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Introduction: Current oxygen monitoring by pulse oximetry has limitations and cannot provide estimates of the oxygen content in the microvasculature, where oxygen is used. Resonance Raman spectroscopy (RRS) provides noninvasive microvascular oxygen measurement. The objectives of this study were to (i) measure the correlation between preductal RRS microvascular oxygen saturations (RRS-StO2) and central venous oxygen saturation (SCVO2), (ii) develop normative data for RRS-StO2 measurements in healthy preterm infants, and (iii) determine the effect of blood transfusion on RRS-StO2. Methods: Thirty-three buccal and thenar RRS-StO2 measurements were performed in 26 subjects to correlate RRS-StO2 with SCVO2. Thirty-one measurements were performed in 28 subjects to develop normative RRS-StO2 values, and eight subjects were enrolled in the transfusion group to assess changes in RRS-StO2 with blood transfusion. Results: There were good correlations for buccal (r = 0.692) and thenar (r = 0.768) RRS-StO2 versus SCVO2. The median RRS-StO2 in healthy subjects was 76% (IQR 68.7–80.8). There was a significant increase of 7.8 ± 4.6% in the thenar RRS-StO2 after blood transfusion. Conclusions: RRS appears to be a safe and noninvasive means of monitoring microvascular oxygenation. Thenar RRS-StO2 measurements are more feasible and practical to use than buccal. In healthy preterm infants, the median RRS-StO2 was calculated based on measurements across various gestational age and gender. More studies evaluating the effects of gestational age of RRS-StO2 in various critical clinical settings are needed to confirm the findings. [ABSTRACT FROM AUTHOR]

Background: The ability to monitor tissue oxygenation in neonates remains a challenge due to limited blood supply and the reliance on invasive procedures. Resonance Raman spectroscopy noninvasively measures tissue oxygenation (RRS-StO2). Peripheral tissue oxygenation using this novel technology has not been described in neonates. Objectives: To examine the relationship between short-term RRS-StO2 measurements and central venous saturation (ScvO2) and pulse oximetry (SpO2) in preterm and term neonates. Methods: Ninety-seven term neonates had buccal and plantar RRS-StO2 measurements performed. In 15 preterm neonates, similar measurements were obtained in conjunction with ScvO2 in the first week of life. Simultaneous SpO2 and heart rate were also recorded. Results: In healthy neonates, buccal RRS-StO2 values negatively correlated with the day of life. No correlation existed between buccal and plantar RRS-StO2 values and ScvO2 or SpO2. Greater intra-patient plantar RRS-StO2 variability was seen in preterm neonates with increasing respiratory support. Conclusions: Neonatal RRS-StO2 measurements are feasible short term but do not correlate with ScvO2 and SpO2. Healthy neonates had greater differences and variability in RRS-StO2 values, illustrating an evolving microcirculation not detected with pulse oximetry. Greater RRS-StO2 variability in sick neonates requiring respiratory support may indicate microcirculatory instability despite being within target SpO2 ranges. Further study is needed to establish if RRS-StO2 monitoring is an accurate representation of tissue oxygenation. [ABSTRACT FROM AUTHOR]