Sleep Assessment in Critically Ill Subjects With Acute Hypoxemic Respiratory Failure.

BACKGROUND: Sleep deprivation alters respiratory muscle performance and may precipitate respiratory failure. This study aimed to assess sleep in subjects admitted to ICU for acute hypoxemic respiratory failure and its role in the risk of intubation.

METHODS: This was a prospective observational single-center cohort study including subjects admitted to ICU for de novo acute hypoxemic respiratory failure defined as breathing frequency ≥ 25 breaths/min or clinical signs of respiratory distress and PaO2 /FIO2 < 300 mm Hg while receiving high-flow nasal oxygen. Subjects with altered consciousness, central nervous or psychiatric disorders, continuous sedation or neuroleptic medication, or were uncooperative were excluded. Sleep was assessed by complete polysomnography (PSG) the night following ICU admission. The main outcome was to assess sleep among subjects with acute hypoxemic respiratory failure and to compare sleep between subjects who eventually required intubation to those who did not.

RESULTS: Over a 24-month inclusion period, 34 subjects had complete PSG, among whom 5 (15%) required intubation in the ICU. Total sleep time was 4.2 h in median (interquartile range 2.9-6.8); deep-sleep duration was 70 min (34-127), and rapid eye movement (REM) sleep duration was 9 min (0-28). Among them, 13 subjects (38%) had no REM sleep. Total sleep time and duration of deep and REM sleep stages did not differ between subjects who required intubation and those successfully treated with high-flow nasal oxygen.

CONCLUSIONS: Whereas total sleep time remained relatively preserved in critically ill subjects with acute hypoxemic respiratory failure, REM sleep time was uncommon or completely absent in a large number of subjects. Sleep did not differ between subjects who required intubation and those who did not. However, given a trend toward an increased risk of intubation in subjects with a complete absence of REM sleep, further studies are needed to better explore the impact of REM sleep on the risk of intubation.