Brain dysfunction may impact ability to breathe spontaneously, study finds

Brain dysfunction may impact ability to breathe spontaneously, study finds - article image

Acute brain dysfunction may cause atypical sleep or absence of REM sleep in normocapnic patients, resulting in markedly longer mechanical ventilation weaning duration, according to a new study published in the European Respiratory Journal.

The study is the first to strongly suggest a causal link between sleep abnormalities and length of mechanical ventilation.

Researchers performed polysomnography (PSG) in 45 normocapnic patients with difficult weaning. Presence of atypical sleep, duration of sleep stages, including rapid eye movement (REM) sleep and electroencephalogram (EEG) reactivity at eyes opening, were assessed by a neurologist.

The researchers found that 20 patients had atypical sleep and an absence of REM or deep sleep. Of those with atypical sleep, weaning took up to five days, while weaning in patients with ‘normal’ sleep took just two days, which the researchers describe as being significantly shorter.

The authors note that prior to PSG, patients with atypical sleep had received more sedation and been under mechanical ventilation for a longer duration than patients with normal sleep, but state that at the time of PSG, the level of consciousness, the delirium score and respiratory parameters did not differ between patients with atypical sleep and those with normal sleep.

Sequential Organ Failure Assessment (SOFA) score was higher and muscle weakness was more frequent and severe in patients with long weaning time, but multivariate analysis showed that the only variables that significantly affected weaning time were presence of atypical sleep.

The researchers state that the presence of atypical sleep and the lack of REM may be a sign of acute brain dysfunction, resulting in greater disease severity and influencing the ability to breathe spontaneously.

The study did not repeat PSG or EEG recordings over time to demonstrate whether or not sleep quality was improved at the time of weaning trial success.

Dr Magdy Younes discusses the new research in an accompanying editorial, ‘To sleep: perchance to ditch the ventilator’, also published in the latest issue of the ERJ.