Pulse Oximetry Histogram Profiles Before and After Red Blood Cell Transfusion in Very Preterm Infants: A Prospective Observational Cohort

TL;DR

RBC transfusions in very preterm infants improved anemia but had limited effects on oxygenation stability, with variations seen in higher-risk groups.

Contribution

This study introduces SpO2 histograms as a potential tool to assess heterogeneous oxygenation responses after RBC transfusion in preterm infants.

Findings

RBC transfusion increased hemoglobin but did not significantly improve oxygenation stability in preterm infants.

Higher-risk subgroups like BPD and low birth weight infants showed persistent oxygenation instability.

SpO2 histograms showed modest discrimination for predicting outcomes like ROP and BPD.

Abstract

What are the main findings?
Continuous SpO2 histogram monitoring showed only modest, non-significant shifts in hypoxemia, target-range oxygenation, and hyperoxemia over 72 h after RBC transfusion in very preterm infants.Despite a substantial hemoglobin increase after transfusion, oxygenation instability persisted and varied across higher-risk subgroups (BPD and birth weight < 1000 g).

Continuous SpO2 histogram monitoring showed only modest, non-significant shifts in hypoxemia, target-range oxygenation, and hyperoxemia over 72 h after RBC transfusion in very preterm infants.

Despite a substantial hemoglobin increase after transfusion, oxygenation instability persisted and varied across higher-risk subgroups (BPD and birth weight < 1000 g).

What are the implications of the main findings?
RBC transfusion should not be assumed to consistently normalize bedside oxygenation patterns; SpO2 histograms may provide a practical adjunct for assessing heterogeneous responses beyond hemoglobin values alone.Early post-transfusion histogram profiles may be useful for hypothesis generation and future risk-stratification studies for outcomes such as BPD and ROP, warranting validation in larger cohorts.

RBC transfusion should not be assumed to consistently normalize bedside oxygenation patterns; SpO2 histograms may provide a practical adjunct for assessing heterogeneous responses beyond hemoglobin values alone.

Early post-transfusion histogram profiles may be useful for hypothesis generation and future risk-stratification studies for outcomes such as BPD and ROP, warranting validation in larger cohorts.

Background/Objectives: Red blood cell (RBC) transfusion is frequently used to treat anemia of prematurity, yet bedside metrics that capture its short-term impact on oxygenation stability are limited. We assessed whether pulse oximetry histogram-derived oxygen saturation (SpO2) exposure changes after transfusion and whether responses differ across clinical subgroups. Methods: This prospective observational cohort included preterm infants born <32 weeks’ gestation who received a standardized RBC transfusion (15 mL/kg). Continuous SpO2 histograms quantified the percentage of monitored time spent in hypoxemia (<85%), normoxemia (86–95%), and hyperoxemia (≥96%) during four intervals: 24 h pre-transfusion and 24, 48, and 72 h post-transfusion. Repeated-measures and subgroup analyses (BPD, sex, birth weight < 1000 g) were performed. Results: Thirty-three infants were analyzed (gestational age 29.4 ± 2.1 weeks; birth weight 1220.6 ± 316.9 g). Hemoglobin increased from 8.6 ± 1.1 to 11.7 ± 1.0 g/dL (p < 0.001). Cohort-level histogram shifts were modest: normoxemia increased from 68.4 ± 12.1% to 72.6 ± 11.4% at 24 h (p = 0.18), hypoxemia decreased from 10.3 ± 6.5% to 6.6 ± 4.8% (p = 0.09), and hyperoxemia remained stable (21.3 ± 9.2% to 20.8 ± 8.5%; p = 0.44). Infants with BPD and those <1000 g showed persistently higher hypoxemia and/or hyperoxemia at 72 h compared with counterparts. Exploratory ROC analyses showed modest discrimination of 24 h hypoxemia for ROP (AUC 0.71) and 72 h hyperoxemia for BPD (AUC 0.74). Conclusions: RBC transfusion corrected anemia but did not produce a consistent cohort-level improvement in SpO2 histogram stability. Histogram metrics may help characterize heterogeneous oxygenation responses and support hypothesis generation for individualized monitoring strategies.

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