Forearm and Calf Tissue Oxygenation in Term Neonates Measured with Near-Infrared Spectroscopy

Neonatal somatic oxygenation and perfusion assessment using near-infrared spectroscopy : Part of the series on near-infrared spectroscopy by the European Society of Paediatric Research Special Interest Group "Near-Infrared Spectroscopy"

In this narrative review, we summarize the current knowledge and applications of somatic near-infrared spectroscopy (NIRS), with a focus on intestinal, renal, limb, and multi-site applications in neonates. Assessing somatic oxygenation at various body locations in neonates may aid in the understanding of underlying pathophysiology of organ injury. Considering cerebral autoregulation may be active to protect the brain during systemic circulatory failure, peripheral somatic oxygenation may potentially provide an early indication of neonatal cardiovascular failure and ultimate hypoxemic injury to vital organs including the brain. Certain intestinal oxygenation patterns appear to be associated with the onset and course of necrotizing enterocolitis, whereas impaired renal oxygenation may indicate the onset of acute kidney injury after various types of hypoxic events. Peripheral muscle oxygenation measured at a limb may be particularly effective in the early prediction of shock in neonates. Using multi-site NIRS may complement current approaches and clinical investigations to alert for neonatal tissue hypoxemia, and potentially even guide management. However, somatic NIRS has its inherent limitations in regard to accuracy. Interpretation of organ-specific values can also be challenging. Last, currently there are limited prospective intervention studies, and clinical benefits need to be examined further, after the clarification of critical threshold-values. IMPACT: The assessment of somatic oxygenation using NIRS may contribute to the prediction of specific diseases in hemodynamically challenged neonates. Furthermore, it may give early warning signs for impending cardiovascular failure, and impaired cerebral circulation and oxygenation. We present a comprehensive overview of the literature on applications of NIRS to various somatic areas, with a focus on its potential clinical applicability, including future research directions. This paper will enable prospective standardized studies, and multicenter collaboration to obtain statistical power, likely to advance the field.

Peripheral fractional oxygen extraction measured with near-infrared spectroscopy in neonates-A systematic qualitative review

BACKGROUND

Peripheral fractional oxygen extraction (pFOE) measured with near-infrared spectroscopy (NIRS) in combination with venous occlusion is of increasing interest in term and preterm neonates.

OBJECTIVE

The aim was to perform a systematic qualitative review of literature on the clinical use of pFOE in term and preterm neonates and on the changes in pFOE values over time.

METHODS

A systematic search of PubMed, Embase and Medline was performed using following terms: newborn, infant, neonate, preterm, term, near-infrared spectroscopy, NIRS, oximetry, spectroscopy, tissue, muscle, peripheral, arm, calf, pFOE, OE, oxygen extraction, fractional oxygen extraction, peripheral perfusion and peripheral oxygenation. Additional articles were identified by manual search of cited references. Only studies in human neonates were included.

RESULTS

Nineteen studies were identified describing pFOE measured with NIRS in combination with venous occlusion. Nine studies described pFOE measured on the forearm and calf at different time points after birth, both in stable preterm and term neonates without medical/respiratory support or any pathological findings. Nine studies described pFOE measured at different time points in sick preterm and term neonates presenting with signs of infection/inflammation, anemia, arterial hypotension, patent ductus arteriosus, asphyxia or prenatal tobacco exposure. One study described pFOE both, in neonates with and without pathological findings.

CONCLUSION

This systematic review demonstrates that pFOE may provide additional insight into peripheral perfusion and oxygenation, as well as into disturbances of microcirculation caused by centralization in preterm and term neonates with different pathological findings.

SYSTEMATIC REVIEW REGISTRATION

[https://www.crd.york.ac.uk/prospero/], identifier [CRD42021249235].

Oropharyngeal suctioning in neonates immediately after delivery: influence on cerebral and peripheral tissue oxygenation

BACKGROUND

Routine oropharyngeal suctioning in term vigorous neonates immediately after birth is a questionable practice. Current recommendations favor suctioning only in the presence of considerable obstruction due to secretions, blood or other matter. We aimed to analyze the influence of oropharyngeal suctioning on cerebral and peripheral muscle oxygenation in term neonates during transition immediately after birth.

METHODS

We included term neonates after elective cesarean section for this prospective observational study. Oropharyngeal suctioning was performed based on the clinicians' judgment of threatening airway obstruction. From a total of 138 enrolled neonates, 36 were suctioned and then compared to 36 controls matched for gestational age. Heart rate (HR) and pre/postductal arterial oxygen saturation (SpO2pre/SpO2post) were measured by pulse oximetry. Cerebral (rSO2brain) and pre/postductal peripheral muscle tissue oxygenation (rSO2pre/rSO2post) were measured by near infrared spectroscopy during the first 15min of life.

RESULTS

All neonates in both groups experienced normal postnatal transition with normal Apgar scores (Apgar 9/10/10) and with no events of apnea or bradycardia induced by suctioning. SpO2pre values were slightly lower at 2 and 4min after birth. Suctioning had no main and interaction effect on HR, SpO2post, rSO2brain, rSO2pre and rSO2post in the first 15min after birth.

CONCLUSION

In the present study we were able to show that, in term neonates, when correctly indicated, immediate postnatal oropharyngeal suctioning does not compromise cerebral and peripheral muscle tissue oxygenation. However, any suction maneuver must be performed with caution and strict indication during neonatal transition.

Peripheral Muscle Near-Infrared Spectroscopy in Neonates: Ready for Clinical Use? A Systematic Qualitative Review of the Literature

BACKGROUND

Peripheral muscle near-infrared spectroscopy (NIRS) measurements are of increasing interest especially in the care of critically ill patients.

OBJECTIVE

The aim was to perform a systematic qualitative review on peripheral muscle NIRS measurements in the clinical care of term and preterm neonates.

METHODS

A systematic search of PubMed and Ovid Embase was performed using the following terms: neonate, neonates, newborn, newborns, infant, infants, near-infrared spectroscopy, NIRS, oxygenation, perfusion, oxygen extraction, peripheral, tissue, muscle, calf, forearm and thigh. Additional articles were identified by a manual search of the cited references. Only human studies were included.

RESULTS

Twenty-one studies were identified to use peripheral muscle NIRS measurements as a single method, 17 studies combined cerebral and peripheral muscle NIRS measurements and 1 study used multi-site NIRS measurements in human neonates. Two randomized studies were identified. Two additional publications were included because they provided important general information about peripheral muscle NIRS measurements.

CONCLUSION

In the care of critically ill neonates peripheral muscle NIRS measurements alone or in combination with cerebral or multi-site NIRS measurements provide useful additional information about peripheral circulation and oxygenation. This method is a promising tool in the recognition of early states of centralization (compensated shock) in this vulnerable group of patients. However, before this method can be used in the clinical routine it has to be tested as monitoring to guide interventions in further studies.

Difference in cerebral and peripheral hemodynamics among term and preterm infants during the first three days of life

BACKGROUND

The relationship between cerebral and peripheral hemodynamics during the early postnatal period has not been clarified.

OBJECTIVES

To evaluate cerebral and peripheral oxygenation and blood volumes between term and preterm infants during the first 3 days of life.

MATERIALS AND METHODS

We performed near-infrared time-resolved spectroscopy on 32 term infants (term group) and 40 preterm infants (preterm group), with an optode placed on their forehead and upper arm. The cerebral blood volume (CBV), peripheral blood volume (PBV), cerebral Hb oxygen saturation (cSO2) and peripheral Hb oxygen saturation (pSO2) were measured at 3-6, 12, 24, 48 and 72 h after birth.

RESULTS

The CBV in the term group (2.45 ± 0.47 ml/100 g) was significantly higher than that in the preterm group (1.97 ± 0.33 ml/100 g). In contrast to the CBV, the PBV in the preterm group (3.63 ± 0.76 ml/100 g) was significantly higher than that in the term group (3.26 ± 0.56 ml/100 g). In the preterm group, there was a significant positive relationship between the CBVs and PBVs at each time point except at 72 h after birth. Despite the differences in blood volumes, there were no differences in the cSO2 and pSO2 between the two groups.

CONCLUSIONS

The contrasting results in the CBV and PBV between the term and preterm infants might be explained by differences in the maturation of the physiological mechanism to control CBV and PBV.

Regional tissue oxygen saturation: comparability and reproducibility of different devices

Comparability and reproducibility of different near-infrared spectroscopy devices measuring regional tissue oxygen saturation remain poor. Aim of the present study was to compare values and reproducibility of cerebral∕peripheral "tissue-oxygenation-index" (TOI; NIRO 300, Hamamatsu(®), Japan) with cerebral∕peripheral "regional-oxygen-saturation" (rSO; INVOS5100, Somanetics(®), USA), and to analyze the influence of quality criteria.

METHODS

cTOI and crSO2 were measured on the left forehead, pTOI and prSO2 were measured on the left calf. To analyse reproducibility, optodes were reapplied five times. A quality criterion was introduced for cTOI, crSO2 and prSO2. For pTOI quality criteria were introduced in combination with a venous occlusion technique.

RESULTS

Cerebral measurements were performed in 37 neonates. cTOI (72.7+∕-6.2%) was lower than crSO2 (83.3+∕-5.8%) (p < 0.001). The mean difference between cTOI and crSO2 was 10%. Mean standard deviations of cTOI and crSO2 were similar (cTOI: 4.9+∕-3.6; crSO2: 4.5+∕-2.6). Peripheral measurements were performed in 39 neonates. pTOI (66.0+∕-7.9%) was lower than prSO2 (82.0+∕-7.0%)(p < 0.001). The mean difference between pTOI and prSO2 was 15%. Mean standard deviations of pTOI (3.7+∕-2.6%) were lower than of prSO2 (5.0+∕-3.0%) (p = 0.047).

CONCLUSION

TOI values were significantly lower than rSO2 values, in cerebral and peripheral measurements. Reproducibility was higher for pTOI than for prSO2.

Combination of different noninvasive measuring techniques: a new approach to increase accuracy of peripheral near infrared spectroscopy

One of the problems of near-infrared-spectroscopy (NIRS) measurements is low reproducibility. The aim of the present study was to introduce quality criteria to increase reproducibility of peripheral NIRS measurements. In a prospective cohort study in 40 neonates, repeated NIRS measurements were performed on the calf. During five "reapplication" periods (of NIRS optodes), five "measurements" (venous occlusions) were performed. Tissue oxygenation index (TOI), mixed venous oxygenation (SvO2), fractional oxygen extraction (FOE), hemoglobin flow (Hbflow), oxygen delivery (DO2), and oxygen consumption (VO2) were assessed. Measurements with linear changes during venous occlusions were included for further analysis (first quality criterion: R(2)>0.95). The second quality criterion was the equation 0 < or = TOI-SvO2 < or = (SaO2-SvO2)x0.2. Variance components and mean standard deviations were analyzed after introduction of the quality criteria. Variance components of reapplication and measurement decreased after introduction of the second quality criterion (TOI: 46.6-35.0%, SvO2: 76.8-38.2%, FOE: 73.1-37.5%, Hbflow: 70.3-51.9%, DO2: 71.5-52.7%, and VO2: 70.9-63.8%). Mean standard deviations of TOI (6.6+/-3.0 to 4.7+/-3.2%), SvO2 (11.1+/-4.8 to 5.7+/-3.9%), FOE (11.3+/-4.8 to 5.9+/-4.0%), Hbflow (4.3+/-2.0 to 2.9+/-1.6 micromol100 mLmin), and DO2 (17.8+/-7.6 to 11.4+/-6.2 micromol100 mLmin) decreased significantly, too. Only 12% of measurements fulfilled both quality criteria. With the introduction of two quality criteria, test-retest variability of peripheral NIRS measurements decreased significantly and reproducibility increased significantly.