Seminars in respiratory and critical care medicine
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Hypoventilation in neuromuscular disease is attributed to both respiratory muscle weakness and reduced chemoreceptor sensitivity essential in ventilatory drive. Acute or chronic respiratory failure is seen in a spectrum of neuromuscular disease; whereas some are treatable others are progressive and devastating. ⋯ The timing of respiratory failure is variable, but knowledge of the clinical aspects, pathogenesis, and treatment of respiratory failure and hypoventilation may be helpful in evaluating the patient with neuromuscular disease. For those with progressive and terminal disease, additional factors such as end of life care, especially ventilation and cough, may be useful for the patient, caregivers, and treating medical personnel.
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Semin Respir Crit Care Med · Jun 2009
ReviewCentral congenital hypoventilation syndrome: changing face of a less mysterious but more complex genetic disorder.
Central congenital hypoventilation syndrome (CCHS) is a disorder in which affected individuals fail to breathe during sleep despite progressive hypercapnia and hypoxia. Discovery of the genetic link between PHOX2B gene mutations and CCHS represents a breakthrough in the diagnosis of CCHS, identification of patients with late-onset central hyperventilation syndrome (LO-CHS), association of mutated alleles with disease severity, and clues to the pathophysiology responsible for the disorder. ⋯ Management of CCHS and LO-CHS is primarily directed at optimizing respiratory status, most often with nighttime mechanical ventilatory support and monitoring with polysomnography. Multidisciplinary care is also necessary to promote better outcomes and long-term survival.
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The term obesity hypoventilation syndrome (OHS) refers to the combination of obesity and chronic hypercapnia that cannot be directly attributed to underlying cardiorespiratory disease. Despite a plethora of potential pathophysiological mechanisms for gas exchange and respiratory control abnormalities that have been described in the obese, the etiology of hypercapnia in OHS has been only partially elucidated. Of particular note, obesity and coincident hypercapnia are often associated with some form of sleep disordered breathing (apnea/hypopnea or sustained periods of hypoventilation). ⋯ A unifying view of how this comes about is presented in the following review. In brief, our concept is that chronic sustained hypercapnia (as in obesity hypoventilation) occurs when the disorder of ventilation that produces acute hypercapnia interacts with inadequate compensation (both during sleep and during the periods of wakefulness); neither alone is sufficient to fully explain the final result. The following discussion will amplify on both the potential reasons for acute hypercapnia in the obese and on what is known about the failure of compensation that must occur in these subjects.
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Semin Respir Crit Care Med · Jun 2009
ReviewHypoventilation in asthma and chronic obstructive pulmonary disease.
Chronic hypoventilation is a marker of disease severity in asthma and chronic obstructive pulmonary disease (COPD). The degree to which this predicts severity or objective measures of lung function is variable, and more reliable for COPD than for asthma. ⋯ There is consensus that early treatment with noninvasive ventilation for acute hypoventilation due to a COPD exacerbation is not only highly effective, but it reduces mortality, the need for endotracheal intubation, and hospital length of stay. There is probable benefit to the use of noninvasive ventilation in acute asthma, but the evidence to support this is far less robust than for COPD.
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The diaphragm is a chief muscle of inspiration. Its paralysis can lead to dyspnea and can affect ventilatory function. Diaphragmatic paralysis can be unilateral or bilateral. ⋯ In bilateral diaphragm paralysis or in patients with ventilatory failure continuous positive airway pressure or mechanical ventilation and tracheostomy are generally needed. Prognosis is good in unilateral paralysis, especially in the absence of underlying neurological or pulmonary process. Prognosis is usually poor in patients with advanced lung disease, bilateral paralysis, and chronic demyelinating conditions.