Oxygen saturation targets for adults with acute hypoxemia in low and lower-middle income countries: a scoping review with analysis of contextual factors

Knowing the target oxygen saturation (SpO₂) range that results in the best outcomes for acutely hypoxemic adults is important for clinical care, training, and research in low-income and lower-middle income countries (collectively LMICs). The evidence we have for SpO₂ targets emanates from high-income countries (HICs), and therefore may miss important contextual factors for LMIC settings. Furthermore, the evidence from HICs is mixed, amplifying the importance of specific circumstances. For this literature review and analysis, we considered SpO₂ targets used in previous trials, international and national society guidelines, and direct trial evidence comparing outcomes using different SpO₂ ranges (all from HICs). We also considered contextual factors, including emerging data on pulse oximetry performance in different skin pigmentation ranges, the risk of depleting oxygen resources in LMIC settings, the lack of access to arterial blood gases that necessitates consideration of the subpopulation of hypoxemic patients who are also hypercapnic, and the impact of altitude on median SpO₂ values. This process of integrating prior study protocols, society guidelines, available evidence, and contextual factors is potentially useful for the development of other clinical guidelines for LMIC settings. We suggest that a goal SpO₂ range of 90-94% is reasonable, using high-performing pulse oximeters. Answering context-specific research questions, such as an optimal SpO₂ target range in LMIC contexts, is critical for advancing equity in clinical outcomes globally.

Randomized Trial of Oxygen Saturation Targets during and after Resuscitation and Reversal of Ductal Flow in an Ovine Model of Meconium Aspiration and Pulmonary Hypertension

Neonatal resuscitation (NRP) guidelines suggest targeting 85-95% preductal SpO₂ by 10 min after birth. Optimal oxygen saturation (SpO₂) targets during resuscitation and in the post-resuscitation management of neonatal meconium aspiration syndrome (MAS) with persistent pulmonary hypertension (PPHN) remains uncertain. Our objective was to compare the time to reversal of ductal flow from fetal pattern (right-to-left), to left-to-right, and to evaluate pulmonary (Q_PA), carotid (Q_CA)and ductal (Q_DA) blood flows between standard (85-94%) and high (95-99%) SpO₂ targets during and after resuscitation. Twelve lambs asphyxiated by endotracheal meconium instillation and cord occlusion to induce MAS and PPHN were resuscitated per NRP guidelines and were randomized to either standard (85-94%) or high (95-99%) SpO₂ targets. Out of twelve lambs with MAS and PPHN, six each were randomized to standard and high SpO₂ targets. Median [interquartile range] time to change in direction of blood flow across the ductus arteriosus from right-to-left, to left-to-right was significantly shorter with high SpO₂ target (7.4 (4.4-10.8) min) compared to standard SpO₂ target (31.5 (21-66.2) min, p = 0.03). Q_PA was significantly higher during the first 10 min after birth with higher SpO₂ target. At 60 min after birth, the Q_PA, Q_CA and Q_DA were not different between the groups. To conclude, targeting SpO₂ of 95-99% during and after resuscitation may hasten reversal of ductal flow in lambs with MAS and PPHN and transiently increase Q_PA but no differences were observed at 60 min. Clinical studies comparing low and high SpO₂ targets assessing hemodynamics and neurodevelopmental outcomes are warranted.

Evidence to Support Oxygen Guidelines for Children with Emergency Signs in Developing Countries: A Systematic Review and Physiological and Mechanistic Analysis

There are currently no evidence-based oxygen saturation targets for treating children with life-threatening conditions. We reviewed evidence of SpO2 targets for oxygen therapy in children with emergency signs as per WHO Emergency Triage Assessment and Treatment guidelines. We systematically searched for physiological data and international guidelines that would inform a safe approach. Our findings suggest that in children with acute lung disease who do not require resuscitation, a threshold SpO2 for commencing oxygen of 90% will provide adequate oxygen delivery. Although there is no empirical evidence regarding oxygen saturation to target in children with emergency signs from developing countries, a SpO2 of ≥ 94% during resuscitation may help compensate for common situations of reduced oxygen delivery. In children who do not require resuscitation or are stable post resuscitation with only lung disease, a lower limit of SpO2 for commencing oxygen of 90% will provide adequate oxygen delivery and save resources.