Regional cerebral and splanchnic tissue oxygen saturation in preterm infants - Longitudinal normative measurements

Value of near-infrared spectroscopy in evaluating the risk of neonatal necrotizing enterocolitis: A systematic review and meta-analysis

PURPOSE

Recently, near-infrared spectroscopy (NIRS) has been proposed for diagnosing patients with neonatal necrotizing enterocolitis (NEC). However, a consensus on the credibility of NIRS in evaluating NEC risk has not been reached. This meta-analysis aimed to evaluate the relationship between NEC and splanchnic regional tissue oxygen saturation (SrSO2) and cerebral regional tissue oxygen saturation (CrSO2) detected by NIRS to clarify the clinical value of NIRS in evaluating the risk of NEC.

METHODS

Studies using NIRS to monitor regional tissue oxygen saturation (rSO2) in neonates with NEC published in PubMed, Web of Science, Embase, and the Cochrane Library were searched from their inception to 30 July 2023. Mean difference (MD), pooled sensitivity, and pooled specificity, along with their 95 % confidence intervals (CI), were calculated, and the random-effects model was used for analysis. This study was registered with PROSPERO (no. CRD42022326783).

RESULTS

Fourteen studies including 938 neonates (172 NEC, 766 controls) were identified. SrSO2 was significantly decreased in patients with NEC (MD: -12.52, 95 % CI: -15.95, -9.08; P < 0.00001), and this decrease was observed even before the diagnosis of NEC (MD: -13.79, 95 % CI: -17.97, -9.62; P < 0.00001). The pooled sensitivity and specificity of SrSO2 were 0.80 (95 % CI: 0.69, 0.88) and 0.90 (95 % CI: 0.61, 0.98), respectively. However, no significant difference in CrSO2 was found (MD: -4.37, 95 % CI: -10.62, 1.88; P = 0.17).

CONCLUSIONS

SrSO2, detected by NIRS, could be a valuable non-invasive method for differentiating NEC from non-NEC neonates. It could differentiate prior to NEC diagnosis.

[Application of near-infrared spectroscopy in the early identification of neonatal gastrointestinal diseases]

Necrotizing enterocolitis (NEC) is one of the most common gastrointestinal diseases in neonatal intensive care units, characterized by rapid progression and a high mortality rate. Local intestinal ischemia and hypoxia are significant contributors to NEC. Feeding intolerance (FI), which refers to a range of gastrointestinal manifestations arising from the inability to tolerate enteral nutrition, is one of the most common clinical issues in neonates, and preventing and treating FI is crucial for improving neonatal survival rates. Near-infrared spectroscopy is a clinical tool that can be used at the bedside to monitor regional oxygen saturation. It is non-invasive, reliable, and sustainable, and its feasibility and safety in assessing intestinal blood circulation have been validated. Early identification of intestinal ischemia and differentiation of FI from precursor symptoms of NEC, as well as predicting the occurrence of NEC, are extremely important for reducing intestinal injury and adverse long-term outcomes. In recent years, there has been new research progress related to the monitoring of intestinal tissue oxygen saturation and cerebral oxygen saturation for the early identification of FI and precursor symptoms of NEC, and this article provides a review of these developments.

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.

Abdominal Near Infrared Spectroscopy can be reliably used to measure splanchnic oxygenation changes in preterm infants

OBJECTIVE

Near-infrared spectroscopy (NIRS) allows assessment of regional tissue oxygen delivery and extraction. There are doubts regarding reliability of gut NIRS measurements. This study assesses reliability of NIRS for monitoring gut oxygenation.

STUDY DESIGN

Splanchnic tissue haemoglobin index (sTHI), tissue oxygenation index (sTOI) and fractional tissue oxygen extraction (sFTOE) changes during blood transfusion were measured using NIRS and compared to stable control infants. Infants were grouped into 3 chronological age groups: 1-7, 8-28 and ≥29 days of life.

RESULTS

sTHI, sTOI significantly increased, and sFTOE reduced following blood transfusion in all age group infants (n = 59), with no changes seen in control infants (n = 12). Baseline characteristics including gestational age and feed volumes did not differ between groups.

CONCLUSION

Gut perfusion measured by NIRS improved in infants who received blood transfusion, a change not seen in the control group, thus suggesting NIRS is a reliable method to measure splanchnic tissue oxygenation.

[Value of intestinal regional oxygen saturation and C-reactive protein in the diagnosis of necrotizing enterocolitis in preterm infants]

OBJECTIVES

To study the clinical value of intestinal regional oxygen saturation (rSO₂) and C-reactive protein (CRP) in the diagnosis of necrotizing enterocolitis (NEC) in preterm infants.

METHODS

A prospective observational study was conducted among the preterm infants who were hospitalized in Children's Hospital Affiliated to Anhui Medical University, from October 2020 to December 2021, with 22 infants in the NEC group and 35 infants in the non-NEC group. Intestinal rSO₂ was monitored 24 hours after a confirmed diagnosis of NEC in the NEC group, and serum CRP levels were measured before anti-infection therapy. In the non-NEC group, intestinal rSO₂ monitoring and serum CRP level measurement were performed at the corrospording time points. The two groups were compared in terms of intestinal rSO₂ and serum CRP level. The receiver operating characteristic (ROC) curve was used to analyze the value of intestinal rSO₂ alone, serum CRP alone, and intestinal rSO₂ combined with CRP in the diagnosis of NEC in preterm infants.

RESULTS

Compared with the non-NEC group, the NEC group had a significantly lower level of intestinal rSO₂ (P<0.05) and a higher serum CRP level (P<0.05). The ROC curve analysis showed that intestinal rSO₂ had an optimal cut-off value of 50.75% in the diagnosis of NEC in preterm infants, with a sensitivity of 81.8%, a specificity of 85.7%, and an area under the ROC curve (AUC) of 89.4%; CRP had an optimal cut-off value of 12.05 mg/L in the diagnosis of NEC in preterm infant, with a sensitivity of 72.7%, a specificity of 74.3%, and an AUC of 74.8%; intestinal rSO₂ combined with CRP had a sensitivity of 90.9%, a specificity of 77.1%, and an AUC of 91.9% in the diagnosis of NEC. The AUC of intestinal rSO₂ alone in the diagnosis NEC was higher than that of CRP (P<0.05). There was no significant difference in the AUC between intestinal rSO₂ alone and intestinal rSO₂ combined with CRP (P>0.05).

CONCLUSIONS

The value of intestinal rSO₂ in the diagnosis NEC is higher than that of CRP, and is equivalent to that of the combination of intestinal rSO₂ and CRP in preterm infants.

Splanchnic-cerebral oxygenation ratio associated with packed red blood cell transfusion in preterm infants

BACKGROUND

Splanchnic-cerebral oxygenation ratio (SCOR), the ratio of splanchnic tissue oxygen (StO₂ s) to simultaneously measured cerebral tissue oxygen (StO₂ c), has been described as a surrogate to detect impaired splanchnic oxygenation associated with hypoperfusion status such as necrotizing enterocolitis. This concept is based on the presumption that any change in SCOR indicates a corresponding change in splanchnic tissue oxygenation as the numerator, whereas cerebral tissue oxygenation as the denominator remains stable. However, it is questionable to utilise this concept to detect splanchnic oxygenation changes in the context of packed red blood cell transfusion (PRBCT).

AIM

The current study examines the contribution of both cerebral and splanchnic oxygenation components to PRBCT-associated SCOR changes in preterm infants.

DESIGN

Prospective cohort study.

SETTING

Neonatal intensive care.

PATIENTS

Hemodynamically stable infants: Gestation <32 weeks; birth weight <1500 g; postmenstrual age <37 weeks: tolerating ≥120 ml/kg/day feed volume.

INTERVENTIONS

PRBCT at 15 ml/kg, over 4 h.

MAIN OUTCOME MEASURES

Transfusion-associated changes were determined by performing mixed models for repeated measures analysis between the 4-h mean pre-transfusion values (SCOR 0, StO₂ s 0, and StO₂ c 0) and the post-transfusion hourly mean values for the next 28 h (SCOR 1-28, StO₂ s 1-28, and StO₂ c 1-28). Dunnett's method was used to adjust for the multiplicity of the p value.

RESULTS

Of 30 enrolled infants 14 [46.7%] male; median [IQR] birth weight, 923 [655-1064] g; gestation, 26.4 [25.5-28.1] weeks; enrolment weight, 1549 [1113-1882] g; and postmenstrual age, 33.6 [32.4-35.0] weeks, one infant was excluded because of corrupted NIRS data. With the commencement of PRBCT, SCOR demonstrated a downward trend throughout the study period. This drift was associated with an increasing StO₂ c trend, while StO₂ s remained unchanged throughout the study period.

CONCLUSIONS AND RELEVANCE

PRBCT-associated SCOR decrease suggests improvement in cerebral oxygenation rather than worsening splanchnic oxygenation. Our study underlines that it is necessary to determine individual components of SCOR, namely cerebral and splanchnic StO₂ to understand SCOR changes in the context of PRBCT.

Biomarkers of gut injury in neonates - where are we in predicting necrotising enterocolitis?

Despite advances in neonatal care Necrotising Enterocolitis (NEC) continues to have a significant mortality and morbidity rate, and with increasing survival of those more immature infants the population at risk of NEC is increasing. Ischaemia, reperfusion, and inflammation underpin diseases affecting intestinal blood flow causing gut injury including Necrotising Enterocolitis. There is increasing interest in tissue biomarkers of gut injury in neonates, particularly those representing changes in intestinal wall barrier and permeability, to determine whether these could be useful biomarkers of gut injury. This article reviews current and newly proposed markers of gut injury, the available literature evidence, recent advances and considers how effective they are in clinical practice. We discuss each biomarker in terms of its effectiveness in predicting NEC onset and diagnosis or predicting NEC severity and then those that will aid in surveillance and identifying those infants are greatest risk of developing NEC.

Could Near Infrared Spectroscopy (NIRS) be the new weapon in our fight against Necrotising Enterocolitis?

There is no ideal single gut tissue or inflammatory biomarker available to help to try and identify Necrotising Enterocolitis (NEC) before its clinical onset. Neonatologists are all too familiar with the devastating consequences of NEC, and despite many advances in neonatal care the mortality and morbidity associated with NEC remains significant. In this article we review Near Infrared Spectroscopy (NIRS) as a method of measuring regional gut tissue oxygenation. We discuss its current and potential future applications, including considering its effectiveness as a possible new weapon in the early identification of NEC.