Time outside targeted oxygen saturation range and retinopathy of prematurity

To better understand the impact of hypoxia and hyperoxia on neonatal morbidity and mortality, we examined the number of hypoxia and hyperoxia events as well as percentage of time spent outside oxygen saturation targets in relationship to threshold retinopathy of prematurity (tROP) and mortality in preterm infants.

Saturation data in 2-second sampling from pulse oximeters was prospectively collected in a single NICU. Average SaO2, low and high saturation events, duration of events, and percentage of time infants spent outside of oxygen saturation range were collected and analyzed continuously during the hospitalization.

102 infants <1500g or <32 weeks gestation were enrolled. There were 125, 112, and 43 hypoxia events/day and 106, 80, and 34 hyperoxia events/day for tROP (N=8), non-survivor (N=16) and non-tROP patients (N=78), respectively. Infants were outside saturation targets for 2:35, 1:38, and 1:03 (hypoxia) and 2:02, 1:25, and 0:38 hours/day (hyperoxia) for tROP, non-survivor and non-tROP, respectively. Time spent outside saturation range (hypoxia, hyperoxia and total time) for the hospital course was higher in tROP (P≤0.006) and non-survivor (P≤0.005) compared with non-tROP patients. The three groups defined themselves in the first 10 days after birth, with regard to duration of hypoxia (P=0.0003), hyperoxia (P=0.0004) and total time outside the targeted saturation range (P=0.0006).

Information such as the duration and number of hypoxia and hyperoxia events, as well as total time outside the targeted saturation range, could be factored into assessing clinical interventions and research studies in the prevention, treatment and evaluation of neonatal outcomes.