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Table 2 Comparison of patients with normal sleep architecture and those with atypical sleep or no rapid eye movement (REM) sleep

From: Role of sleep on respiratory failure after extubation in the ICU

 

Normal sleep (N = 15)

Atypical or no REM sleep (N = 37)

P value

Patient characteristics

Age (years)

71 [61–76]

67 [58–76]

0.34

Male sex, n (%)

11 (73%)

24 (65%)

0.75

Body mass index (kg/m2)

31 [27–37]

28 [25–32]

0.19

Simplified Acute Physiological Score II at admission (points)

40 [30–57]

50 [38–66]

0.13

Duration of mechanical ventilation before extubation (days)

4 [3–15]

9 [6–16]

0.14

Sedation before polysomnography (number of days)

2 [1–6]

4 [2–9]

0.09

Sedation-free days at time of polysomnography (days)

2 [2–6]

3 [2–5]

0.29

Difficult or prolonged weaninga, n (%)

6 (40%)

12 (32%)

0.75

Respiratory parameters before extubation

Maximal inspiratory pressure (cmH2O)

55 [37–60]

50 [36–62]

0.73

P0.1 (cmH2O)

4 [3, 4]

3 [3, 4]

0.04

pH, units

7.45 [7.44–7.49]

7.46 [7.43–7.49]

0.96

PCO2 (mmHg)

41 [39–47]

41 [34–44]

0.11

PaO2/FiO2 (mmHg)

200 [183–276]

256 [195–303]

0.24

Ineffective cough, n (%)

1 (7%)

5 (14%)

0.66

Abundant secretions, n (%)

4 (27%)

7 (19%)

0.71

Clinical parameters at time of PSG

Sequential Organ Failure Assessment (points)

3.0 [2.0–3.5]

3.0 [2.0–4.0]

0.63

Richmond Agitation Sedation Scale (points)

0 [0–0]

0 [0–0]

0.53

Intensive care delirium screening checklist (points)

0 [0–0]

1 [0–2]

0.086

Delirium, n/n assessed (%)

2/14 (14%)

6 (16%)

> 0.99

Medical Research Council (MRC) score (points)

60 [57–60]

48 [33–59]

0.01

ICU-acquired weakness (MRC < 48), n/n total (%)

2/12 (17%)

15/32 (47%)

0.09

Prophylactic noninvasive ventilation, n (%)

10 (67%)

16 (43%)

0.22

Sleep quantity

Duration of polysomnography recording (h)

16.9 [15.5–17.5]

16.2 [14.2–17.2]

0.27

Sleep duration (h)

4.2 [3.5–5.0]

1.7 [0.9–3.4]

< 0.001

Sleep efficiency (%)

25 [21–30]

11 [6–18]

< 0.001

Duration of light or atypical sleep (min)

129 [70–214]

87 [44–123]

0.12

Duration of deep sleep stage 3 (min)

99 [40–120]

4 [0–36]

< 0.001

Duration of REM sleep stage (min)

13 [10–24]

0 [0–0]

< 0.001

Sleep quality

Absence of deep sleep, n (%)

0 (0%)

15 (41%)

0.002

Absence of REM sleep, n (%)

0 (0%)

33 (89%)

< 0.001

Atypical sleep, n (%)

0 (0%)

10 (27%)

0.046

Pathological wakefulness, n (%)

1 (7%)

11 (30%)

0.14

Altered EEG reactivity at eye-opening test, n/n assessed (%)

3/14 (21%)

12/34 (35%)

0.50

Sleep fragmentation

Arousals and awakenings, events per hour of sleep

37 [22–40]

42 [24–50]

0.44

Average sound pressure level, decibels

58 [55–64]

57 [55–59]

0.47

Sound level events above 60 decibels, n events/h

25 [18–41]

28 [20–37]

0.85

Outcomes

Post-extubation respiratory failure, n (%)

2 (13%)

10 (27%)

0.47

Reintubation in ICU, n (%)

1 (7%)

7 (19%)

0.41

Mortality in ICU, n (%)

0 (0%)

1 (3%)

> 0.99

  1. Values are given in median [25th–75th percentiles] and compared using the non-parametric Fisher exact test for categorical variables and the Mann–Whitney test for continuous variables
  2. P values are indicated in italic when the variables are statistically different between the 2 groups (P < 0.05)
  3. P0.1: negative airway pressure generated against occlusion during the first 0.1 s of spontaneous ventilation; REM sleep: rapid eye movement sleep; ICU: intensive care unit; EEG reactivity: electroencephalographic reactivity
  4. aDifficult or prolonged weaning refer to patients who were not extubated within the first 24 h after the initial spontaneous breathing trial