Oxygen saturation targets in neonatal care: A narrative review

Abstract

Optimal oxygenation requires the delivery of oxygen to meet tissue metabolic demands while minimizing hypoxic pulmonary vasoconstriction and oxygen toxicity. Oxygen saturation by pulse oximetry (SpO₂) is a continuous, non-invasive method for monitoring oxygenation. The optimal SpO₂ target varies during pregnancy and neonatal period. Maternal SpO₂ should ideally be ≥95 % to ensure adequate fetal oxygenation. Term neonates can be resuscitated with an initial oxygen concentration of 21 %, while moderately preterm infants require 21-30 %. Extremely preterm infants may need higher FiO₂, followed by titration to desired SpO₂ targets. During the NICU course, extremely preterm infants managed with an 85-89 % SpO₂ target compared to 90-94 % are associated with a reduced incidence of severe retinopathy of prematurity (ROP) requiring treatment, but with higher mortality. During the later stages of ROP progression, studies suggest that higher SpO₂ targets may help limit progression. A target SpO₂ of 90-95 % is generally reasonable for term infants with respiratory disease or pulmonary hypertension, with few exceptions such as severe acidosis, therapeutic hypothermia, and possibly dark skin pigmentation, where 93-98 % may be preferred. Infants with cyanotic heart disease and single-ventricle physiology have lower SpO₂ targets to avoid pulmonary over-circulation. In low- and middle-income countries (LMICs), the scarcity of oxygen blenders and continuous monitoring may pose a challenge, increasing the risks of both hypoxia and hyperoxia, which can lead to mortality and ROP, respectively. Strategies to mitigate hyperoxia among preterm infants in LMICs are urgently needed to reduce the incidence of ROP.

Keywords: Free radicals; Hyperoxia; Hypoxia; Oxygen; Pulmonary vascular resistance.