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Table 1 Characteristics, sleep quality and outcomes of the 52 patients included in the study

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

 

N = 52

Patient characteristics

Age (years)

68 [59–76]

Male sex, n (%)

35 (67%)

Body mass index (kg/m2)

30 [25–34]

Simplified Acute Physiological Score II at admission (points)

48 [36–62]

Acute respiratory failure as main reason of intubation, n (%)

43 (83%)

Duration of mechanical ventilation before extubation (days)

9 [4–16]

Sedation before polysomnography (number of days)

3 [2–9]

Sedation-free days at time of polysomnography (days)

3 [2–5]

Difficult or prolonged weaninga, n (%)

18 (35%)

Respiratory parameters before extubation

Maximal inspiratory pressure (cmH2O)

51 [36–62]

P0.1 (cmH2O)

3.4 [3.3–3.6]

pH, units

7.46 [7.43–7.49]

PCO2 (mmHg)

41[36–45]

PaO2/FiO2 (mmHg)

250 [186–300]

Ineffective cough, n (%)

6 (12%)

Abundant secretions, n (%)

11 (21%)

Clinical parameters at time of PSG

Sequential Organ Failure Assessment (points)

3 [2–4]

Richmond Agitation Sedation Scale (points)

0 [0–0]

Intensive care delirium screening checklist (points)

0.0 [0.0–1.5]

Delirium, n/n assessed (%)

8/51 (16%)

Medical Research Council (MRC) score (points)

52 [36–60]

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

17/44 (39%)

Prophylactic noninvasive ventilation, n (%)

26 (50%)

Sleep quantity

Duration of polysomnography recording (h)

16.7 [14.9–17.4]

Sleep duration (h)

2.4 [1.1–4.2]

Sleep efficiency (%)

16 [7–24]

Duration of light or atypical sleep (min)

94 [46–175]

Duration of deep sleep stage 3 (min)

17 [0–66]

Duration of REM sleep stage (min)

0 [0–8]

Sleep quality

Absence of deep sleep, n (%)

15 (29%)

Absence of REM sleep, n (%)

33 (63%)

Atypical sleep, n (%)

10 (19%)

Pathological wakefulness, n (%)

12 (23%)

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

15/48 (31%)

Sleep fragmentation

Arousals and awakenings, events per hour of sleep

25 [13–32]

Average sound pressure level, decibels

57 [55–61]

Sound level events above 60 decibels, n events/h

27 [19–39]

Outcomes

Post-extubation respiratory failure, n (%)

12 (23%)

Reintubation within the 7 days following extubation, n (%)

7 (13%)

Reintubation in ICU, n (%)

8 (15%)

Mortality in ICU, n (%)

1 (2%)

  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. 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
  3. aDifficult or prolonged weaning refer to patients who were not extubated within the first 24 h after the initial spontaneous breathing trial