Atypical sleep linked to weaning failure in prolonged ventilation patients

Key takeaways:

• Atypical sleep electroencephalogram patterns were found in 11 of 44 ventilated patients.
• A greater proportion of those with atypical vs. usual sleep had subsyndromal delirium.

Among patients being weaned from prolonged ventilation in a long-term acute care facility, nearly all of those with atypical sleep electroencephalogram patterns failed to wean, according to results published in CHEST.

“Brain dysfunction, as evidenced by the biologic signal of atypical sleep, persisted in patients at a long-term acute care facility, far beyond the timepoint that led to initial critical illness in the acute ICU and was associated with weaning failure,” Hameeda Shaikh, MD, director of the medical ICU at Edward J. Hines Veteran Affairs Hospital, told Healio.

“This observation will inform the everyday clinician that brain dysfunction, likely modulated by sleep via the glymphatic pathway that allows for clearance of CNS metabolites during sleep, is an important factor in the pathogenesis of failure to wean from mechanical ventilation,” Shaikh added.

In this study, Shaikh and colleagues analyzed 44 alert, nondelirious patients being weaned from prolonged mechanical ventilation (median, 38 days) at a long-term acute care facility to find out whether or not they experience atypical sleep electroencephalogram (EEG) patterns.

Researchers also assessed characteristics/outcomes from EEG power spectral analysis during wakefulness, overnight polysomnography and weaning failure in those with atypical sleep vs. those with usual sleep.

Notably, Shaikh told Healio it was sometimes a challenge to conduct sleep studies in this patient population.

“Our patients were unable to phonate, as they were ventilated via tracheostomy tube connected to a ventilator,” Shaikh said. “Further, any perceived patient discomfort or irritation had to be patiently and carefully assessed by the investigator obtaining the sleep study.

“Nursing care, with frequent repositioning of the patient, often resulted in lead displacement,” she continued. “This issue was best addressed by having the investigator be present in the room to assist with patient repositioning.”

Within the total cohort, atypical sleep EEG was found in 11 patients (median age, 69 years; 36% women; Acute Physiology and Chronic Health Evaluation II [APACHE II] score, 15), whereas the remaining 33 patients (median age, 67 years; 45% women; APACHE II score, 12) had usual sleep.

A greater proportion of those with atypical vs. usual sleep had subsyndromal delirium (36% vs. 6%; P < .027), and Shaikh told Healio this suggests that “atypical sleep patterns may be the biological signal for brain dysfunction.”

“The parallel between EEG patterns of atypical sleep patients in our study and patients experiencing delirium (a form of brain dysfunction) was totally unexpected as we excluded patients who screened positive for delirium using the [Confusion Assessment Method (CAM)]-ICU,” Shaikh said. “This suggests that the CAM-ICU is of little diagnostic value in patients being weaned from prolonged mechanical ventilation.”

Between the atypical sleep group and the usual sleep group, relative delta power (median, 53% vs. 41%), relative alpha power (14% vs. 21%), relative beta power (6% vs. 11%) and the slow-to-fast power ratio (4.39 vs. 2.17) — all during wakefulness — significantly differed (P < .001).

Additionally, rapid eye movement sleep took up a smaller percentage of total sleep time in the atypical vs. usual sleep group (4% vs. 11%; P < .02). Other sleep EEG characteristics including total sleep time, sleep efficiency and the sleep fragmentation index did not significantly differ between the two groups.

Nearly every patient with atypical sleep failed to wean (91%), whereas only 45% of those with usual sleep experienced failure (P = .013).

Lastly, length of stay, mortality and home discharge did not significantly differ when comparing those with atypical vs. usual sleep, according to researchers.

“Pharmacologic and nonpharmacologic therapy may promote sleep consolidation and lower the incidence of delirium in critically ill patients,” Shaikh told Healio. “Whether these interventions can facilitate the return to normal sleep patterns and their impact on outcomes of patients being weaned from mechanical ventilation is unknown.”

Looking to the future, Shaikh recommends use of wireless technology.

“Wireless EEG devices may improve the ease of obtaining polysomnographic recordings in the ICU and long-term acute care hospitals,” Shaikh said.

“The identification of atypical sleep can be challenging, and obtaining the full sleep EEG montage ensured that the interpreting investigators had an ample number of EEG channels on which to base the analysis,” Shaikh added. “Whether or not power spectral analysis or the calculation of the ‘odds ratio product’ on a limited number of channels could provide comparable information is unknown.”