by breathing too fast (hyperventilation). This can be due to central causes, like head injuries, strokes, anxiety-hyperventilation, pain, fear, stress, drugs, and certain medications, and toxins.

Lack of oxygen (hypoxia) can make us breathe faster in an attempt to get more oxygen, but this can also cause us to lose too much CO2.

Lung-related causes include blood clots in the lungs (pulmonary embolisms), collapsed lung (pneumothorax), lung infections (pneumonia), and flare-ups of conditions like asthma or chronic obstructive pulmonary disease (COPD).

“Medically induced” or iatrogenic causes usually happen when a patient on a breathing machine (ventilator) breathes too fast.

Risk Factors and Frequency for Hypocarbia

The likelihood and spread of a disease can differ based on its specific cause. Similarly, the extent of illness and risk of death are also dependent on the particular cause of the disease. Younger patients generally have better chances of recovery. The most frequently seen imbalance of acid and base levels in seriously ill patients is ‘respiratory alkalosis’.

Signs and Symptoms of Hypocarbia

Hypocarbia is a health problem that arises when a person’s body has less carbon dioxide than it should have. People experiencing hypocarbia are often hyperventilating, or breathing too fast, which is why one common symptom is a feeling of shortness of breath. Because various health issues can cause hypocarbia, the exact signs and symptoms can vary widely. They can include:

Shortness of breath
Fever and chills
Swelling in the arms or legs
Difficulty breathing while lying down
Weakness or fatigue
Chest pain
Wheezing or coughing up blood
Past injuries, surgeries, or sicknesses
Nausea, abdominal pain, or weight loss
Dizziness, confusion, or fainting

In more serious cases, people may also have seizures. Though, these typically only happen if the person also has low oxygen levels in their blood.

Because hypocarbia can cause the blood vessels in your brain to narrow, it can also lead to other symptoms such as dizziness, confusion, or passing out. Sometimes, feeling a strange tingling in your hands and feet, sweaty palms, or numbness can indicate hypocarbia.

This condition can also interfere with how your body uses vitamin D, leading to symptoms typically seen with Vitamin D deficiency such as widespread body pain (fibromyalgia) and muscle spasms (tetany).

During a medical examination, doctors often notice fast breathing (tachypnea) and a rapid heartbeat (tachycardia) in patients. The movements and breathing rate are typically more noticeable in acute, or sudden-onset cases, while in long-term cases, these symptoms may not be as evident.

Furthermore, a doctor might observe Trousseau and Chvostek signs, which are particular reactions signaling a low amount of calcium in the blood. This happens because the body’s chemistry is off-kilter due to the hypocarbia.

It’s also worth noting that many lung diseases can cause hyperventilation and hypocarbia. Depending on the particular lung condition, a doctor could observe different symptoms during a lung exam, such as abnormal sounds associated with pneumonia, asthma, or left ventricular failure.

Testing for Hypocarbia

If you’re experiencing a range of symptoms that could be caused by a number of conditions, your doctor will start by asking you questions about your medical history and doing a physical exam in order to narrow down the possible causes. An important test that helps doctors make their diagnosis is an arterial blood gas test, which checks for any imbalances in the acidity of your blood. Blood tests to measure the levels of different electrolytes (minerals) in your body, such as sodium, potassium, magnesium, phosphate, and calcium, are also useful as any changes to these can lead to further problems.

If your body is responding to a quick-onset (“acute”) illness or condition, a test to measure your bicarbonate levels (a type of salt) can tell your doctor a lot. When you’re sick, your bicarbonate level drops 2 mEq/L for each decrease of 10 mmHg in the amount of carbon dioxide in your blood. For longer-term (“chronic”) conditions, however, the bicarbonate level decreases by 5 mEq/L for each drop of 10 mmHg in the carbon dioxide level. Regardless of whether your medical issue is new or ongoing, your bicarbonate levels don’t usually go below 12 mmHg if your primary issue is lung-related.

If you’re not getting enough oxygen (hypoxic), your doctor will use a test called the A-a gradient to find the cause. If this test gives a high result, it might be because of a blockage in your lung’s blood vessels (pulmonary embolism), and further checks will be done to investigate this.

A chest X-ray is an important test for everyone as it helps the doctors find out if there’s a problem with the structure of your lungs or if there is an infection. It can also help tell if fluid is collecting in your lungs. A chest computed tomography (CT) scan can be arranged if your symptoms suggest that this could be useful.

Finally, if your doctor suspects a problem with your brain or nervous system, a CT or magnetic resonance imaging (MRI) scan of your head can be done. They may also suggest a lumbar puncture – a test where a small amount of fluid is taken from around your spine for testing the levels of white blood cells, glucose, and proteins. This can help the doctors identify any neurological issues.

Treatment Options for Hypocarbia

Hypocapnia, or low levels of carbon dioxide (CO2) in your blood, is typically treated by addressing the root cause to try and reduce the rate of breathing if possible. Years ago, people would treat this condition by breathing into a paper bag to raise the CO2 levels in their lungs. However, it was eventually found that this method increased the likelihood of negative outcomes, including a higher risk of death, so it’s no longer suggested as a treatment method.

For patients with elevated anxiety levels, medications to reduce anxiety might be needed. If the hypocapnia is caused by an infection, antibiotics might be given based on lab results from samples of phlegm or blood. If a blood clot is the cause, medications that help prevent blood clots are needed.

If someone cannot breathe on their own due to severe lung problems, such as sudden respiratory failure, a major COPD flare-up, or an intense asthma attack, they might require a breathing machine to support their respiratory function. Patients who rely on a ventilator as part of their regular treatment may need the settings of the device adjusted to reduce the rate of breathing.

If low CO2 levels are intentional, perhaps due to medical procedures, then medical personnel will closely monitor blood gas levels. In extreme cases, doctors can directly lower the blood’s pH level by using acidic substances, although this isn’t a common practice.

When a person’s carbon dioxide (CO2) levels are abnormally low, which is called hypocarbia, it can be the result of a variety of different conditions. These conditions can be related to normal body changes, such as pregnancy, or related to external factors like a hyperventilation syndrome. Further, there are several health issues that could lead to hypocarbia:

Asthma exacerbation
Irregular heart rhythms such as atrial fibrillation, flutter, and tachycardia
Different types of pneumonia caused by bacteria or acquired from the community
Bacterial sepsis
An exacerbation of chronic obstructive pulmonary disease (COPD)
Head trauma
Heatstroke
High thyroid hormone levels (hyperthyroidism) and thyrotoxicosis
Hyperventilation syndrome
Idiopathic pulmonary fibrosis – a chronic lung disease causing tissue thickening
Meningitis
Conditions causing shifts in body’s acid-base balance like metabolic acidosis or alkalosis
Heart attack (myocardial infarction)
Panic disorder
Collapsed lung (pneumothorax)
Lung related issues like pulmonary edema and embolism
Salicylate toxicity – poisoning by aspirin or similar medicines
Theophylline toxicity
Viral pneumonia

What to expect with Hypocarbia

Hypocarbia, which refers to low levels of carbon dioxide in the blood, is generally harmless and patients typically handle it pretty well. Therefore, the outcome often hinges on what’s actually causing the hypocarbia and how well a person responds to the treatment for that underlying cause.

Possible Complications When Diagnosed with Hypocarbia

Patients generally handle hypocarbia, a condition of abnormally low carbon dioxide in the blood, without major problems. Therefore, there aren’t notable complications arising solely due to a low level of carbon dioxide in the blood (low PaCO2).

Preventing Hypocarbia

If you experience hypocarbia, which means you have low levels of carbon dioxide (CO2) in your blood due to anxiety or a panic disorder, it’s crucial to learn how to manage your breathing rate during episodes of intense anxiety. This will help regulate your CO2 levels and alleviate your symptoms. In the past, people were advised to breathe into a paper bag to increase their CO2 levels, but this method is no longer suggested.

Frequently asked questions

Hypocarbia, also known as hypocapnia, is a condition where the levels of carbon dioxide (CO2) in the lungs and blood are lower than the usual range. It is a result of the body processing fats, sugars, and proteins, and is managed by the lungs and kidneys to keep CO2 levels stable.

Signs and symptoms of Hypocarbia include: - Shortness of breath - Fever and chills - Swelling in the arms or legs - Difficulty breathing while lying down - Weakness or fatigue - Chest pain - Wheezing or coughing up blood - Past injuries, surgeries, or sicknesses - Nausea, abdominal pain, or weight loss - Dizziness, confusion, or fainting In more serious cases, people may also have seizures, especially if they also have low oxygen levels in their blood. Hypocarbia can cause the blood vessels in the brain to narrow, leading to symptoms such as dizziness, confusion, passing out, strange tingling in the hands and feet, sweaty palms, or numbness. It can also interfere with the body's use of vitamin D, resulting in symptoms typically seen with Vitamin D deficiency, such as widespread body pain (fibromyalgia) and muscle spasms (tetany). During a medical examination, doctors often notice fast breathing (tachypnea) and a rapid heartbeat (tachycardia) in patients with hypocarbia. Acute cases may have more noticeable movements and breathing rate, while long-term cases may not exhibit these symptoms as prominently. Doctors might also observe Trousseau and Chvostek signs, which are specific reactions indicating low calcium levels in the blood due to the body's chemistry being disrupted by hypocarbia. It is important to note that many lung diseases can cause hyperventilation and hypocarbia, and depending on the specific lung condition, doctors may observe different symptoms during a lung exam, such as abnormal sounds associated with pneumonia, asthma, or left ventricular failure.

Hypocarbia can occur when the body loses too much carbon dioxide (CO2) through bodily systems that help balance pH levels or changes in the lungs. Breathing faster or deeper, as well as certain illnesses or conditions, can cause hypocarbia.

The doctor needs to rule out the following conditions when diagnosing Hypocarbia: - Asthma exacerbation - Irregular heart rhythms such as atrial fibrillation, flutter, and tachycardia - Different types of pneumonia caused by bacteria or acquired from the community - Bacterial sepsis - An exacerbation of chronic obstructive pulmonary disease (COPD) - Head trauma - Heatstroke - High thyroid hormone levels (hyperthyroidism) and thyrotoxicosis - Hyperventilation syndrome - Idiopathic pulmonary fibrosis - a chronic lung disease causing tissue thickening - Meningitis - Conditions causing shifts in the body's acid-base balance like metabolic acidosis or alkalosis - Heart attack (myocardial infarction) - Panic disorder - Collapsed lung (pneumothorax) - Lung-related issues like pulmonary edema and embolism - Salicylate toxicity - poisoning by aspirin or similar medicines - Theophylline toxicity - Viral pneumonia

The types of tests that are needed for Hypocarbia include: - Arterial blood gas test to check for imbalances in the acidity of the blood - Blood tests to measure the levels of electrolytes such as sodium, potassium, magnesium, phosphate, and calcium - Bicarbonate level test to assess the levels of bicarbonate in the blood - A-a gradient test to determine the cause of hypoxia - Chest X-ray or CT scan to evaluate the structure of the lungs and detect infections or fluid accumulation - CT or MRI scan of the head to assess the brain and nervous system - Lumbar puncture to test the levels of white blood cells, glucose, and proteins in the fluid around the spine.

Hypocapnia, or low levels of carbon dioxide (CO2) in the blood, is typically treated by addressing the underlying cause and attempting to reduce the rate of breathing if possible. Breathing into a paper bag, which was previously used as a treatment method, is no longer suggested due to the increased risk of negative outcomes, including a higher risk of death. Treatment options may include addressing anxiety levels with medications, administering antibiotics if the cause is an infection, providing medications to prevent blood clots if a blood clot is the cause, or using a breathing machine to support respiratory function in severe cases. In intentional cases or during medical procedures, blood gas levels are closely monitored, and in extreme cases, doctors may directly lower the blood's pH level using acidic substances, although this is not a common practice.

When treating Hypocarbia, there can be side effects such as a higher risk of death if the patient breathes into a paper bag to raise CO2 levels in their lungs. However, this method is no longer suggested as a treatment. Other side effects can include negative outcomes and complications if the root cause of Hypocarbia is not properly addressed.

The prognosis for Hypocarbia depends on the underlying cause and how well a person responds to treatment for that cause. Generally, Hypocarbia is harmless and patients typically handle it well. Younger patients generally have better chances of recovery.

You should see a doctor specializing in pulmonology or respiratory medicine for Hypocarbia.

Cerebral Vasoconstriction Hormones and Body Chemistry Hyperventilation Hypocalcemia Respiratory Alkalosis