Oxygen targeting in preterm infants: a physiological interpretation

Area of Science:

• Neonatalogy
• Pediatric Critical Care
• Respiratory Physiology

Background:

• Randomized trials comparing low (85-89%) versus high (91-95%) target oxygen saturation (SpO2) in extremely preterm infants show inconsistent outcomes for mortality and morbidity.
• Variability in pulse oximeter accuracy, probe placement, and the complex relationship between SpO2, SaO2, and PaO2 may have led to non-distinct comparison groups.

Purpose of the Study:

• To evaluate the effectiveness of different target oxygen saturation ranges in extremely preterm infants.
• To address the persistent uncertainty regarding the optimal SpO2 target range for this vulnerable population.

Main Methods:

• Analysis of randomized controlled trials comparing low-target SpO2 (85-89%) with high-target SpO2 (91-95%).
• Consideration of methodological limitations including pulse oximetry inaccuracies and physiological differences in oxygen transport.

Main Results:

• Despite methodological challenges leading to overlapping SpO2 ranges, some studies reported significant differences in mortality, necrotizing enterocolitis, and severe retinopathy of prematurity.
• Observed differences may be linked to the duration infants spent outside target ranges (SpO2 <85% or >95%).

Conclusions:

• Significant uncertainty remains regarding the ideal SpO2 target range for extremely preterm infants.
• Further research is warranted, focusing on novel oxygenation assessment methods and strategies to minimize both hypoxemia (<85% SpO2) and hyperoxemia (>95% SpO2).
• An intermediate, wider target range (87-93%) might mitigate some observed adverse outcomes.