Predictive value of near-infrared spectroscopy on neurodevelopmental outcome after surgery for congenital heart disease in infancy

Distinct profiles of cerebral oxygenation in focal vs. secondarily generalized EEG seizures in children undergoing cardiac surgery

Objectives

Seizures are common in children undergoing cardiopulmonary bypass (CPB). Cerebral oxygen saturation (ScO2) by near-infrared spectroscopy is routinely monitored in many centers, but the relations between the levels and changes of ScO2 and brain injuries remain incompletely understood. We aimed to analyze the postoperative profiles of ScO2 and cerebral blood flow velocity in different types of EEG seizures in relation to brain injuries on MRI.

Methods

We monitored continuous EEG and ScO2 in 337 children during the first 48 h after CPB, which were analyzed in 3 h periods. Cerebral blood flow peak systolic velocity (PSV) in the middle cerebral artery was measured daily by transcranial Doppler. Postoperative cerebral MRI was performed before hospital discharge.

Results

Based on the occurrence and spreading types of seizures, patients were divided into three groups as patients without seizures (Group N; n = 309), those with focal seizures (Group F; n = 13), or with secondarily generalized seizures (Group G; n = 15). There were no significant differences in the onset time and duration of seizures and incidence of status epilepticus between the two seizures groups (Ps ≥ 0.27). ScO2 increased significantly faster across Group N, Group G, and Group F during the 48 h (p < 0.0001) but its overall levels were not significantly different among the three groups (p = 0.30). PSV was significantly lower (p = 0.003) but increased significantly faster (p = 0.0003) across Group N, Group G, and Group F. Group F had the most severe brain injuries and the highest incidence of white matter injuries on MRI among the three groups (Ps ≤ 0.002).

Conclusion

Postoperative cerebral oxygenation showed distinct profiles in secondarily generalized and particularly focal types of EEG seizures in children after CPB. A state of 'overshooting' ScO2 with persistently low PSV was more frequently seen in those with focal seizures and more severe brain injury. Information from this study may have important clinical implications in detecting brain injuries when monitoring cerebral oxygenation in this vulnerable group of children after CPB.

Neurodevelopmental outcomes of preterm and growth-restricted neonate with congenital heart defect: a systematic review and meta-analysis

The purpose of the study is to assess the risks of neurodevelopmental morbidity among preterm and growth restricted youth with congenital heart defects (CHD). This systematic review and meta-analysis included observational studies assessing neurodevelopmental outcomes among children with CHD born preterm (i.e., before 37 weeks of gestation) or growth restricted (small-for-gestational age (SGA) with a birthweight < the 10th percentile or with low birthweight (LBW) < 2500 g). Studies were identified in Medline and Embase databases from inception until May 2022, with data extracted by two blinded reviewers. Risk of bias was assessed using the Critical Appraisal Skills Programme cohort checklist. Meta-analysis involved the use of random-effects models. Main outcome measures were neurodevelopmental outcomes including overall cognitive impairment and intellectual disability, IQ, communication, and motor skills scores. From 3573 reports, we included 19 studies in qualitative synthesis and 6 meta-analysis studies. Risk of bias was low in 8/19 studies. Cognitive impairment and intellectual disability were found in 26% (95% CI 20-32, I2 = 0%) and 19% (95% CI 7-35, I2 = 82%) of preterm children with CHD, respectively. Two studies documented a lower IQ score for SGA children who underwent CHD operations in comparison to non-SGA children who also underwent CHD operations. Two studies have reported lower IQ, communication, and motor skills in children with hypoplastic left heart syndrome (HLHS) and low birth weight compared to those with HLHS and expected birth weight.

CONCLUSIONS

Based on a low level of evidence, prematurity and/or growth retardation appear to accentuate specific neurodevelopmental outcomes in certain CHD subgroups. Further evidence is needed to confirm these findings.

TRIAL REGISTRATION

PROSPERO [CRD42020201414].

WHAT IS KNOWN

• Children born with CHD, preterm birth, or growth restriction at birth are independently at higher risk for neurodevelopmental impairment. • The additional effect of preterm birth and/or growth restriction on neurodevelopmental outcomes in children with CHD remains unclear.

WHAT IS NEW

• Prematurity and/or growth retardation appear to accentuate specific neurodevelopmental outcomes in certain CHD subgroups. • Children with CHD, particularly those born preterm or with growth restriction, should undergo lifelong systematic comprehensive neurodevelopmental assessment.

Changes in Cerebral Regional Oxygen Saturation Variability in Neonates Undergoing Cardiac Surgery: A Prospective Cohort Study

Near-infrared spectroscopy is routinely used in the monitoring of cerebral regional oxygen saturation (crSO2) in neonates following congenital heart surgery. Decreased postoperative crSO2 variability in these patients is associated with worse clinical outcomes, including neurodevelopmental outcomes. We sought to explore changes in crSO2 variability between the preoperative and postoperative periods and associations with short-term clinical outcomes in neonates undergoing cardiac surgery. We performed a prospective cohort study of neonates undergoing cardiac surgery with cardiopulmonary bypass between November 2019 and May 2021. We calculated crSO2 variability using averaged 1 min of crSO2 values for a minimum of 12 h before, and the first 48 h following surgery. 37 neonates (median age at start of monitoring 4 days (interquartile range 2-5 days)) were included in our study. We observed a 30% decrease in crSO2 variability between the preoperative and postoperative monitoring periods (p < 0.001). Preoperative crSO2 variability increased by 9% (p = 0.009) for each additional postnatal day. There were no associations between the degree of decrease in crSO2 variability postoperatively and class of cardiac lesion (e.g., aortic arch obstruction, single ventricle physiology) or short-term postoperative clinical outcomes. There was a significant decrease in postoperative crSO2 variability following neonatal cardiac surgery as compared to the preoperative period, likely influenced by several factors. The impact of interventions on crSO2 variability and resultant influence on long-term outcomes, such as neurodevelopmental outcomes, requires further exploration.

Age Difference of the Relationship Between Cerebral Oxygen Saturation and Physiological Parameters in Pediatric Cardiac Surgery with Cardiopulmonary Bypass: Analysis Using the Random-Effects Model

Recently, monitoring of cerebral oxygen saturation (ScO₂) has become widespread in pediatric cardiac surgery. Our previous study reported that mean blood pressure (mBP) was the major contributor to ScO₂ throughout cardiac surgery with cardiopulmonary bypass (CPB) in children weighing under 10 kg. We speculated that this result might be attributable to incomplete cerebral autoregulation in such young children. Accordingly, our hypothesis is that the relationship between ScO₂ and the physiological parameters may change according to the growth of the children. ScO₂ was measured with an INVOS 5100C (Somanetics, Troy, MI). Random-effects analysis was employed with ScO₂ as a dependent variable, and seven physiological parameters (mBP, central venous pressure, nasopharyngeal temperature, SaO₂, hematocrit, PaCO₂, and pH) were entered as independent covariates. The analysis was performed during the pre-CPB, CPB, and post-CPB periods by dividing the patients into two groups: infants (Infant Group) and children who were more than 1 year old (Child Group). The Infant and Child Groups consisted of 28 and 21 patients. In the random-effects analysis, mBP was the major contributor to ScO₂ during CPB in both groups. During the pre-CPB period, the effect of mBP was strongest in the Infant group. However, its effect was second to that of SaO₂ in the Child Group. During the post-CPB period, SaO₂ and mBP still affected ScO₂ in the Infant group. However, the dominant contributors were unclear in the Child Group. Cerebral autoregulation may be immature in infants. In addition, it may be impaired during CPB even after 1 year of age.

Factor Analysis of the Einstein Neonatal Neurobehavioral Assessment Scale in Infants with Congenital Heart Disease and Healthy Controls

Background: Administration of the Einstein Neonatal Neurobehavioral Assessment Scale (ENNAS) can be time-consuming, and items can be highly correlated. We aimed to determine: (1) its factor analytic structure; (2) the validity of the factor structure; and (3) the associations of physiologic measures with factor scores. Methods: A factor analysis reduced 21 ENNAS items into 5 factors in 57 congenital heart disease (CHD) and 35 healthy infants. Multiple linear regressions examined the association of factor scores with group, gestational age, and physiologic variables. Results: 5-factor solution: 1 (Orienting Reflex), 2 (Extensor Axial Tone), 3 (Primitive Reflexes), 4 (Flexor Tone), 5 (Reflexive Tone Around Extremity Joints). Moderate to strong evidence supported: face, discriminant, and construct validity of these factors, with Factor 2 having the strongest. Conclusions: Components of Factor 2 may provide similar information about neonatal development, thus reducing the time for and burden of administration for researchers and clinicians.

Clinical significance of assessing cerebral blood volume by time-domain near-infrared spectroscopy in children with congenital heart disease

BACKGROUND

Despite providing cerebral tissue oxygen saturation (StO₂ ), the lack of quantitative information for continuous wave near-infrared spectroscopy (CW-NIRS) is an obstacle in evaluating cerebral hemodynamic conditions. Time-domain NIRS (TD-NIRS) provides both StO₂ and cerebral blood volume and has recently become clinically available.

AIM

To investigate if the additional monitoring of cerebral blood volume by TD-NIRS facilitates the understanding of cerebral hemodynamic conditions in patients with congenital heart disease.

METHODS

Preoperative TD-NIRS values were retrospectively reviewed in patients who underwent a cardiac surgery or catheter examination. We compared the values between patients with single and two ventricles. Moreover, we investigated the association of these values with the demographic and clinical variables.

RESULTS

There was no significant difference in StO2 between single ventricle and two ventricles groups (median: 59.9 vs. 54.4, median difference [95% CI]: -4.06 [-9.90 to 2.90], p = .37). However, cerebral blood volume was significantly higher in the single ventricle group (median: 4.68 vs. 2.84, median difference [95% CI]: -2.01 [-2.88 to -1.06], p < .001). Spearman's rank correlation analysis demonstrated an association between StO2 and postmenstrual age (r = 0.35, p = .03). In contrast, cerebral blood volume was correlated with single ventricle physiology (r = 0.62, p < .001), postmenstrual age (r = 0.74, p < .001), central venous pressure (r = 0.38, p = .02), and SaO2 (r = -0.38, p = .02). The multivariable regression analysis identified the postmenstrual age, single ventricle physiology, and SaO2 as independent factors associated with cerebral blood volume. In the logistic analysis, cerebral blood volume was identified as a significant predictor of unfavorable conditions.

CONCLUSION

Cerebral blood volume monitoring detected differences in cerebral hemodynamic conditions, related to the age and the type of ventricle physiologies. However, the differences were not apparent in StO₂ . The additional monitoring of cerebral blood volume by TD-NIRS would facilitate a better understanding of cerebral hemodynamic conditions in patients with congenital heart disease.

Cerebral hemoglobin oxygenation in children with congenital heart disease

BACKGROUND

It is important to identify the pathological characteristics of cerebral circulation and oxygen metabolism at the bedside in children with congenital heart disease (CHD) to prevent neurodevelopmental impairments. The brain regional oxygen saturation index (rSO₂ ) can be easily obtained at the bedside with near-infrared spectroscopy and has been widely used in the management of children with CHD in recent years.

METHODS

To determine if the rSO₂ before or after CHD surgery is a good predictor of cerebral oxygen metabolism, we investigated the impact of different clinical variables on the correlation between rSO₂ and reference values under steady ratios of hemoglobin oxygen saturation in the internal jugular vein (SjvO₂ ) or femoral artery (SaO₂ ) (0.75:0.25, 0.66:0.34, and 0.50:0.50) in 186 children with CHD undergoing cardiac catheterization.

RESULTS

In three patient groups-double ventricles before surgery, double ventricles after surgery, and single ventricle before surgery-there were significant relationships between rSO₂ and the reference values of SO₂ under all three steady ratios of SjvO₂ and SaO₂ . No relationship with the reference values was found for the single ventricle after surgery group.

CONCLUSIONS

Regional oxygen saturation index is useful for assessing cerebral oxygenation in children with CHD, but knowledge of the underlying cardiac pathology in CHD, especially in the case of a single ventricle after surgery, is important for the correct interpretation of rSO₂ measurements obtained using near-infrared spectroscopy.

Contrast-enhanced ultrasound of the pediatric brain

Brain contrast-enhanced ultrasound (CEUS) is an emerging application that can complement gray-scale US and yield additional insights into cerebral flow dynamics. CEUS uses intravenous injection of ultrasound contrast agents (UCAs) to highlight tissue perfusion and thus more clearly delineate cerebral pathologies including stroke, hypoxic-ischemic injury and focal lesions such as tumors and vascular malformations. It can be applied not only in infants with open fontanelles but also in older children and adults via a transtemporal window or surgically created acoustic window. Advancements in CEUS technology and post-processing methods for quantitative analysis of UCA kinetics further elucidate cerebral microcirculation. In this review article we discuss the CEUS examination protocol for brain imaging in children, current clinical applications and future directions for research and clinical uses of brain CEUS.

Physical Functioning After Admission to the PICU: A Scoping Review

Supplemental Digital Content is available in the text.

Objectives:

To conduct a scoping review to 1) describe findings and determinants of physical functioning in children during and/or after PICU stay, 2) identify which domains of physical functioning are measured, 3) and synthesize the clinical and research knowledge gaps.

Data Sources:

A systematic search was conducted in PubMed, Embase, Cumulative Index to Nursing and Allied Health Literature, and Cochrane Library databases following the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for Scoping Reviews guidelines.

Study Selection:

Two investigators independently screened and included studies against predetermined criteria.

Data Extraction:

One investigator extracted data with review by a second investigator. A narrative analyses approach was used.

Data Synthesis:

A total of 2,610 articles were identified, leaving 68 studies for inclusion. Post-PICU/hospital discharge scores show that PICU survivors report difficulties in physical functioning during and years after PICU stay. Although sustained improvements in the long-term have been reported, most of the reported levels were lower compared with the reference and baseline values. Decreased physical functioning was associated with longer hospital stay and presence of comorbidities. A diversity of instruments was used in which mobility and self-care were mostly addressed.

CONCLUSIONS:

The results show that children perceive moderate to severe difficulties in physical functioning during and years after PICU stay. Longitudinal assessments during and after PICU stay should be incorporated, especially for children with a higher risk for poor functional outcomes. There is need for consensus on the most suitable methods to assess physical functioning in children admitted to the PICU.

Cerebral regional oxygen saturation variability in neonates following cardiac surgery

BACKGROUND

Reduced cerebral regional oxygen saturation (crSO₂) variability in neonates, as measured by near-infrared spectroscopy, following cardiac surgery with deep hypothermic circulatory arrest (DHCA) is associated with poor neurodevelopmental outcomes. We sought to evaluate the variability of crSO₂ in a cohort of neonates following cardiac surgery with brief or no exposure to DHCA.

METHODS

Variability of averaged 1-min crSO₂ values was calculated for the first 48 h following cardiac surgery in consecutive neonates over a 30-month period. Neonates requiring aortic arch repair underwent antegrade cerebral perfusion with either brief or no exposure to DHCA.

RESULTS

There were 115 neonates included in the study. Reduced crSO₂ variability was observed in neonates with aortic arch obstruction (p = 0.02) and non-survivors (p = 0.02). Post hoc analysis demonstrated that the reduction in crSO₂ variability was not as marked as in previously studied neonates with aortic arch obstruction who received DHCA alone (p < 0.001).

CONCLUSIONS

Neonates with aortic arch obstruction have reduced crSO₂ variability following cardiac surgery. The reduction in crSO₂ variability observed in aortic arch obstruction is likely influenced by a number of factors, including perioperative perfusion technique. The impact of interventions on crSO₂ variability and resultant influence on neurodevelopmental outcomes requires further study.

IMPACT

Neonates with aortic arch obstruction have reduced crSO₂ variability following cardiac surgery, which has been associated with poor neurodevelopmental outcomes, and is likely influenced by a number of factors, including perioperative perfusion technique. The contribution of perioperative perfusion technique to crSO₂ variability following neonatal cardiac surgery is significant. Monitoring of crSO₂ variability may provide insights into the adequacy of cerebral perfusion in neonates following cardiac surgery.

Association between early cerebral oxygenation and neurodevelopmental impairment or death in premature infants

OBJECTIVE

To assess the relationship between cerebral oxygenation in the first 72 h of life and neurodevelopmental impairment (NDI) at 2 years corrected age in former premature infants.

STUDY DESIGN

Prospective observational cohort study of 127 infants <32 weeks GA at birth with cerebral oxygenation monitoring using NIRS in the first 72 h of life.

RESULTS

Using a threshold cutoff for cerebral hypoxia, infants with NDI or death had increased duration of hypoxia (4 vs 2.3%, p = 0.001), which was more pronounced in the 23-27 week subgroup (7.6 vs 3.2%, p < 0.001). Individual generalized estimating equations to adjust for repeated measures were modeled in this subgroup for the physiologic parameters including StO₂. StO₂ < 67% was a predictor for death or NDI (OR 2.75, 95% CI 1.006, 7.5132, p = 0.049).

CONCLUSION

An increased duration of cerebral hypoxia is associated with NDI or death in infants born <32 weeks GA.

Relationships between Physiologic and Neuropsychologic Functioning after Fontan

OBJECTIVE

To investigate potential relationships between neuropsychologic functioning and cardiac, gastroenterologic/hepatologic, and pulmonary complications in the single ventricle heart disease (SVHD) post-Fontan population.

STUDY DESIGN

Following the initiation of a Fontan Multidisciplinary Clinic, patients with SVHD were evaluated systematically according to a clinical care pathway, and data from multiple subspecialty evaluations were collected prospectively from 2016 to 2019. Biomarkers of cardiology, pulmonary, and hepatology/gastroenterology functioning were abstracted, along with neuropsychologic testing results. Bivariate correlations and regression analyses examined cross-sectional relationships between physiologic predictors and neuropsychologic outcomes.

RESULTS

The sample included a cohort of 68 youth with SVHD age 3-19 years, after Fontan palliation. Sleep-disordered breathing was related to poorer visual-motor integration skills (r = -0.33; P < .05) and marginally related to poorer executive functioning (r = -0.33; P = .05). Lower arterial blood oxygen content was related to poorer executive functioning (r = .45; P < .05). Greater atrioventricular valve regurgitation was related to lower parent-rated adaptive functioning (ρ = -0.34; P < .01). These results were maintained in regression analyses controlling for history of stroke and/or seizures.

CONCLUSIONS

We demonstrated associations between neuropsychologic functioning and potentially modifiable aspects of physiologic functioning in a prospectively evaluated cohort of patients with SVHD with Fontan physiology. Our findings emphasize the importance of multidisciplinary screening and care after a Fontan procedure and suggest avenues for intervention that may improve patient outcomes and quality of life.

Sensitivity of a Next-Generation NIRS Device to Detect Low Mixed Venous Oxyhemoglobin Saturations in the Single Ventricle Population

Regional cerebral oxygenation index (rSO2) based on near-infrared spectroscopy (NIRS) is frequently used to detect low venous oxyhemoglobin saturation (ScvO2). We compared the performance of 2 generations of NIRS devices. Clinically obtained, time-matched cerebral rSO2 and ScvO2 values were compared in infants monitored with the FORE-SIGHT (n = 73) or FORE-SIGHT ELITE (n = 47) by linear regression and Bland-Altman analyses. In both devices, cerebral rSO2 correlated poorly with measured ScvO2 (FORE-SIGHT partial correlation 0.50 [95% confidence interval {CI}, 0.40-0.58]; FORE-SIGHT ELITE partial correlation 0.47 [0.39-0.55]) and mean bias was +8 (standard deviation [SD] 13.2) for FORE-SIGHT and +14 (SD 12.5) for FORE-SIGHT ELITE. When ScvO2 was <30%, rSO2 was <40 in 8% of FORE-SIGHT ELITE readings. Future NIRS should be validated in more hypoxic cohorts.

Onset of brain injury in infants with prenatally diagnosed congenital heart disease

BACKGROUND

The exact onset of brain injury in infants with congenital heart disease (CHD) is unknown. Our aim was, therefore, to assess the association between prenatal Doppler flow patterns, postnatal cerebral oxygenation and short-term neurological outcome.

METHODS

Prenatally, we measured pulsatility indices of the middle cerebral (MCA-PI) and umbilical artery (UA-PI) and calculated cerebroplacental ratio (CPR). After birth, cerebral oxygen saturation (rcSO2) and fractional tissue oxygen extraction (FTOE) were assessed during the first 3 days after birth, and during and for 24 hours after every surgical procedure within the first 3 months after birth. Neurological outcome was determined preoperatively and at 3 months of age by assessing general movements and calculating the Motor Optimality Score (MOS).

RESULTS

Thirty-six infants were included. MOS at 3 months was associated with MCA-PI (rho 0.41, P = 0.04), UA-PI (rho -0.39, P = 0.047, and CPR (rho 0.50, P = 0.01). Infants with abnormal MOS had lower MCA-PI (P = 0.02) and CPR (P = 0.01) and higher UA-PI at the last measurement (P = 0.03) before birth. In infants with abnormal MOS, rcSO2 tended to be lower during the first 3 days after birth, and FTOE was significantly higher on the second day after birth (P = 0.04). Intraoperative and postoperative rcSO2 and FTOE were not associated with short-term neurological outcome.

CONCLUSION

In infants with prenatally diagnosed CHD, the prenatal period may play an important role in developmental outcome. Additional research is needed to clarify the relationship between preoperative, intra-operative and postoperative cerebral oxygenation and developmental outcome in infants with prenatally diagnosed CHD.

Differences Between Central Venous and Cerebral Tissue Oxygen Saturation in Anaesthetised Patients With Diabetes Mellitus

The brain has high oxygen extraction, thus the regional cerebral tissue oxygen saturation (rSO₂) is lower than the central venous oxygen saturation (ScvO₂). We hypothesised that diabetes widens the physiological saturation gap between ScvO₂ and rSO₂ (gSO₂), and the width of this gap may vary during various phases of cardiac surgery. Cardiac surgery patients with (n = 48) and without (n = 91) type 2 diabetes mellitus (T2DM) underwent either off-pump coronary artery bypass (OPCAB) or other cardiac surgery necessitating cardiopulmonary bypass (CPB) were enrolled. rSO₂ was measured by near-infrared spectroscopy (NIRS) and ScvO₂ was determined simultaneously from central venous blood. rSO₂ was registered before and after anaesthesia induction and at different stages of the surgery. ScvO₂ did not differ between the T2DM and control patients at any stage of surgery, whereas rSO₂ was lower in T2DM patients, compared to the control group before anaesthesia induction (60.4 ± 8.1%[SD] vs. 67.2 ± 7.9%, p<0.05), and this difference was maintained throughout the surgery. After anaesthesia induction, the gSO₂ was higher in diabetic patients undergoing CPB (20.2 ± 10.4% vs. 12.4 ± 8.6%, p < 0.05) and OPCAB grafting surgeries (17.0 ± 7.5% vs. 9.5 ± 7.8%, p < 0.05). While gSO₂ increased at the beginning of CPB in T2DM and control patients, no significant intraoperative changes were observed during the OPCAB surgery. The wide gap between ScvO₂ and rSO₂ and their uncoupled relationship in patients with diabetes indicate that disturbances in the cortical oxygen saturation cannot be predicted from the global clinical parameter, the ScvO₂. Thus, our findings advocate the monitoring value of NIRS in T2DM.

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.

Oxygen saturations and neurodevelopmental outcomes in single ventricle heart disease

OBJECTIVES

To evaluate whether the degree of hypoxemia following stage-I and stage-II palliative surgeries predicts neurodevelopmental outcomes at 14 months of age in children with single ventricle congenital heart disease (SVCHD).

DESIGN

We analyzed longitudinal data from two Pediatric Heart Network (PHN) randomized controlled trials, with a total of 328 subjects. Oxygen saturations, measured via pulse oximetry, at time of discharge from stage-I and stage-II surgeries were the primary predictors of interest, and Bayley Scales of Infant Development-II (BSID-II) scores at 14 months old were the primary outcome measure. Relevant covariates from previously-published PHN studies were also included in regression models.

RESULTS

Oxygen saturations at time of discharge from stage-I and stage-II surgeries were not related to BSID-II scores. Having one or more oxygen saturation measurements below 80% was also not associated with BSID-II scores, and neither was change in oxygen saturations over time. These relationships were not altered by inclusion of relevant covariates.

CONCLUSIONS

In this large cohort of children with SVCHD, oxygen saturations post-stage-I and post-stage-II palliation surgeries as measured via pulse oximetry were not associated with neurodevelopmental outcomes at 14 months of age. The relationship between oxygen saturations and neurodevelopment in SVCHD is likely complex, and neurodevelopment is known to be affected by a number of factors. Pulse oximetry may also be an insufficient proxy for cerebral oxygen delivery. Clinically, pulse oximetry readings during the interstage and post-stage-II surgery periods are not a reliable predictor of future neurodevelopmental risk.

Perioperatively Inhaled Hydrogen Gas Diminishes Neurologic Injury Following Experimental Circulatory Arrest in Swine

This study used a swine model of mildly hypothermic prolonged circulatory arrest and found that the addition of 2.4% inhaled hydrogen gas to inspiratory gases during and after the ischemic insult significantly decreased neurologic and renal injury compared with controls. With proper precautions, inhalational hydrogen may be administered safely through conventional ventilators and may represent a complementary therapy that can be easily incorporated into current workflows. In the future, inhaled hydrogen may diminish the sequelae of ischemia that occurs in congenital heart surgery, cardiac arrest, extracorporeal life-support events, acute myocardial infarction, stroke, and organ transplantation.

Changes of Cerebral Oxygenation in Sequential Glenn and Fontan Procedures in the Same Children

Recently, it is common to perform the Fontan procedure after the Glenn procedure as surgical repair for the univentricular heart. How the brain oxygen saturation (rSO₂) values change with the cardiac restoration and the process of growth during these procedures in individual children remains unknown. In this study, we retrospectively studied rSO₂ data as well as the perioperative clinical records of 30 children who underwent both Glenn and Fontan procedures by the same surgeon in the same institute. The rSO₂ was measured at the beginning and end of each procedure with an INVOS 5100C. Cerebral perfusion pressure was calculated by subtracting central venous pressure from mean arterial pressure. Arterial oxygen saturation (SaO₂) and the hemoglobin concentration were obtained as candidates affecting rSO₂ changes at the start and the end of both procedures. The rSO₂ increased during the Glenn procedure, but this increase was slight and insignificant. On the other hand, the rSO₂ significantly increased during the Fontan procedure. Significant increases in SaO₂ were observed only between the beginning and end of the Fontan procedure. Correlation coefficients determined by linear regression analysis were more than 0.5 between rSO₂ and SaO₂ in both procedures. Multiple linear regression analysis showed that SaO₂ was the key determinant of the rSO₂. The rSO₂ increases step by step from the Glenn to the Fontan procedure in the same patient. Within each procedure, SaO₂ is the key determinant of the rSO₂. The significance of rSO₂ monitoring in these procedures should be further evaluated.

Near-infrared spectroscopy as a predictor of clinical deterioration: a case report of two infants with duct-dependent congenital heart disease

Background

Some infants with congenital heart disease are at risk of in-hospital cardiac arrest. To better foresee cardiac arrest in infants with congenital heart disease, it might be useful to continuously assess end-organ perfusion. Near-infrared spectroscopy is a non-invasive method to continuously assess multisite regional tissue oxygen saturation.

Case presentation

We report on two infants with duct-dependent congenital heart disease who demonstrated a gradual change in cerebral and/or renal tissue oxygen saturation before cardiopulmonary resuscitation was required. In both cases, other clinical parameters such as heart rate, arterial oxygen saturation and blood pressure did not indicate that deterioration was imminent.

Conclusions

These two cases demonstrate that near-infrared spectroscopy might contribute to detecting a deteriorating clinical condition and might therefore be helpful in averting cardiopulmonary collapse and need for resuscitation in infants with congenital heart disease.

Does metabolic alkalosis influence cerebral oxygenation in infantile hypertrophic pyloric stenosis?

BACKGROUND

This pilot study focuses on regional tissue oxygenation (rSO₂) in patients with infantile hypertrophic pyloric stenosis in a perioperative setting. To investigate the influence of enhanced metabolic alkalosis (MA) on cerebral (c-rSO₂) and renal (r-rSO₂) tissue oxygenation, two-site near-infrared spectroscopy (NIRS) technology was applied.

MATERIALS AND METHODS

Perioperative c-rSO₂, r-rSO₂, capillary blood gases, and electrolytes from 12 infants were retrospectively compared before and after correction of MA at admission (T1), before surgery (T2), and after surgery (T3).

RESULTS

Correction of MA was associated with an alteration of cerebral oxygenation without affecting renal oxygenation. When compared to T1, 5-min mean (± standard deviation) c-rSO₂ increased after correction of MA at T2 (72.74 ± 4.60% versus 77.89 ± 5.84%; P = 0.058), reaching significance at T3 (80.79 ± 5.29%; P = 0.003). Furthermore, relative 30-min c-rSO₂ values at first 3 h of metabolic compensation were significantly lowered compared with postsurgical states at 16 and 24 h. Cerebral oxygenation was positively correlated with levels of sodium (r = 0.37; P = 0.03) and inversely correlated with levels of bicarbonate (r = -0.34; P = 0.05) and base excess (r = -0.36; P = 0.04). Analysis of preoperative and postoperative cerebral and renal hypoxic burden yielded no differences. However, a negative correlation (r = -0.40; P = 0.03) regarding hematocrite and mean r-rSO₂, indirectly indicative of an increased renal blood flow under hemodilution, was obtained.

CONCLUSIONS

NIRS seems suitable for the detection of a transiently impaired cerebral oxygenation under state of pronounced MA in infants with infantile hypertrophic pyloric stenosis. Correction of MA led to normalization of c-rSO₂. NIRS technology constitutes a promising tool for optimizing perioperative management, especially in the context of a possible diminished neurodevelopmental outcome after pyloromyotomy.

Cerebral oxygen saturation during the first 72h after birth in infants diagnosed prenatally with congenital heart disease

BACKGROUND

Evidence suggests that hypoxic-ischemic brain injury in infants with congenital heart disease already occurs during early life. The aim of our study was, therefore, to assess the course of regional cerebral oxygen saturation (r_cSO₂) and fractional tissue oxygen extraction (FTOE) during the first 72h after birth in infants with prenatally diagnosed duct-dependent congenital heart disease. In addition, we identified clinical parameters that were associated with r_cSO₂.

MATERIALS AND METHODS

We included 56 infants with duct-dependent congenital heart disease. We measured arterial oxygen saturation (SpO₂) and r_cSO₂ during the first 72h after birth. Simultaneously, we calculated FTOE.

RESULTS

We observed median r_cSO₂ values of approximately 60%, a decreasing FTOE from 0.34 on day 1 to 0.28 on day 3 and stable preductal SpO₂ values around 90%. Several clinical variables were associated with r_cSO₂. In a multiple linear regression model only type of CHD and preductal SpO₂ were significant predictors of r_cSO₂ during the first three days after birth. Infants with a duct-dependent pulmonary circulation had up to 12% lower r_cSO₂ values than infants with a duct-dependent systemic circulation.

CONCLUSION

We demonstrated that, during the first three days after birth, cerebral oxygen saturation is low in infants with duct-dependent congenital heart disease. Furthermore, this study provides preoperative reference values of r_cSO₂ and FTOE in infants with duct-dependent CHD.

Near Infrared Spectroscopy as a Hemodynamic Monitor in Critical Illness

OBJECTIVES

The objectives of this review are to discuss the technology and clinical interpretation of near infrared spectroscopy oximetry and its clinical application in patients with congenital heart disease.

DATA SOURCE

MEDLINE and PubMed.

CONCLUSION

Near infrared spectroscopy provides a continuous noninvasive assessment of tissue oxygenation. Over 20 years ago, near infrared spectroscopy was introduced into clinical practice for monitoring cerebral oxygenation during cardiopulmonary bypass in adults. Since that time, the utilization of near infrared spectroscopy has extended into the realm of pediatric cardiac surgery and is increasingly being used in the cardiac ICU to monitor tissue oxygenation perioperatively.

The Role of Regional Oxygen Saturation Using Near-Infrared Spectroscopy and Blood Lactate Levels as Early Predictors of Outcome After Pediatric Cardiac Surgery

BACKGROUND

The purpose of the study was to evaluate the association between regional oxygen saturation (rSO2) desaturation score (calculated by multiplying the rSO2 < 50% by time in seconds the preoperative baseline value) measured with near-infrared spectroscopy and the peak of lactate with postoperative major morbidities in pediatric patients who undergo cardiac surgery.

METHODS

We retrospectively analyzed the postoperative course of 152 patients between January 2012 and December 2013, for whom we continuously monitored cerebral rSO2 using near-infrared spectroscopy and serial arterial blood lactate levels for at least 48 hours.

RESULTS

The median age at surgery was 128 days (interquartile range [IQR], 17-537 days). Thirty-nine patients had a single ventricle physiology (26%) and 135 patients (89%) required the use of cardiopulmonary bypass (median time of 130 minutes; IQR, 93-172 minutes). Median postoperative peak lactate level was 3 mmol/L (IQR, 2-5.3 mmol/L); 52 patients (34%) had a postoperative lactate level > 4.6 mmol/L. The median postoperative rSO2 desaturation score was 157 (IQR, 0-2050); 62 patients (41%) had an rSO2 desaturation score > 345. Fifty-seven patients (37%) had postoperative major morbidities. Using a multivariable regression model only rSO2 desaturation score > 345 was independently associated with major morbidities after surgery (odds ratio, 27.26; 95% confidence interval, 10.18-73.00). The proportion of patients with an rSO2 desaturation score > 345 within 240 minutes after surgery was higher than the rate of those who showed a peak of lactate > 4.6 mmol/L (84% vs 59%; P = 0.05).

CONCLUSIONS

The postoperative rSO2 desaturation score has a stronger association with major postoperative morbidities than lactate and it also provides an earlier warning sign of hemodynamic or metabolic compromise.

[Near-infrared spectroscopy as an auxiliary tool in the study of child development]

OBJECTIVE:

To investigate the applicability of Near-Infrared Spectroscopy (NIRS) for cortical hemodynamic assessment tool as an aid in the study of child development.

DATA SOURCE:

Search was conducted in the PubMed and Lilacs databases using the following keywords: ''psychomotor performance/child development/growth and development/neurodevelopment/spectroscopy/near-infrared'' and their equivalents in Portuguese and Spanish. The review was performed according to criteria established by Cochrane and search was limited to 2003 to 2013. English, Portuguese and Spanish were included in the search.

DATA SYNTHESIS:

Of the 484 articles, 19 were selected: 17 cross-sectional and two longitudinal studies, published in non-Brazilian journals. The analyzed articles were grouped in functional and non-functional studies of child development. Functional studies addressed the object processing, social skills development, language and cognitive development. Non-functional studies discussed the relationship between cerebral oxygen saturation and neurological outcomes, and the comparison between the cortical hemodynamic response of preterm and term newborns.

CONCLUSIONS:

NIRS has become an increasingly feasible alternative and a potentially useful technique for studying functional activity of the infant brain.

Near infrared spectroscopy: experience on esophageal atresia infants

OBJECTIVE

Near infrared spectroscopy (NIRS) gradually became the gold standard to guide anesthetic conduction during cardiac surgery, and nowadays, it is commonly utilized to monitor cerebral oxygenation during invasive procedures. Preterm babies also benefit from this non-invasive monitoring to prevent neurological sequelae. However, few data are available on NIRS perioperative changes in newborn operated on for major non-cardiac malformations. Aim of the present study is to evaluate the usefulness of NIRS assessment during and after esophageal atresia (EA) correction and its correlation with clinical behavior.

PATIENTS AND METHODS

All patients treated for EA from May 2011 were prospectively enrolled in the study. All infants underwent "open" correction of EA and cerebral and splanchnic NIRS was applied up to 48h after surgery. Body temperature, blood pressure, pH, paSO2, paCO2, and urine output, were recorded during NIRS registration. Mann-Whitney test and 1-way ANOVA (Kruskal-Wallis and Dunn's multiple comparison tests) were used as appropriate.

RESULTS

Seventeen patients were enrolled into the study and 13 were available for the analysis. Four patients were excluded because of poor NIRS registration. Cerebral and renal NIRS values significantly decreased at 24h post-operatively (p<0.05). Interestingly, all parameters studied as possible confounders in NIRS remained stable during the study period. Urine output significantly decreased.

CONCLUSION

Our data confirmed that perioperative monitoring of tissue oxygenation during neonatal esophageal surgery is feasible. Cerebral and renal NIRS evaluation, as for cardiac patients, may guide anesthetic conduction and postoperative care. Out data suggest a newly observed hemodynamic reorganization during esophageal surgery involving renal and, probably, splanchnic blood flow redistribution, demonstrated by the observed subsequent significant post-operative transitory decrease in urinary output. Reducing the decrement in cerebral and renal NIRS values may improve, and ideally eliminate, the well-known late sequelae linked to hemodynamic changes during surgery. More studies are needed to better understand the causes of the NIRS described hemodynamic changes and, therefore, correct them.

The state of affairs of neurologic monitoring by near-infrared spectroscopy in pediatric cardiac critical care

PURPOSE OF REVIEW

The decreasing postoperative mortality in patients with congenital heart disease has enabled an increasing interest in preventing morbidity, especially from the central nervous system. Near-infrared spectroscopy, a noninvasive technology that provides an estimate of tissue oxygenation, has been introduced in the intensive care unit and has gained popularity over the last decade. This review aims to ascertain its ability to affect outcome.

RECENT FINDINGS

Recent studies have started to incorporate cerebral near-infrared spectroscopy in the assessment, evolution, and outcomes of surgical patients with congenital heart disease. These studies often represent small single-center high-risk cohorts that are evaluated in a retrospective or an observational manner. Nevertheless, new data are starting to indicate that near-infrared spectroscopy may be helpful not only in the assessment of critical care parameters, such as cardiac output performance or likelihood of adverse events, but, most notably, in the long-term neurological outcome.

SUMMARY

In addition to additional corroborative trials from different centers, a critical question that remains to be answered is whether targeting cerebral near-infrared spectroscopy values, as part of goal-directed therapy protocols, can help to improve outcome overall.

Neurodevelopmental outcomes after infant cardiac surgery with circulatory arrest and intermittent perfusion

BACKGROUND

Optimal perfusion strategies for neuroprotection during infant cardiac surgery remain undefined. Despite encouraging experimental data, neurodevelopmental (ND) outcomes after cardiac surgery in neonates and infants using deep hypothermic circulatory arrest (DHCA) with a period of intermittent perfusion have not been reported, and it is not known whether DHCA can be extended while preserving ND outcomes.

METHODS

Cross-sectional ND evaluation with the Bayley Scales of Infant and Toddler Development, Third Edition was conducted at 24 months of age. Retrospective clinical data were extracted from the electronic medical record.

RESULTS

Forty patients underwent cardiac surgery during the first year of life using a period of uninterrupted DHCA (24 patients) or DHCA interrupted by a period of intermittent perfusion (16 patients). Total duration of DHCA ranged from 5 to 74 minutes and did not predict ND scores. Despite a longer exposure to DHCA in the intermittent perfusion group (55 minutes [1,3 interquartile [IQ] 45.3 to 65.5] versus 38 minutes [1,3 IQ 32 to 40.8]), no differences in ND scores were detected. Significant comorbidities, duration of intensive care unit and hospital stay, as well as multiple procedures with DHCA were independent predictors of ND outcomes at 24 months of age.

CONCLUSIONS

Despite extended duration of total DHCA, the use of a period of intermittent perfusion to limit uninterrupted DHCA periods to less than 45 minutes could lead to ND outcomes similar to those of patients exposed to brief periods of DHCA. Deep hypothermic circulatory arrest with intermittent perfusion may facilitate implementation of prospective studies to identify the optimal cerebral perfusion strategy.

Near-infrared spectroscopy: exposing the dark (venous) side of the circulation

The safety of anesthesia has improved greatly in the past three decades. Standard perioperative monitoring, including pulse oximetry, has practically eliminated unrecognized arterial hypoxia as a cause for perioperative injury. However, most anesthesia-related cardiac arrests in children are now cardiovascular in origin, and standard monitoring is unable to detect many circulatory abnormalities. Near-infrared spectroscopy provides noninvasive continuous access to the venous side of regional circulations that can approximate organ-specific and global measures to facilitate the detection of circulatory abnormalities and drive goal-directed interventions to reduce end-organ ischemic injury.

[Cerebral near-infrared spectroscopy (NIRS) in paediatric anaesthesia]

Cerebral oximetry allows continuous real-time and non-invasive monitoring of cerebral oxygen saturation (cSO(2)), by measuring oxyhaemoglobin and deoxyhaemoglobin near infrared light absorption, similarly to pulse oximetry. cSO(2) measurement predominantly reflects brain venous compartment, and is correlated with jugular venous saturation. As jugular venous saturation, cSO(2) must therefore be interpreted as a measure of balance between transport and consumption of O(2) in the brain. Cerebral oximetry should be used as a trend monitoring, because its accuracy is insufficient to be considered as reliable measure of absolute value of ScO(2). In adult, correction of intraoperative cerebral desaturation reduces hospital stay, heavy morbidity and mortality, and serious postoperative neurocognitive impairment after cardiac and major abdominal surgery. In children, the occurrence of intra- and postoperative cerebral desaturations during congenital heart surgery is associated with increased neurological morbi-mortality. Cerebral oximetry could be a useful monitoring during anaesthesia of (ex) preterm neonates, due to the risk of impaired cerebral blood flow autoregulation in these patients.

Effect of the adjunct of carbon dioxide during cardiopulmonary bypass on cerebral oxygenation

INTRODUCTION

Over the last few years, near-infrared spectroscopy (NIRS) has been introduced to study cerebral haemodynamics and oxygenation. This paper points out how the use of an external source of CO2 effects on the absolute value of cerebral NIRS during cardiac surgery on cardiopulmonary bypass.

PATIENTS AND METHODS

Between January 2010 and September 2011, 368 patients underwent congenital heart disease correction on cardiopulmonary bypass (CPB). Nineteen patients, with a mean age of 26 days (range 6-120 days), required an external source of CO2 to correct hypocarbia during cardiopulmonary bypass. Different parameters were monitored: NIRS value, oxygen saturation, oxygen partial pressure, CO2 partial pressure, haematocrit, mean arterial pressure and pH. They were analyzed during different phases of the surgical procedure: before, during and after CO2 infusion.

RESULTS

There were no deaths during the hospital stay. The NIRS value increased significantly (p<0.05) after the addition of CO2, from a starting value of 52.9 to a final value of 63.4. PaCO2 was found to increase too: from 31.3 mmHg to 40.6 mmHg. On the other hand, both values decreased when the CO2 was removed, to respective final values of 55.8 and 34.4 mmHg. Mean arterial pressure, haematocrit and PaO2 didn't modify significantly during this period.

CONCLUSIONS

Nowadays, NIRS is usually used in cardiac surgery to reduce possible risks of neurological damage. The importance of the role of pCO2 in the cerebral vascular resistance and in cerebral blood flow has already been proven. This research demonstrates a relationship between pCO2 and the NIRS value. This paper could introduce an important correcting tool when an inadequate NIRS value occurs although the level of oxygenation, haematocrit and mean arterial pressure are acceptable and the arterial line is accurately positioned.