Table 2.
Tidal breathing measurements in infants with and without bronchopulmonary dysplasia
| Tidal Breathing Measurements | No. | No Bronchopulmonary Dysplasia* | Bronchopulmonary Dysplasia* | Mean or Median Difference (95% CI†) | P Value‡ |
|---|---|---|---|---|---|
| RIP | |||||
| Phase angle, degrees | 429 | 77.4 ± 45.1 | 81.5 ± 45.9 | 4.0 (−4.8 to 12.9) | 0.37 |
| Respiratory rate, breaths/min | 429 | 60.1 ± 7.9 | 61.0 ± 10.4 | 1.0 (−0.8 to 2.7) | 0.28 |
| Tpef/Te | 429 | 0.50 ± 0.02 | 0.49 ± 0.04 | −0.009 (−0.015 to −0.003) | <0.01 |
| %RCi | 429 | 0.16 ± 0.27 | 0.16 ± 0.31 | −0.01 (−0.06 to 0.05) | 0.77 |
| Sleep oximetry (room air only) | |||||
| No. of desaturations ≥4%/s | 260 | 0.42 (0.18 to 0.82) | 0.61 (0.35 to 0.88) | 0.19 (0.05 to 0.36) | 0.03 |
| Longest apnea, s | 66 | 4.5 (3.5 to 5.5) | 3.2 (2.5 to 3.3) | −1.4 (−1.6 to −0.9) | 0.03 |
| Fall in O2 saturation/s, % | 188 | 1.6 (1.2 to 2.1) | 1.5 (1.0 to 2.1) | −0.1 (−0.3 to 0.2) | 0.69 |
| Lowest SpO2, % | 255 | 87.5 (83.0 to 91.0) | 85.0 (82.5 to 88.0) | −2.5 (−4.0 to 1.0) | 0.17 |
Definition of abbreviations: CI = confidence interval; RCi = contribution of rib cage expansion to inspiratory tidal volume; RIP = respiratory inductance plethysmography; SD = standard deviation; SpO2 = oxygen saturation as measured by pulse oximetry; Tpef/Te = ratio of time to peak expiratory flow over total expiratory time.
*
Data presented as mean ± SD or median (interquartile range).
†
95% CIs of median differences obtained through bootstrap method (31).
‡
t test with equal variance or Wilcoxon test.