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Table 2 Ventilation settings and asynchronies recorded

From: Neurally adjusted ventilatory assist (NAVA) versus pressure support ventilation: patient-ventilator interaction during invasive ventilation delivered by tracheostomy

Total population (n = 61)

PSV

NAVA

p

Median

95% CI

Minimum

Maximum

Median

95% CI

Minimum

Maximum

Level of support

10a

8–12

3

24

0.6b

0.5–0.8

0.1

3

NA

Expiratory trigger PSV (%)

30

30–35

15

50

NA

NA

NA

NA

NA

Inspiratory trigger PSV (1–10)

6

5–6

1

9

NA

NA

NA

NA

NA

Macro-asynchronies

 Auto-triggering

0

0–0.2

0

4.1

0

0–0.08

0

24

0.0182

 % auto-triggering

0

0–0.6

0

18.4

0

0–0.19

0

24

0.0251

 Double triggering

0.1

0–0.3

0

5.3

0.1

0–0.20

0

24

0.0223

 % double triggering

0.3

0–0.5

0

16.6

0.4

0–0.79

0

24

0.0063

 Ineffective triggering

0

0–0.08

0

14.4

0

0–0.13

0

24

0.4363

 % ineffective triggering

0

0–0.19

0

33.9

0

0–0.46

0

24

0.3272

 Macro-asynchrony index (%)

1.6

1–3.18

0

33.9

1.64

0.4–2.5

0

24

0.6420

Micro-asynchronies

 Premature cycling-off

0.13

0–0.6

0

4

0

0–0

0

24

< 0.0001

 % premature cycling-off

0.3

0–1.9

0

31

0

0–0

0

24

< 0.0001

 Late cycling-off

0.123

0–0.38

0

11.4

0

0–0

0

24

0.0002

 % late cycling-off

0.5

0–1.24

0

27.7

0

0–0

0

66

0.0013

 Inspiratory trigger delay

0.88

0.5–1.75

0

25.9

0

0–0.13

0

24

< 0.0001

 % inspiratory trigger delay

3.55

1.8–5.96

0

81.9

0

0–0.4

0

24

< 0.0001

 Micro-asynchrony index (%)

9.8

6.8–15.7

0

100.7

0.35

0–0.86

0

24

< 0.0001

Total asynchronies

 Total AI (%)

14

9.9–21.7

0

101.8

2.1

0.8–3.9

0

24

< 0.0001

 Patients with AI > 10%

 

38

62.3%

  

7

11.5%

  

Respiratory rate (cycle/min)

28

25–29

12.6

46

26

25–28

11

46.6

0.0323

VT expired (ml)

400

381–418

194.8

947

366

336–388

207.1

982

0.0020

Volume/min (l/min)

11.4

10–13

5.5

21.7

11.4

11–12.2

6

20.4

0.8953

VT (ml/kg PBW)

6.2

5.9–6.4

3.1

12.4

5.8

5.3–6.2

3.3

12.9

0.0009

PEEP (cmH2O)

6

5–6

3

10

5

5–5

3

10

0.0029

Eadi peak

15.7

12.4–19.7

3.3

84.75

15.2

12.5–18.2

6.72

84

0.1142

  1. Results are expressed as medians, 95% confidence intervals (CIs) or number (%)
  2. Significant p values are shown in bold typeface
  3. AI asynchrony index, Eadi electrical activity of the diaphragm, NA not available, NAVA neurally adjusted ventilatory assist, PDW predicted body weight, PEEP positive end-expiratory pressure, PSV pressure support ventilation, VT tidal volume
  4. aResults expressed in cmH2O
  5. bResults expressed in cmH2O/μV