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Hypercapnia is a condition that arises from high carbon dioxide levels in the blood. The normal value of the carbon dioxide level in adults are 22 to 29 mmol/L. A value of 33mmol/l in a patient will indicate hypercapnia. It is often caused by hypoventilation, which is disordered breathing causing poor oxygen entrance into the lungs and poor carbon dioxide emission from the lungs. Chronic obstructive pulmonary disease (COPD) is a well-known lung pathology that can result in hypercapnia. CO2 is an acid anhydride and it dissolves in water as, CO2, H2O, H2CO3, which is an acid. Therefore, too much carbon dioxide level in the blood will cause respiratory acidosis. How to lower the carbon dioxide level in blood? The body's main response to hypercapnia is to get rid of more carbonic acid and hold on to as much bicarbonate based in the kidneys.
Causes Of Hypercapnia
There are multiple causes that can give rise to high carbon dioxide levels in the blood. They can be mainly classified as respiratory and non-respiratory causes;
1. Chronic Obstructive Pulmonary Disease (COPD)
This is one of the most common causes of hypercapnia. COPD can be due to chronic bronchitis and emphysema. Chronic inflammation of the bronchi in bronchitis gradually results in narrowing of the airways, making less carbon dioxide wash out. In emphysema, there is the destruction of alveoli resulting in ventilation & perfusion miss-match. That will also ultimately elevate the blood carbon dioxide level.
2. Sleep Apnea
When a person is suffering from sleep apnea, he or she may experience shallow breathing or pauses in breathing during sleep. Poor breathing can make the blood carbon dioxide level rise up.
3. Neuromuscular Disorders
Diseases like myasthenia gravis, Guillen Barre syndrome, Duchenne muscular dystrophy are few neuromuscular disorders that can interfere with proper breathing. Multiple sclerosis and encephalitis can be classified under neurological conditions which can cause hypercapnia.
Brain stem stroke is another neurological condition that can stop the patient's spontaneous breathing because the respiratory center is situated there.
4. Adverse Effects Due To Drugs
Drugs like benzodiazepines, opioids, etc. can give rise to respiratory arrest as a fatal adverse effect.
When your blood carbon dioxide level is higher than normal, you may start feeling the following symptoms mainly involving thoughts, memory, and sleep. They are a headache, memory loss, sleep disturbance, anxiety, and personality changes. The above symptoms will be experienced in the early stage of acidosis. In conditions like acute respiratory failure, there will be a drastic reduction in blood pH levels. Effects involving several organs may arise with this sudden lowering of the pH level. That includes reduced heart muscle function, disturbances in heart rhythm, producing arrhythmias, hypotension.
How To Lower High Carbon Dioxide Levels In Blood?
Hypercapnia causing acidosis can be classified into acute and chronic respiratory acidosis. Chronic respiratory acidosis is most commonly occurring due to underlying lung pathology. So, when discussing how to lower high carbon dioxide levels in the blood, management of the underlying lung pathology gets the priority.
- When describing pharmacological intervention, there are multiple types of drugs available. Bronchodilators, dilate the airway and make breathing easier. There are short-acting drugs, ex: -salbutamol which is mainly used in the acute setup. Drugs like salmeterol are long-acting and are used in long-term follow-up.
- Ipratropium is another drug that dilates the airway. But the mechanism of action differs from beta-agonists. This drug has an anti-muscarinic effect and blocks acetylcholine binding onto the muscarinic receptors.
- Corticosteroids also play a major role in pharmacological management. Prednisolone is the most commonly used oral steroid. Hydrocortisone is given via intravenous route. Both these drugs act via reducing the ongoing inflammation of the airway.
All above-mentioned drugs will assist in airway dilation and make breathing easier. More CO2 will be washed out from the lungs and the blood carbon dioxide level will be lowered. So, all the above treatment options can be described under how to lower high carbon dioxide levels in the blood.
- Non-pharmacological management is mainly by supplementing with oxygen for inhalation. There are two methods. Non-invasive Bi-positive pressure (Bi-PAP) ventilation and mechanical ventilation.
- Oxygen can be administered directly via a facemask but, the concentration should be managed cautiously because COPD patients are most of the time hypercapnic and their respiratory drive is hypoxia. If the hypoxic drive is corrected their breathing will get diminished.
- Non-invasive Bi-positive pressure (Bi-PAP) is a popular method among clinicians to assist ventilation in COPD patients when they develop hypoxia with high carbon dioxide blood level. In Bi-PAP breathing is assisted by a flow of air that comes through a mouthpiece or nasal mask.
- When they are not responding to Bi-PAP, and respiratory muscles get fatigued mechanical ventilation becomes the only option to keep the carbon dioxide levels at the reference range. A tube will be inserted into the airway through the mouth and this procedure is called intubation.
- The clinician may advise on avoidance of lung irritants by quitting smoking and limiting their exposure to chemicals, dust, and fumes as supportive conservative management options. If the lungs and airways are excessively damaged the patient will have to undergo surgical treatment to lower blood carbon dioxide level. It includes lung volume reduction surgeries, where the damaged lung tissue is removed and lung transplant surgery, where a donor lung tissue is transplanted.
Since too much carbon dioxide in the blood can be harmful to the patient with fatal outcomes, it is important to detect and treat the condition promptly. It should be done, following the provided guidelines for how to lower the carbon dioxide level in blood.