Neonatal intermittent hypoxemia events are associated with diagnosis of bronchopulmonary dysplasia at 36 weeks postmenstrual age

Abstract

Background: Bronchopulmonary dysplasia (BPD) is a chronic lung disease and major pulmonary complication after premature birth. We have previously shown that increased intermittent hypoxemia (IH) events have been correlated to adverse outcomes and mortality in extremely premature infants. We hypothesize that early IH patterns are associated with the development of BPD.

Methods: IH frequency, duration, and nadirs were assessed using oxygen saturation (SpO₂) waveforms in a retrospective cohort of 137 extremely premature newborns (<28 weeks gestation). Daily levels of inspired oxygen and mean airway pressure exposures were also recorded.

Results: Diagnosis of BPD at 36 weeks postmenstrual age was associated with increased daily IH, longer IH duration, and a higher IH nadir. Significant differences were detected through day 7 to day 26 of life. Infants who developed BPD had lower mean SpO₂ despite their exposure to increased inspired oxygen and increased mean airway pressure.

Conclusions: BPD was associated with more frequent, longer, and less severe IH events in addition to increased oxygen and pressure exposure within the first 26 days of life. Early IH patterns may contribute to the development of BPD or aid in identification of neonates at high risk.

Figure 1:. Patterns of Hypoxemia during the First Four Weeks of Life.

Longitudinal daily means (±SEM) of bronchopulmonary dysplasia (BPD) group (triangles) vs No BPD group (circles). Lines indicate covariate adjusted modeling. Mean oxygen saturations (SpO₂) A) was significantly lower in the BPD group at days 7, 14, 21, and 26 (p < 0.001). Frequency of intermittent hypoxemia (IH) events B) was significantly increased in the BPD group at days 21 and 26 (p ≤ 0.01). Mean duration of IH events C) was significantly increased in the BPD group at days 14, 21, and 26 (p ≤ 0.001). SpO₂ nadir of IH events D) was higher at days 7 and 14 (p ≤ 0.001).

Figure 2:. Stratification of Events by Time Interval during the First Four Weeks of Life.

Longitudinal daily means (±SEM) of bronchopulmonary dysplasia (BPD) group (triangles) vs No BPD group (circles). Lines indicate covariate adjusted modeling. Intermittent hypoxemia (IH) events with a time interval between events of <1 minute apart A), 1–20 minutes apart B), and >20 minutes part C). IH events occurring between 1–20 minutes apart were significantly increased in the BPD group at days 21 and 26 (p < 0.001). Events <1 minute apart or >20 minutes apart did not significantly differ between groups.

Figure 3:. Inspired Oxygen and Mean Airway Pressure during the First Four Weeks of Life.

Longitudinal daily means (±SEM) of bronchopulmonary dysplasia (BPD) group (triangles) vs No BPD group (circles). Lines indicate covariate adjusted modeling. Mean fraction of inspired oxygen (FiO₂) A) was significantly higher in the BPD group at days 7, 14, 21, and 26 (p < 0.0001). Mean airway pressure (MAP) B) was significantly higher in the BPD group at days 7, 14, 21, and 26 (p < 0.0001).