Changes in cerebral and somatic oxygenation during stage 1 palliation of hypoplastic left heart syndrome using continuous regional cerebral perfusion

The Comparison of Cerebral Oxygenation among Mechanically Ventilated Children Receiving Protocolized Sedation and Analgesia versus Clinician's Decision in Pediatric Intensive Care Unit

Introduction

Adequate sedation and analgesia are two crucial factors affecting recovery of intensive care patients. Improper use of sedation and analgesia in intensive care patients may adversely lead to brain oxygen desaturation. This study aims to determine cerebral oxygenation as measured by near-infrared spectroscopy (NIRS) and inotropic interventions received among mechanically ventilated children in the pediatric intensive care unit (PICU).

Methods

This study is a nested case - control study in the PICU of Indonesian tertiary hospital. Children aged 1 month to 17 years on mechanical ventilation and were given sedation and analgesia were included in the study. Subjects were divided into two groups according to the protocol of the main study (Clinical Trial ID NCT04788589). Cerebral oxygenation was measured by NIRS at five time points (before sedation, 5-min, 1, 6, and 12 h after sedation).

Results

Thirty-nine of the 69 subjects were categorized into the protocol group and the rest were in the control group. A decrease of >20% NIRS values was found among subjects in the protocol group at 5-min (6.7%), 1-h (11.1%), 6-h (26.3%), and 12-h (23.8%) time-point. The mean NIRS value was lower and the inotropic intervention was more common in the control group (without protocol), although not statistically significant.

Conclusion

This study found that mechanically ventilated children who received sedation and analgesia based on the protocol had a greater decrease of >20% NIRS values compared to the other group. The use of sedation and analgesia protocols must be applied in selected patients after careful consideration.

Use of Renal Near-Infrared Spectroscopy and Urinary Neutrophil Gelatinase-Associated Lipocalin Monitoring as Indicators of Acute Kidney Injury in Pediatric Cardiac Surgery

Acute kidney injury (AKI) is a common complication following cardiac surgery under cardiopulmonary bypass (CPB) in children. A prospective study for examining urinary neutrophil gelatinase-associated lipocalin (NGAL) and renal near-infrared spectroscopy (NIRS) trends during AKI was conducted among pediatric patients undergoing cardiac surgery with CPB. Urinary NGAL showed a significant difference between intensive care unit admission (0 h) and 2 h post-admission (p < 0.001) and remained significant up to 4 h (p < 0.05). The renal NIRS in the AKI group showed a significant rate of decrease and lower values during the intraoperative period (p < 0.05). The cumulative median saturation of renal regional saturation of oxygen (rSO2) during CPB was 1637.5% min in the AKI group and 943.0% min in the non-AKI group. The median renal rSO2 scores at a reduction of 20% and 25% were significantly higher (p < 0.001) in the AKI group. Our results suggest that monitoring renal rSO2 scores and limiting their decline might be useful in preventing AKI. The combination of NGAL, renal rSO2, and renal rSO2 scores might be useful in the early diagnosis of AKI during pediatric cardiac surgery.

Current Status and Future Directions of Neuromonitoring With Emerging Technologies in Neonatal Care

Neonatology has experienced a significant reduction in mortality rates of the preterm population and critically ill infants over the last few decades. Now, the emphasis is directed toward improving long-term neurodevelopmental outcomes and quality of life. Brain-focused care has emerged as a necessity. The creation of neonatal neurocritical care units, or Neuro-NICUs, provides strategies to reduce brain injury using standardized clinical protocols, methodologies, and provider education and training. Bedside neuromonitoring has dramatically improved our ability to provide assessment of newborns at high risk. Non-invasive tools, such as continuous electroencephalography (cEEG), amplitude-integrated electroencephalography (aEEG), and near-infrared spectroscopy (NIRS), allow screening for seizures and continuous evaluation of brain function and cerebral oxygenation at the bedside. Extended and combined uses of these techniques, also described as multimodal monitoring, may allow practitioners to better understand the physiology of critically ill neonates. Furthermore, the rapid growth of technology in the Neuro-NICU, along with the increasing use of telemedicine and artificial intelligence with improved data mining techniques and machine learning (ML), has the potential to vastly improve decision-making processes and positively impact outcomes. This article will cover the current applications of neuromonitoring in the Neuro-NICU, recent advances, potential pitfalls, and future perspectives in this field.

Effects of Arterial Carbon Dioxide Tension on Cerebral and Somatic Regional Tissue Oxygenation and Blood Flow in Neonates After the Norwood Procedure With Deep Hypothermic Cardiopulmonary Bypass

Neonates undergoing the Norwood procedure for hypoplastic left heart syndrome are at higher risk of impaired systemic oxygen delivery with resultant brain, kidney, and intestinal ischemic injury, shock, and death. Complex developmental, anatomic, and treatment-related influences on cerebral and renal-somatic circulations make individualized treatment strategies physiologically attractive. Monitoring cerebral and renal circulations with near infrared spectroscopy can help drive rational therapeutic interventions. The primary aim of this study was to describe the differential effects of carbon dioxide tension on cerebral and renal circulations in neonates after the Norwood procedure. Using a prospectively-maintained database of postoperative physiologic and hemodynamic parameters, we analyzed the relationship between postoperative arterial carbon dioxide tension and tissue oxygen saturation and arteriovenous saturation difference in cerebral and renal regions, applying univariate and multivariate multilevel mixed regression techniques. Results were available from 7,644 h of data in 178 patients. Increases in arterial carbon dioxide tension were associated with increased cerebral and decreased renal oxygen saturation. Differential changes in arteriovenous saturation difference explained these effects. The cerebral circulation showed more carbon dioxide sensitivity in the early postoperative period, while sensitivity in the renal circulation increased over time. Multivariate models supported the univariate findings and defined complex time-dependent interactions presented graphically. The cerebral and renal circulations may compete for blood flow with critical limitations of cardiac output. The cerebral and renal-somatic beds have different circulatory control mechanisms that can be manipulated to change the distribution of cardiac output by altering the arterial carbon dioxide tension. Monitoring cerebral and renal circulations with near infrared spectroscopy can provide rational physiologic targets for individualized treatment.

The effect of selective cerebral perfusion on cerebral versus somatic tissue oxygenation during aortic coarctation repair in neonates and infants

Background

Suboptimal tissue perfusion and oxygenation may be the root cause of certain perioperative complications in neonates and infants having complicated aortic coarctation repair. Practical, effective, and real-time monitoring of organ perfusion and/or tissue oxygenation may provide early warning of end-organ mal-perfusion.

Methods

Neonates/infants who were scheduled for aortic coarctation repair with cardiopulmonary bypass (CPB) and selective cerebral perfusion (SCP) from January 2015 to February 2017 in Children’s Hospital of Nanjing Medical University participated in this prospective observational study. Cerebral and somatic tissue oxygen saturation (SctO₂ and SstO₂) were monitored on the forehead and at the thoracolumbar paraspinal region, respectively. SctO₂ and SstO₂ were recorded at different time points (baseline, skin incision, CPB start, SCP start, SCP end, aortic opening, CPB end, and surgery end). SctO₂ and SstO₂ were correlated with mean arterial pressure (MAP) and partial pressure of arterial blood carbon dioxide (PaCO₂).

Results

Data of 21 patients were analyzed (age=75±67 days, body weight=4.4±1.0 kg). SstO₂ was significantly lower than SctO₂ before aortic opening and significantly higher than SctO₂ after aortic opening. SstO₂ correlated with leg MAP when the measurements during SCP were (r=0.67, p<0.0001) and were not included (r=0.46, p<0.0001); in contrast, SctO₂ correlated with arm MAP only when the measurements during SCP were excluded (r=0.14, p=0.08 vs. r=0.66, p<0.0001). SCP also confounded SctO₂/SstO₂’s correlation with PaCO₂; when the measurements during SCP were excluded, SctO₂ positively correlated with PaCO₂ (r=0.65, p<0.0001), while SstO₂ negatively correlated with PaCO₂ (r=-0.53, p<0.0001).

Conclusions

SctO₂ and SstO₂ have distinct patterns of changes before and after aortic opening during neonate/infant aortic coarctation repair. SctO₂/SstO₂’s correlations with MAP and PaCO₂ are confounded by SCP. The outcome impact of combined SctO₂/SstO₂ monitoring remains to be studied.

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.

Advancement of a standardised enteral feeding protocol in functional single ventricle patients following stage I palliation using cerebro-somatic near-infrared spectroscopy

INTRODUCTION

Infants with single ventricle following stage I palliation are at risk for poor nutrition and growth failure. We hypothesise a standardised enteral feeding protocol for these infants that will result in a more rapid attainment of nutritional goals without an increased incidence of gastrointestinal co-morbidities.

MATERIALS AND METHODS

Single-centre cardiac ICU, prospective case series with historical comparisons. Feeding cohort consisted of consecutive patients with a single ventricle admitted to cardiac ICU over 18 months following stage I palliation (n = 33). Data were compared with a control cohort and admitted to the cardiac ICU over 18 months before feeding protocol implementation (n = 30). Feeding protocol patients were randomised: (1) protocol with cerebro-somatic near-infrared spectroscopy feeding advancement criteria (n = 17) or (2) protocol without cerebro-somatic near-infrared spectroscopy feeding advancement criteria (n = 16).

RESULTS

Median time to achieve goal enteral volume was significantly higher in the control compared to feeding cohort. There were no significant differences in enteral feeds being held for feeding intolerance or necrotising enterocolitis between cohorts. Feeding cohort had significant improvements in discharge nutritional status (weight, difference admit to discharge weight, weight-for-age z score, volume, and caloric enteral nutrition) and late mortality compared to the control cohort. No infants in the feeding group with cerebro-somatic near-infrared spectroscopy developed necrotising enterocolitis versus 4/16 (25%) in the feeding cohort without cerebro-somatic near-infrared spectroscopy (p = 0.04).

CONCLUSIONS

A feeding protocol is a safe and effective means of initiating and advancing enteral nutrition in infants following stage I palliation and resulted in improved nutrition delivery, weight gain, and nourishment status at discharge without increased incidence of gastrointestinal co-morbidities.

Standardization of the Perioperative Management for Neonates Undergoing the Norwood Operation for Hypoplastic Left Heart Syndrome and Related Heart Defects

OBJECTIVES

In-hospital complications after the Norwood operation for single ventricle heart defects account for the majority of morbidity and mortality. Inpatient care variation occurs within and across centers. This multidisciplinary quality improvement project standardized perioperative management in a large referral center.

DESIGN

Quality improvement project.

SETTING

High volume cardiac center, tertiary care children's hospital.

PATIENTS

Neonates undergoing Norwood operation.

INTERVENTIONS

The quality improvement team developed and implemented a clinical guideline (preoperative admission to 48 hr after surgery). The composite process metric, Guideline Adherence Score, contained 13 recommendations in the guideline that reflected consistent care for all patients.

MEASUREMENTS AND MAIN RESULTS

One-hundred two consecutive neonates who underwent Norwood operation (January 1, 2013, to July 12, 2016) before guideline implementation were compared with 50 consecutive neonates after guideline implementation (July 13, 2016, to May 4, 2018). No preguideline operations met the goal Guideline Adherence Score. In the first 6 months after guideline implementation, 10 of 12 operations achieved goal Guideline Adherence Score and continued through implementation, reaching 100% for the last 10 operations. Statistical process control analysis demonstrated less variability and decreased hours of postoperative mechanical ventilation and cardiac ICU length of stay during implementation. There were no statistically significant differences in major hospital complications or in 30-day mortality. A higher percentage of patients were extubated by postoperative day 2 after guideline implementation (67% [30/47] vs 41% [41/99], respectively; p = 0.01). Of these patients, reintubation within 72 hours of extubation significantly decreased after guideline implementation (0% [0/30] vs 17% [7/41] patients, respectively; p = 0.02).

CONCLUSIONS

This initiative successfully implemented a standardized perioperative care guideline for neonates undergoing the Norwood operation at a large center. Positive statistical process control centerline shifts in Guideline Adherence Score, length of postoperative mechanical ventilation, and cardiac ICU length of stay were demonstrated. A higher percentage were successfully extubated by postoperative day 2. Establishment of standard processes can lead to best practices to decrease major adverse events.

Interventions Associated With Treatment of Low Cardiac Output After Stage 1 Norwood Palliation

BACKGROUND

Mortality after stage 1 palliation of hypoplastic left heart syndrome remains significant. Both cardiac output (CO) and systemic vascular resistance (SVR) contribute to hemodynamic vulnerability. Simultaneous measures of mean arterial pressure and somatic regional near infrared spectroscopy saturation can classify complex hemodynamics into 4 distinct states, with a low-CO state of higher risk. We sought to identify interventions associated with low-CO state occupancy and transition.

METHODS

Perioperative data were prospectively collected in an institutional review board-approved database. Hemodynamic state was classified as high CO, high SVR, low SVR, and low CO using bivariate analysis. Associations of static and dynamic support levels and state classifications over 48 postoperative hours were tested between states and across transitions using mixed regression methods in a quasi-experimental design.

RESULTS

Data from 10,272 hours in 214 patients were analyzed. A low-CO state was observed in 142 patients for 1107 hours. Both low CO and extracorporeal membrane oxygenation had increased mortality risk. The low-CO state was characterized by lower milrinone but higher catecholamine dose. Successful transition out of low CO was associated with increased milrinone dose and hemoglobin concentration. Increasing milrinone and hemoglobin levels predicted reduced risk of low CO in future states.

CONCLUSIONS

Bivariate classification objectively defines hemodynamic states and transitions with distinct support profiles. Maintaining or increasing inodilator and hemoglobin levels were associated with improved hemodynamic conditions and were predictive of successful future transitions from the low-CO state.

Haemodynamic effects of premedication for neonatal intubation: an observational study

OBJECTIVE

To examine changes in blood pressure (BP), cardiac output (CO) and cerebral regional oxygen saturation (rScO2) with administration of premedication for neonatal intubation.

DESIGN

Pilot, prospective, observational study. Oxygen saturation, heart rate, CO, rScO2 and BP data were collected. Monitoring began 5 min prior to premedication and continued until spontaneous movement.

SETTING

Single-centre, level 3 neonatal intensive care unit PATIENTS: 35 infants, all gestational ages. 81 eligible infants: 66 consented, 15 refused.

INTERVENTIONS

Intravenous atropine, fentanyl or morphine, ±cisatracurium MAIN OUTCOME MEASURES: BP, CO, rScO2 RESULTS: n=37 intubations. Mean gestational age and median birth weight were 31 4/7 weeks and 1511 g. After premedication, 10 episodes resulted in a BP increase from baseline and 27 in a BP decrease. Of those whose BP decreased, 17 had <20% decrease and 10 had ≥20% decrease. Those with <20% BP decrease took an average of 2.5 min to return to baseline while those with a ≥20% BP decline took an average of 15.2 min. Three did not return to baseline by 35 min. Following intubation, further declines in BP (21%-51%) were observed in eight additional cases. One infant required a bolus for persistently low BPs. CO and rScO2 changes were statistically similar between the two groups.

CONCLUSION

About 30% of infants dropped their BP by ≥20% after premedication for elective intubation. These BP changes were not associated with any significant change in rScO2 or CO. More data are needed to better characterise the immediate haemodynamic changes and clinical outcomes associated with premedication.

An Elusive Prize: Transcutaneous Near InfraRed Spectroscopy (NIRS) Monitoring of the Liver

Introduction: We postulate a relationship between a transcutaneous hepatic NIRS measurement and a directly obtained hepatic vein saturation. If true, hepatic NIRS monitoring (in conjunction with the current dual-site cerebral-renal NIRS paradigm) might increase the sensitivity for detecting shock since regional oxygen delivery changes in the splanchnic circulation before the kidney or brain. We explored a reliable technique for hepatic NIRS monitoring as a prelude to rigorously testing this hypothesis. This proof-of-concept study aimed to validate hepatic NIRS monitoring by comparing hepatic NIRS measurements to direct hepatic vein samples obtained during cardiac catheterization. Method: IRB-approved prospective pilot study of hepatic NIRS monitoring involving 10 patients without liver disease who were already undergoing elective cardiac catheterization. We placed a NIRS monitor on the skin overlying liver during catheterization. Direct measurement of hepatic vein oxygen saturation during the case compared with simultaneous hepatic NIRS measurement. Results: There was no correlation between the Hepatic NIRS values and the directly measured hepatic vein saturation (R = -0.035; P = 0.9238). However, the Hepatic NIRS values correlated with the cardiac output (R = 0.808; P = 0.0047), the systolic arterial blood pressure (R = 0.739; P = 0.0146), and the diastolic arterial blood pressure (R = 0.7548; P = 0.0116). Conclusions: Using the technique described, hepatic NIRS does not correlate well with the hepatic vein saturation. Further optimization of the technique might provide a better measurement. Hepatic NIRS does correlate with cardiac output and thus may still provide a valuable additional piece of hemodynamic information when combined with other non-invasive monitoring.

Selective Use of Inpatient Interstage Management After Norwood Procedure

BACKGROUND

We report our intermediate-term results after Norwood procedure, including use of an interstage inpatient management strategy for high-risk patients, and seek to create a predictive model for probability of discharge.

METHODS

A single-site retrospective review was conducted for all patients undergoing Norwood procedure from 2006 to 2016 (N = 177). We compared those discharged home with those who either remained hospitalized until Glenn procedure or died before Norwood procedure discharge. Multivariable logistic regression was used to develop a predictive model for discharge.

RESULTS

During the study period, 120 (68%) patients were discharged home, 45 (25%) remained hospitalized, and 12 (7%) died before Glenn procedure (median age: 71 days). Interstage survival for those discharged after Norwood procedure was 100%. Longitudinal survival for the cohort was 86%, 81%, and 77% at 1, 5, and 10 years, resepectively. Ten-year survival was significantly greater for the discharged group compared with the interstage inpatients (86% vs 56%, P < .001). A reduced predictive model of discharge included lower gestational age (odds ratio [OR]: 0.95), lower median income for ZIP code (OR: 0.4), lower birth-weight-for-age z-score (OR: 0.56), longer cardiopulmonary bypass time (OR: 0.45), and Blalock-Taussig shunt (OR: 0.32).

CONCLUSIONS

Survival up to 10 years after Norwood procedure is good using a strategy of inpatient care for a subset of high-risk patients to mitigate home interstage mortality. A probabilistic model used after Norwood procedure was able to predict interstage discharge with good accuracy, but will require external validation to ensure generalizability. Further work is also needed to determine optimal palliative pathways for the high-risk patients because of the notable attrition beyond successful bidirectional Glenn procedure.

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.

Postoperative cerebral oxygenation was not associated with new brain injury in infants with congenital heart disease

OBJECTIVE

The aim of this study was to evaluate postoperative indices of cerebral oxygenation and autoregulation in infants with critical congenital heart disease in relation to new postoperative ischemic brain injury.

METHODS

This prospective, clinical cohort included 77 infants with transposition of the great arteries (N = 19), left ventricular outflow tract obstruction (N = 30), and single ventricle physiology (N = 28) undergoing surgery at 30 days or less of life. Postoperative near-infrared spectroscopy and physiologic monitoring were applied to extract mean arterial blood pressure, regional cerebral oxygen saturation, fractional tissue oxygen extraction, and regional cerebral oxygen saturation mean arterial blood pressure correlation coefficient (≥0.5 considered sign of impaired cerebral autoregulation). New postoperative ischemic injury was defined as moderate-severe white matter injury or focal infarction on magnetic resonance imaging. Low cardiac output syndrome was measured as lactate greater than 4 mmol/L with pH less than 7.30.

RESULTS

After surgery, regional cerebral oxygen saturation was decreased in all congenital heart disease groups with a notable increase in regional cerebral oxygen saturation between 6 and 12 hours after surgery, on average with a factor of 1.4 (range, 1.1-2.4). Both single ventricle physiology and postoperative low cardiac output syndrome were associated with lower regional cerebral oxygen saturation and increased time with correlation coefficient of 0.5 or greater. New postoperative ischemic injury was seen in 39 patients (53%) and equally distributed across congenital heart disease groups. Postoperative regional cerebral oxygen saturation, fractional tissue oxygen extraction, and correlation coefficient were not independently associated with new postoperative white matter injury or focal infarction (mixed-model analysis, all F > 0.12).

CONCLUSIONS

Postoperative indices of cerebral oxygenation and cerebral autoregulation are not independent predictors of new ischemic brain injury in infants with critical congenital heart disease. Further exploration of the complex interplay among low regional cerebral oxygen saturation, low cardiac output syndrome, and heart defect is required to identify potential biomarkers enabling early intervention for ischemic brain injury.

A Case of Persistence of Normal Tissue Oxygenation Monitored by Near-Infrared Spectroscopy (NIRS) Values Despite Prolonged Perioperative Cardiac Arrest

Patient: Male, 65

Final Diagnosis: Aortic dissection

Symptoms: Hemiplegia • hypotension

Medication:—

Clinical Procedure: Emergent surgery

Specialty: Surgery

S100B and its relation to cerebral oxygenation in neonates and infants undergoing surgery for congenital heart disease

OBJECTIVES

Neonates and infants undergoing surgery for congenital heart disease are at risk for developmental impairment. Hypoxic-ischemic brain injury might be one contributing factor. We aimed to investigate the perioperative release of the astrocyte protein S100B and its relation to cerebral oxygenation.

METHODS

Serum S100B was measured before and 0, 12, 24, and 48 hours after surgery. Cerebral oxygen saturation was derived by near-infrared spectroscopy. S100B reference values based on preoperative samples; concentrations above the 75th percentile were defined as elevated. Patients with elevated S100B at 24 or 48 hours were compared to cases with S100B in the normal range. Neonates (≤28 days) and infants (>28 and ≤365 days) were analyzed separately due to age-dependent release of S100B.

RESULTS

Seventy-four patients underwent 94 surgical procedures (neonates, n = 38; infants, n = 56). S100B concentrations were higher in neonates before and after surgery at all time points (P ≤ .015). Highest values were noticed immediately after surgery. Postoperative S100B was elevated after 15 (40.5%) surgeries in neonates. There was no difference in pre-, intra-, or postoperative cerebral oxygenation. In infants, postoperative S100B was elevated after 23 (41.8%) procedures. Preoperative cerebral oxygen saturations tended to be lower (53 ± 12% vs 59 ± 12%, P = .069) and arterial-cerebral oxygen saturation difference was higher (35 ± 11% vs 28 ± 11%, P = .018) in infants with elevated postoperative S100B. In the early postoperative course, cerebral oxygen saturation was lower (54 ± 13% vs 63 ± 12%, P = .011) and arterial-cerebral oxygen saturation difference was wider (38 ± 11% vs 30 ± 10%, P = .008). Cerebral oxygen saturation was also lower for the entire postoperative course (62 ± 18% vs 67 ± 9%, P = .047).

CONCLUSIONS

Postoperative S100B was elevated in about 40% of neonates and infants undergoing cardiac surgery. Infants with elevated postoperative S100B had impaired perioperative cerebral tissue oxygenation. No relation between S100B and cerebral oxygenation could be demonstrated in neonates.

Simultaneous Near-Infrared Spectroscopy (NIRS) and Amplitude-Integrated Electroencephalography (aEEG): Dual Use of Brain Monitoring Techniques Improves Our Understanding of Physiology

Continuous brain monitoring tools are increasingly being used in the neonatal intensive care unit (NICU) to assess brain function and cerebral oxygenation in neonates at high risk for brain injury. Near infrared spectroscopy (NIRS) is useful in critically ill neonates as a trend monitor to evaluate the balance between tissue oxygen delivery and consumption, providing cerebral and somatic oximetry values, and allowing earlier identification of abnormalities in hemodynamics and cerebral perfusion. Amplitude-integrated electroencephalography (aEEG) is a method for continuous monitoring of cerebral function at the bedside. Simultaneous use of both monitoring modalities may improve the understanding of alterations in hemodynamics and risk of cerebral injury. Several studies have described correlations between aEEG and NIRS monitoring, especially in infants with hypoxic-ischemic encephalopathy (HIE), but few describe the combined use of both monitoring techniques in a wider range of clinical scenarios. We review the use of NIRS and aEEG in neonates and describe four cases where abnormal NIRS values were immediately followed by changes in brain activity as seen on aEEG allowing the impact of a hemodynamic disturbance on the brain to be correlated with the changes in the aEEG background pattern. These four clinical scenarios demonstrate how simultaneous neuromonitoring with aEEG and NIRS provides important clinical information. We speculate that routine use of these combined monitoring modalities may become the future standard for neonatal neuromonitoring.

Perioperative Cerebral Oxygenation Metabolism in Neonates with Hypoplastic Left Heart Syndrome or Transposition of the Great Arteries

Optimizing oxygen delivery to the brain is one of the main goals in children with congenital heart defects after surgery. It has been shown that cerebral oxygen saturation (cSO2) is depressed within the first day after neonatal cardiopulmonary bypass surgery. However, peri-operative cerebral oxygen metabolism has not yet been assessed in previous studies. The aim of this study was to describe the peri-operative changes in cerebral oxygen metabolism in neonates with congenital heart defects following cardiopulmonary bypass surgery. Prospective observational cohort study. PICU of a tertiary referral center. Fourteen neonates with hypoplastic left heart syndrome (HLHS) undergoing Norwood procedure and 14 neonates with transposition of great arteries (TGA) undergoing arterial switch operation (ASO) were enrolled. Pediatric heart surgery. We measured non-invasively regional cSO2 and microperfusion (rcFlow) using tissue spectrometry and laser Doppler flowmetry before and after surgery. Cerebral fractional tissue oxygen extraction (cFTOE), the arterio-cerebral difference in oxygen content (acDO2) and approximated cerebral metabolic rate of oxygen (aCMRO2) were calculated. According to the postsurgical hemodynamics, arterial saturation (aSO2) normalized immediately after surgery in the TGA group, whereas HLHS patients still were cyanotic. cSO2 significantly increased in TGA group over 48 h after ASO (p = 0.004) and was significantly higher compared to HLHS group after Norwood procedure. cFTOE as a risk marker for brain injury was elevated before surgery (TGA group 0.37 ± 0.10, HLHS group 0.42 ± 0.12) and showed a slight decrease after ASO (p = 0.35) but significantly decreased in patients after Norwood procedure (p = 0.02). Preo-peratively, acDO2 was significantly higher in patients with HLHS compared to patients with TGA (7.7 ± 2.5 vs. 5.2 ± 1.6 ml/dl, p = 0.005), but normalized in the posto-perative course. Before surgery, the aCMRO2 was slightly higher in the HLHS group (5.1 ± 1.5 vs. 3.9 ± 2.5 AU, p = 0.14), but significantly decreased after Norwood procedure (- 1.6 AU, p = 0.009). There was no difference in rcFlow between both groups and between the points in time prior and after surgery. Neonates undergoing cardiac surgery suffer from peri-operative changes in hemodynamics and cerebral hypoxemic stress. The cerebral oxygen metabolism seems to be more affected in cyanotic children with functionally univentricular hearts compared to post-operative acyanotic patients. Additional stress factors must be avoided to achieve the best possible neurological outcome.

Markers of peripheral perfusion during high-flow regional cerebral perfusion for aortic arch repair

OBJECTIVES

High-flow regional cerebral perfusion (HFRCP) provides cerebral and somatic oxygen delivery through collateral vessels during aortic arch repair in small children; however, optimal flow conditions during HFRCP have not been established. We sought to identify markers of peripheral perfusion during HFRCP.

METHODS

Between 2009 and 2016, in total 20 consecutive pediatric patients undergoing aortic arch repair with HFRCP were enrolled in this prospective, observational study. Median age was 20 days (range, 6-116 days); median body weight was 2.77 kg (range, 1.8-4.98 kg). Oxygen delivery ratio (Do₂R) was calculated as the oxygen delivery during HFRCP divided by the oxygen delivery before HFRCP. Regional oxygen saturations on the forehead and on the thigh (rSo₂T) were monitored during HFRCP, and postoperative creatinine kinase and lactate concentrations were measured as postoperative outcomes. Multivariate analyses were performed to clarify the effectiveness of Do₂R and rSo₂T as markers of peripheral perfusion during HFRCP.

RESULTS

No deaths or neurologic impairments occurred. Multivariate analysis showed that the lowest rSo₂T (P = .005) and cardiopulmonary bypass time (P = .012) predicted postoperative creatinine kinase concentration. Do₂R was the only factor to predict postoperative lactate concentration (P < .001). Receiver operating characteristic analysis showed that Do₂R less than 0.66 predicted risk of high postoperative lactate concentration (>5.0 mmol/L), with area under the curve of 0.95.

CONCLUSIONS

For aortic arch repair in small children, rSo₂T and Do₂R during HFRCP are useful markers for predicting peripheral perfusion. Maintaining higher Do₂R during HFRCP minimizes postoperative increases in lactate and creatinine kinase concentrations.

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.

Postoperative kidney oxygen saturation as a novel marker for acute kidney injury after adult cardiac surgery

OBJECTIVE

Acute kidney injury is a severe complication and one of the stronger risk factors for death in patients undergoing cardiac surgery. The relationship between postoperative brain oxygen saturation and kidney oxygen saturation with acute kidney injury in adults undergoing cardiac surgery has not been determined. We designed a single-center prospective study to determine if the continuous monitoring of postoperative brain oxygen saturation and kidney oxygen saturation could predict postoperative acute kidney injury.

METHODS

We conducted a prospective open cohort study from January to September 2017. The primary outcome was postoperative acute kidney injury using the Kidney Disease: Improving Global Outcomes criteria. Brain oxygen saturation and kidney oxygen saturation, the metrics of which were area measurements (%-min), were recorded during the surgery and the first 48 hours after the cardiac procedure. Receiver operating characteristic curve analysis was used to evaluate the predictive power of kidney oxygen saturation for acute kidney injury.

RESULTS

A total of 121 consecutive patients were enrolled. Thirty-five patients (28.9%) developed acute kidney injury. Brain oxygen saturation showed no statistical difference in both groups; however, kidney oxygen saturation was related to acute kidney injury (P = .001). Receiver operating characteristic curve analysis showed that kidney oxygen saturation could predict the risk of acute kidney injury. Kidney oxygen saturation less than 65% (area under the curve-receiver operating characteristic, 0.679 ± 0.054, 95% confidence interval, 0.573-0.785, P = .002) and 20% decrease from baseline (area under the curve-receiver operating characteristic, 0.639 ± 0.059, 95% confidence interval, 0.523-0.755, P = .019) showed the better performance, respectively.

CONCLUSIONS

Postoperative kidney oxygen saturation is related to the development of cardiac surgery-associated acute kidney injury. Continuous kidney saturation monitoring might be a promising, noninvasive tool for predicting acute kidney injury during the postoperative period for adult patients after cardiac surgery.

Near-infrared spectroscopy might be a useful tool for predicting the risk of vascular complications after pediatric liver transplants: Two case reports

In patients that have undergone liver transplants, a postoperative reduction in the blood flow of the liver graft represents a critical complication. We recently encountered an interesting phenomenon; that is, we found that the rSO₂ level of the liver graft, as measured by NIRS, drops in patients that subsequently require an emergency liver biopsy. An 8-month-old female and an 8-month-old male underwent living donor liver transplants for biliary atresia. In both cases, a reduction in rSO₂ was detected before an emergency liver biopsy was required. As a result of biopsy examinations, both patients were diagnosed with acute graft rejection. NIRS might be useful for graft management during the postoperative period in pediatric patients that undergo liver transplantation. After a liver transplant, a reduction in the rSO₂ of the graft might be indicative of the onset of vascular complications.

Cerebral near-infrared spectroscopy (NIRS) for perioperative monitoring of brain oxygenation in children and adults

BACKGROUND

Various techniques have been employed for the early detection of perioperative cerebral ischaemia and hypoxia. Cerebral near-infrared spectroscopy (NIRS) is increasingly used in this clinical scenario to monitor brain oxygenation. However, it is unknown whether perioperative cerebral NIRS monitoring and the subsequent treatment strategies are of benefit to patients.

OBJECTIVES

To assess the effects of perioperative cerebral NIRS monitoring and corresponding treatment strategies in adults and children, compared with blinded or no cerebral oxygenation monitoring, or cerebral oxygenation monitoring based on non-NIRS technologies, on the detection of cerebral oxygen desaturation events (CDEs), neurological outcomes, non-neurological outcomes and socioeconomic impact (including cost of hospitalization and length of hospital stay).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 12), Embase (1974 to 20 December 2016) and MEDLINE (PubMed) (1975 to 20 December 2016). We also searched the World Health Organization (WHO) International Clinical Trials Registry Platform for ongoing studies on 20 December 2016. We updated this search in November 2017, but these results have not yet been incorporated in the review. We imposed no language restriction.

SELECTION CRITERIA

We included all relevant randomized controlled trials (RCTs) dealing with the use of cerebral NIRS in the perioperative setting (during the operation and within 72 hours after the operation), including the operating room, the postanaesthesia care unit and the intensive care unit.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies, assessed risk of bias and extracted data. For binary outcomes, we calculated the risk ratio (RR) and its 95% confidence interval (CI). For continuous data, we estimated the mean difference (MD) between groups and its 95% CI. As we expected clinical and methodological heterogeneity between studies, we employed a random-effects model for analyses and we examined the data for heterogeneity (I2 statistic). We created a 'Summary of findings' table using GRADEpro.

MAIN RESULTS

We included 15 studies in the review, comprising a total of 1822 adult participants. There are 12 studies awaiting classification, and eight ongoing studies.None of the 15 included studies considered the paediatric population. Four studies were conducted in the abdominal and orthopaedic surgery setting (lumbar spine, or knee and hip replacement), one study in the carotid endarterectomy setting, and the remaining 10 studies in the aortic or cardiac surgery setting. The main sources of bias in the included studies related to potential conflict of interest from industry sponsorship, unclear blinding status or missing participant data.Two studies with 312 participants considered postoperative neurological injury, however no pooled effect estimate could be calculated due to discordant direction of effect between studies (low-quality evidence). One study (N = 126) in participants undergoing major abdominal surgery reported that 4/66 participants experienced neurological injury with blinded monitoring versus 0/56 in the active monitoring group. A second study (N = 195) in participants having coronary artery bypass surgery reported that 1/96 participants experienced neurological injury in the blinded monitoring group compared with 4/94 participants in the active monitoring group.We are uncertain whether active cerebral NIRS monitoring has an important effect on the risk of postoperative stroke because of the low number of events and wide confidence interval (RR 0.25, 95% CI 0.03 to 2.20; 2 studies, 240 participants; low-quality evidence).We are uncertain whether active cerebral NIRS monitoring has an important effect on postoperative delirium because of the wide confidence interval (RR 0.63, 95% CI 0.27 to 1.45; 1 study, 190 participants; low-quality evidence).Two studies with 126 participants showed that active cerebral NIRS monitoring may reduce the incidence of mild postoperative cognitive dysfunction (POCD) as defined by the original studies at one week after surgery (RR 0.53, 95% CI 0.30 to 0.95, I2 = 49%, low-quality evidence).Based on six studies with 962 participants, there was moderate-quality evidence that active cerebral oxygenation monitoring probably does not decrease the occurrence of POCD (decline in cognitive function) at one week after surgery (RR 0.62, 95% CI 0.37 to 1.04, I2 = 80%). The different type of monitoring equipment in one study could potentially be the cause of the heterogeneity.We are uncertain whether active cerebral NIRS monitoring has an important effect on intraoperative mortality or postoperative mortality because of the low number of events and wide confidence interval (RR 0.63, 95% CI 0.08 to 5.03, I2= 0%; 3 studies, 390 participants; low-quality evidence). There was no evidence to determine whether routine use of NIRS-based cerebral oxygenation monitoring causes adverse effects.

AUTHORS' CONCLUSIONS

The effects of perioperative active cerebral NIRS monitoring of brain oxygenation in adults for reducing the occurrence of short-term, mild POCD are uncertain due to the low quality of the evidence. There is uncertainty as to whether active cerebral NIRS monitoring has an important effect on postoperative stroke, delirium or death because of the low number of events and wide confidence intervals. The conclusions of this review may change when the eight ongoing studies are published and the 12 studies awaiting assessment are classified. More RCTs performed in the paediatric population and high-risk patients undergoing non-cardiac surgery (e.g. neurosurgery, carotid endarterectomy and other surgery) are needed.

Elevated cranial ultrasound resistive indices are associated with improved neurodevelopmental outcomes one year after pediatric cardiac surgery: A single center pilot study

OBJECTIVE

To determine if a non-invasive, repeatable test can be used to predict neurodevelopmental outcomes in patients with congenital heart disease.

METHODS

This was a prospective study of pediatric patients less than two months of age undergoing congenital heart surgery at the Children's Health Children's Medical Center at Dallas. Multichannel near-infrared spectroscopy (NIRS) was utilized during the surgery, and ultrasound (US) resistive indices (RI) of the major cranial vessels were obtained prior to surgery, immediately post-operatively, and prior to discharge. Pearson's correlation, Fischer exact t test, and Fischer r to z transformation were used where appropriate.

RESULTS

A total of 16 patients were enrolled. All had US data. Of the sixteen patients, two died prior to the neurodevelopmental testing, six did not return for the neurodevelopmental testing, and eight patients completed the neurodevelopmental testing. There were no significant correlations between the prior to surgery and prior to discharge US RI and neurodevelopmental outcomes. The immediate post-operative US RI demonstrated a strong positive correlation with standardized neurodevelopmental outcome measures. We were able to demonstrate qualitative differences using multichannel NIRS during surgery, but experienced significant technical difficulties implementing consistent monitoring.

CONCLUSIONS

A higher resistive index in the major cerebral blood vessels following cardiac surgery in the neonatal period is associated with improved neurological outcomes one year after surgery. Obtaining an ultrasound with resistive indices of the major cerebral vessels prior to and after surgery may yield information that is predictive of neurodevelopmental outcomes.

Perioperative Near-Infrared Spectroscopy Monitoring in Neonates With Congenital Heart Disease: Relationship of Cerebral Tissue Oxygenation Index Variability With Neurodevelopmental Outcome

OBJECTIVES

To evaluate the value of perioperative cerebral near-infrared spectroscopy monitoring using variability analysis in the prediction of neurodevelopmental outcomes in neonates undergoing surgery for congenital heart disease.

DESIGN

Retrospective cohort study.

SETTING

Urban, academic, tertiary-care children's hospital.

PATIENTS

Neonates undergoing surgery with cardiopulmonary bypass for congenital heart disease.

INTERVENTIONS

Perioperative monitoring of continuous cerebral tissue oxygenation index by near-infrared spectroscopy and subsequent neurodevelopmental testing at 6, 15, and 21 months of age.

MEASUREMENTS AND MAIN RESULTS

We developed a new measure, cerebral tissue oxygenation index variability, using the root mean of successive squared differences of averaged 1-minute cerebral tissue oxygenation index values for both the intraoperative and first 24-hours postoperative phases of monitoring. There were 62 neonates who underwent cerebral tissue oxygenation index monitoring during surgery for congenital heart disease and 44 underwent subsequent neurodevelopmental testing (12 did not survive until testing and six were lost to follow-up). Among the 44 monitored patients who underwent neurodevelopmental testing, 20 (45%) had abnormal neurodevelopmental indices. Patients with abnormal neurodevelopmental indices had lower postoperative cerebral tissue oxygenation index variability when compared with patients with normal indices (p = 0.01). Adjusting for class of congenital heart disease and duration of deep hypothermic circulatory arrest, lower postoperative cerebral tissue oxygenation index variability was associated with poor neurodevelopmental outcome (p = 0.02).

CONCLUSIONS

We found reduced postoperative cerebral tissue oxygenation index variability in neonatal survivors of congenital heart disease surgery with poor neurodevelopmental outcomes. We hypothesize that reduced cerebral tissue oxygenation index variability may be a surrogate for impaired cerebral metabolic autoregulation in the immediate postoperative period. Further research is needed to investigate clinical implications of this finding and opportunities for using this measure to drive therapeutic interventions.

Can transcutaneous near infrared spectroscopy detect severe hepatic ischemia: a juvenile porcine model

BACKGROUND

Vascular complications following pediatric liver transplantation occur in 8-10% of cases, and no continuous, non-invasive monitoring for this problem exists. Near infrared spectroscopy (NIRS) allows non-invasive, continuous, transcutaneous assessment of hemoglobin oxygenation (StO₂ ) 1-4 cm below the skin surface.

AIMS

We hypothesized that transcutaneous NIRS would be able to detect severe hepatic ischemia, and tested this in an animal model using 15-20 kg and 5-7 kg juvenile pigs.

MATERIALS AND METHODS

Direct liver surface and transcutaneous hepatic tissue hemoglobin oxygen saturation (StO₂ ) were measured during occlusions of the hepatic artery and portal vein. Changes in hepatic delivery of oxygen (HepDO₂ ) were calculated for each ischemic challenge and compared to changes in direct liver surface (DirHepStO₂ ) and transcutaneous liver StO₂ measurements (CutHepStO₂ ).

RESULTS

In the 15-20 kg animals during complete occlusion, CutHepStO₂ decreased by 6.0(±4.9)%, whilst DirHepStO₂ decreased by 83.7(±7.2)%. In the 5-7 kg animals during complete occlusion, CutHepStO₂ decreased by 27.4(±8.5)%, whilst DirHepStO₂ decreased by 82.8(±4.6)%.

CONCLUSION

Transcutaneous hepatic StO₂ monitoring cannot reliably detect severe hepatic ischemia in a juvenile porcine model, although a stronger and potentially useful signal is seen in 5-7 kg pigs. Trials of this technology should be currently restricted to situations where the organ is less than 1 cm from the skin surface, corresponding to infants of <10 kg.

Landmark papers in pediatric cardiac anesthesia: documenting the history of the specialty

Pediatric cardiac anesthesia has developed over the past eight decades into a specialty delivering complex clinical care and contributing remarkable scientific progress. The history of this development can be traced through journal articles that mark the strides of the specialty. This article discusses journal articles, chosen by the author, that he considers had a significant impact on the practice of pediatric cardiac anesthesia or are of historical interest.

Brain Monitoring and Protection During Pediatric Cardiac Surgery

With advances in medical care, survival after cardiac surgery for congenital heart disease has dramatically improved, and attention is increasingly focused on longterm functional morbidities, especially neurodevelopmental outcomes, with their profound consequences to patients and society. There are multiple reasons for concern about brain injury. Some cardiac defects are associated with brain anomalies and altered cerebral blood flow regulation. Brain imaging studies have demonstrated that injury to gray and white matter is quite frequent before heart surgery in neonates. Cardiopulmonary bypass and deep hypothermic circulatory arrest are associated with shortand longer-term adverse neurologic outcome. Additional brain injury can occur during the patient's recovery from surgery. Strategies to optimize neurologic outcome continue to evolve. With new technological developments, perioperative neurologic monitoring of small children has become easier, and data suggest these modalities usefully identify adverse neurologic events and might predict outcome. Monitoring methods to be discussed include processed electroencephalography, near infrared spectroscopy, and transcranial Doppler ultrasound. Alternative perfusion techniques to deep hypothermic circulatory arrest have been developed, such as regional antegrade cerebral perfusion during cardiopulmonary bypass. Other neuroprotective strategies employed during open-heart surgery include temperature regulation, acid-base management, degree of hemodilution, blood glucose control and anti-inflammatory therapies. Evidence of the impact of these measures on neurologic outcome is examined, and deficiencies in our current understanding of neurologic function in children with congenital heart disease are identified.

Toward translating near-infrared spectroscopy oxygen saturation data for the non-invasive prediction of spatial and temporal hemodynamics during exercise

Image-based computational fluid dynamics (CFD) studies conducted at rest have shown that atherosclerotic plaque in the thoracic aorta (TA) correlates with adverse wall shear stress (WSS), but there is a paucity of such data under elevated flow conditions. We developed a pedaling exercise protocol to obtain phase contrast magnetic resonance imaging (PC-MRI) blood flow measurements in the TA and brachiocephalic arteries during three-tiered supine pedaling at 130, 150, and 170 % of resting heart rate (HR), and relate these measurements to non-invasive tissue oxygen saturation [Formula: see text] acquired by near-infrared spectroscopy (NIRS) while conducting the same protocol. Local quantification of WSS indices by CFD revealed low time-averaged WSS on the outer curvature of the ascending aorta and the inner curvature of the descending aorta (dAo) that progressively increased with exercise, but that remained low on the anterior surface of brachiocephalic arteries. High oscillatory WSS observed on the inner curvature of the aorta persisted during exercise as well. Results suggest locally continuous exposure to potentially deleterious indices of WSS despite benefits of exercise. Linear relationships between flow distributions and tissue oxygen extraction calculated from [Formula: see text] were found between the left common carotid versus cerebral tissue [Formula: see text] and the dAo versus leg tissue [Formula: see text]. A resulting six-step procedure is presented to use NIRS data as a surrogate for exercise PC-MRI when setting boundary conditions for future CFD studies of the TA under simulated exercise conditions. Relationships and ensemble-averaged PC-MRI inflow waveforms are provided in an online repository for this purpose.

Rationale for Implementation of Warm Cardiac Surgery in Pediatrics

Cardiac surgery was developed thanks to the introduction of hypothermia and cardiopulmonary bypass in the early 1950s. The deep hypothermia protective effect has been essential to circulatory arrest complex cases repair. During the early times of open-heart surgery, a major concern was to decrease mortality and to improve short-term outcomes. Both mortality and morbidity dramatically decreased over a few decades. As a consequence, the drawbacks of deep hypothermia, with or without circulatory arrest, became more and more apparent. The limitation of hypothermia was particularly evident for the brain and regional perfusion was introduced as a response to this problem. Despite a gain in popularity, the results of regional perfusion were not fully convincing. In the 1990s, warm surgery was introduced in adults and proved to be safe and reliable. This option eliminates the deleterious effect of ischemia-reperfusion injuries through a continuous, systemic coronary perfusion with warm oxygenated blood. Intermittent warm blood cardioplegia was introduced later, with impressive results. We were convinced by the easiness, safety, and efficiency of warm surgery and shifted to warm pediatric surgery in a two-step program. This article outlines the limitations of hypothermic protection and the basic reasons that led us to implement pediatric warm surgery. After tens of thousands of cases performed across several centers, this reproducible technique proved a valuable alternative to hypothermic surgery.

A Cross-Sectional Survey of Near-Infrared Spectroscopy Use in Pediatric Cardiac ICUs in the United Kingdom, Ireland, Italy, and Germany

OBJECTIVES

Despite the increasing use of near-infrared spectroscopy across pediatric cardiac ICUs, there is significant variability and equipoise with no universally accepted management algorithms. We aimed to explore the use of near-infrared spectroscopy in pediatric cardiac ICUs in the United Kingdom, Ireland, Italy, and Germany.

DESIGN

A cross-sectional multicenter, multinational electronic survey of one consultant in each pediatric cardiac ICU.

SETTING

Pediatric cardiac ICUs in the United Kingdom and Ireland (n = 13), Italy (n = 12), and Germany (n = 33).

INTERVENTIONS

Questionnaire targeted to establish use, targets, protocols/thresholds for intervention, and perceived usefulness of near-infrared spectroscopy monitoring.

RESULTS

Overall, 42 of 58 pediatric cardiac ICUs (72%) responded: United Kingdom and Ireland, 11 of 13 (84.6%); Italy, 12 of 12 (100%); and Germany, 19 of 33 (57%, included all major centers). Near-infrared spectroscopy usage varied with 35% (15/42) reporting that near-infrared spectroscopy was not used at all (7/42) or occasionally (8/42); near-infrared spectroscopy use was much less common in the United Kingdom (46%) when compared with 78% in Germany and all (100%) in Italy. Only four units had a near-infrared spectroscopy protocol, and 18 specifically used near-infrared spectroscopy in high-risk patients; 37 respondents believed that near-infrared spectroscopy added value to standard monitoring and 23 believed that it gave an earlier indication of deterioration, but only 19 would respond based on near-infrared spectroscopy data alone. Targets for absolute values and critical thresholds for intervention varied widely between units. The reasons cited for not or occasionally using near-infrared spectroscopy were expense (n = 6), limited evidence and uncertainty on how it guides management (n = 4), difficulty in interpretation, and unreliability of data (n = 3). Amongst the regular or occasional near-infrared spectroscopy users (n = 35), 28 (66%) agreed that a multicenter study is warranted to ascertain its use.

CONCLUSIONS

Although most responding units used near-infrared spectroscopy for high-risk patients, the majority (31/35 [88%]) did not have any protocols or guidelines for intervention. Target thresholds and intervention algorithms are needed to support the use of near-infrared spectroscopy in pediatric cardiac ICUs; an international multicenter study is warranted.

Perioperative cerebral hemodynamics and oxygen metabolism in neonates with single-ventricle physiology

Congenital heart disease (CHD) patients are at risk for neurodevelopmental delay. The etiology of these delays is unclear, but abnormal prenatal cerebral maturation and postoperative hemodynamic instability likely play a role. A better understanding of these factors is needed to improve neurodevelopmental outcome. In this study, we used bedside frequency-domain near infrared spectroscopy (FDNIRS) and diffuse correlation spectroscopy (DCS) to assess cerebral hemodynamics and oxygen metabolism in neonates with single-ventricle (SV) CHD undergoing surgery and compared them to controls. Our goals were 1) to compare cerebral hemodynamics between unanesthetized SV and healthy neonates, and 2) to determine if FDNIRS-DCS could detect alterations in cerebral hemodynamics beyond cerebral hemoglobin oxygen saturation (SO 2). Eleven SV neonates were recruited and compared to 13 controls. Preoperatively, SV patients showed decreased cerebral blood flow (CBFi ), cerebral oxygen metabolism (CMRO 2i ) and SO 2; and increased oxygen extraction fraction (OEF) compared to controls. Compared to preoperative values, unstable postoperative SV patients had decreased CMRO 2i and CBFi , which returned to baseline when stable. However, SO 2 showed no difference between unstable and stable states. Preoperative SV neonates are flow-limited and show signs of impaired cerebral development compared to controls. FDNIRS-DCS shows potential to improve assessment of cerebral development and postoperative hemodynamics compared to SO 2 alone.

Combined Cerebral and Renal Near-Infrared Spectroscopy After Congenital Heart Surgery

The maintenance of an adequate oxygen supply to tissues after congenital heart surgery is essential for good outcomes. The objective of this study was to assess the usefulness of near-infrared spectroscopy (NIRS) for estimating central venous oxygen saturation (ScvO2) using both cerebral and renal measurements, explore its relation with cardiac output measurements and check its ability to detect low cardiac output. A prospective observational pilot study was conducted in patients weighing <10 kg undergoing cardiopulmonary bypass surgery. Spectroscopy probes were placed on the forehead and renal area, and serial cardiac output measurements were obtained by femoral transpulmonary thermodilution over the first 24 h after surgery. In the 15 patients studied, ScvO2 was correlated with cerebral (r = 0.58), renal (r = 0.60) and combined (r = 0.71) measurements. Likewise, the systolic index was correlated with the NIRS signals: cerebral (r = 0.60), renal (r = 0.50) and combined (r = 0.66). Statistically significant differences were found in the NIRS measures registered in the 29 low cardiac output events detected by thermodilution: cerebral: 62 % (59-65) versus 69 % (63-76); renal: 83 % (70-89) versus 89 % (83-95); and combined 64 % (60-69) versus 72 % (67-76). In our series, combined cerebral and renal monitoring was correlated with central venous oxygen saturation and cardiac output; low cardiac output detection associated a different spectroscopy pattern.

Current research suggests that the future looks brighter for cerebral oxygenation monitoring in preterm infants

Brain injuries remain a significant problem for preterm infants, despite extensive physiological monitoring. Near infrared spectroscopy (NIRS) monitoring in the neonatal intensive care unit has to date remained limited to research activities.

CONCLUSION

This review highlights the increasing clinical application of NIRS in delivery suites and neonatal units. Four randomised controlled trials incorporating NIRS monitoring suggest that the future may indeed be brighter for this technology in the care of very preterm infants.

Near-infrared spectroscopy after high-risk congenital heart surgery in the paediatric intensive care unit

OBJECTIVE

To establish whether the use of near-infrared spectroscopy is potentially beneficial in high-risk cardiac infants in United Kingdom paediatric intensive care units.

DESIGN

A prospective observational pilot study.

SETTING

An intensive care unit in North West England.

PATIENTS

A total of 10 infants after congenital heart surgery, five with biventricular repairs and five with single-ventricle physiology undergoing palliation.

INTERVENTIONS

Cerebral and somatic near-infrared spectroscopy monitoring for 24 hours post-operatively in the intensive care unit.

MEASUREMENT AND MAIN RESULTS

Overall, there was no strong correlation between cerebral near-infrared spectroscopy and mixed venous oxygen saturation (r=0.48). At individual time points, the correlation was only strong (r=0.74) 1 hour after admission. The correlation was stronger for the biventricular patients (r=0.68) than single-ventricle infants (r=0.31). A strong inverse correlation was demonstrated between cerebral near-infrared spectroscopy and serum lactate at 3 of the 5 post-operative time points (1, 4, and 12 hours: r=-0.76, -0.72, and -0.69). The correlation was stronger when the cerebral near-infrared spectroscopy was <60%. For cerebral near-infrared spectroscopy <60%, the inverse correlation with lactate was r=-0.82 compared with those cerebral near-infrared spectroscopy >60%, which was r=-0.50. No correlations could be demonstrated between (average) somatic near-infrared spectroscopy and serum lactate (r=-0.13, n=110) or mixed venous oxygen saturation and serum lactate. There was one infant who suffered a cardiopulmonary arrest, and the cerebral near-infrared spectroscopy showed a consistent 43 minute decline before the event.

CONCLUSIONS

We found that cerebral near-infrared spectroscopy is potentially beneficial as a non-invasive, continuously displayed value and is feasible to use on cost-constrained (National Health Service) cardiac intensive care units in children following heart surgery.

Intraoperative renal near-infrared spectroscopy indicates developing acute kidney injury in infants undergoing cardiac surgery with cardiopulmonary bypass: a case-control study

Introduction

Acute kidney injury (AKI) is a frequent complication after cardiac surgery with cardiopulmonary bypass in infants. Renal near-infrared spectroscopy (NIRS) is used to evaluate regional oximetry in a non-invasive continuous real-time fashion, and reflects tissue perfusion. The aim of this study was to evaluate the relationship between renal oximetry and development of AKI in the operative and post-operative setting in infants undergoing cardiopulmonary bypass surgery.

Methods

In this prospective study, we enrolled 59 infants undergoing cardiopulmonary bypass surgery for congenital heart disease for univentricular (n = 26) or biventricular (n = 33) repair. Renal NIRS was continuously measured intraoperatively and for at least 24 hours postoperatively and analysed for the intraoperative and first 12 hours, first 24 hours and first 48 hours postoperatively. The renal oximetry values were correlated with the paediatric risk, injury, failure, loss, end (pRIFLE) classification for AKI, renal biomarkers and the postoperative course.

Results

Twenty-eight (48%) infants developed AKI based on pRIFLE classification. Already during intraoperative renal oximetry and further in the first 12 hours, 24 hours and 48 hours postoperatively, significantly lower renal oximetry values in AKI patients compared with patients with normal renal function were recorded (P < 0.05). Of the 28 patients who developed AKI, 3 (11%) needed renal replacement therapy and 2 (7%) died. In the non-AKI group, no deaths occurred. Infants with decreased renal oximetry values developed significantly higher lactate levels 24 hours after surgery. Cystatin C was a late parameter of AKI, and neutrophil gelatinase-associated lipocalin values were not correlated with AKI occurrence.

Conclusion

Our results suggest that prolonged low renal oximetry values during cardiac surgery correlate with the development of AKI and may be superior to conventional biochemical markers. Renal NIRS might be a promising non-invasive tool of multimodal monitoring of kidney function and developing AKI in infants undergoing cardiac surgery with cardiopulmonary bypass.

Innominate artery cannulation and antegrade cerebral perfusion for aortic arch reconstruction in infants and children

PURPOSE

Innominate artery cannulation has been widely adopted as a means to perform aortic arch reconstruction with continuous cerebral perfusion in the newborn. Although this technique has been subsequently utilized in infants and children, there is currently no data regarding the safety or efficacy in these older children. The purpose of this study was to review our experience with innominate artery cannulation for aortic arch reconstruction in patients beyond the neonatal period.

METHODS

This was a retrospective review of 42 infants and children who underwent aortic arch reconstruction using the technique of innominate artery cannulation with continuous cerebral perfusion. Of these procedures, 29 (69%) were primary arch reconstructions, while 13 (31%) were aortic arch reoperations. The median age at surgery was 8 months, and 22 patients underwent concomitant intracardiac repairs.

RESULTS

There was no operative mortality in this cohort of 42 patients undergoing aortic arch reconstruction. There was also no overt evidence of neurologic injury. Specifically, none of the patients demonstrated a neurologic deficit, clinical seizure, or unexpected delay in regaining a normal state of consciousness. The median duration of antegrade cerebral perfusion was 34 minutes. The median duration of hospital stay was 11 days. No patient required reoperation on the aortic arch with a median of 45-month follow-up.

CONCLUSIONS

Innominate artery cannulation is a safe and effective technique for aortic arch reconstruction in nonneonates. We conclude that antegrade cerebral perfusion is a useful technique for aortic arch reconstruction in this patient population.

Near-infrared spectroscopy as continuous real-time monitoring for kidney graft perfusion

BACKGROUND

Near-infrared spectroscopy (NIRS) is a non-invasive technique designed to study regional oxygenation (rSO(2)) by measuring the absorption of chromophores. This study investigated the role of NIRS in the real-time monitoring of kidney graft perfusion for 72 h post-transplantation.

METHODS

Consecutive children undergoing living related donor (LRD) or deceased donor (DD) kidney transplantation (KTP) were prospectively enrolled between April 2010 and August 2011. Renal rSO(2) values were registered continuously for 3 days and correlated with hourly urine output, serum creatinine, and urinary neutrophil gelatinase-associated lipocalin (u-NGAL).

RESULTS

Twenty-four children were included, 6 underwent LRD and 18 DD KTP. Median age was 12.5 years (interquartile range [IQR] 3.5-16.6) and median body weight was 37 kg (IQR 13-49.7). Four patients experienced delayed graft function (DGF). Renal Doppler ultrasound showed normal vascularization patterns in all children. Median basal renal rSO(2) value was 68.8 % (IQR 59.3-76.2), significantly lower than the end-of-period result (83.6 %; IQR 79.2-90.4; p < 0.0001). Renal rSO(2) values showed significant correlation with serum creatinine (rs = -0.62; p < 0.05) and estimated glomerular filtration rate (eGFR) (rs = 0.64; p < 0.05). No correlation was shown between rSO(2) and diuresis. Increased rSO(2) was also found in patients who experienced DGF. u-NGAL exhibited a trend toward a decrease from baseline in both DD and LRD KTPs, with a strong negative correlation with rSO(2).

CONCLUSIONS

rSO(2) assessed by NIRS strongly correlates with common markers of kidney graft function and perfusion, allowing continuous real-time monitoring of blood flow in renal grafts.

Splanchnic oxygen saturation immediately after weaning from cardiopulmonary bypass can predict early postoperative outcomes in children undergoing congenital heart surgery

This study compared the abilities of cerebral, renal, and splanchnic regional oxygen saturation (rSO2) immediately after weaning from cardiopulmonary bypass (CPB) to predict early postoperative outcomes for children undergoing congenital heart surgery. The study enrolled 73 children (ages 0.1-72 months) undergoing corrective or palliative cardiac surgery requiring CPB. Laboratory and hemodynamic variables were analyzed at the time of successful weaning from CPB. Using near-infrared spectroscopy, cerebral, renal, and splanchnic rSO2 values were obtained simultaneously. Early postoperative outcome measures included the maximum vasoactive inotropic score (VIS(max)) during the first 36 postoperative hours, the duration of mechanical ventilation, and the postoperative hospital length of stay. In the univariate analysis, cerebral, renal, and splanchnic rSO2 values correlated significantly with early postoperative outcomes. However, splanchnic rSO2 was the only independent factor predicting VIS(max) (β = -0.302, P = 0.021), duration of mechanical ventilation (β = -0.390, P = 0.002), and postoperative hospital length of stay (β = -0.340, P = 0.001) by multivariate analyses. Splanchnic rSO2 had a larger receiver operating characteristic area under the curve (AUC) for determining high VIS(max), prolonged mechanical ventilation, and longer postoperative hospital stay (AUC 0.775, 0.792, and 0.776, respectively) than cerebral (AUC 0.630, 0.638, and 0.632, respectively) and renal (AUC 0.703, 0.716, and 0.715, respectively) rSO2. After weaning from CPB, splanchnic rSO2 may be superior to rSO2 measured from brain and kidney in predicting an increased requirement for vasoactive inotropic support, a prolonged mechanical ventilation, and a longer postoperative hospital stay for children.

Changes in cerebral oxygen saturation correlate with S100B in infants undergoing cardiac surgery with cardiopulmonary bypass

OBJECTIVES

The relationship of cerebral saturation measured by near-infrared spectroscopy with serum biomarker of brain injury S100B was investigated in infants undergoing cardiac surgery with cardiopulmonary bypass.

DESIGN

Prospective cohort study.

SETTING

Single-center children's hospital.

PATIENTS

Forty infants between 1 and 12 months old weighing greater than or equal to 4 kg with congenital heart disease undergoing cardiac surgery with cardiopulmonary bypass were enrolled.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Serum S100B was measured at eight time points over 72 hours using enzyme-linked immunosorbent assay. Physiologic data including arterial, cerebral, and somatic regional oxygen saturations measured by near-infrared spectroscopy were synchronously recorded at 1-minute intervals from anesthesia induction through 72 postoperative hours. The arterial-cerebral oxygen saturation difference was calculated as the difference between arterial saturation and cerebral regional saturation. Thirty-eight patients, 5.4 ± 2.5 months old, were included in the analysis; two were excluded due to the use of postoperative extracorporeal membrane oxygenation. Seventeen patients (44.7%) had preoperative cyanosis. S100B increased during cardiopulmonary bypass in all patients, from a median preoperative baseline of mean ± SE: 0.055 ± 0.038 to a peak of 0.610 ± 0.038 ng/mL, p less than 0.0001. Patients without preoperative cyanosis had a higher S100B peak at the end of cardiopulmonary bypass. Although the absolute cerebral regional saturation on cardiopulmonary bypass was not associated with S100B elevation, patients who had arterial-cerebral oxygen saturation difference greater than 50 at any time during cardiopulmonary bypass had a higher S100B peak (mean ± SE: 1.053 ± 0.080 vs 0.504 ± 0.039 ng/mL; p < 0.0001).

CONCLUSIONS

A wide cerebral arteriovenous difference measured by near-infrared spectroscopy during cardiopulmonary bypass is associated with increased serum S100B in the perioperative period and may be a modifiable risk factor for neurological injury.