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Table 2 Sleep characteristics (11 subjects)

From: Sound level intensity severely disrupts sleep in ventilated ICU patients throughout a 24-h period: a preliminary 24-h study of sleep stages and associated sound levels

Sleep values 24-h night and day sleep Day (08h00–22h00) Night (22h00–08h00) Day vs. night p
TST, min 502.2 [283.2–718.9] 168.5 [142.5–243.3] 356.9 [188.6–590.9] 0.001
N1, min 112.1 [41.2–155.1] 32.1 [6.9–38.8] 98.2 [29.3–123.1] 0.002
N1, %TST 22.3 [14.6–30.7] 17.3 [4.6–21.7] 21.5 [7.5–28.5] NS
N2, min 315.2 [242.1–480.3] 125.5 [52.3–144.7] 233.0 [143.3–364.0] 0.002
N2, %TST 62.7 [54.2–77.3] 68.7 [64.2–78.3] 62.1 [55.4–69.6] NS
N3, min 55.2 [0–81.5] 23.5 [0–81.5] 39.7 [0–98.8] NS
N3, %TST 9.0 [0–19.7] 3.5 [0–22.6] 6.5 [0–23.6] NS
REM, min 20.1 [0–41.1] 5.3 [0–15.1] 19.8 [0–0.38] 0.04
REM, %TST 4.0 [0–9.7] 1.5 [0–3.9] 3.9 [0–10.1] NS
Arousals, n/h 20 [6–32.6] 2 [0–16.6] 20 [8–22.7] 0.03
  1. Data are median [interquartile range], TST = total sleep time, REM = rapid eye movement sleep, N1, N2, N3 = non-REM slow wave sleep stage N1, N2 and N3