Cerebral and somatic near-infrared spectroscopy in normal newborns

A narrative review of the clinical applications of renal NIRS and integration with cerebral NIRS in the NICU

Organ perfusion and regional tissue oxygen saturation (rSO2) can be measured non-invasively using near-infrared spectroscopy (NIRS). While cerebral NIRS monitoring in neonates has been widely used, the adoption of renal NIRS is still evolving. This narrative review explores the application of renal NIRS in neonates and proposes an algorithm for integrating renal and cerebral NIRS in the neonatal intensive care unit. Decreased renal regional oxygenation (RrSO2) suggests decreased renal O2 delivery/perfusion or increased O2 consumption, warranting evaluation for acute kidney injury, anemia, hemodynamically significant patent ductus arteriosus, or hypotension. Increased RrSO2 indicates increased renal O2 delivery/perfusion or decreased O2 consumption, necessitating assessment for hyperoxia or established kidney injury. Combining cerebral and renal NIRS provides a comprehensive evaluation, allowing for the detection of early clinical changes. This integrated monitoring approach holds promise for improving neonatal outcomes. However, further large-scale studies are needed to establish normal ranges and guide therapeutic interventions.

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.

Normal regional tissue oxygen saturation in neonates: a systematic qualitative review

BACKGROUND

The aim of this systematic qualitative review was to give an overview of reference ranges defined as normal values or centile charts of regional tissue oxygen saturation measured by near-infrared spectroscopy (NIRS) in term and preterm neonates.

METHODS

A systematic search of MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials was performed. Additional articles were identified by manual search of cited references. Only human studies in neonates were included.

RESULTS

Nineteen studies were identified. Eight described regional tissue oxygen saturation during fetal-to-neonatal transition, six during the first 3 days after birth, four during the first 7 days after birth, and one during the first 8 weeks after birth. Nine described regional tissue oxygen saturation in term, nine in preterm neonates, and one in both. Eight studies published centile charts for cerebral regional tissue oxygen saturation, and only five included large cohorts of infants. Eleven studies described normal values for cerebral, muscle, renal, and abdominal regional tissue oxygen saturation, the majority with small sample sizes. Four studies of good methodological quality were identified describing centile charts of cerebral regional tissue oxygen saturation.

CONCLUSIONS

In clinical settings, quality centile charts are available and should be the preferred method when using NIRS monitoring.

IMPACT

Near-infrared spectroscopy (NIRS) enables a bed-side non-invasive continuous monitoring of tissue oxygenation. When using NIRS monitoring in a clinical setting, centile charts with good quality are available and should be preferred to normal values. High-quality reference ranges of regional tissue oxygenation in term and preterm born neonates are an important step toward routine clinical application of NIRS.

Update in Pediatric Neurocritical Care: What a Neurologist Caring for Critically Ill Children Needs to Know

Currently nearly one-quarter of admissions to pediatric intensive care units (PICUs) worldwide are for neurocritical care diagnoses that are associated with significant morbidity and mortality. Pediatric neurocritical care is a rapidly evolving field with unique challenges due to not only age-related responses to primary neurologic insults and their treatments but also the rarity of pediatric neurocritical care conditions at any given institution. The structure of pediatric neurocritical care services therefore is most commonly a collaborative model where critical care medicine physicians coordinate care and are supported by a multidisciplinary team of pediatric subspecialists, including neurologists. While pediatric neurocritical care lies at the intersection between critical care and the neurosciences, this narrative review focuses on the most common clinical scenarios encountered by pediatric neurologists as consultants in the PICU and synthesizes the recent evidence, best practices, and ongoing research in these cases. We provide an in-depth review of (1) the evaluation and management of abnormal movements (seizures/status epilepticus and status dystonicus); (2) acute weakness and paralysis (focusing on pediatric stroke and select pediatric neuroimmune conditions); (3) neuromonitoring modalities using a pathophysiology-driven approach; (4) neuroprotective strategies for which there is evidence (e.g., pediatric severe traumatic brain injury, post-cardiac arrest care, and ischemic stroke and hemorrhagic stroke); and (5) best practices for neuroprognostication in pediatric traumatic brain injury, cardiac arrest, and disorders of consciousness, with highlights of the 2023 updates on Brain Death/Death by Neurological Criteria. Our review of the current state of pediatric neurocritical care from the viewpoint of what a pediatric neurologist in the PICU needs to know is intended to improve knowledge for providers at the bedside with the goal of better patient care and outcomes.

Association of Early Postoperative Regional Oxygen Saturation Measures and Development of Necrotizing Enterocolitis in Neonates Following Cardiac Surgery

Necrotizing enterocolitis (NEC) is a relatively common complication in neonates with single ventricle physiology following heart surgery. Near-infrared spectroscopy (NIRS) is used to measure regional oxygen saturations in neonates in the postoperative period. We sought to investigate the association of somatic regional oxygen saturation (srSO2) and cerebral regional oxygen saturation (crSO2) in the early postoperative period and the subsequent development of NEC. We performed a retrospective cohort study of neonates who underwent cardiac surgery with cardiopulmonary bypass from October 2017 to September 2021 at the University of Virginia Children's Hospital. Values of srSO2 and crSO2 were captured over the first 48 h following surgery. 166 neonates were included and the median age at time of surgery was 8 days. NEC was diagnosed in 18 neonates following heart surgery with a median interval from surgery to diagnosis of 7 days. Neonates with single ventricle physiology had lower average crSO2 (62% vs 78%, p < 0.001), average srSO2 (72% vs 86%, p < 0.001), average crSO2 to srSO2 ratio (0.874 vs 0.913, p < 0.001), and an increased average srSO2-crSO2 difference (10% vs 8%, p = 0.03). Adjusting for single ventricle physiology, lower average crSO2 was associated with the development of definite NEC (modified Bell's criteria stage IIa and higher) (OR = 0.86, 95% CI 0.78-0.96, p = 0.007). Lower crSO2 values in the early postoperative period in neonates following cardiac surgery was associated with an increased risk in the subsequent development of NEC.

Noninvasive Neuromonitoring Modalities in Children Part I: Pupillometry, Near-Infrared Spectroscopy, and Transcranial Doppler Ultrasonography

BACKGROUND

Noninvasive neuromonitoring in critically ill children includes multiple modalities that all intend to improve our understanding of acute and ongoing brain injury.

METHODS

In this article, we review basic methods and devices, applications in clinical care and research, and explore potential future directions for three noninvasive neuromonitoring modalities in the pediatric intensive care unit: automated pupillometry, near-infrared spectroscopy, and transcranial Doppler ultrasonography.

RESULTS

All three technologies are noninvasive, portable, and easily repeatable to allow for serial measurements and trending of data over time. However, a paucity of high-quality data supporting the clinical utility of any of these technologies in critically ill children is currently a major limitation to their widespread application in the pediatric intensive care unit.

CONCLUSIONS

Future prospective multicenter work addressing major knowledge gaps is necessary to advance the field of pediatric noninvasive neuromonitoring.

Regional pulmonary oxygen saturations in late preterm and term infants with respiratory distress at birth

BACKGROUND

Measurement of regional pulmonary oxygen saturation by near-infrared spectroscopy is a novel monitorization method. This study aimed to determine the early regional pulmonary oxygen saturations in neonates with respiratory distress.

METHODS

This observational study was conducted at the delivery room in infants above 35 weeks of gestation who developed respiratory distress immediately after birth. Preductal oxygen saturation (Covidien Nellcor®) and regional oxygen saturations of both apical (raSO2 ) and basal regions (rbSO2 ) of right lung were measured (Covidien INVOS®) within the first 15 min of life and compared to those of healthy neonates.

RESULTS

Of the 165 infants included to the study, 15 were late preterm and 55 developed respiratory distress. Infants with respiratory distress had significantly lower gestational age and birth weight. Regional pulmonary oxygenations at both apex and basal lung areas were positively correlated with SpO2 in all infants. The rbSO2 was significantly lower than raSO2 until 10th minute of life regardless of respiratory distress. The fractionized tissue oxygen extraction of both apical and basal lung areas was significantly higher in infants with respiratory distress until 5th minute of life.

CONCLUSION

This study is one of the pioneer studies evaluating the early pulmonary oxygenation values of infants with respiratory distress. Oxygenation of apical lung regions are better than basal areas. Higher fractionized tissue oxygen extraction showed the impaired pulmonary perfusion in infants with respiratory distress.

The Use of Cerebral Near-Infrared Spectroscopy in Neonatal Hypoxic-Ischemic Encephalopathy: A Systematic Review of the Literature

BACKGROUND

Cerebral near-infrared spectroscopy (cNIRS) is a noninvasive technology used to trend cerebral perfusion at the bedside. cNIRS has potential as a valuable tool in the evaluation of infants with suspected hypoxic-ischemic encephalopathy (HIE). Trending cerebral perfusion with cNIRS can provide information regarding cerebral metabolism as HIE is evolving, which may offer insight into the extent of brain injury.

PURPOSE

The purpose of this systematic review is to investigate the use of cNIRS as a neurocritical tool in the management of neonatal HIE by evaluating its ability to detect acute neurological compromise, including acute brain injury and seizure activity, as well as its potential to identify infants at high risk for long-term neurodevelopmental impairment.

METHODS

A literature search was conducted using PubMed, CINAHL, and Web of Science databases to review articles investigating cNIRS technology in the acute management of HIE.

RESULTS

Eight studies were identified and included in this systematic review. Correlations were observed between cNIRS trends and neurological outcomes as later detected by MRI. cNIRS has potential as a bedside neuromonitoring tool in the management of HIE to detect infants at high risk for brain injury.

IMPLICATIONS FOR PRACTICE

Existing research supports the value of trending cNIRS in HIE management. Documented normal cNIRS values for both term and preterm infants in the first few days of life is approximately 60% to 80%. A steadily increasing cNIRS reading above an infant's baseline and a value of more than 90% should prompt further evaluation and concern for significant neurological injury.

Routine Diaper Change Alters Kidney Oxygenation in Premature Infants: A Non-A Priori Analysis

BACKGROUND

Reduction in oxygen delivery to developing kidneys of premature infants may be an important source for acute kidney injury in premature infants.

PURPOSE

To describe changes in continuous kidney oxygenation (RrSO 2 ) measures before, during, and after routine diaper changes.

METHODS

Non-a priori analysis of a prospective cohort that received continuous measurement of RrSO 2 with near-infrared spectroscopy (NIRS) over the first 14 days of life demonstrating acute RrSO 2 drops surrounding diaper changes.

RESULTS

In total, 26 of 38 (68%) infants (≤1800 g) from our cohort exhibited acute drops in RrSO 2 that temporally correlated with diaper changes. Mean (SD) RrSO 2 baseline prior to each diaper change event was 71.1 (13.2), dropped to 59.3 (11.6) during diaper change, and recovered to 73.3 (13.2). There was a significant difference between means when comparing baseline to diaper change ( P < .001; 95% CI, 9.9 to 13.8) and diaper change to recovery ( P < .001; 95% CI, -16.9 to -11.2). The mean decrease in RrSO 2 during diaper change averaged 12 points (17%) below 15-minute RrSO 2 mean prior to diaper change, with quick recovery to prediaper change levels. No decreases in SpO 2 , blood pressure, or heart rate were documented during the intermittent kidney hypoxic events.

IMPLICATIONS FOR PRACTICE AND RESEARCH

Routine diaper changes in preterm infants may increase the risk for acute reductions in RrSO 2 as measured by NIRS; however, the impact on kidney health remains unknown. Larger prospective cohort studies assessing kidney function and outcomes related to this phenomenon are needed.

Noninvasive Monitoring to Demonstrate Postoperative Differences in Regional Hemodynamics in Newborn Infants With d-Transposition of the Great Arteries and Hypoplastic Left Heart Syndrome

BACKGROUND

The adequacy of tissue O₂ delivery in infants receiving intensive care is difficult to measure directly. Regional O₂ (rSO₂) and fractional tissue O₂ extraction (FTOE), the ratio of O₂ consumption to O₂ delivery, obtained from newer noninvasive tools, such as near-infrared spectroscopy (INVOS) and microvascular tissue oximetry (T-Stat) can provide important information on the adequacy of tissue oxygenation and aid in managing critically ill infants.

METHODS

We prospectively evaluated differences in rSO₂ and FTOE in 26 infants with hypoplastic left heart syndrome (HLHS) (n = 12) or d-transposition of the great arteries (d-TGA) (n = 14). Continuous noninvasive monitoring of SpO₂, heart rate, and perfusion index with pulse oximetry, cerebral-rSO₂ and renal-rSO₂ with INVOS, and buccal tissue oxygenation using T-Stat were performed during immediate postoperative period for 24 hours.

RESULTS

The SpO₂ and rSO₂ in infants with d-TGA were higher compared with the infants with HLHS at all measured sites (buccal mucosa, cerebral, and renal). Significant regional differences were also observed in FTOE across all infants with the highest at the buccal mucosa tissue level, followed by cerebral and renal measurement sites. As compared with infants with d-TGA, infants with HLHS had higher regional FTOE and heart rate, with a lower arterial O₂ content and perfusion index.

CONCLUSIONS

Our study demonstrates the utility of noninvasive hemodynamic monitoring to assess regional oxygenation and perfusion, as evidenced by significant differences in infants with HLHS and d-TGA, conditions with different circulation physiologies. Such comprehensive monitoring can potentially aid in evaluating treatment strategies aimed at preventing organ damage from O₂ insufficiency.

Utilizing Near-Infrared Spectroscopy to Identify Pediatric Trauma Patients Needing Lifesaving Interventions: A Prospective Study

OBJECTIVES

The aim of this study was to prospectively investigate the role of near-infrared spectroscopy (NIRS) in identifying pediatric trauma patients who required lifesaving interventions (LSIs).

METHODS

Prospective cohort study of children age 0 to 18 years who activated the trauma team response between August 15, 2017, and February 12, 2019, at a large, urban pediatric emergency department (ED).The relationship between the lowest somatic NIRS saturation and the need for LSIs (based on published consensus definition) was investigated. Categorical variables were analyzed by χ 2 test, and continuous variables were analyzed by Student t test.

RESULTS

A total of 148 pediatric trauma patients had somatic NIRS monitoring and met the inclusion criteria. Overall, 65.5% were male with a mean ± SD age of 10.9 ± 6.0 years. Injuries included 67.6% blunt trauma and 28.4% penetrating trauma with mortality of 3.4% (n = 5). Overall, the median lowest somatic NIRS value was 72% (interquartile range, 58%-88%; range, 15%-95%), and 43.9% of patients had a somatic NIRS value <70%. The median somatic NIRS duration recorded was 11 minutes (interquartile range, 7-17 minutes; range, 1-105 minutes). Overall, 36.5% of patients required a LSI including 53 who required a lifesaving procedure, 17 required blood products, and 17 required vasopressors. Among procedures, requiring a thoracostomy was significant.Pediatric trauma patients with a somatic NIRS value <70% had a significantly increased odds of requiring a LSI (odds ratio, 2.11; 95% confidence interval, 1.07-4.20). Somatic NIRS values <70% had a sensitivity and specificity of 56% and 63%, respectively.

CONCLUSIONS

Pediatric trauma patients with somatic NIRS values <70% within 30 minutes of ED arrival have an increased odds of requiring LSIs. Among LSIs, pediatric trauma patients requiring thoracostomy was significant. The role of NIRS in incrementally improving the identification of critically injured children in the ED and prehospital setting should be evaluated in larger prospective multicenter studies.

Optimal neuromonitoring techniques in neonates with hypoxic ischemic encephalopathy

Neonates with hypoxic ischemic encephalopathy (HIE) are at significant risk for adverse outcomes including death and neurodevelopmental impairment. Neuromonitoring provides critical diagnostic and prognostic information for these infants. Modalities providing continuous monitoring include continuous electroencephalography (cEEG), amplitude-integrated electroencephalography (aEEG), near-infrared spectroscopy (NIRS), and heart rate variability. Serial bedside neuromonitoring techniques include cranial ultrasound and somatic and visual evoked potentials but may be limited by discrete time points of assessment. EEG, aEEG, and NIRS provide distinct and complementary information about cerebral function and oxygen utilization. Integrated use of these neuromonitoring modalities in addition to other potential techniques such as heart rate variability may best predict imaging outcomes and longer-term neurodevelopment. This review examines available bedside neuromonitoring techniques for the neonate with HIE in the context of therapeutic hypothermia.

Use of combined cerebral and somatic renal near infrared spectroscopy during noncardiac surgery in children: a proposed algorithm

Cerebral near infrared spectroscopy (NIRS) monitoring has been extensively applied in neonatology and in cardiac surgery, becoming a standard in many pediatric cardiac centers. However, compensatory physiological mechanisms favor cerebral perfusion to the detriment of peripheral tissue oxygenation. Therefore, simultaneous measurement of cerebral and somatic oxygen saturation has been advocated to ease the differential diagnosis between central and peripheral sources of hypoperfusion, which may go undetected by standard monitoring and not mirrored by cerebral NIRS alone. A clinical algorithm already exists in cardiac surgery, aimed to correct intraoperative cerebral oxygen desaturations. A similar algorithm still lacks in noncardiac pediatric surgery. The goal of this paper is to propose a clinical algorithm for the combined use of cerebral and somatic NIRS monitoring during anesthesia in the pediatric population undergoing noncardiac surgery. A panel of experienced pediatric anesthetists developed the algorithm that is based on the clinical experience and intraoperative observations. It aims to lessen the current variability in interpreting NIRS measurement. Multisite NIRS monitoring was achieved applying one pediatric sensor to the forehead for cerebral tissue perfusion reading and a second one to the decumbent lumbar region for recording somatic renal tissue perfusion. The algorithm describes a sequence of acts aimed to identify the putative cause of intraoperative organ tissue desaturation and suggests clinical interventions expected to restore adequate tissue perfusion. It is composed of two arms: the main arm includes patients with an observed decrease in cerebral perfusion (CrO2), the second one includes those with a stable CrSO2 with declining RrSO2. Described also are five clinical cases of infants and neonates in whom pathological alterations of organ perfusion were detected using intraoperative multisite NIRS monitoring, portrayed in the accompanying figures (Annex).

Changes in regional oxygen saturation of the kidney and brain of infants during hospitalization

BACKGROUND

In pre-term infants, the postnatal changes in the regional oxygen saturation (rSO₂) of the brain and kidney are unclear.

METHODS

We performed a prospective observational study. We measured the cerebral/renal rSO₂ ratio and recorded the associated clinical features of infants born at 23 to 41 weeks of gestation weekly from the early postnatal period to discharge.

RESULTS

The median cerebral/renal rSO₂ ratios (interquartile ranges) between birth and the expected date of birth were 1.13 (1.06-1.26) at 23-24 weeks (n = 7), 1.18 (1.10-1.32) at 25-26 weeks (n = 11), 1.24 (1.11-1.37) at 27-28 weeks (n = 9), 1.12 (1.05-1.19) at 29-30 weeks (n = 4), 1.11 (1.03-1.15) at 31-32 weeks (n = 5), 1.02 (0.98-1.06) at 33-34 weeks (n = 9), 0.98 (0.94-1.06) at 35-36 weeks (n = 19), and 0.95 (0.86-0.99) at 37-41 weeks of gestation (n = 22). The median cerebral/renal rSO₂ ratio did not significantly change after birth, but with increasing gestational age, the cerebral/renal rSO₂ ratio at the expected date of birth decreased (r = - 0.74, p < 0.001). Nephrotoxic drugs did not affect cerebral/renal rSO₂ at the expected date of birth, after adjustment for clinical factors.

CONCLUSIONS

Unlike in most infants born after the late pre-term period, the renal rSO₂ remained lower than the cerebral rSO₂ on the expected date of birth in infants born very pre-term.

Renal versus cerebral saturation trajectories: the perinatal transition in preterm neonates

BACKGROUND

The aim of this study was to develop reference renal saturation (rSrO₂) curves in premature infants, depict how they differ from cerebral saturation (rScO₂) curves, and evaluate the effect of blood pressure on these values using near-infrared spectroscopy (NIRS).

METHODS

This is a prospective cohort study of 57 inborn infants <12 h and <30 weeks gestation. rScO₂, rSrO₂, fractional tissue oxygen extraction (FTOE), and mean arterial blood pressure (MAP) were continuously monitored every 30 s for 96 h. Quantile regression was used to establish nomograms, and mean saturation values were evaluated for different MAP ranges.

RESULTS

Median rSrO₂ at the start of monitoring was ~10% higher than rScO₂. rSrO₂ showed a significant decline over time while rScO₂ peaked at 26 h. FTOE demonstrated a similar but inverse trend to their saturation counterparts. rScO₂ declined as MAP increased, while rSrO2 showed a peak and decline as MAP increased.

CONCLUSIONS

We provide rSrO₂ reference curves for the first 4 days of life, which differ in their trajectory from rScO₂ and from what has previously been reported for rSrO₂ in the full-term population. In addition, we observed a peak and decline in renal saturation with increasing MAP, suggesting a renovascular response to blood pressure changes.

IMPACT

This article depicts reference renal saturation curves during the perinatal transition in preterm infants. We show how renal saturation compares to cerebral saturation trends over time. We describe a peak and decline in renal saturation with increasing MAP, suggesting a renovascular response to blood pressure changes.

Hemodynamic Assessment of a Large Pulmonary Arteriovenous Malformation in a Neonate: Case Report and Review of Literature

Herein we report the case of a neonate with a prenatally diagnosed large pulmonary arteriovenous malformation, managed with minimally invasive hemodynamic monitoring in our Neonatal Intensive Care Unit. The combination of Near-Infrared Spectroscopy and Pressure Recording Analytical Method could guide neonatal management of critical cases of vascular anomalies: immediate data are offered to clinicians, from which therapeutic decisions such as timing of surgical resection are made to achieve a positive outcome. We also systemically collected and summarized information on patients' characteristics of previous cases reported in literature to data, and we compared them to our case.

Is there an association of near-infrared spectroscopy with low cardiac output and adverse outcomes in single-ventricle patients after stage 1 palliation?

Objective

Our primary objective study was to evaluate the association between near-infrared spectroscopy (NIRS) and low cardiac output (LCO) in patients with single-ventricle physiology after stage 1 palliation.

Methods

In this retrospective study, infants ≤6 months of age with single-ventricle physiology who underwent stage 1 palliation were included. Cerebral and renal NIRS values at various time intervals after surgery were compared between patients with low and normal cardiac output. LCO within the first 48 after surgery was defined as per the pediatric cardiac critical care consortium database. NIRS values were also compared with other adverse outcomes such as cardiac arrest, need for extracorporeal membrane oxygenation and mortality. The receiver operative characteristic curve was generated to determine an optimal cut-off NIRS value for detecting LCO.

Results

Ninety-one patients with median (Interquartile range) age of 10 days (6-26) and weight of 3.3 kg (3-3.5) were included in the study. Cerebral NIRS at 1 h (41.2 vs. 49.5; P = 0.002), 6 h (44 vs. 52.2; P = 0.001), and 12 h (51.8 vs. 56; P = 0.025) was significantly lower in the grouP with LCO compared to no LCO. Cerebral NIRS at 6 h was independently associated with LCO (P = 0.018), and cerebral NIRS at 6 h ≤57% had 91% sensitivity and 72% specificity to detect LCO.

Conclusions

Cerebral NIRS ≤57% at 6 h after surgery detected LCO after stage 1 palliation in single-ventricle patients. Cerebral or renal NIRS was not associated with adverse outcomes and therefore, may not be useful in predicting adverse outcomes in this population.

Regional pulmonary oxygen saturations immediately after birth

BACKGROUND

Partial oxygen saturation (SpO₂) increases within minutes during transition from the intrauterine to extrauterine life. This study aims to determine the postnatal course of pulmonary regional oxygen saturation (rSO₂) measured by Near-Infrared Spectroscopy (NIRS).

METHODS

We conducted an observational study at the delivery room in infants above 35 weeks of gestation who did not need resuscitation and did not develop respiratory distress. Preductal pulse oximetry (Covidien NellcorTM) and right pulmonary apex oxygen saturation (raSO₂) and basal oxygen saturation (rbSO₂) (Covidien INVOSTM) were measured, starting from the postnatal third minute of life, until the 15th minute. The correlations between SpO₂ and pulmonary rSO₂ were analyzed.

RESULTS

Of the 110 infants included in the study, 87 were term and 23 were late preterms. The gestational age and birth weight were 38.5 ± 1.36 weeks and 3285 ± 508 g, respectively. Median (5th-95th percentile) raSO₂ and rbSO₂ were 79% (58-95%) and 78% (46-95%) at the third minute, respectively. The rSO₂ values measured from both sides increased and reached a steady-state around postnatal 9 min, similar to SpO₂ values. The pulmonary NIRS values were significantly higher for babies born by C-Section compared to babies born by vaginal delivery (p < 0.05).

CONCLUSION

We found that rSO₂ measurements increased within minutes in the postnatal period in late preterm and term babies without respiratory distress and reached a plateau at the postnatal 9th minute. The normal values obtained from this preliminary study may be used to predict the prognosis of cases with respiratory distress.

Utilizing Near-Infrared Spectroscopy (NIRS) to Identify Pediatric Trauma Patients Needing Lifesaving Interventions (LSIs): A Retrospective Study

OBJECTIVES

The aim of this study was to investigate the role of near-infrared spectroscopy (NIRS) in identifying pediatric trauma patients who required lifesaving interventions (LSIs).

METHODS

Retrospective chart review of children age 0 to 18 years who activated the trauma team response between January 1, 2015 and August 14, 2017, at a large, urban pediatric emergency department. The lowest somatic NIRS saturation and the need for LSIs (based on published consensus definition) were abstracted from the chart. χ2 and descriptive statistics were used for analysis.

RESULTS

The charts of 84 pediatric trauma patients were reviewed. Overall, 80% were boys with a mean age of 10.4 years (SD, 6.2 years). Injuries included 56% blunt trauma and 36% penetrating trauma with mortality of 10.7% (n = 9). Overall, the median lowest NIRS value was 67% (interquartile range, 51-80%; range, 15%-95%) and 54.8% of the patients had a NIRS value less than 70%. The median somatic NIRS duration recorded was 12 minutes (interquartile range, 6-17 minutes; range, 1-59 minutes). Overall, 50% of patients required a LSI, including 39 who required a lifesaving procedure, 11 required blood products, and 14 required vasopressors. Pediatric trauma patients with NIRS less than 70% had a significantly increased odds of requiring a LSI (odds ratio, 2.67; 95% confidence interval, 1.10-6.47). NIRS less than 70% had a sensitivity and specificity of 67% and 57% respectively.

CONCLUSIONS

Pediatric trauma patients with somatic NIRS less than 70% within 30 minutes of emergency department arrival are associated with the need for LSIs. Continuous NIRS monitoring in the pediatric trauma population should be evaluated prospectively.

Fluid management, electrolytes imbalance and renal management in neonates with neonatal encephalopathy treated with hypothermia

Kidney dysfunction and acute kidney injury (AKI) frequently accompanies neonatal encephalopathy and contributes to neonatal morbidity and mortality. While there are currently no proven therapies for the treatment of AKI, understanding the pathophysiology along with early recognition and treatment of alterations in fluid, electrolyte and metabolic homeostasis that accompany AKI offer opportunity to reduce associated morbidity. Promising new tests and technologies, including urine and serum biomarkers and renal near-infrared spectroscopy offer opportunities to improve diagnosis and monitoring of neonates at risk for kidney injury. Furthermore, recent advances in neonatal kidney supportive therapies such as hemofiltration and hemodialysis may further improve outcomes in this population. This chapter provides an overview of disorders of fluid balance, electrolyte homeostasis and kidney function associated with neonatal encephalopathy and therapeutic hypothermia. Recommendations for fluid and electrolyte management based upon published literature and authors' opinions are provided.

Renal Oxygenation Measured by Near-Infrared Spectroscopy in Neonates

BACKGROUND

Acute kidney injury (AKI) affects approximately 30% of infants admitted to the neonatal intensive care unit (NICU), and increases mortality risk by 50%. Current diagnostic criteria (serum creatinine rise with oliguria) cannot detect early-onset AKI, as up to 50% of nephron damage may occur by the time these abnormalities present. Once AKI is established, clinical management is often ineffective; therefore, prevention is key. Near-infrared spectroscopy (NIRS) offers a feasible, noninvasive approach to continuously monitor renal oxygenation trends over time, serving as a surrogate marker for renal perfusion.

PURPOSE

To provide an overview of NIRS principles for measuring renal oxygenation, and to describe current evidence of how this technology is being used among infants admitted to the NICU relative to the prediction and identification of AKI.

METHODS

A comprehensive search of PubMed and CINHAL focused on renal NIRS studies in NICU preterm and term infants was conducted.

RESULTS

Findings from 34 studies were included. In term infants, reduced renal oxygenation correlated to invasive SvO2 monitoring, predicted survivability and AKI. In preterm infants, reduced renal oxygenation was associated with AKI in one study, yet contrasting findings were reported in those with patent ductus arteriosus, including those who received prostaglandin inhibitors. Normative data in all infants were sparse.

IMPLICATIONS FOR PRACTICE

Renal NIRS may offer a noninvasive measurement of kidney hypoperfusion that may precede conventional diagnostic measures.

IMPLICATIONS FOR RESEARCH

Normative data are lacking, the threshold for renal ischemia is not defined, and consensus guiding clinical treatment based on NIRS data is nonexistent.

Cerebral and Somatic Oxygen Saturation in Neonates with Congenital Heart Disease before Surgery

Background: We investigated preoperative cerebral (ScO₂) and abdominal (StO₂) regional oxygen saturations according to cardiac diagnosis in neonates with critical CHD, their time trends, and the clinical and biochemical parameters associated with them. Methods: Thirty-seven neonates with a prenatal diagnosis of CHD were included. ScO₂ and StO₂ values were continuously evaluated using near-infrared spectroscopy. Measurements were obtained hourly before surgery. A linear mixed effects model was used to assess the effects of time and cardiac diagnosis on regional oxygenation and to explore the contributing factors. Results: Regional oxygenation differed according to cardiac diagnosis (p < 0.001). ScO₂ was lowest in the patients with severe atrioventricular valvar regurgitation (AVVR) (48.1 ± 8.0%). StO₂ tended to be lower than ScO₂, and both worsened gradually during the period between birth and surgery. There was also a significant interaction between cardiac diagnosis and time. The factors related to ScO₂ were hemoglobin and arterial saturation, whereas no factor was associated with StO₂. Conclusions: Preoperative ScO₂ and StO₂ in critical CHD differed according to cardiac diagnosis. ScO₂ in the patients with severe AVVR was very low, which may imply cerebral hypoxia. ScO₂ gradually decreased, suggesting that the longer the time to surgery, the higher the risk of hypoxic brain injury.

Cerebral oxygen saturation and cerebrovascular instability in newborn infants with congenital heart disease compared to healthy controls

Objective

Infants with Congenital Heart Disease (CHD) are at risk for developmental delays, though the mechanisms of brain injury that impair development are unknown. Potential causes could include cerebral hypoxia and cerebrovascular instability. We hypothesized that we would detect significantly reduced cerebral oxygen saturation and greater cerebrovascular instability in CHD infants compared to the healthy controls.

Methods

We performed a secondary analysis on a sample of 43 term infants (28 CHD, 15 healthy controls) that assessed prospectively in temporal cross-section before or at 12 days of age. CHD infants were assessed prior to open-heart surgery. Cerebral oxygen saturation levels were estimated using Near-Infrared Spectroscopy, and cerebrovascular stability was assessed with the response of cerebral oxygen saturation after a postural change (supine to sitting).

Results

Cerebral oxygen saturation was 9 points lower in CHD than control infants in both postures (β = -9.3; 95%CI = -17.68, -1.00; p = 0.028), even after controlling for differences in peripheral oxygen saturation. Cerebrovascular stability was significantly impaired in CHD compared to healthy infants (β = -2.4; 95%CI = -4.12, -.61; p = 0.008), and in CHD infants with single ventricle compared with biventricular defects (β = -1.5; 95%CI = -2.95, -0.05; p = 0.04).

Conclusion

CHD infants had cerebral hypoxia and decreased cerebral oxygen saturation values following a postural change, suggesting cerebrovascular instability. Future longitudinal studies should assess the associations of cerebral hypoxia and cerebrovascular instability with long-term neurodevelopmental outcomes in CHD infants.

The Relationships of Cerebral and Somatic Oxygen Saturation with Physiological Parameters in Pediatric Cardiac Surgery with Cardiopulmonary Bypass: Analysis Using the Random-Effects Model

Recently, tissue oxygenation in pediatric heart surgery is measured by using near-infrared spectroscopy. Monitoring of cerebral oxygen saturation (ScO₂) is most common but that of somatic tissue oxygen saturation (SrO₂) is also gradually becoming widespread. However, the value of their monitoring is not well established. One of the reasons for this may be that the physiological factors affecting ScO₂ and SrO₂ have not been sufficiently clarified. Accordingly, we prospectively observed the changes in ScO₂ and SrO₂ simultaneously throughout cardiac surgery with cardiopulmonary bypass (CPB) in children weighing under 10 kg and evaluated their relationships with physiological parameters by using the random-effects model. ScO₂ and SrO₂ were measured with an INVOS 5100C (Somanetics, Troy, MI, USA). The random-effects analysis was applied for ScO₂ and SrO₂, as dependent variables, and seven physiological parameters (mean blood pressure, central venous pressure, rectal temperature, SaO₂, hematocrit PaCO₂, and pH) were entered as independent covariates. The analysis was performed during the pre-CPB, CPB, and post-CPB periods. Next, the same analysis was performed by dividing the patients into univentricular and biventricular physiological types. Forty-one children were evaluated. Through the whole surgical period, ScO₂ correlated strongly with mean blood pressure regardless of the physiological type. On the other hand, the contribution of mean blood pressure to SrO₂ was weak and various other parameters were related to SrO₂ changes. Thus, the physiological parameters affecting ScO₂ and SrO₂ were rather different. Accordingly, the significance of monitoring of cerebral and somatic tissue oxygen saturation in pediatric cardiac surgery should be further evaluated.

Cerebral Blood Flow Monitoring in High-Risk Fetal and Neonatal Populations

Cerebrovascular pressure autoregulation promotes stable cerebral blood flow (CBF) across a range of arterial blood pressures. Cerebral autoregulation (CA) is a developmental process that reaches maturity around term gestation and can be monitored prenatally with both Doppler ultrasound and magnetic resonance imaging (MRI) techniques. Postnatally, there are key advantages and limitations to assessing CA with Doppler ultrasound, MRI, and near-infrared spectroscopy. Here we review these CBF monitoring techniques as well as their application to both fetal and neonatal populations at risk of perturbations in CBF. Specifically, we discuss CBF monitoring in fetuses with intrauterine growth restriction, anemia, congenital heart disease, neonates born preterm and those with hypoxic-ischemic encephalopathy. We conclude the review with insights into the future directions in this field with an emphasis on collaborative science and precision medicine approaches.

Comparison of bilateral cerebral and somatic tissue oxygenation with near-infrared spectroscopy in cyanotic and acyanotic pediatric patients receiving cardiac surgery

INTRODUCTION

Compromise of tissue oxygenation during surgery is associated with increased mortality and morbidity in the postoperative period in patients with congenital cardiac disorders. It may be monitored with near-infrared spectroscopy (NIRS). We aimed to evaluate the tissue oxygenation and factors which may affect it by bilateral cerebral and somatic NIRS levels during cardiopulmonary bypass and to compare the NIRS values of cyanotic and acyanotic patient groups.

MATERIAL AND METHODS

Two groups of patients with cyanotic and acyanotic congenital heart diseases were included in the study. Each group consisted of 15 patients between 0 and 5 years of age. All data were collected following anesthesia induction (T1), the 10th (T2) and 30th min (T3) of cardiopulmonary bypass (CPB), every 30 min during CPB (T4, T5, T6) and 1 h after (TS). Bilateral and somatic NIRS, blood gases, mean arterial pressure, and temperatures were recorded.

RESULTS

Left and right somatic NIRS values in groups at all measurements did not differ significantly. Left and right cerebral NIRS values at T2 and T3 in cyanotic patients were significantly higher than in acyanotic patients. Mean arterial pressure and lactate levels at T1 and T3 measurements were responsible for left cerebral NIRS changes and mean arterial pressure on right cerebral NIRS values.

CONCLUSIONS

Monitorization of tissue perfusion has critical importance during CPB of patients with congenital heart defects. Oxygenation may easily and reliably be measured with NIRS. Cerebral and somatic NIRS are more pronounced in cyanotic patients and cerebral NIRS is strongly associated with mean arterial pressure and circulating lactate levels.

Recommendations for hemodynamic monitoring for critically ill children-expert consensus statement issued by the cardiovascular dynamics section of the European Society of Paediatric and Neonatal Intensive Care (ESPNIC)

BACKGROUND

Cardiovascular instability is common in critically ill children. There is a scarcity of published high-quality studies to develop meaningful evidence-based hemodynamic monitoring guidelines and hence, with the exception of management of shock, currently there are no published guidelines for hemodynamic monitoring in children. The European Society of Paediatric and Neonatal Intensive Care (ESPNIC) Cardiovascular Dynamics section aimed to provide expert consensus recommendations on hemodynamic monitoring in critically ill children.

METHODS

Creation of a panel of experts in cardiovascular hemodynamic assessment and hemodynamic monitoring and review of relevant literature-a literature search was performed, and recommendations were developed through discussions managed following a Quaker-based consensus technique and evaluating appropriateness using a modified blind RAND/UCLA voting method. The AGREE statement was followed to prepare this document.

RESULTS

Of 100 suggested recommendations across 12 subgroups concerning hemodynamic monitoring in critically ill children, 72 reached "strong agreement," 20 "weak agreement," and 2 had "no agreement." Six statements were considered as redundant after rephrasing of statements following the first round of voting. The agreed 72 recommendations were then coalesced into 36 detailing four key areas of hemodynamic monitoring in the main manuscript. Due to a lack of published evidence to develop evidence-based guidelines, most of the recommendations are based upon expert consensus.

CONCLUSIONS

These expert consensus-based recommendations may be used to guide clinical practice for hemodynamic monitoring in critically ill children, and they may serve as a basis for highlighting gaps in the knowledge base to guide further research in hemodynamic monitoring.

Comparison of Bilateral Cerebro-Renal Tissue Oxygenations in Healthy Children

OBJECTIVE

To investigate right and left cerebral tissue (ctSO₂) and renal tissue oxygenations (rtSO₂) in otherwise healthy children.

METHODS

In this observational cross-sectional study, one hundred children seen as outpatients for well child care or common non-critical complaints, were included. Bilateral ctSO₂ and rtSO₂ were recorded simultaneously with INVOS™ 5100 device.

RESULTS

The median age was 6.7 y (IQR 3-10.4) and median weight was 21 kg (IQR 13-33). Right and left sided ctSO₂ and rtSO₂ values were 78.7% ± 6.0% and 79.1% ± 5.7%; 81.5% ± 9.4% and 81.4% ± 9.5% respectively. There were no differences in right and left cerebral and renal near infrared spectroscopy (NIRS) values, and no age centered lateralization effect. Renal measurements were higher than cerebral counterparts in 63% of the children. Interaction between age and regional oxygenation was significant. For both sides, renal oxygenation was higher than that of cerebrum in older children, whereas the opposite held true with younger age.

CONCLUSIONS

There are no right and left side differences in ctSO₂ and rtSO₂ values in otherwise healthy children. On the other hand, there seem to be differences between cerebral and renal regions with a significant age effect. Acknowledging its limitations, this study sheds light on laterality and cranial and renal NIRS measurements in otherwise healthy children, and may contribute to the interpretation of NIRS data in critically ill patients.

Cerebral oxygenation and blood flow in normal term infants at rest measured by a hybrid near-infrared device (BabyLux)

BACKGROUND

The BabyLux device is a prototype optical neuro-monitor of cerebral oxygenation and blood flow for neonatology integrating time-resolved reflectance spectroscopy and diffuse correlation spectroscopy.

METHODS

Here we report the variability of six consecutive 30 s measurements performed in 27 healthy term infants at rest. Poor data quality excluded four infants.

RESULTS

Mean cerebral oxygenation was 59.6 ± 8.0%, with intra-subject standard deviation of 3.4%, that is, coefficient of variation (CV) of 5.7%. The inter-subject CV was 13.5%. Mean blood flow index was 2.7 × 10^-8 ± 1.56 × 10^-8 (cm²/s), with intra-subject CV of 27% and inter-subject CV of 56%. The variability in blood flow index was not reduced by the use of individual measures of tissue scattering, nor accompanied by a parallel variability in cerebral oxygenation.

CONCLUSION

The intra-subject variability for cerebral oxygenation variability was improved compared to spatially resolved spectroscopy devices, while for the blood flow index it was comparable to that of other modalities for estimating cerebral blood flow in newborn infants. Most importantly, the simultaneous measurement of oxygenation and flow allows for interpretation of the high inter-subject variability of cerebral blood flow as being due to error of measurement rather than to physiological instability.

Near-Infrared Spectroscopy in Pediatric Congenital Heart Disease

Near-infrared spectroscopy (NIRS) is widely used to monitor tissue oxygenation in the pediatric cardiac surgical population. Clinicians who use NIRS must understand the underlying measurement principles in order to interpret and use this monitoring modality appropriately. The aims of this narrative review are to provide a brief overview of NIRS technology, discuss the normative and critical values of cerebral and somatic tissue oxygen saturation and the interpretation of these values, present the clinical studies (and their limitations) of NIRS as a perioperative monitoring modality in the pediatric congenital heart disease population, and introduce the emerging and future applications of NIRS.

Regional tissue oxygenation monitoring in the neonatal intensive care unit: evidence for clinical strategies and future directions

Near-infrared spectroscopy (NIRS)-based monitoring of regional tissue oxygenation (rSO₂) is becoming more commonplace in the neonatal intensive care unit (NICU). While increasing evidence supports rSO₂ monitoring, actual standards for applying this noninvasive bedside technique continue to evolve. This review highlights the current strengths and pitfalls surrounding practical NIRS-based monitoring in the neonatal population. The physiologic background of rSO₂ monitoring is discussed, with attention to understanding oxygen delivery/consumption mismatch and its effects on tissue oxygen extraction. The bedside utility of both cerebral and peripheral rSO₂ monitoring in the NICU is then explored from two perspectives: (1) disease/event-specific "responsive" monitoring and (2) "routine," continuous monitoring. Recent evidence incorporating both monitoring approaches is summarized with emphasis on practical applicability in the NICU. Finally, a future paradigm for a broad-based NIRS monitoring strategy is presented, with attention towards improving personalization of neonatal care and ultimately enhancing long-term outcomes.

Absorption spectra of early stool from preterm infants need to be considered in abdominal NIRS oximetry

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency of the preterm infant. Low abdominal tissue oxygen saturation (StO2) measured by near-infrared spectroscopy (NIRS) oximetry may be an early sign of NEC relevant for treating or even preventing NEC. However, current commercial NIRS oximeters provide inaccurate StO2 readings because they neglect stool as an abdominal absorber. To tackle this problem, we determined the optical properties of faeces of preterm infants to enable a correct abdominal StO2 measurement. In 25 preterm born infants (median age 31 0/7 ± 2 1/7 weeks, weight 1478 ± 511 g), we measured their first five stool probes with a VIS/NIR spectrometer and calculated the optical properties using the Inverse Adding Doubling (IAD) method. We obtained two absorption spectra representing meconium and transitional stool. Probabilistic cluster analysis correctly classified 96 out of 107 stool probes. The faeces spectra need to be considered to enable correct abdominal StO2 measurements with NIRS oximetry.

Near-Infrared Spectroscopy in the Diagnostic Evaluation of Mitochondrial Disorders: A Neonatal Intensive Care Unit Case Series

We assessed the utility of near-infrared spectroscopy to evaluate neonates with mitochondrial disorders. We observed abnormally high cerebral oxygen saturation levels indicating insufficient tissue oxygen utilization. We propose that near-infrared spectroscopy may be an additional tool in the diagnostic evaluation of a suspected mitochondrial disorder.

Multisite measurement of regional oxygen saturation in Fontan patients with and without protein-losing enteropathy at rest and during exercise

BACKGROUND

Protein-losing enteropathy (PLE) is a severe complication of Fontan circulation with increased risk of end-organ dysfunction. We evaluated tissue oxygenation via near-infrared spectroscopy (NIRS) at different exercise levels in Fontan patients.

METHODS

Assessment of multisite NIRS during cycle ergometer exercise and daily activities in three groups: Fontan patients with PLE; without PLE; patients with dextro-transposition of the great arteries (d-TGA); comparing univentricular with biventricular circulation and Fontan with/without PLE. Renal threshold analysis (<65%;<55%;<45%) of regional oxygen saturation (rSO2) was performed.

RESULTS

Fontan patients showed reduced rSO2 (p < 0.05) in their quadriceps femoris muscle compared with biventricular d-TGA patients at all time points. rSO2 in renal tissue was reduced at baseline (p = 0.002), exercise (p = 0.0062), and daily activities (p = 0.03) in Fontan patients with PLE. Renal threshold analysis identified critically low renal rSO2 (rSO2 < 65%) in Fontan patients with PLE during exercise (95% of monitoring time below threshold) and daily activities (83.7% time below threshold).

CONCLUSION

Fontan circulation is associated with decreased rSO2 values in skeletal muscle and hypoxemia of renal tissue solely in patients with PLE. Reduced rSO2 already during activities of daily life, might contribute to comorbidities in patients with Fontan circulation, including PLE and renal failure.

Lack of Variability in Cerebral Oximetry Tendency in Infants with Severe Hypoxic-Ischemic Encephalopathy Under Hypothermia

Cerebral oximetry using near-infrared spectroscopy (NIRS) provides continuous, noninvasive assessment of the degree of hemoglobin saturation of the brain tissue. Previous studies suggest that high values of regional cerebral tissue oxygen saturation (rScO₂) during the first days in neonates with significant hypoxic-ischemic encephalopathy (HIE) are correlated with an adverse neurological outcome. However, the results are not consistent among the studies. To examine the correlation of rScO₂ values and their variability over time with HIE severity, amplitude integrated electroencephalography (aEEG) background and seizure activity, neuron-specific enolase levels in cerebrospinal fluid, magnetic resonance imaging (MRI) findings, and neurological outcome. Retrospective study that included all consecutive infants with moderate-to-severe HIE born at ≥35 weeks gestational age admitted between January 2011 and December 2014. NIRS monitoring was initiated at admission and maintained during therapeutic hypothermia up to 12 hours after rewarming. To analyze rScO₂, different periods (0-6, 6-24, 24-48, 48-72, and 72-100 hours of life) and three ranges (<55%, 55-90%, >90%) were considered. Variability in each patient was considered ≤5% when changes in rScO₂ values in all periods were ≤5%. Twenty-three newborns were included. Infants who suffered from severe HIE, seizures, abnormal aEEG background, altered MRI or death, and abnormal outcome had rScO₂ values >90% and with less variability (≤5%). rScO₂ values >90% and a lack of variability over time in infants with HIE during cooling provide useful information about the severity of neurological status.

NIRS improves hemodynamic monitoring and detection of risk for cerebral injury: cases in the neonatal intensive care nursery

Near-infrared spectroscopy (NIRS) monitoring provides a noninvasive, bedside measure of cerebral and somatic oxygenation in neonates at risk for hemodynamic instability and brain injury. This technology has been increasingly utilized in the neonatal intensive care unit, however, clinicians perceive a lack of evidence for the added value of NIRS monitoring. We present six clinical scenarios illustrating the value of NIRS monitoring for the diagnosis and management of critically ill newborns.

Renal Saturation and Acute Kidney Injury in Neonates with Hypoxic Ischemic Encephalopathy Undergoing Therapeutic Hypothermia

OBJECTIVE

To investigate the range of renal near-infrared spectroscopy (NIRS) measures in neonates undergoing therapeutic hypothermia for hypoxic ischemic encephalopathy (HIE) and to determine the association between renal NIRS measures and the development of acute kidney injury (AKI).

STUDY DESIGN

A retrospective chart review was conducted of neonates with moderate to severe HIE who received therapeutic hypothermia at a tertiary care center from 2014 to 2016. Neonates had routine continuous NIRS monitoring of cerebral and renal saturation (Rsat) as part of their clinical care for 72 hours of cooling and until 24 hours after rewarming. The outcome of AKI was defined by an abnormal rate of decline of serum creatinine over the first 5 days of life. Mixed effects models determined the association between renal NIRS measures and AKI over time.

RESULTS

Of 38 neonates with HIE undergoing cooling, 15 (39%) developed AKI. Rsat was lower than cerebral saturation during cooling (P < .01), but Rsat increased over time after rewarming, while renal oxygen extraction levels decreased (P < .0001). Neonates with AKI had higher Rsat levels (P < .01) compared with those without AKI after 24 hours of life. Using receiver operating characteristic curves, Rsat >75% by 24-48 hours predicted AKI with a sensitivity of 79% and specificity of 82% (area under the receiver operating characteristic curve = 0.76).

CONCLUSIONS

Throughout cooling, neonates with AKI had higher Rsat measures than those without AKI. These differences may reflect lower oxygen extraction by the injured kidney. NIRS monitoring of Rsat may identify neonates with HIE at risk of developing AKI.

Hemodynamic Changes During Rewarming Phase of Whole-Body Hypothermia Therapy in Neonates with Hypoxic-Ischemic Encephalopathy

OBJECTIVE

To delineate the systemic and cerebral hemodynamic response to incremental increases in core temperature during the rewarming phase of therapeutic hypothermia in neonatal hypoxic-ischemic encephalopathy (HIE).

STUDY DESIGN

Continuous hemodynamic data, including heart rate (HR), mean arterial blood pressure (MBP), cardiac output by electrical velocimetry (CO_EV), arterial oxygen saturation, and renal (RrSO₂) and cerebral (CrSO₂) regional tissue oxygen saturation, were collected from 4 hours before the start of rewarming to 1 hour after the completion of rewarming. Serial echocardiography and transcranial Doppler were performed at 3 hours and 1 hour before the start of rewarming (T-3 and T-1; "baseline") and at 2, 4, and 7 hours after the start of rewarming (T+2, T+4, and T+7; "rewarming") to determine Cardiac output by echocardiography (CO_echo), stroke volume, fractional shortening, and middle cerebral artery (MCA) flow velocity indices. Repeated-measures analysis of variance was used for statistical analysis.

RESULTS

Twenty infants with HIE were enrolled (mean gestational age, 38.8 ± 2 weeks; mean birth weight, 3346 ± 695 g). During rewarming, HR, CO_echo, and CO_EV increased from baseline to T+7, and MBP decreased. Despite an increase in fractional shortening, stroke volume remained unchanged. RrSO₂ increased, and renal fractional oxygen extraction (FOE) decreased. MCA peak systolic flow velocity increased. There were no changes in CrSO₂ or cerebral FOE.

CONCLUSIONS

In neonates with HIE, CO significantly increases throughout rewarming. This is due to an increase in HR rather than stroke volume and is associated with an increase in renal blood flow. The lack of change in cerebral tissue oxygen saturation and extraction, in conjunction with an increase in MCA peak systolic velocity, suggests that cerebral flow metabolism coupling remained intact during rewarming.

Cardiopulmonary Resuscitation in Infants and Children With Cardiac Disease: A Scientific Statement From the American Heart Association

Cardiac arrest occurs at a higher rate in children with heart disease than in healthy children. Pediatric basic life support and advanced life support guidelines focus on delivering high-quality resuscitation in children with normal hearts. The complexity and variability in pediatric heart disease pose unique challenges during resuscitation. A writing group appointed by the American Heart Association reviewed the literature addressing resuscitation in children with heart disease. MEDLINE and Google Scholar databases were searched from 1966 to 2015, cross-referencing pediatric heart disease with pertinent resuscitation search terms. The American College of Cardiology/American Heart Association classification of recommendations and levels of evidence for practice guidelines were used. The recommendations in this statement concur with the critical components of the 2015 American Heart Association pediatric basic life support and pediatric advanced life support guidelines and are meant to serve as a resuscitation supplement. This statement is meant for caregivers of children with heart disease in the prehospital and in-hospital settings. Understanding the anatomy and physiology of the high-risk pediatric cardiac population will promote early recognition and treatment of decompensation to prevent cardiac arrest, increase survival from cardiac arrest by providing high-quality resuscitations, and improve outcomes with postresuscitation care.

Applications of near infrared spectroscopy in the neonate

PURPOSE OF REVIEW

There has been a significant increase in the utilization of NIRS in neonatal care over the last few years, with some centers now routinely utilizing this monitoring technique for direct intervention at the bedside. In this review, we provide a summary of the most up-to-date evidence on near infrared spectroscopy utilization, with particular emphasis on measurement of cerebral oxygenation in preterm infants.

RECENT FINDINGS

There have been significant advances in the technology, leading to an increase in the number of available devices and in the use of this monitoring tool to reduce cerebral injury in preterm infants. The role of NIRS in assessing cerebral autoregulation in preterm and term infants, in evaluating somatic oxygenation, and in the management of newborns with hypoxic ischaemic encephalopathy is discussed.

SUMMARY

Two recent pilot randomized controlled trials highlight the potential of cerebral oxygenation monitoring to direct management in the delivery room and the neonatal intensive care unit. However, we urge caution against routine use and await the results of further studies in this area before considering this type of monitoring as standard of care.

Low near infrared spectroscopic somatic oxygen saturation at admission is associated with need for lifesaving interventions among unplanned admissions to the pediatric intensive care unit

To investigate the association between low near infrared spectroscopy (NIRS) somatic oxygen saturation (<70%) at admission and the need for lifesaving interventions (LSI) in the initial 24 h of a PICU admission. Retrospective chart review of all unplanned admissions to the pediatric intensive care unit (PICU) with NIRS somatic oxygen saturation data available within 4 h of admission, excluding admissions with a cardiac diagnosis. LSI data were collected for the first 24 h after admission. Hemodynamic parameters, laboratory values, illness severity scores and diagnoses were collected. Included PICU admissions were stratified by lowest NIRS value in the first 4 h after admission: low NIRS (<70%) and normal NIRS (≥70%) groups. Rate of LSI from 4 h to 24 h was compared between the two groups. Association of LSI with NIRS saturation and other clinical and laboratory parameters was measured by univariate and multivariate methods. We reviewed 411 consecutive unplanned admissions to the PICU of which 184 (44%) patients underwent NIRS monitoring. A higher proportion of patients who underwent somatic NIRS monitoring required LSIs compared to those without NIRS monitoring (36.4 vs 5.7% respectively, p < 0.0001). The proportion of patients who required LSI was higher in the group with low NIRS (<70%) within the first 4 h compared to those with normal NIRS (≥70%) (77.1 vs 22.1%, p < 0.0001). Fluid resuscitation, blood products and vasoactive medications were the most common LSIs. Multivariable modeling showed NIRS < 70% and heart rate > 2SD for age to be associated with LSIs. ROC curve analysis of the combination of NIRS < 70% and HR >2SD for age had an area under the curve of 0.79 with 78% sensitivity and 76% specificity for association with LSI. Compared to the normal NIRS group, the low NIRS group had higher mortality (10.4 vs 0.7%, p = 0.005) and longer median hospital length of stay (2.9 vs 1.6 days, p < 0.0001). Low somatic NIRS oxygen saturation (<70%) in the first 4 h of an unplanned PICU admission is associated with need for higher number of subsequent lifesaving interventions up to 24 h after admission. Noninvasive, continuous, somatic NIRS monitoring may identify children at high risk of medical instability.

End-Organ Saturation Differences in Early Neonatal Transition for Left- versus Right-Sided Congenital Heart Disease

BACKGROUND

For neonates with congenital heart disease (CHD), left-sided (LL) and right-sided (RL) single ventricular physiologies (LL, hypoplastic left heart syndrome; RL, tricuspid atresia or pulmonary atresia with intact ventricular septum) may demonstrate distinct changes in tissue saturation in the first 72 h of life. Near-infrared spectroscopy (NIRS) can measure regional cerebral saturation (Csat) and renal saturation (Rsat) to clarify differences between LL and RL over time.

OBJECTIVES

Our primary objective was to measure changes in Csat and Rsat in the first 72 h of life using NIRS between CHD infants with LL compared to RL. The secondary objective was to correlate NIRS values to an echocardiographic marker of perfusion.

METHOD

Newborns with hypoplastic left heart syndrome, tricuspid atresia, and pulmonary atresia with intact ventricular septum from 2013 to 2016 underwent routine NIRS monitoring. Csat, Rsat, and systemic saturations (SpO2) in the first 72 h of life were retrospectively analyzed and the echocardiographic descending aorta velocity time integral (VTI) was measured. Mixed effects models compared differences over time between LL and RL.

RESULTS

The final cohort included 13 LL, 12 RL, and 4 controls. Csat decreased for RL compared to LL (p = 0.005), while Rsat decreased for both (p = 0.008). Over time, SpO2 increased for LL but decreased for RL (p = 0.046). Compared to the controls, infants with CHD had lower Csat, lower Rsat, and lower SpO2. The descending aorta VTI was correlated with Rsat (R2 = 0.24, p = 0.02).

CONCLUSION

NIRS Csat measures were better preserved in LL compared to RL. Rsat decreased in both groups through time. The correlation between the descending aorta VTI and Rsat suggests an association between NIRS measures of renal saturation and renal perfusion.