Table 1: Comparison of Normal Sleep versus Sleep in the Intensive Care Unit.
Normative sleep data of healthy adults are summarized here, based on a systematic review and meta-analysis of polysomnography data.38 Sleep data of ICU patients are summarized here, based on a systematic review of actigraphy data (total sleep time, sleep efficiency, and wake after sleep onset)19 and from seminal polysomnography studies in ICU patients (NREM stages N1, N2, N3, and REM).39–42
| Sleep Parameter | Normal Sleep: Healthy Adults38 | Sleep: ICU Patients19,39–42 |
|---|---|---|
| Total Sleep Time | Ages 18–34: 6.84 hours Ages 35–59: 6.44 hours Ages 50–64: 6.2 hours Ages 65–79: 5.77 hours Ages ≥ 80: 3.31 hours Mean: 6.6 hours |
Range, nighttime: 4.4–7.8 hours Range, 24-hour cycle: 7.1–12.1 hours |
| Sleep Efficiency | Ages 18–34: 89% Ages 35–59: 85.4% Ages 50–64: 83.2% Ages 65–79: 77.5% Ages ≥ 80: 45.7% Mean: 85.7% |
Range: 61–75% |
| Wake After Sleep Onset | Ages 18–34: 32.1 minutes Ages 35–59: 51.1 minutes Ages 50–64: 64 minutes Ages 65–79: 77.1 minutes Ages ≥ 80: Not available Mean: 48.2 minutes |
Range: 12–204 minutes |
| NREM Stage N1 | Ages 18–34: 6% Ages 35–59: 8% Ages 50–64: 8.7% Ages 65–79: 9.3% Ages ≥ 80: 27.5% Mean: 7.9% |
Accounts for more than half of total sleep time |
| NREM Stage N2 | Ages 18–34: 51.3% Ages 35–59: 52.2% Ages 50–64: 52.8% Ages 65–79: 53.3 % Ages ≥ 80: 43.5% Mean: 51.4% |
Slightly decreased or normal |
| NREM Stage N3 | Ages 18–34: 21.4% Ages 35–59: 20.4% Ages 50–64: 18.1% Ages 65–79: 19.9% Ages ≥ 80: 19.1% Mean: 20.4% |
Marked decrease in slow wave sleep |
| REM Stage | Ages 18–34: 19.8% Ages 35–59: 19.3% Ages 50–64: 18.7% Ages 65–79: 17.7% Ages ≥ 80: 9.9% Mean: 19% |
Marked decrease or almost absent |
Table Abbreviations/Definitions:
Total sleep time: total time spent in sleep stages.
Sleep efficiency: total sleep time divided by total time spend in bed. Wake after sleep onset: time spent awake after onset of sleep.
NREM: non-rapid eye movement sleep.
REM: rapid eye movement sleep.