Atypical Sleep in Ventilated Patients

Abstract

Objectives Standard sleep scoring criteria may be unreliable when applied to critically ill patients. We sought to quantify typical and atypical polysomnographic findings in critically ill patients and to begin development and reliability testing of methodology to characterize the atypical polysomnographic tracings that confound standard sleep scoring criteria. Design Prospective convenience sample. Setting Two academic, tertiary care medical centers. Patients Thirty-seven critically ill, mechanically ventilated, medical ICU patients. Interventions None. Measurements and Main Results Mechanically ventilated subjects were monitored by continuous polysomnography. After noting frequent atypical polysomnographic findings (i.e., lack of stage N2 markers, the presence of polymorphic delta, burst suppression, or isoelectric electroencephalography), attempts to use standard sleep scoring criteria alone were abandoned. Atypical polysomnographic findings were characterized and used to develop a modified scoring system. Polysomnographic data were scored manually via this revised scoring scheme. Of 37 medical ICU patients enrolled, 36 experienced atypical sleep, which accounted for 85% of all recorded data, with 5.1% normal sleep and 9.4% wake. Coupling observed patient arousal levels with polysomnographic characteristics revealed that standard polysomnographic staging criteria did not reliably determine the presence or absence of sleep. Rapid eye movement occurred in only five patients (14%). The revised scoring system incorporating frequently seen atypical characteristics yielded very high interrater reliability (weighted κ = 0.80; bootstrapped 95% CI, [0.48, 0.89]). Conclusions Analysis of polysomnographic data revealed profound deficiencies in standard scoring criteria due to a predominance of atypical polysomnographic findings in ventilated patients. The revised scoring scheme proved reliable in sleep staging and may serve as a building block in future work.

Feasibility study of unattended polysomnography in medical intensive care unit patients

“…Atypical sleep seems to occur in a significant fraction of critically ill patients and may clarify prior difficulties in ICU PSG scoring. 49 Although atypical sleep may signal pathophysiology related to delirium, medication use or severity of illness, no direct correlation among these clinical factors and atypical sleep was found in our cohort or of those previously described. 35, 39 Notably, Drouot et al saw this atypical pattern in non-sedated patients who were in respiratory failure, and we note that 44% of the atypical sleep patients in our study were on none of the following medications: benzodiazepines, opioids or sleep aids.…”

Feasibility of Continuous Actigraphy in Patients in a Medical Intensive Care Unit

“…13 Polysomnography has demonstrated that sleep in critically ill patients is fragmented, short in duration, and frequently occurs during daytime hours 2,3 ; however, its widespread use in ICU populations is challenging because of the cumbersome equipment, the prohibitive cost, and the need for expert interpretation of atypical tracings of unclear significance. 3 For these reasons, polysomnography is not feasible to use throughout a patient’s ICU stay. 14 In the area of mobilization, a recently developed ICU mobility scale provides an ordinal measure of activity levels.…”

The effects of mechanical ventilation on the quality of sleep of hospitalised patients in the Intensive Care Unit

“…In the case of the analysed trials where all research investigated the influence of mechanical ventilation on the quality and quantity of sleep, there was a significant variability and focus in the design of the trials. The groups included small numbers of patients (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24) hospitalised in ICUs (either general or specialised) in tertiary (university) hospitals. A total of 192 patients were included in the review.…”

“…The first trial that provided relevant evidence of these changes was the trial by Cooper et al [15]. In line with this finding, the authors further developed additional criteria to increase the sensitivity of sleep architecture evaluations in critical conditions [18,19].…”

“…The sleep of ICU patients with altered consciousness is fragmented and its architecture is disrupted [10,13,15,16]. There is a growing number of trials that indicate that the standard brain electrical activity monitoring evaluation, which is currently valid and recommended [17], is not reliable in critically ill patients [15,18,19]. The reliability of standard evaluation in the general population is relatively high, the kappa coefficient (κ) is in the range of 0.68-0.82, while in the group of critically ill patients this coefficient is significantly lower 0.19 [20].…”