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Table 2 Feasibility outcomes

From: Neurally adjusted ventilatory assist versus pressure support ventilation: a randomized controlled feasibility trial performed in patients at risk of prolonged mechanical ventilation

Variable

NAVA (n = 36)a

PSV (n = 36)a

Assigned mode adherence, % (median, 95% CI)b

83.1 (64.0–97.1)

100.0 (100.0–100.0)

Compliant participants (≥ 65% adherence), n (%, 95% CI)c

24 (66.7, 50.3–80.0)

36 (100.0, 89.0–100.0)

Proportion of time cross-over, % (median, 95% CI)c

16.9% (2.9–37.5)

0.0 (0.0–0.0)

Total time in NAVA, h (median, IQR)

42.5 (4.5–150.5)

0.0 (0.0–0.0)

Total time in PSV, h (median, IQR)

12.0 (2.0–29.0)

89.0 (13–185.5)

Participants with cross-over, n (%)

28 (77.8)

3 (8.1)

Reasons for cross-over, n (%)d

 Edi signal problem

10 (27.8)

–

  Edi signal noise or interference

8 (22.2)

–

  Low or absent Edi

2 (5.6)

–

 Clinical rationale/clinical team preference

11 (30.6)

3 (8.3)

  General instability or deterioration

7 (19.4)

1 (2.8)

  Tachypnoea

1 (2.8)

–

  Ventilator dyssynchrony

1 (2.8)

3 (8.3)

 Lack of trial awareness

5 (13.9)

–

 Clinical inexperience with NAVA

4 (11.1)

–

 NAVA tube insertion difficulty

2 (5.6)

–

 NAVA catheter removed for tor transfer

1 (2.8)

–

 Not documented

8 (22.2)

–

Participants with > 1 reason for cross-over

8 (22.2)

–

  1. NAVA neurally adjusted ventilatory assist, PSV pressure support ventilation, IQR interquartile range, Edi electrical activity of the diaphragm, CI confidence interval
  2. aThree NAVA arm participants and 2 PSV arm participants did not use either NAVA or PSV and were therefore excluded
  3. bProportion of time in assigned mode = time in the mode assigned at randomization (NAVA or PSV) as a proportion of total time in continuous, spontaneously triggered ventilation modes, either PSV or NAVA. Crossed over hours due to initial set-up (within 4 h of randomization) or SBT (PSV ≤ 5 cm H2O) were permitted in the protocol and discounted from this calculation
  4. cCompliance = ≥ 65% adherence to the ventilation mode assigned at randomization
  5. dParticipants may experience > 1 reason for cross-over; therefore, the sum of percentages is not 100%