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Table 3 Lung function test results in VLBW infants according to the duration of mechanical ventilation

From: Effect of intubation and mechanical ventilation on exhaled nitric oxide in preterm infants with and without bronchopulmonary dysplasia measured at a median postmenstrual age of 49 weeks

  Not ventilated infants Intubated and ventilated < 7days Intubated and ventilated ≥ 7days p-value
N = 84 N = 47 N = 45
Tidal breathing     
VT (mL/kg) 8.61 8.01 7.68** 0.034
(7.37 - 9.80) (6.70 - 9.67) (6.96 - 8.64)
RR (1/min) 40.9 44.8 44.4* 0.045
(36.0 - 47.1) (35.5 - 56.1) (38.0 - 55.7)
V’E (mL/min/kg) 346.2 373.0 353.0 0.452
(297.8 - 398.4) (311.2 - 407.3) (299.0 - 402.7)
tptef/te (%) 20.7% 22.1% 21.1% 0.898
  (17.4% - 26.2%) (16.3% - 27.0%) (17.1% - 27.2%)  
te (s) 0.857 0.770 0.753* 0.025
  (0.720 - 0.962) (0.593 - 0.990) (0.577 - 0.861)  
PTIF (mL/s/kg) 18.9 19.6 18.0 0.351
  (15.4 - 21.3) (16.6 - 22.6) (16.4 - 20.7)  
PTEF (mL/s/kg) 17.1 18.0 17.9 0.150
  (14.6 - 19.4) (15.2 - 22.0) (14.5 - 20.9)  
MTIF (mL/s/kg) 13.4 14.0 13.1 0.642
  (11.5 - 15.4) (12.0 - 16.3) (11.8 - 15.7)  
MTEF (mL/s/kg) 10.0 11.1 10.4 0.375
  (8.6 - 12.0) (9.3 - 12.5) (8.9 - 13.0)  
Respiratory mechanics     
Crs (mL/kPa/kg) 10.6 9.2 8.9*** 0.002
  (9.0 - 11.0) (7.6 - 11.6) (6.7 - 10.5)  
Rrs (kPa/L/s) 5.96 6.55 6.15 0.094
  (4.61 - 7.30) (5.07 - 8.62) (5.17 - 7.86)  
Exhalation gas analysis     
eNO (ppb) 10.0 6.6** 10.4 0.005
  (6.3 - 13.6) (4.2 - 10.7) (7.2 - 13.8)  
V’NO (nL/s) 0.50 0.39** 0.54 0.005
  (0.34 - 0.72) (0.24 - 0.54) (0.37 - 0.66)  
Blood gas analysis     
paO2 (mmHg) 73.3 66.6* 65.6*** < 0.001
  (65.5 - 83.0) (58.6 - 78.0) (58.5 - 70.9)  
paCO2 (mmHg) 39.9 42.2* 44.6*** < 0.001
  (37.7 - 43.7) (39.1 - 45.8) (41.1 - 47.3)  
  1. *p < 0.05, ** p < 0.01, *** p < 0.001 when compared to not ventilated infants. Data represent median (interquartile range). Statistically significant values are printed in bold.