Hypercapnia: Causes, Symptoms & Treatment

Hypercapnia occurs when the blood becomes overly acidic with carbon dioxide. It causes the upper airways to stop functioning adequately. If the patient is not treated quickly, the worst-case scenario can result in carbon dioxide narcosis and death from respiratory failure.

What is hypercapnia?

In medicine, hypercapnia is an excessively high level of CO2 in the (arterial) blood. In healthy people, the arterial partial pressure is 40 mmHg or less. Patients with hypercapnia have a value above 45 mmHg. In hypercapnia, a distinction is made between an acute and a chronic form. If a person cannot exhale the carbon dioxide produced or inhaled as a metabolic byproduct for certain reasons, it is accumulated in the blood. The partial pressure of CO2 in the alveoli then increases. The greater the over-acidification (acidosis) of the blood with the gas, the more the respiratory activity of the lungs is impeded. Respiratory insufficiency (shortness of breath) results. Hypercapnia may also occur as a symptom of another condition, such as Pickwick’s syndrome in patients with severe obesity. If respiratory insufficiency is not treated in time, serious damage to the brain and heart occurs. In the worst case, CO2 anesthesia occurs with subsequent death from respiratory failure.

Causes

Hypercapnia can have a variety of causes. For example, adverse circumstances (accident) cause inhalation of extremely CO2-containing breathing air. CO2 rebreathing, as in sudden infant death syndrome (SID), can also cause hypercapnia. Metabolic alkalosis, triggered by acute potassium deficiency, can also lead to the occurrence of excessive CO2 accumulation in the blood. Inadequate respiratory function (respiratory insufficiency) due to damage to the alveoli (crushing of the chest due to an accident) or due to an obstruction in the airways are also causative factors in the occurrence of blood hyperacidity with CO2. Other triggers are: Damage to the respiratory center in the brain due to a cerebral infarction, impairment of the nerve pathways to the chest muscles due to paraplegia, pulmonary embolism, pulmonary tumor, severe asthma attacks, shortness of breath due to severe cold, severe pulmonary emphysema, or even pneumonia. So can septic shock, certain neuromuscular diseases, ingestion of an inappropriate medication (steroids, dehydrating medications, sedatives, anesthetics), and accidental administration of oxygen in patients with chronic obstructive pulmonary disease (COPD). They have severe hyperacidity of the blood anyway because of the permanent overload of their airways. The latter, however, causes the activation of the breathing reflex. If oxygen is then inadvertently supplied, the respiratory stimulus is inhibited and, in the worst case, respiratory arrest occurs.

Symptoms, complaints, and signs

Symptoms of mild hypercapnia include flushing of the skin, headache, clearly visible blood vessels, muscle twitching, increased heart rate, and mild confusion. As partial CO2 pressure increases, tremors then occur, increased breathing in an attempt to compensate for the shortness of breath, blood pressure increases, and dizziness. If the affected person then receives no help and the partial pressure rises above 50 mmHg, seizures, sweating, palpitations, panic and hypoxia (undersupply of oxygen to the body) occur. The heartbeat slows down, blood pressure drops sharply. Disturbances of consciousness follow with increasing drowsiness. The patient falls into a coma (CO2 narcosis). If ventilation is not given at this stage of hypercapnia, his lips turn blue (cyanosis) and death results from respiratory arrest.

Diagnosis and course of the disease

Hypercapnia can be diagnosed with the help of an arterial blood gas analysis. This includes measuring the pH and oxygen saturation of the blood. If the pH falls below 7.35, respiratory acidosis is present. Acidosis of the blood causes constriction of the blood vessels in the lungs, while simultaneously dilating those of the brain and the rest of the body. As a result, there is an increased concentration of potassium in the blood, which impairs cardiac function and can lead to cardiac arrhythmias. At a partial pressure of more than 60 mmHg, the patient falls into a coma.

Complications

Without treatment, hypercapnia can cause death of the patient in the worst case.In this case, the affected person usually dies of anesthesia by carbon dioxide, because the blood is extremely overacidified. Eventually, respiratory arrest occurs, which also leads to cardiac arrest. In acute emergencies, urgent treatment by a physician is therefore necessary. Furthermore, the affected person suffers from a high heartbeat and a frenzy. Likewise, headaches occur and the patient’s skin is usually red. The muscles twitch involuntarily and tremor occurs. The quality of life is extremely reduced by hypercapnia and the affected person also suffers from dizziness and nausea. It is not uncommon for loss of consciousness to occur, during which patients may also sustain injuries from a fall. Most sufferers also exhibit a panic attack when the symptoms of hypercapnia occur. In any case, the treatment of the disease is acute and must keep the affected person alive. Furthermore, the underlying disease must also be treated. Whether further complications occur with this treatment depends greatly on the underlying disease and usually cannot be universally predicted. In most cases, however, life expectancy is reduced by hypercapnia.

When should you see a doctor?

If symptoms such as skin redness, headache, and muscle twitching are noticed, hypercapnia may be underlying. A doctor should be consulted if these symptoms occur for no apparent reason and persist for more than three to four days. If other symptoms develop, such as an elevated pulse or confusion, a doctor must be consulted the same day. If the hypercapnia remains untreated, seizures, rapid heartbeat and sweating will set in – at the latest then medical advice is required. If consciousness disorders increase, the emergency services must be alerted. External signs such as a blue coloration of the lips, usually associated with circulatory collapse, require immediate first aid measures. Subsequently, the affected person must receive emergency medical care or be taken to a hospital. Hypercapnia often occurs in conjunction with potassium deficiency, severe colds or pneumonia. Septic shock and the use of certain medications may also be causative factors. If the above symptoms occur in connection with these diseases and risk factors, a physician must be consulted immediately. In addition to the family doctor, a pulmonologist or a specialist in internal medicine is the right person to contact.

Treatment and therapy

The initial emergency medical treatment consists of removing the constricting clothing from the fainting patient and elevating his or her chest. The legs should be placed lower. Then the oxygen mask is applied. Fluids should be administered sparingly, if at all. In the intensive care unit, apart from continuing to ventilate the patient, treatment of his underlying disease can then take place. He is ventilated by intubation or with the aid of an oxygen mask. He is connected to the BIPAP (Biphasic Positive Airway Pressure). This innovative ventilator allows the awakening patient to breathe at the lower and also at the upper pressure level. This stimulates diaphragmatic activity, which in turn initiates activation of the respiratory pump. If the patient breathes in more, the upper pressure level is lowered until both pressure levels correspond to each other. Extubation of the hypercapnic patient then occurs. In the case of chronic ventilatory insufficiency, ventilating the patient is more difficult because he or she is usually only slightly sedated and the medical staff must wait until the patient stops breathing on his or her own. Hypercapnia sufferers still receive additional beta sympathomimetics and theophylline. If an overdose of sedatives or opiates is the cause of the blood acidosis, Anexate or naloxone are administered.

Outlook and prognosis

Hypercapnia has an unfavorable prognosis. In severe cases and without treatment, the condition leads to respiratory failure, resulting in the patient’s death. In the event of an accident or sudden infant death syndrome, there is little chance of timely medical attention to ensure the survival of the affected individual. If air with a high CO² content is inhaled, the affected person will be in an acute life-threatening condition, with hardly any treatment options available or the necessary help arriving on the scene too late.If hypercapnia occurs as a result of marked obesity or intense pneumonia, there is also little chance of recovery. In most cases, life-prolonging measures are initiated because the underlying disease is already so advanced that recovery can only be documented in very rare cases. Hypercapnia can lead to loss of consciousness in addition to death. This significantly increases the likelihood of sequelae or permanent impairment. Only with an early treatment of the existing underlying disease as well as sufficient cooperation of the patient for an improvement of health, there is a realistic chance for an alleviation of the symptoms. Complete freedom from symptoms is seldom achieved, but is generally quite possible under certain conditions. If no irreparable damage to respiratory function has occurred, it can occur.

Prevention

To prevent hypercapnia, it is recommended never to abuse steroids, laxatives, opiates, sedatives, and other medications. This applies to both the duration of use and the dosage of the substances. Recreational divers should refrain from sparging. Those suffering from COPD or taking diuretics or steroids should be sure to have their blood levels checked at frequent intervals. In addition, frequent ventilation of enclosed spaces can help prevent dangerous hypercapnia.

Follow-up

In most cases of hypercapnia, the options for aftercare are relatively limited. In this context, they are only available to the affected person after successful treatment, so that first and foremost the disease itself must be detected and treated at an early stage. The earlier the hypercapnia is detected, the better the further course of the disease usually is. It is not always possible to achieve a complete cure, so that in many cases the patient’s life expectancy is limited by this disease. Patients with this disease must take care of their lungs at all costs. Smoking should be avoided. Likewise, a healthy lifestyle with a healthy diet generally has a positive effect on the course of the disease. Heavy strain on the body or strenuous and physical activities should be avoided. Taking medication can also have a positive effect on the course of the disease. The affected person must pay attention to a correct dosage with a regular application. Furthermore, support and care from one’s family and friends is also very important to relieve the patient.

This is what you can do yourself

As a rule, hypercapnia requires immediate treatment by an emergency physician. This may prevent the patient’s death. The complaint itself can be prevented relatively easily by the individual not abusing steroids or laxatives. Other medications that can lead to this condition should also not be taken in high amounts. Hypercapnia can likewise be prevented by regularly ventilating closed rooms, as this will bring fresh, low-carbon dioxide air into the room from outside. If hypercapnia does occur, the first priority is to call an emergency physician. Until the emergency physician arrives, the affected person’s clothing must be loosened if it is constricting his or her body. Furthermore, the chest must be elevated and the legs positioned low to relieve discomfort. Fluids should also be administered only in very small quantities. Further treatment is then carried out by the emergency physician with the aid of a ventilator. During the course of treatment, it is important for affected persons to pay attention to the intake of medication. Regular checking of blood values can also prevent possible complications and discomfort.