What is Carbon Dioxide Narcosis?
Hypercapnia is a medical condition where there’s too much carbon dioxide (CO2) in your blood. This condition can result in many different health issues, the most severe one being CO2 narcosis, which can cause a decreased level of consciousness. If not identified and treated promptly, CO2 narcosis can lead to a coma or even death. This condition can affect various organs in your body, which can worsen your health.
There are many reasons why someone might have hypercapnia, but one of the most common is a medical condition called chronic obstructive pulmonary disease (COPD), a chronic lung disease that affects a person’s ability to breathe. The goal of treating hypercapnia is to address the root problem causing it. This often requires a team of medical professionals working together to get the best outcome for the patient.
What Causes Carbon Dioxide Narcosis?
Overall, CO2 narcosis happens when there’s too much carbon dioxide (CO2) in the body. This can occur due to many reasons but it helps to think of them in three categories: lessened breathing, increased “dead space” in the lungs, and higher CO2 production.
First, the amount of air a person breathes in a minute (determined by the number of breaths and the size of each breath) can reduce due to any factors affecting the respiratory center located in the medulla, a part of our brain. This center controls our urge to breathe, based on feedback from various signals. Noteworthy causes for this reduction include overdose of sedative drugs, stroke, and extreme cold exposure. There are also many nerves and muscles involved in breathing, and any diseases affecting these can lead to reduced airflow. Such ailments include a range of neurological and muscular disorders, nerve damage, and certain toxins.
Second, increased “physiological dead space” in the lungs happens when a part of the lung that doesn’t participate in exchanging gases increases. This means there are parts of the lungs where air is going, but blood flow (needed for gas exchange) isn’t correspondingly present. This can occur due to pressure on small lung blood vessels, destruction of these vessels in certain lung diseases or due to a major blood clot in the lung.
Next, anything that increases the production of CO2 can drive the CO2 narcosis. This isn’t usually the main cause but can contribute in conditions where the body’s metabolic rate is higher due to conditions like infection, overactive thyroid, or fever.
Exposure to environments with lots of CO2, like volcanoes or areas with geothermal activity, can also pose a risk for CO2 poisoning.
Another unique situation is oxygen-induced CO2 retention, which can occur in some people with a chronic lung condition when given extra oxygen.
Risk Factors and Frequency for Carbon Dioxide Narcosis
Information regarding CO2 narcosis is hard to gather due to the many different diseases that can lead to it. However, we can make a broad estimate based on the fact that most cases of high carbon dioxide levels in the blood stem from lung diseases that increase the amount of air the lungs cannot use. In fact, around 5% of people in the US suffer from COPD, a common lung disease, and it is more common in women than men. But, it’s important to note that not everyone with COPD will develop CO2 narcosis. The likelihood of having COPD grows with age and is particularly common in people over the age of 45.
Signs and Symptoms of Carbon Dioxide Narcosis
When examining a patient for the first time, it’s important to consider their airway, breathing, and circulation status. After ensuring these areas are secure, doctors will continue with gathering the patient’s medical history and conducting a physical examination, which may include a neurologic exam and a Glasgow coma scale (GCS) assessment.
The patient’s condition severity changes based on the amount of carbon dioxide (PaCO2) present in the bloodstream. With a small increase in PaCO2, the patient might have mild symptoms like a headache, shortness of breath, rapid breathing, or feeling drowsy. As carbon dioxide levels rise, patients can become disoriented, have slow breathing, and ultimately fall into a coma if they develop a condition called CO2 narcosis, which is a severely depressed level of consciousness. They may initially breathe quickly due to this condition, but over time their breathing slows down.
The patient’s skin appearance can also change depending on their breathing. If the patient is still breathing well, the skin color will look normal. However, if the breathing slows down due to high carbon dioxide levels, the patient might lack adequate oxygen, resulting in a blueish skin color.
- Headache
- Shortness of breath
- Rapid breathing
- Feeling drowsy
- Disorientation
- Slow breathing
- Normal skin color (if breathing is good)
- Blueish skin color (if breathing is poor)
CO2 narcosis is often examined in patients with a history of sedative use or chronic lung diseases like COPD. However, there are various causes that could contribute to this condition. Risk factors like drug use, smoking, obesity, and underlying diseases can help identify this condition. Interestingly, the patient doesn’t always need to have low oxygen levels to have high carbon dioxide levels. Sometimes, a patient with hypersensitive lungs can retain carbon dioxide, even while on supplemental oxygen, leading to a deceptive oxygen level but high carbon dioxide levels. This situation can happen in conditions like COPD. These patients may be breathing rapidly to maintain a satisfactory oxygen level, but this fast breathing allows less time for exhaling, leading to high carbon dioxide levels. Even if they are provided with supplemental oxygen, their carbon dioxide levels can increase if they have a suppression of the respiratory drive.
Testing for Carbon Dioxide Narcosis
Lab tests and other examinations can give a clear picture of why a patient may be experiencing CO2 narcosis, a condition where there’s too much carbon dioxide (CO2) in your blood. These tests may include:
A complete blood count: This can tell if the patient has polycythemia, a condition where the body produces too many red blood cells due to long-term low oxygen levels in the blood.
Chemical tests on the blood (serum chemistry): This can measure levels of bicarbonate, a chemical your body produces when it’s trying to balance out an increased acidity from too much CO2 in the blood (chronic hypercapnia).
ABG (arterial blood gas) analysis: This critical test measures the levels of gases in your arteries, like oxygen and carbon dioxide. If the PaCO2 (partial pressure of CO2) is over 45 mmHg (which is higher than normal levels), it’s considered hypercapnia. Whether this hypercapnia is a sudden or long-standing condition depends on the patient’s pH, a measure of how acidic or alkaline the blood is. Acute hypercapnia usually comes with a pH lower than 7.35. Chronic hypercapnia, on the other hand, often shows a near-normal pH.
Testing for drugs or toxins in the blood (toxicology screen): This is helpful for detecting certain drugs like opiates and benzodiazepines in the body, which might be causing the condition.
Tests that measure how well the thyroid gland is working (thyroid function tests): This can check for hypothyroidism, a condition where the thyroid gland isn’t producing enough hormones, which could be contributing to CO2 narcosis.
A chest X-ray: This can show if the patient’s lungs are over-inflated, if the diaphragms are flat, or if there are any abnormalities in the chest or diaphragms.
Scans of the neck or brain using computed tomography (CT scan): These are only done in particular cases, like if there’s a high suspicion of a stroke, cancer, or injury that has dissected (torn) arteries.
Treatment Options for Carbon Dioxide Narcosis
When a patient first comes in for treatment, the doctors start by checking their breathing and blood circulation. Once these are determined to be stable, the doctors then proceed with the treatment. The purpose of the treatment is to identify what’s causing the high levels of carbon dioxide in the patient’s body and fix it.
For instance, if the patient is suffering from a flare-up of chronic obstructive pulmonary disease (COPD), a condition that makes it hard to breathe, the doctors treat them with bronchodilators and steroids. Bronchodilators are medications that help open up the airways in your lungs, and steroids are used to reduce inflammation.
If it’s suspected that the patient has overdosed on a drug, doctors consider antidotes that can reverse the effects of those specific drugs. For example, naloxone is used for an opioid overdose. If the patient has a serious case of pneumonia, an infection that inflames the air sacs in one or both lungs, they would need to be treated with antibiotics.
If the patient is having a severe allergic reaction, also known as anaphylaxis, that’s affecting their airway, they would need a tube placed down their throat to help them breathe and would also be given treatments including antihistamines (H1 and H2 blockers), corticosteroids, and epinephrine (adrenaline).
If the patient is unconscious or has very weak breathing or is about to experience respiratory failure, they would need to be intubated also. Intubation involves inserting a tube into the patient’s airway through their mouth or nose to assist with breathing, and it usually followed by mechanical ventilation, a machine that helps the patient breathe.
If the patient is experiencing CO2 narcosis, a condition where high levels of carbon dioxide in the blood cause reduced consciousness, they should not receive non-invasive ventilation because of a high risk of ingesting stomach contents into the lungs. These patients need to be closely monitored in the intensive care unit (ICU), and their blood gas levels will be rechecked to monitor improvement while they’re on mechanical ventilation.
If the patient has new or unexpected high carbon dioxide levels, the treatment goal is to get this back to normal. If the high carbon dioxide levels are ongoing, the goal is to get it back to the patient’s usual levels. If the patient has been exposed to high levels of carbon dioxide in their environment, the first step is to get the person away from that environment, and then the treatment plan outlined above is followed.
What else can Carbon Dioxide Narcosis be?
Patients who show signs of being less alert or responsive could be experiencing a variety of health problems. These may include exposure to harmful substances, use of sedative drugs, metabolic issues, infections, and abnormalities in the upper or lower parts of the brain. It’s important for doctors to look into all these potential causes.
One specific condition that could cause a depressed level of consciousness is CO2 narcosis, which also causes high levels of carbon dioxide in the blood. To diagnose this condition and rule out others, doctors depend on the symptoms the patient is experiencing, laboratory test results, and medical imaging.
What to expect with Carbon Dioxide Narcosis
The outlook for a condition called CO2 narcosis, an excessive amount of carbon dioxide in the blood that can cause confusion or unconsciousness, depends on various factors. These factors include the patient’s age, any other health conditions they have, the root cause of the CO2 narcosis, the symptoms they are experiencing, how serious these symptoms are, and how their body responds to treatment.
Possible Complications When Diagnosed with Carbon Dioxide Narcosis
In treating a person with excess carbon dioxide in their blood due to chronic obstructive pulmonary disease (COPD), a possible complication could occur if too much of this excess is corrected. The overcorrection may result in a high blood pH (alkalemia), which might reduce the urge to breathe and potentially trigger seizures. Moreover, patients using mechanical ventilation systems can experience a range of complications such as lung damage from pressure (barotrauma) or volume (volutrauma), oxygen toxicity, pneumonia related to the use of a ventilator, or a condition known as auto-PEEP.
Possible Complications:
- High blood pH (Alkalemia)
- Reduced urge to breathe
- Potential seizures
- Lung damage from pressure (Barotrauma)
- Lung damage from volume (Volutrauma)
- Oxygen toxicity
- Pneumonia related to the use of a ventilator
- Auto-PEEP condition
Preventing Carbon Dioxide Narcosis
Understanding which patients might develop complications from their existing illnesses is very important. Being aware of the early signs of hypercapnia, which is an excessive amount of carbon dioxide (CO2) in the bloodstream, can help prevent their health from worsening into a condition called CO2 narcosis, where high levels of CO2 can cause drowsiness or unconsciousness. Early warning signs of CO2 narcosis may include increased confusion and difficulty in breathing.
Once these symptoms are detected, medical treatment should be sought straight away. One factor that can increase the risk of developing these conditions is tobacco abuse. As such, we strongly recommend that patients stop using tobacco. Details about treatments that can support quitting tobacco, like nicotine replacement therapy and other cessation techniques, should also be shared for their awareness and consideration.