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Table 2 Main sleep characteristics of the patients in whom polysomnography could be accurately scored

From: Impact of earplugs and eye mask on sleep in critically ill patients: a prospective randomized study

  Control group (n = 28) Intervention group (n = 23) p Value
Total sleep time per 18 ha, minutes 301 (229–398) 290 (146–410) 0.91
Total sleep time during nighttimeb, minutes 274 (177–329) 286 (120–392) 0.77
N1 Stage, minutes 29 (17–59.5) 29 (6–50) 0.42
N2 Stage, minutes 182 (102–229) 146 (84–223) 0.32
N3 Stage, minutes 31 (7–69) 58 (24–86) 0.16
N3 stage, % of total sleep time 11 [3–23] 21 [7–28] 0.09
REM sleep, minutes 32 (6–48) 35 (9–60) 0.64
Sleep efficiencya, % per 18 h 27 (21–38) 26 (14–42) 0.72
Short awakenings (<1 minute), n 11 (5–20) 8 (3–13) 0.23
Prolonged awakenings (>1 minute), n 31 (21–47) 21 (19–26) 0.02
Awakenings and arousals, n/TST 26 (13–46) 24 (15–29) 0.39
Self-assessed sleep quality, VAS 50 (32–70) 50 (40–60) 0.81
  1. REM Rapid eye movement, TST Total sleep time, VAS Visual analogue scale from zero (poor sleep quality) to 100 (excellent sleep quality)
  2. aTotal recording period is from 2:00 p.m. to 8:00 a.m.
  3. bNighttime is from 10:00 p.m. to 8:00 a.m.