Near-infrared spectroscopy (NIRS) measured tissue oxygenation in neonates with gastroschisis: a pilot study

Near-infrared spectroscopy for perioperative assessment and neonatal interventions

Perioperative applications of near-infrared spectroscopy (NIRS) to monitor regional tissue oxygenation and perfusion in cardiac and noncardiac surgery are of increasing interest in neonatal care. Complex neonatal surgery can impair adequate oxygen delivery and tissue oxygen consumption and increase the risk of neurodevelopmental delay. Coupled with conventional techniques, NIRS monitoring may enable targeted hemodynamic management of the circulation in both cardiac and noncardiac surgical procedures. In this narrative review, we discuss the application of perioperative NIRS in specific neonatal interventions, including surgical intervention for congenital heart defects, definitive closure of the patent ductus arteriosus, neurological and gastrointestinal disorders, and use of extracorporeal membrane oxygenation. We identified areas for future research within disease-specific indications and offer a roadmap to aid in developing evidence-based targeted diagnostic and management strategies in neonates. IMPACT: There is growing recognition that perioperative NIRS monitoring, used in conjunction with conventional monitoring, may provide critical hemodynamic information that either complements clinical impressions or delivers novel physiologic insight into the neonatal circulatory and perfusion pathways.

Newer indications for neuromonitoring in critically ill neonates

Continuous neuromonitoring in the neonatal intensive care unit allows for bedside assessment of brain oxygenation and perfusion as well as cerebral function and seizure identification. Near-infrared spectroscopy (NIRS) reflects the balance between oxygen delivery and consumption, and use of multisite monitoring of regional oxygenation provides organ-specific assessment of perfusion. With understanding of the underlying principles of NIRS as well as the physiologic factors which impact oxygenation and perfusion of the brain, kidneys and bowel, changes in neonatal physiology can be more easily recognized by bedside providers, allowing for appropriate, targeted interventions. Amplitude-integrated electroencephalography (aEEG) allows continuous bedside evaluation of cerebral background activity patterns indicative of the level of cerebral function as well as identification of seizure activity. Normal background patterns are reassuring while abnormal background patterns indicate abnormal brain function. Combining brain monitoring information together with continuous vital sign monitoring (blood pressure, pulse oximetry, heart rate and temperature) at the bedside may be described as multi-modality monitoring and facilitates understanding of physiology. We describe 10 cases in critically ill neonates that demonstrate how comprehensive multimodal monitoring provided greater recognition of the hemodynamic status and its impact on cerebral oxygenation and cerebral function thereby informing treatment decisions. We anticipate that there are numerous other uses of NIRS as well as NIRS in conjunction with aEEG which are yet to be reported.

[Monitoring of gastrointestinal dysfunction by near-infrared spectroscopy in children with sepsis: a prospective study]

OBJECTIVES

To investigate the incidence and mortality of gastrointestinal dysfunction in children with sepsis, the application of near-infrared spectroscopy (NIRS) in monitoring mesenteric regional tissue oxygen saturation (rSO2), and the association between rSO2 and gastrointestinal dysfunction.

METHODS

In this prospective study, 79 children with sepsis in the pediatric intensive care unit (sepsis group) and 40 children who underwent physical examination in the Department of Child Healthcare (healthy control group) from January to December, 2021 were enrolled as subjects. The related medical data were collected, including general information on admission and at discharge, treatment during hospitalization, and laboratory examination results. NIRS was used to measure mesenteric rSO2. Clinical characteristics were compared between the patients with and without gastrointestinal dysfunction.

RESULTS

For the 79 children with sepsis, the incidence rate of gastrointestinal dysfunction was 49% (39/79), and the mortality rate of the children with gastrointestinal dysfunction was 26% (10/39). The children with gastrointestinal dysfunction had a longer duration of mechanical ventilation and a higher 28-day mortality rate (P<0.05). The children with gastrointestinal dysfunction had a significantly lower median rSO2 (64%) than the children without gastrointestinal dysfunction (72%) and the healthy control group (78%) (P<0.05).

CONCLUSIONS

There are high incidence and mortality rates of gastrointestinal dysfunction in children with sepsis, and the reduction in rSO2 may be associated with the development of gastrointestinal dysfunction.

NIRS as a biomarker of bowel ischaemia & surgical pathology: A meta-analysis of studies in newborns

OBJECTIVE

We performed a meta-analysis on Near-infrared Spectroscopy (NIRS) as a biomarker of bowel ischaemia.

SUMMARY BACKGROUND DATA

NIRS allows non-invasive assessment of gastrointestinal regional oxygen saturation (GrSO₂). Studies to date have focused on the feasibility of NIRS in clinical practice and its reproducibility. GrSO₂ can be used alone, or in conjunction with cerebral NIRS to give a Cerebral Splanchnic Oxygenation Ratio (CSOR). We assess published data on abdominal NIRS as a marker of bowel ischaemia.

METHODS

A literature review was conducted using the PRISMA method. Data on GrSO₂ and CSOR in controls and patients with confirmed ischaemia was included in a meta-analysis, and used to identify a diagnostic threshold.

RESULTS

14 studies were identified. Meta-analysis demonstrated that GrSO₂ (p < 0.01) and CSOR (p < 0.01) were significantly lower in neonates with bowel pathology associated with ischaemia than controls. Area under the curve for GrSO₂ was 0.80, with Youden's index highest (0.52) at a GrSO₂ of 42% (specificity 91% and sensitivity 62%). For CSOR, area under the curve is 0.89, with Youden's index highest (0.69) at 0.76 (specificity of 80%, sensitivity 90%).

CONCLUSIONS

Splanchnic NIRS correlates with bowel ischaemia. Low GrSO₂ is consistently associated with ischaemia, although a specific cut off level in each patient is hard to define. However, values below 42% correlate strongly with ischaemia while values above 52% are more suggestive of patients without bowel pathology. CSOR of below 0.76 is strongly suggestive of ischaemia. Trends within individuals are likely to be able to provide even more clinically correlatable and diagnostic data.