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Table 4 Performance of the Flow Index and other routinely used parameters in etecting breaths with high inspiratory effort

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

 

Threshold

Specificity

Sensitivity

PPV

NPV

AUC

P value

Flow index

4.5 (3.0–5.1)

0.84 (0.70–0.89)

0.81 (0.72–0.90)

0.34 (0.23–0.43)

0.98 (0.97–0.99)

0.89 (0.85–0.93)

–

RR (breaths min−1)

26 (25–26)

0.47 (0.58–0.51)

0.69 (0.58–0.79)

0.12 (0.10–0.14)

0.93 (0.91–0.96)

0.55 (0.49–0.61)

< 0.001

RR/VT (breaths L−1 min−1)

40 (40–40)

0.64 (0.60–0.68)

0.67 (0.57–0.78)

0.17 (0.14–0.20)

0.95 (0.93–0.97)

0.55 (0.49–0.61)

 < 0.001

VT/IBW (mL kg−1)

8.8 (8.8–8.8)

0.64 (0.59–0.69)

0.69 (0.58–0.81)

0.17 (0.14–0.19)

0.95 (0.94–0.97)

0.66 (0.60–0.72)

< 0.001

P0.1 (cmH2O)

1.4 (1.1–1.4)

0.75 (0.63–0.80)

0.75 (0.66–0.85)

0.24 (0.19–0.28)

0.97 (0.95–0.98)

0.77 (0.71–0.82)

< 0.001

  1. Estimates of sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the best threshold (chosen by identifying the top-left corner value in the retrieving operating characteristic curve) for detecting breaths at high inspiratory effort using variables studied as predictors. 95% confidence intervals (95% CI) were obtained by 2000 bootstrapped samples. P values were computed by evaluating bootstrapping tests for the AUC of every variable versus the AUC of the Flow Index. Abbreviations RR, respiratory rate; VT, tidal volume; IBW, ideal body weight; P0.1, airway occlusion pressure; PPV, positive predictive value; NPV, negative predictive value; AUC, area under the retrieving operative characteristic curve