Normal cerebral, renal and abdominal regional oxygen saturations using near-infrared spectroscopy in preterm infants

Abstract

Objective: The aim of this study is to characterize baseline regional oxygen saturations (rSO(2)) in stable preterm infants during the first weeks of life.

Study design: Cerebral, renal and abdominal rSO(2) were continuously monitored from the time of birth to 21 days in twelve preterm infants of 29-34 weeks gestation. Regional saturations were evaluated for trends over time, variability and differences between gestational ages (GAs) and reported pediatric values.

Result: Both cerebral (66-83%) and renal (64-87%) rSO(2) baselines were within the range of reported neonatal values but consistently decreased over the first weeks of life (P<0.01). The baseline abdominal rSO(2) was 32-66% and increased with GA (P=0.05). The rSO(2) variability was lowest for cerebral measurements and highest at the abdomen. Abdominal rSO(2) variability decreased over time (P≤0.05).

Conclusion: Daily baseline rSO(2) in preterm infants changes over the first weeks of life, especially at the abdomen. Evolution in baseline rSO2 over time may indicate regional developmental maturation of physiological oxygen balance.

Figure 1

Daily mean rSO2±s.d. demonstrating interindividual daily variability at cerebral (a), renal (b) and abdominal (c) sites for two GA groups. n=6 for each GA group. ^*Significant difference from 32 to 33 weeks (P<0.05).

Figure 2

Mean percentage of time rSO₂ measured 15 above or below an individual's daily mean at each site. Data are representative of daily intraindividual variability from baseline. ^*P⩽0.05; abdominal variability is significantly less each week with no significant difference between renal and abdominal means during week 3.

Figure 3

Correlation between hemoglobin concentration [Hgb] (g per 100 ml) and rSO₂ at cerebral (a), renal (b) and abdominal (c) sites. Correlation between weight (g) and rSO₂ at cerebral (d), renal (e) and abdominal (f) sites.