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Table 2 Ventilatory parameters at the three levels of PSV

From: Flow Index accurately identifies breaths with low or high inspiratory effort during pressure support ventilation

 

PSlow

PSbase

PShigh

P value

Pmusc (cmH2O)

6.2 (5.2–9.0)

[2.4–20.5]

2.3 (1.8–6.7)

[0.2–13.7]

1.3 (0.4–1.8)

[0.1–11.8]

< 0.001

Flow Index

3.8 (2.7–5.4)

[0.9–15.3]

2.6 (1.4–4.1)

[0.7–11.0]

1.5 (1.1–1.9)

[0.6–5.9]

< 0.001

RR (breaths min−1)

30 (23–35)

[15–49]

25 (19–33)

[12–47]

19 (16–25)

[9–31]

0.001

RR/VT (breathsâ‹…L−1 min−1)

74 (45–110)

[27–135]

49 (31–78)

[15–120]

28 (20–48)

[7–69]

< 0.001

VT/IBW (mL kg−1)

6.9 (5.8–8.0)

[3.4–10.4]

8.1 (6.7–9.4)

[3.8–11.9]

10.6 (8.4–12.0)

[5.9–16.1]

< 0.001

\({\dot{\text{V}}}\)E (L⋅min−1)

11.2 (8.3–13.6)

[5.9–20.6]

11.2 (7.7–15.7)

[5.0–20.1]

12.2 (8.8–13.8)

[5.2–18.7]

0.979

P0.1 (cmH2O)

1.4 (0.9–1.8)

[0.3–3.4]

1.0 (0.7–1.2)

[0.1–2.4]

0.6 (0.2–1.0)

[0.0–1.6]

< 0.001

PTP (cmH2O s min−1)

75.9 (65.3–150.6)

[25.8–299.2]

25.4 (17.4–83.8)

[1.1–201.1]

9.7 (2.0–12.8)

[0.1–144.1]

< 0.001

PTPtot (cmH2O s min−1)

197.01 (123.06–260.76)

[33.5–437.0]

109.43 (39.84–179.63)

[0.2–355.3]

35.05 (10.20–61.64)

[2.6–257.8]

< 0.001

PS (cmH2O)

3 (1–4)

[0–11]

8 (5–12)

[1–14]

17 (14–20)

[10–24]

< 0.001

  1. Measurements for each subject were grouped by mean at the 3 different levels of pressure support. Data are shown as median (1st–3rd) [range] for the 24 subjects and P values obtained with Kruskal Wallis test at 3 different pressure support levels
  2. Pmusc, pressure generated by respiratory muscles; RR, respiratory rate; VT, tidal volume; IBW, ideal body weight; \({\dot{\text{V}}}\)E, minute ventilation; P0.1, airway occlusion pressure; PTP, pressure time product from the start of the inspiratory flow; PTPtot, pressure time product from the start of the inspiratory effort; PS, pressure support