Nocturnal hypoventilation – identifying & treating syndromes.

Nocturnal hypoventilation is a common feature of disorders affecting the function of the diaphragm or central respiratory drive mechanisms. The ensuing change in gas exchange is initially confined to rapid eye movement (REM) sleep, but over time buffering of the raised carbon dioxide produces a secondary depression of respiratory drive that will further reduce ventilation not only during sleep but eventually during wakefulness as well. Failure to identify and treat nocturnal hypoventilation results in impairments in daytime function, quality of life and premature mortality. While some simple daytime tests of respiratory function can identify at risk individuals, these cannot predict the nature or severity of any sleep disordered breathing present. Nocturnal monitoring of gas exchange with or without full polysomnography is the only way to comprehensively assess this disorder, especially in the early stages of its evolution. Non invasive ventilation used during sleep is the most appropriate approach to reverse the consequences of nocturnal hypoventilation, although continuous positive airway pressure (CPAP) may be effective in those individuals where a significant degree of upper airway obstruction is present. When appropriately selected patients use therapy on a regular basis, significant improvements in quality of life, exercise capacity and survival can be achieved, irrespective of the underlying disease process.

Nem tudo é apnéia obstrutiva no capítulo dosdistúrbios respiratórios do sono: a síndrome de Pickwick: [revisão] / There is more than obstructive apnea in the respiratory slep disorders? chapter: the Pickwick syndrome: [review]

Para o clínico geral e os médicos de outras especialidades, tornou-se muito difícil distinguir todos os dezesseis distúrbios respiratórios do sono atualmente reconhecidos, devido ao imenso volume de conhecimento que se acumula e sua constante reorganização. O objetivo desta revisão é fornecer as principais informações a respeito de uma dessas síndromes respiratórias assaz prevalentes, mas menos conhecidas do que a síndrome da apnéia obstrutiva do sono, ou seja, a síndrome da hipoventilação relacionada à obesidade ou síndrome de Pickwick. A síndrome da hipoventilação relacionada à obesidade tem importância econômica e clínica significativa e sua prevalência aumenta à medida que aumenta a da obesidade, sendo importante o diagnóstico precoce. É uma síndrome distinta da apnéia do sono e diagnosticada com polissonografia respiratória, preferencialmente com medida da PETCO2 e gasometria arterial de repouso, além dos exames para detecção de comorbidades e para exclusão de outras causas de hipoventilação noturna. O tratamento inicial mais eficaz é a ventilação com pressão positiva, preferencialmente não invasiva. Os tratamentos adicionais, incluindo-se dietas, cirurgia bariátrica e tratamento das comorbidades, são geralmente necessários. O aumento da qualidade de vida e de sobrevida, bem como a redução dos custos sociais com o tratamento são indiscutíveis. São apresentados aspectos relevantes da evolução histórica, das definições, da fisiopatologia, do diagnóstico e do tratamento.

Its has become difficult for clinicians, who do not daily deal with sleep disturbances, to know and distinguish all sixteen respiratory sleep disturbances currently recognized, due to the huge volume of knowledge accumulated and its constant restructuring. This review goal is to provide basic understanding about a prevalent respiratory syndrome, which is not as well known as the obstructive sleep apnea syndrome: the Pickwick or obesity hypoventilation syndrome. Obesity hypoventilation syndrome has high economic and clinic significance, and its prevalence increases with the increase in obesity prevalence. An early diagnosis is essential. It is a syndrome distinct from obstructive sleep apnea syndrome and can be investigated with respiratory polysomnography, preferentially with PETCO2 measurement, nd arterial gasometry at rest, besides other tests targeted to detect comorbidities and to exclude other causes of nocturnal hypoventilation. The most efficient initial treatment known is non-invasive positive pressure ventilation. Additional treatment, including diet, bariatric surgery and comorbidities treatment, is usually necessary. An increase in survive and life quality, as well as a decrease in social cost with treatment are indisputable. Relevant aspects of history, definitions, physiopathology, diagnosis and treatment are presented.