Hypercapnia is a condition characterized by elevated levels of carbon dioxide in the blood. This primarily occurs when the lungs are incapable of expelling the carbon dioxide from the body.
Affected individuals have an elevated blood pressure and there is a significant decrease in the neural activity. Patients also complain of lethargy, confusion and headache. In addition to these, other symptoms include increase in arterial blood pressure along with increased cardiac output, which eventually predisposes the individual to develop arrhythmias .
In severe cases, when PaCO2 increases beyond 75mm Hg, then individuals also experience convulsions, disorientation, hyperventilation and panic. In extreme cases, development of such symptoms can gradually lead to unconsciousness and finally death.
Measurement of arterial blood gases in patients with hypercapnia is indicated in the preliminary levels. This would give insight about the levels of carbon dioxide accumulated in the blood. In order to diagnose the underlying etiology, it is necessary to conduct various tests such as pulmonary function tests. This would help in confirming the presence of chronic obstructive pulmonary disease. In addition, chest radiographs also form an important part of the diagnostic procedure .
In instances, when hypercapnic respiratory failure is suspected, the levels of thyroid hormone should be detected in order to determine hypothyroidism. Studies have shown that hypothyroidism is a major reversible factor that causes respiratory failure.
Hypercapnia also has deleterious effect on the cardiovascular system; therefore, electrocardiography should be performed to rule out the presence of cardiovascular disease as the underlying cause. This test would also help in detection of arrhythmias.
The primary line of treatment for hypercapnic patients is careful administration of oxygen in order to prevent the condition from deteriorating. However, too much or too little oxygen can have its own share of ill effects, and therefore the amount of oxygen to be given should be carefully decided.
Once the condition of the patient has been stabilized, and hemodynamic status have been brought under control then efforts should be channelized for correcting the underlying condition. In severe cases, if signs of respiratory failure are evident, then concerned patients need to be stabilized through ventilator support. Affected individuals would also be required non-invasive positive pressure ventilation .
Treating underlying conditions can successfully restore lung functioning. Long-term oxygen therapy is indicated in patients with chronic obstructive pulmonary disease and which has a poor prognosis. Clinical trials have suggested that, the development of hypercapnia has been observed to be an adaptive mechanism in certain group of individuals, which helps in reduction of energy for the ventilator work. Such a type of adaptive mechanism can be an important marker indicating favorable prognosis in individuals with hypercapnia.
Hypercapnia is often a common accompaniment of chronic obstructive pulmonary disease. Other causes include exposure to toxins, overdose of certain drugs, hypoventilation and lung disease. Individuals with diminished consciousness can also develop hypercapnia. Environments having high concentration of carbon dioxide, practically observed in conditions of volcanic eruptions, can also lead to increased inhalation of the gas, eventually leading to the condition of hypercapnia. Hypercapnia is often observed in hospitalized patients who are being treated for chronic obstructive pulmonary disease, because such patients are treated through the method of hypoxic drive which employs administration of oxygen to such patients. Such a type of method can many a times turn life threatening .
Individuals suffering from obesity hypoventilation syndrome, eventually also develop hypercapnia as a secondary complication. In a study conducted on 219 patients with obstructive sleep apnea syndrome, it was revealed that 17% of patients also develop hypercapnia. In addition, the study also showed that, hypercapnia also developed in 13% patients with obesity hypoventilation syndrome. The relationship between these conditions majorly occurs due to restrictive ventilator defect .
Hypercapnia is defined as carbon dioxide levels more than 45mmHg. Increase in concentration of carbon dioxide can also have a profound effect on the levels of carbonic acid which may drop dramatically. Such series of events give rise to condition of respiratory acidosis .
Respiratory acidosis can also occur in conditions of chronic obstructive pulmonary disease, obesity hypoventilation syndrome, chest wall disorders, obstructive sleep apnea and central nervous system depression. Factors that significantly affect the ventilation also have an effect on the exhalation of carbon dioxide from the blood and give rise to respiratory acidosis .
Several predisposing factors can be taken care of to prevent the onset of hypercapnia. Effective management of hypothyroidism can significantly reduce the onset of hypercapnia. In addition, controlling and proper correction of chronic obstructive pulmonary disease can also help prevent development of hypercapnia .
Hypercapnia, defined as abnormally elevated carbon dioxide levels in the blood, often triggers a spontaneous effect that increases the need for oxygen and hence induces increase in breathing. This in turn induces arousal during sleep. In cases, when such a type of reflex does not occur, then it can turn fatal and is one of the major reasons for sudden infant death syndrome. Hypercapnia is known to cause rapid onset of intracellular acidosis, if it not timely controlled .