Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0085383 (hypocapnia)
 1,697 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Central sleep apnea is a disorder characterized by apneic episodes during sleep with no associated ventilatory effort. More commonly than not these apneas are seen in patients who also have obstructive and mixed events. Although patients with this disorder frequently complain of insomnia and depression, frank hypersomnolence is rarely encountered. As these complaints are common ones seen in numerous clinical situations, and since sleep studies are rarely conducted to investigate their etiology, the true incidence of central sleep apnea has not been determined. The etiology of central apnea remains unknown, although the association between these breathing events and a number of other disease processes has increased our understanding of the disorder. Central apneas during sleep commonly occur after hyperventilation with the associated hypocapnic alkalosis. This occurs at high altitude when hyperventilation is induced by hypoxia and at sea level when spontaneous nocturnal hyperventilation occurs. This suggests that PCO2 is the primary stimulus to ventilation during sleep and that loss of this drive, as occurs with hypocapnia, may produce dysrhythmic breathing. Patients with complete absence of ventilatory chemosensitivity such as occurs with Ondine's curse (central alveolar hypoventilation) or the obesity-hypoventilation syndrome may also have central apneas. For reasons that remain unexplained, central sleep apnea is commonly seen in patients with congestive heart failure, nasal obstruction, and certain neurologic disorders. However, in most patients with central sleep apnea no obvious cause or association can be found. The treatment of this disorder is not entirely satisfactory. If it is severe, mechanical ventilation during sleep can be provided by any one of a number of techniques. However, for the patient who simply complains of insomnia and is found to have a moderate number of central apneas, the treatment choices are limited. Acetazolamide has been shown to decrease central apneas during short-term use, but results have been variable with prolonged administration. Other ventilatory stimulants seem to have little efficacy. Interestingly, oxygen administration has been shown to reduce central apneas considerably in a number of studies, although the explanation for its success is unknown. Central sleep apnea therefore remains a relatively rare disorder whose etiology is not fully understood and whose treatment is not completely satisfactory.
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PMID:Central sleep apnea. 393 82

In about 20% of patients admitted to an Intensive Care Unit (ICU) the indication of mechanical ventilation (MV) is a neurological disease. These patients have a prolonged MV stay and high mortality. The appropriate use of MV in patients with acute brain injury (ABI) is critical considering that MV by itself is able to induce or worsen an underlying lung injury. Patients with ABI have a higher risk to develop pulmonary complications. During endotracheal intubation the activation of airway reflexes should be prevented, because they may increase intracranial pressure. Tracheostomy is indicated to improve airway management and it is performed in about 33% of these patients. Indications for MV are loss of spontaneous respiratory effort, changes in lung compliance, gas exchange impairment and ventilatory failure due to muscle fatigue or neuromuscular junction dysfunction. During MV, hypoxemia should be avoided. The pC0(2) level has a critical role in cerebral blood flow regulation; therefore a normal pCO must be maintained in order to guarantee an optimal cerebral blood flow. Despite that, hypocapnia has been used in patients with increased intracranial pressure, at the present it is not recommended. Its use should be limited to the emergency management of intracranial hypertension, while the underlying cause is being treated. Non-conventional ventilatory modes as prone position ventilation, high-frequency oscillatory ventilation and extracorporeal C02 removal can be used in patients with ABI. All of them have specific risks and should be employed cautiously This paper reviews upper airway management and MV in patients with acute brain injury.
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PMID:[Mechanical ventilation in patients with acute brain injury]. 2187 73