Oxygen saturation/FIO2 ratio at 36 weeks' PMA in 1005 preterm infants: Effect of gestational age and early respiratory disease patterns.

OBJECTIVE

To assess oxygen diffusion at 36 weeks' post-menstrual age in preterm infants by means of the non-invasive oxygen saturation/fraction of inspired oxygen ratio (36w-SFR) and to identify factors associated with 36w-SFR - ie, gestational age (GA) and early respiratory disease patterns (ERP).

METHODS

Retrospective analysis of prospectively collected data.

SETTING

Neonatal Intensive Care Unit.

PATIENTS

1005 preterm infants born below 32 weeks' GA.

INTERVENTIONS

36w-SFR was the mean of SFR values over 24 h on the day infants reached 36 weeks' PMA.

MAIN OUTCOME MEASURES

36w-SFR.

STATISTICS

descriptive statistics, univariate, and multivariate analysis to study associations of 36w-SFR, including GA and ERP.

RESULTS

36w-SFR was significantly different between infants with and without bronchopulmonary dysplasia (BPD) (371 vs 467, P < 0.001), and according to ERP (LowFIO2 466, pulmonary improvement-PI 460, pulmonary deterioration-PD 405, early persistent pulmonary deterioration-EPPD 344, P < 0.001). Significant differences were found either in BPD and in non-BPD patients according to ERP (P < 0.001). Patients without BPD had significant differences in 36w-SFR according to GA (P < 0.001), while infants with BPD and increasing GA at birth had a non-significant trend for increased 36w-SFR (P = 0.621). Factors associated with 36w-SFR were GA, being small for GA, sepsis, human milk feeding, and ERP.

CONCLUSIONS

Preterm infants without BPD had a spectrum of oxygen diffusion impairment that was inversely associated with GA at birth. Infants with different patterns of ERP had significant differences in 36w-SFR.