Table 3.
Tidal breathing data obtained near the time of discharge in infants with and without postdischarge respiratory disease after discharge
| Tidal Breathing Measurements | No. | No Postdischarge Respiratory Disease* | Postdischarge Respiratory Disease* | Mean/Median Difference or OR (95% CI†) | P Value‡ |
|---|---|---|---|---|---|
| RIP | |||||
| Phase angle, degrees | 433 | 77.5 ± 44.5 | 80.0 ± 45.9 | 2.5 (−6.6 to 11.5) | 0.59 |
| Respiratory rate, breaths/min | 433 | 60.2 ± 8.2 | 60.6 ± 9.3 | 0.4 (−1.4 to 2.2) | 0.69 |
| Tpef/Te | 433 | 0.49 ± 0.03 | 0.49 ± 0.03 | 0.00 (−0.01 to 0.01) | 0.84 |
| %RCi | 433 | 0.17 ± 0.28 | 0.16 ± 0.29 | −0.01 (−0.07 to 0.04) | 0.67 |
| Sleep oximetry (in room air only) | |||||
| No. of desaturations ≥4%/s | 262 | 0.39 (0.23 to 0.81) | 0.45 (0.20 to 0.85) | 0.06 (−0.03 to 0.18) | 0.75 |
| Longest apnea, s | 66 | 4.2 (3.5 to 5.48) | 4.3 (3.2 to 5.38) | 0.2 (−0.7 to 0.6) | 0.60 |
| Fall in O2 saturation/s, % | 190 | 1.7 (1.1 to 2.05) | 1.6 (1.2 to 2.1) | −0.1 (−0.2 to 0.2) | 0.95 |
| Lowest SpO2, % | 257 | 87.0 (81.0 to 91.0) | 88.0 (84.0 to 91.0) | 1.0 (−1.0 to 3.0) | 0.56 |
| Bronchodilator response | |||||
| Phase angle decrease | 1.60 (1.00 to 2.55) | 0.05 | |||
| No | 67 (61.5) | 106 (50.0) | |||
| Yes | 42 (38.5) | 106 (50.0) | |||
| Tpef/Te increase | 1.54 (0.88 to 2.71) | 0.13 | |||
| No | 88 (80.7) | 155 (73.1) | |||
| Yes | 21 (19.3) | 57 (26.9) |
Definition of abbreviations: CI = confidence interval; OR = odds ratio; 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.
*
Presented as mean ± SD or median (interquartile range) or No. (%).
†
95% CIs of median differences obtained through bootstrap method (31).
‡
t test with equal variance or Wilcoxon test.