Relationship of intraoperative cerebral oxygen saturation to neurodevelopmental outcome and brain magnetic resonance imaging at 1 year of age in infants undergoing biventricular repair

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.

Changes in Near-Infrared Spectroscopy After Congenital Cyanotic Heart Surgery

BACKGROUND

Since oxygen saturation from pulse oximetry (SpO₂) and partial pressure of arterial oxygen (PaO₂) are observed to improve immediately after surgical correction of cyanotic congenital heart disease (CHD), we postulate that cerebral (CrO₂) and somatic (SrO₂) oximetry also improves immediately post-correction. We aim to prospectively examine CrO₂ and SrO₂, before, during, and after surgical correction as well as on hospital discharge in children with cyanotic CHD to determine if and when these variables increase.

METHODS

This is a prospective observational trial. Eligibility criteria included children below 18 years of age with cyanotic CHD who required any cardiac surgical procedure. CrO₂ and SrO₂ measurements were summarized at six time-points for comparison: (1) pre-cardiopulmonary bypass (CPB); (2) during CPB; (3) post-CPB; (4) Day 1 in the pediatric intensive care unit (PICU); (5) Day 2 PICU; and (6) discharge. Categorical and continuous variables are presented as counts (percentages) and median (interquartile range), respectively.

RESULTS

Twenty-one patients were analyzed. 15 (71.4%) and 6 (28.6%) patients underwent corrective and palliative surgeries, respectively. In the corrective surgery group, SpO₂ increased immediately post-CPB compared to pre-CPB [99 (98, 100) vs. 86% (79, 90); p < 0.001] and remained in the normal range through to hospital discharge. Post-CPB CrO₂ did not change from pre-CPB [72.8 (58.8, 79.0) vs. 72.1% (63.0, 78.3); p = 0.761] and even decreased on hospital discharge [60.5 (53.6, 62.9) vs. 72.1% (63.0, 78.3); p = 0.005]. Post-CPB SrO₂ increased compared to pre-CPB [87.3 (77.2, 89.5) vs. 72.7% (65.6, 77.3); p = 0.001] but progressively decreased during PICU stay to a value lower than baseline at hospital discharge [66.9 (57.3, 76.9) vs. 72.7% (65.6, 77.3); p = 0.048].

CONCLUSION

CrO₂ and SrO₂ did not increase after corrective surgery of cyanotic CHD even up to hospital discharge. Future larger studies are required to validate these findings. (This study is registered with ClinicalTrials.gov ID: NCT02417259.).

Congenital Heart Disease and Neurodevelopment: Clinical Manifestations, Genetics, Mechanisms, and Implications

Children with congenital heart disease (CHD) are at increased risk of neurodevelopmental disorders (NDDs) and psychiatric conditions. These include cognitive, adaptive, motor, speech, behavioural, and executive functioning deficits, as well as autism spectrum disorder and psychiatric conditions. Structural and functional neuroimaging have demonstrated brain abnormalities in young children with CHD before undergoing surgical repair, likely as a result of an in utero developmental insult. Surgical factors do not seem to play a significant role in neurodevelopmental outcomes. Specific genetic abnormalities, particularly copy number variants, have been increasingly implicated in both CHD and NDDs. Variations in genes involved in apolipoprotein E (APOE) production, the Wnt signalling pathway, and histone modification, as well as in the 1q21.1, 16p13.1-11, and 8p23.1 genetic loci, have been associated with CHD and NDDs and are important targets for future research. Understanding these associations is important for risk stratification, disease classification, improved screening, and pharmacologic management of individuals with CHD.

Cerebral Oxygen Saturation in Children With Congenital Heart Disease and Chronic Hypoxemia

BACKGROUND

Increased hemoglobin (Hb) concentration accompanying hypoxemia is a compensatory response to maintain tissue oxygen delivery. Near infrared spectroscopy (NIRS) is used clinically to detect abnormalities in the balance of cerebral tissue oxygen delivery and consumption, including in children with congenital heart disease (CHD). Although NIRS-measured cerebral tissue O2 saturation (ScO2) correlates with arterial oxygen saturation (SaO2), jugular bulb O2 saturation (SjbO2), and Hb, little data exist on the interplay between these factors and cerebral O2 extraction (COE). This study investigated the associations of ScO2 and ΔSaO2-ScO2 with SaO2 and Hb and verified the normal range of ScO2 in children with CHD.

METHODS

Children undergoing cardiac catheterization for CHD were enrolled in a calibration and validation study of the FORE-SIGHT NIRS monitor. Two pairs of simultaneous arterial and jugular bulb samples were drawn for co-oximetry, calculation of a reference ScO2 (REF CX), and estimation of COE. Pearson correlation and linear regression were used to determine relationships between O2 saturation parameters and Hb. Data were also analyzed according to diagnostic group defined as acyanotic (SaO2 ≥ 90%) and cyanotic (SaO2 < 90%).

RESULTS

Of 65 children studied, acceptable jugular bulb samples (SjbO2 absolute difference between samples ≤10%) were obtained in 57 (88%). The ΔSaO2-SjbO2, ΔSaO2-ScO2, and ΔSaO2-REF CX were positively correlated with SaO2 and negatively correlated with Hb (all P < .001). Although by diagnostic group ScO2 differed statistically (P = .002), values in the cyanotic patients were within the range considered normal (69% ± 6%). COE estimated by the difference between arterial and jugular bulb O2 content (ΔCaO2-CjbO2, mL O2/100 mL) was not different for cyanotic and acyanotic patients (P = .10), but estimates using ΔSaO2-SjbO2, ΔSaO2-ScO2, or ΔSaO2-ScO2/SaO2 were significantly different between the cyanotic and acyanotic children (P < .001).

CONCLUSIONS

Children with adequately compensated chronic hypoxemia appear to have ScO2 values within the normal range. The ΔSaO2-ScO2 is inversely related to Hb, with the implication that in the presence of reduced Hb, particularly if coupled with a decreased cardiac output, the ScO2 can fall to values associated with brain injury in laboratory studies.

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.

Differential expression of microRNAs following cardiopulmonary bypass in children with congenital heart diseases

Background

Children with congenital heart defects (CHDs) are at high risk for myocardial failure after operative procedures with cardiopulmonary bypass (CPB). Recent studies suggest that microRNAs (miRNA) are involved in the development of CHDs and myocardial failure. Therefore, the aim of this study was to determine alterations in the miRNA profile in heart tissue after cardiac surgery using CPB.

Methods

In total, 14 tissue samples from right atrium were collected from patients before and after connection of the CPB. SurePrint™ 8 × 60K Human v21 miRNA array and quantitative reverse transcription-polymerase chain reaction (RT-qPCR) were employed to determine the miRNA expression profile from three patients before and after connection of the CPB. Enrichment analyses of altered miRNA expression were predicted using bioinformatic tools.

Results

According to miRNA array, a total of 90 miRNAs were significantly altered including 29 miRNAs with increased and 61 miRNAs with decreased expression after de-connection of CPB (n = 3) compared to before CPB (n = 3). Seven miRNAs had been validated using RT-qPCR in an independent cohort of 11 patients. Enrichment analyses applying the KEGG database displayed the highest correlation for signaling pathways, cellular community, cardiovascular disease and circulatory system.

Conclusion

Our result identified the overall changes of the miRNome in right atrium tissue of patients with CHDs after CPB. The differentially altered miRNAs lay a good foundation for further understanding of the molecular function of changed miRNAs in regulating CHDs and after CPB in particular.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-017-1213-9) contains supplementary material, which is available to authorized users.

Brain injury with systemic inflammation in newborns with congenital heart disease undergoing heart surgery

The potential role of systemic inflammation on brain injury in newborns with congenital heart disease (CHD) was assessed by measuring levels of central nervous system (CNS)-derived proteins in serum prior to and following cardiac surgery. A total of 23 newborns (gestational age, 39±1 weeks) with a diagnosis of CHD that required cardiac surgery with cardiopulmonary bypass (CPB) were enrolled in the current study. Serum samples were collected immediately prior to surgery and 2, 24 and 48 h following CPB, and serum levels of phosphorylated neurofilament-heavy subunit (pNF-H), neuron-specific enolase (NSE) and S100B were analyzed. Systemic inflammation was assessed by measuring serum concentrations of complement C5a and complement sC5b9, and the following cytokines: Interleukin (IL)-1β, IL-6, IL-8, IL-10, IL12p70, interferon γ and tumor necrosis factor (TNF)-α. Analysis of cord blood from normal term deliveries (n=26) provided surrogate normative values for newborns. pNF-H and S100B were 2.4- to 2.8-fold higher (P<0.0001) in patient sera than in cord blood prior to surgery and remained elevated following CPB. Pre-surgical serum pNF-H and S100B levels directly correlated with interleukin (IL)-12p70 (ρ=0.442, P<0.05). pNF-H was inversely correlated with arterial pO₂ prior to surgery (ρ=−0.493, P=0.01) and directly correlated with arterial pCO₂ post-CPB (ρ=0.426, P<0.05), suggesting that tissue hypoxia and inflammation contribute to blood brain barrier (BBB) dysfunction and neuronal injury. Serum IL12p70, IL-6, IL-8, IL-10 and TNF-α levels were significantly higher in patients than in normal cord blood and levels of these cytokines increased following CPB (P<0.001). Activation of complement was observed in all patients prior to surgery, and serum C5a and sC5b9 remained elevated up to 48 h post-surgery. Furthermore, they were correlated (P<0.05) with low arterial pO₂, high pCO₂ and elevated arterial pressure in the postoperative period. Length of mechanical ventilation was associated directly with post-surgery serum IL-12p70 and IL-8 concentrations (P<0.05). Elevated serum concentrations of pNF-H and S100B in neonates with CHD suggest BBB dysfunction and CNS injury, with concurrent hypoxemia and an activated inflammatory response potentiating this effect.

Neurodevelopmental Abnormalities and Congenital Heart Disease: Insights Into Altered Brain Maturation

In the past 2 decades, it has become evident that individuals born with congenital heart disease (CHD) are at risk of developing life-long neurological deficits. Multifactorial risk factors contributing to neurodevelopmental abnormalities associated with CHD have been identified; however, the underlying causes remain largely unknown, and efforts to address this issue have only recently begun. There has been a dramatic shift in focus from newly acquired brain injuries associated with corrective and palliative heart surgery to antenatal and preoperative factors governing altered brain maturation in CHD. In this review, we describe key time windows of development during which the immature brain is vulnerable to injury. Special emphasis is placed on the dynamic nature of cellular events and how CHD may adversely impact the cellular units and networks necessary for proper cognitive and motor function. In addition, we describe current gaps in knowledge and offer perspectives about what can be done to improve our understanding of neurological deficits in CHD. Ultimately, a multidisciplinary approach will be essential to prevent or improve adverse neurodevelopmental outcomes in individuals surviving CHD.

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.

Non-invasive Assessment of Cerebral Blood Flow and Oxygen Metabolism in Neonates during Hypothermic Cardiopulmonary Bypass: Feasibility and Clinical Implications

The neonatal brain is extremely vulnerable to injury during periods of hypoxia and/or ischemia. Risk of brain injury is increased during neonatal cardiac surgery, where pre-existing hemodynamic instability and metabolic abnormalities are combined with long periods of low cerebral blood flow and/or circulatory arrest. Our understanding of events associated with cerebral hypoxia-ischemia during cardiopulmonary bypass (CPB) remains limited, largely due to inadequate tools to quantify cerebral oxygen delivery and consumption non-invasively and in real-time. This pilot study aims to evaluate cerebral blood flow (CBF) and oxygen metabolism (CMRO₂) intraoperatively in neonates by combining two novel non-invasive optical techniques: frequency-domain near-infrared spectroscopy (FD-NIRS) and diffuse correlation spectroscopy (DCS). CBF and CMRO₂ were quantified before, during and after deep hypothermic cardiopulmonary bypass (CPB) in nine neonates. Our results show significantly decreased CBF and CMRO₂ during hypothermic CPB. More interestingly, a change of coupling between both variables is observed during deep hypothermic CPB in all subjects. Our results are consistent with previous studies using invasive techniques, supporting the concept of FD-NIRS/DCS as a promising technology to monitor cerebral physiology in neonates providing the potential for individual optimization of surgical management.

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.

Laparoscopy in children and its impact on brain oxygenation during routine inguinal hernia repair

BACKGROUND

The systemic impact of intra-abdominal pressure (IAP) and/or changes in carbon dioxide (CO2) during laparoscopy are not yet well defined. Changes in brain oxygenation have been reported as a possible cause of cerebral hypotension and perfusion. The side effects of anaesthesia could also be involved in these changes, especially in children. To date, no data have been reported on brain oxygenation during routine laparoscopy in paediatric patients.

PATIENTS AND METHODS

Brain and peripheral oxygenation were investigated in 10 children (8 male, 2 female) who underwent elective minimally invasive surgery for inguinal hernia repair. Intraoperative transcranial near-infrared spectroscopy to assess regional cerebral oxygen saturation (rScO2), peripheral oxygen saturation using pulse oximetry and heart rate (HR) were monitored at five surgical intervals: Induction of anaesthesia (baseline T1); before CO2insufflation induced pneumoperitoneum (PP) (T2); CO2PP insufflation (T3); cessation of CO2PP (T4); before extubation (T5).

RESULTS

rScO2decreases were recorded immediately after T1 and became significant after insufflation (P = 0.006; rScO2decreased 3.6 ± 0.38%); restoration of rScO2was achieved after PP cessation (P = 0.007). The changes in rScO2were primarily due to IAP increases (P = 0.06). The HR changes were correlated to PP pressure (P < 0.001) and CO2flow rate (P = 0.001). No significant peripheral effects were noted.

CONCLUSIONS

The increase in IAP is a critical determinant in cerebral oxygenation stability during laparoscopic procedures. However, the impact of anaesthesia on adaptive changes should not be underestimated. Close monitoring and close collaboration between the members of the multidisciplinary paediatric team are essential to guarantee the patient's safety during minimally invasive surgical procedures.

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.

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.

Perioperative risk factors for impaired neurodevelopment after cardiac surgery in early infancy

OBJECTIVE

Historical cohort studies have reported adverse neurodevelopment following cardiac surgery during early infancy. Advances in surgical techniques and perioperative care have coincided with updating of neurodevelopmental assessment tools. We aimed to determine perioperative risk factors for impaired neurodevelopment at 2 years following surgery for congenital heart disease (CHD) in early infancy.

DESIGN AND PATIENTS

We undertook a prospective longitudinal study of 153 full-term infants undergoing surgery for CHD before 2 months of age. Infants were excluded if they had a genetic syndrome associated with neurodevelopmental impairment.

OUTCOME MEASURES

Predefined perioperative parameters were recorded and infants were classified according to cardiac anatomy. At 2 years, survivors were assessed using the Bayley Scales of Infant Development-III.

RESULTS

At 2 years, 130 children (98% of survivors) were assessed. Mean cognitive, language and motor scores were 93.4±13.6, 93.6±16.1 and 96.8±12.5 respectively (100±15 norm). Twenty (13%) died and 12 (9%) survivors had severe impairment (score <70), mostly language (8%). The lowest scores were in infants born with single ventricle physiology with obstruction to the pulmonary circulation who required a neonatal systemic-to-pulmonary artery shunt. Additional risk factors for impairment included reduced gestational age, postoperative elevation of lactate or S100B and repeat cardiac surgery.

CONCLUSIONS

In the modern era of infant cardiac surgery and perioperative care, children continue to demonstrate neurodevelopmental delays. The use of updated assessment tools has revealed early language dysfunction and relative sparing of motor function. Ongoing follow-up is critical in this high-risk population.

Assessment of risk factors for cerebral oxygen desaturation during neonatal and infant general anesthesia: an observational, prospective study

Background

Cerebral oxygen saturation (rSO₂c) decrease from baseline greater than 20 % during infant cardiac surgery was associated with postoperative neurologic changes and neurodevelopmental impairment at 1 year of age. So far, there is no sufficient evidence to support the routine monitoring of rSO₂c during general surgical procedures in children. We aimed to find out the frequency of cerebral desaturation 20 % or more from baseline and to identify possible predictors of change in cerebral oxygen saturation during neonatal and infant general surgery.

Methods

Forty-four infants up to 3 months of age were recruited. Before induction of anesthesia, two pediatric cerebral sensors were placed bilaterally to the forehead region and monitoring of regional cerebral saturation of oxygen was started and continued throughout the surgery. Simultaneously, mean arterial blood pressure (MAP), pulse oximetry (SpO₂), heart rate (HR), endtidal CO₂, expired fraction of sevoflurane and rectal temperature were recorded. The main outcome measure was rSO₂c value drop-off ≥20 % from baseline. Mann-Whitney U-test, chi-squared test, simple and multiple linear regression models were used for statistical analysis.

Results

Forty-three infants were analyzed. Drop-off ≥20 % in rSO₂c from baseline occurred in 8 (18.6 %) patients. There were no differences in basal rSO₂c, SpO₂, HR, endtidal CO₂, expired fraction of sevoflurane and rectal temperature between patients with and without desaturation 20 % or more from baseline. But the two groups differed with regard to gestation, preoperative mechanical ventilation and the use of vasoactive medications and red blood cell transfusions during surgery. Simple linear regression model showed, that gestation, age, preoperative mechanical ventilation and mean arterial pressure corresponding to minimal rSO₂c value during anesthesia (MAP_minrSO2c) were associated with a change in rSO₂c values. Multiple regression model including all above mentioned variables, revealed that only MAP_minrSO2c was predictive for a change in rSO₂c values (β (95 % confidence interval) -0.28 (−0.52–(−0.04)) p = 0.02).

Conclusions

Cerebral oxygen desaturation ≥20 % from baseline occurred in almost one fifth of patients. Although different perioperative factors can predispose to cerebral oxygenation changes, arterial blood pressure seems to be the most important. Gestation as another possible risk factor needs further investigation.

Trial registration

The international registration number NCT02423369. Retrospectively registered on April 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-016-0274-2) contains supplementary material, which is available to authorized users.

Hemodynamic Monitoring in the Acute Management of Pediatric Heart Failure

One of the basic tenets of cardiac critical care is to ensure adequate tissue oxygenation. As with other critical illness such as trauma and acute myocardial infarction studies have demonstrated that making the right diagnosis at the right time improves outcomes. The same is true for the management of patients at risk for or in a state of shock. In order to optimize outcomes an accurate and timely assessment of cardiac function, cardiac output and tissue oxygenation must be made. This review discusses the limitations of the standard assessment of cardiovascular function, and adjunctive monitoring modalities that may be used to enhance the accuracy and timely implementation of therapeutic strategies to improve tissue oxygenation.

Transposition of the Great Arteries and Common Variants

OBJECTIVES

The objectives of this review are to discuss the physiology, perioperative management, surgical correction, and outcomes of infants with transposition of the great arteries and common variants undergoing the arterial switch operation.

DATA SOURCE

MEDLINE and PubMed.

CONCLUSION

The widespread adoption of the arterial switch operation for transposition of great arteries has been one of the more gratifying advances in pediatric cardiovascular care, and represents the simultaneous improvements in diagnostics, surgical and bypass techniques, anesthesia in the neonate, improvements in intensive care technology, nursing strategies, and system-wide care delivery. Many of the strategies adopted for the neonate with transposition of the great arteries have been translated to neonatal care for other congenital heart lesions. Continued work is necessary to investigate the effects of perioperative care on long-term neurodevelopmental outcomes, as well as collaboration between centers to spread "best practices" for outcome, cost, and morbidity reduction.

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.

Goal-directed-perfusion in neonatal aortic arch surgery

Reduction of mortality and morbidity in congenital cardiac surgery has always been and remains a major target for the complete team involved. As operative techniques are more and more standardized and refined, surgical risk and associated complication rates have constantly been reduced to an acceptable level but are both still present. Aortic arch surgery in neonates seems to be of particular interest, because perfusion techniques differ widely among institutions and an ideal form of a so called "total body perfusion (TBP)" is somewhat difficult to achieve. Thus concepts of deep hypothermic circulatory arrest (DHCA), regional cerebral perfusion (RCP/with cardioplegic cardiac arrest or on the perfused beating heart) and TBP exist in parallel and all carry an individual risk for organ damage related to perfusion management, chosen core temperature and time on bypass. Patient safety relies more and more on adequate end organ perfusion on cardiopulmonary bypass, especially sensitive organs like the brain, heart, kidney, liver and the gut, whereby on adequate tissue protection, temperature management and oxygen delivery should be visualized and monitored.

Mesenteric near-infrared spectroscopy and risk of gastrointestinal complications in infants undergoing surgery for congenital heart disease

We hypothesised that lower mesenteric near-infrared spectroscopy values would be associated with a greater incidence of gastrointestinal complications in children weighing <10 kg who were recovering from cardiac surgery. We evaluated mesenteric near-infrared spectroscopy, central venous oxygen saturation, and arterial blood gases for 48 hours post-operatively. Enteral feeding intake, gastrointestinal complications, and markers of organ dysfunction were monitored for 7 days. A total of 50 children, with median age of 16.7 (3.2-31.6) weeks, were studied. On admission, the average mesenteric near-infrared spectroscopy value was 71±18%, and the systemic oxygen saturation was 93±7.5%. Lower admission mesenteric near-infrared spectroscopy correlated with longer time to establish enteral feeds (r=-0.58, p<0.01) and shorter duration of feeds at 7 days (r=0.48, p<0.01). Children with gastrointestinal complications had significantly lower admission mesenteric near-infrared spectroscopy (58±18% versus 73±17%, p=0.01) and higher mesenteric arteriovenous difference of oxygen at admission [39 (23-47) % versus 19 (4-27) %, p=0.02]. Based on multiple logistic regression, admission mesenteric near-infrared spectroscopy was independently associated with gastrointestinal complications (Odds ratio, 0.95; 95% confidence interval, 0.93-0.97; p=0.03). Admission mesenteric near-infrared spectroscopy showed an area under the receiver operating characteristic curve of 0.76 to identify children who developed gastrointestinal complications, with a suggested cut-off value of 72% (78% sensitivity, 68% specificity). In this pilot study, we conclude that admission mesenteric near-infrared spectroscopy is associated with gastrointestinal complications and enteral feeding tolerance in children after cardiac surgery.

Perioperative use of cerebral and renal near-infrared spectroscopy in neonates: a 24-h observational study

BACKGROUND

Neonates undergoing surgery and intensive care still carry a significant morbidity and mortality often related to hypoxic/ischemic events; some of which may go undetected by conventional monitoring. Near-infrared spectroscopy (NIRS) is a noninvasive, continuous method of measuring regional tissue oxygen saturation, and may be used to supplement conventional monitoring to improve neonatal perioperative care. However, high costs and lack of evidence regarding improved outcomes have minimized wider perinatal use of NIRS. The aim of this study was to investigate the applicability of NIRS in neonates and premature infants undergoing noncardiac surgeries.

METHOD

Neonates were monitored with both cerebral and renal NIRS for 24 h after induction of anesthesia and compared with systemic blood pressure (BP), peripheral oxygen saturation (SpO2 ), and heart rate (HR).

RESULTS

A total of 23 368 min of data were collected from 21 neonates. NIRS reported cerebral/renal hypoxia 2.8 (±8.3)%/19.3 (±25.4)% of the time intraoperatively and 9.6 (±17.0)%/9.9 (±18.9)% of the time postoperatively. A moderate positive correlation was found between SpO2 and NIRS (φcerebral = 0.371, φrenal = 0.542). BP showed a weaker positive correlation (φcerebral = 0.231, φrenal = 0.246), and HR no correlation (φcerebral = -0.083, φrenal = -0.029). NIRS reported hypoxia two to three times more frequently than SpO2 , and SpO2 readings were 10-15 s delayed compared to NIRS. Furthermore, NIRS appeared effective at detecting postoperative apnea.

CONCLUSION

Near-infrared spectroscopy is an easily applicable technique that appears effective at detecting hypoxic events and postoperative apneas in neonates. The high incidences of regional hypoxia reported by NIRS in this study imply that there is a need for a more specific regional cerebral and renal monitoring. Despite some practical and economical limitations, NIRS may be considered a useful supplement to perinatal perioperative intensive care.

Cerebral oxygen saturation and tissue hemoglobin concentration as predictive markers of early postoperative outcomes after pediatric cardiac surgery

BACKGROUND

Near-infrared spectroscopy (NIRS) provides an assessment of cerebral oxygenation and tissue hemoglobin concentration.

AIM

The aim of this study was to investigate whether the cerebral oxygenation and hemoglobin concentration measured with NIRS could predict outcomes after pediatric cardiac surgery.

METHOD

We conducted a retrospective observational study in 399 patients who underwent pediatric cardiac surgery. Associations were determined between postoperative outcome and preoperative and postoperative cerebral tissue oxygenation index (TOI), postoperative normalized tissue hemoglobin index (nTHI), concentration changes in oxygenated hemoglobin (Δ[HbO2 ]) and deoxygenated hemoglobin (Δ[HHb]).

RESULTS

Thirty-nine children had major postoperative morbidity and 12 died. Using Spearman's correlation analysis, postoperative lower TOI and higher Δ[HHb] were associated with longer stays in the Intensive Care Unit (ICU) (r = -0.48, P < 0.001, r = 0.31, P < 0.001, respectively) and longer duration of intubation (r = -0.48, P < 0.001, r = 0.31, P < 0.001, respectively) and higher probability of death determined by the Risk Adjusted Classification for Congenital Heart Surgery (RACHS-1) (r = -0.39, P < 0.001, r = 0.23, P < 0.001, respectively). In multivariate regression analysis, postoperative TOI was independently associated with major morbidity and mortality and Δ[HHb] was independently associated with major morbidity. In receiver operating characteristic analysis, postoperative TOI and Δ[HHb] predicted major morbidity (Area under the curve [AUC] = 0.72, 0.68, respectively) and mortality (AUC = 0.81, 0.69, respectively).

CONCLUSION

Lower TOI or higher [HHb] at the end of surgery and higher RACHS-1 category predicted worse outcomes.

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.

Effect of Intercurrent Operation and Cerebral Oxygenation on Developmental Trajectory in Congenital Heart Disease

BACKGROUND

Children with congenital heart disease are at increased risk of abnormal neurodevelopment (ND). Demographic and perioperative physiologic factors have both been associated with developmental outcome. The acute physiologic effect of a surgical procedure, anesthesia, and hospitalization may offset any potential advantage gained from anatomic correction and circulatory palliation. The specific risk/benefit balance on ND outcome of the insult of the operation, offset by the benefit of improved anatomy and physiology, has not been addressed. We therefore sought to identify interval procedural and physiologic factors assessed at outpatient ND evaluation visits that were associated with outcome.

METHODS

The study included children with congenital heart disease at high risk for impaired ND performance with at least three ND assessments using the Bayley Scales of Infant Development-III during the first 3 years of life. The number of cardiac procedures, duration of hospitalization, feeding status, height, weight, and arterial, cerebral, and somatic oxygen saturations by near-infrared spectroscopy were recorded at each visit and used as predictors of language, motor, and cognitive composite scores and slopes (change over time) in general linear models.

RESULTS

Data on 178 children derived from 632 visits (median, 4 visits/child) were analyzed, with ages at first and last assessment of 7.7 and 30.2 months. Fifty-one had 1 ventricle (1V), 88 had 2 ventricles, and 39 had genetic syndrome conditions. Motor performance increased with age in all diagnostic categories. Cognitive and language performance increased with age in 1V patients but exhibited no significant change in 2-ventricle and genetic syndrome groups. At the first visit, 1V patients performed less well than 2-ventricle patients in the motor domain, but the rate of improvement was higher for 1V patients; by 24 months, there were no differences, and both groups were normal in all domains. Performance in genetic syndrome patients was below normal in all domains at the first visit and did not improve. Higher arterial saturation and narrower arterial-cerebral and arterial-somatic near-infrared spectroscopy saturation differences were associated with better or improving motor performance. Incremental cardiopulmonary bypass time, cumulative hospital length of stay, and tube feedings were risk factors in all domains. Total and incremental times for deep hypothermic circulatory arrest, extracorporeal membrane oxygenation, total open and total surgical procedures, and birth weight were not risk factors.

CONCLUSIONS

Patient physiologic status assessed by cerebral and somatic near-infrared spectroscopy is associated with ND performance. Incremental surgical procedures are not associated with ND performance when adjusted for cardiopulmonary bypass time and physiologic status. Treatment strategies that target improved physiologic status may also improve ND outcome.

Neonatal brain oxygenation during thoracoscopic correction of esophageal atresia

Background

Little is known about the effects of carbon dioxide (CO₂) insufflation on cerebral oxygenation during thoracoscopy in neonates. Near-infrared spectroscopy can measure perioperative brain oxygenation [regional cerebral oxygen saturation (rScO₂)].

Aims

To evaluate the effects of CO₂ insufflation on rScO₂ during thoracoscopic esophageal atresia (EA) repair.

Methods

This is an observational study during thoracoscopic EA repair with 5 mmHg CO₂ insufflation pressure. Mean arterial blood pressure (MABP), arterial oxygen saturation (SaO₂), partial pressure of arterial carbon dioxide (paCO₂), pH, and rScO₂ were monitored in 15 neonates at seven time points: baseline (T0), after anesthesia induction (T1), after CO₂-insufflation (T2), before CO₂-exsufflation (T3), and postoperatively at 6 (T4), 12 (T5), and 24 h (T6).

Results

MABP remained stable. SaO₂ decreased from T0 to T2 [97 ± 3–90 ± 6 % (p < 0.01)]. PaCO₂ increased from T0 to T2 [41 ± 6–54 ± 15 mmHg (p < 0.01)]. pH decreased from T0 to T2 [7.33 ± 0.04–7.25 ± 0.11 (p < 0.05)]. All parameters recovered during the surgical course. Mean rScO₂ was significantly higher at T1 compared to T2 [77 ± 10–73 ± 7 % (p < 0.05)]. Mean rScO₂ levels never dropped below a safety threshold of 55 %.

Conclusion

The impact of neonatal thoracoscopic repair of EA with insufflation of CO₂ at 5 mmHg was studied. Intrathoracic CO₂ insufflation caused a reversible decrease in SaO₂ and pH and an increase in paCO₂. The rScO₂ was higher at anesthesia induction but remained stable and within normal limits during and after the CO₂ pneumothorax, which suggest no hampering of cerebral oxygenation by the thoracoscopic intervention. Future studies will focus on the long-term effects of this surgery on the developing brain.

Perioperative and Anesthetic Considerations in Ebstein’s Anomaly

Ebstein’s anomaly is a complex and heterogeneous form of congenital heart disease characterized by malformation and apical displacement of the tricuspid valve leaflets. Patients may present at any time from the neonatal period to adulthood with symptoms ranging from cardiac failure and cyanosis to paroxysmal arrhythmias. Depending on the timing of presentation, various surgical options are available for the management of symptomatic patients. This review will discuss the perioperative and anesthetic management of patients with Ebstein’s anomaly with reference to the more common surgical approaches.

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.

Intraoperative changes in blood pressure associated with cerebral desaturation in infants

BACKGROUND

Intraoperative hypotension has been linked to poor postoperative neurological outcomes. However, the definition of hypotension remains controversial in children. We sought to determine arterial blood pressure threshold values associated with cerebral desaturation in infants.

METHODS

After ethics committee approval, infants younger than 3 months were included in this prospective observational study. Cerebral saturation was assessed using near-infrared spectroscopy. The primary goal of the study was to determine percentage reductions in intraoperative systolic blood pressure (SBP) and mean blood pressure (MBP) associated with decreases in cerebral blood oxygen saturation of >20%, when compared to baseline. Analyses were performed using a bootstrap receiving operator characteristic (ROC) curves with determination of the gray zone.

RESULTS

Sixty patients were recruited and 960 measurement points were recorded. Fifty-nine data points (6.1%) recorded cerebral desaturation of >20% when compared to baseline. The areas under the ROC curves were 0.79 (0.74-0.84) and 0.67 (0.6-0.75) for percentage decreases in SBP and MBP, respectively. Gray zone values with false-positive and negative rates <10% were SBP decreases of 20.5% and 37.5%, respectively, and MBP decreases of 15.5% and 44.5%, respectively.

CONCLUSION

Our results indicate that falls in noninvasive systolic blood pressure of <20% from baseline are associated with a <10% chance of cerebral desaturation in neonates and infants <3 months of age undergoing noncardiac surgery. As such, maintaining systolic blood pressure above this threshold value appears a valid clinical target.

Congenital cardiac anomalies and white matter injury

Cardiac abnormalities are the most common birth defects. Derangement of circulatory flow affects many vital organs; without proper supply of oxygenated blood, the brain is particularly vulnerable. Although surgical interventions have greatly reduced mortality rates, patients often suffer an array of neurological deficits throughout life. Neuroimaging provides a macroscopic assessment of brain injury and has shown that white matter (WM) is at risk. Oligodendrocytes and myelinated axons have been identified as major targets of WM injury, but still little is known about how congenital heart anomalies affect the brain at the cellular level. Further integration of animal model studies and clinical research will define novel therapeutic targets and new standards of care to prevent developmental delay associated with cardiac abnormalities.

Optimal chest compression technique for paediatric cardiac arrest victims

BACKGROUND

The aim of this study was to assess the quality of chest compressions performed by inexperienced rescuers using three different techniques: two-hand, right one-hand, and left one-hand.

METHODS

We performed a prospective, randomised, crossover study in a simulated 6-year-old paediatric manikin model. Each participant performed 2-minute continuous chest compressions, using three different techniques. Chest compression quality data, including compression rate, compression depth, and residual leaning was recorded by a Q-CPR™ compression sensor connected to HeartStart MRx (Philips Healthcare, Andover, MA, USA). To examine trends in chest compression performance over time, each 2-minute period was divided into six consecutive 20-second epochs.

RESULTS

The 36 participants completed 108 two-minute trials, consisting of a total of 25,030 compressions. The mean compression rates [95% confidence interval] were as follows: two-hand, 116.8 [111.7-121.9]; left one-hand, 115.0 [109.9-120.1]; and right one-hand, 115.5 [110.4-120.6] (p = 0.565). The mean compression depth for two-hand was 38.7 mm (37.1-40.2), which was higher than for left one-hand (36.3 mm [34.8-37.9]) or right one-hand (35.4 mm [33.9-37.0]) (p < 0.001). Chest compression depth declined over time, regardless of the technique (p < 0.001). The pattern of compression depth change over time was similar for all techniques (p > 0.999). The residual leaning rate was higher with two-hand (40.7 [27.9-53.5]) than that for left one-hand (29.2 [16.4-42.0]) or right one-hand (25.8 [13.0-38.6]) (p = 0.021).

CONCLUSIONS

For paediatric cardiopulmonary resuscitation by inexperienced rescuers, the two-hand technique has the advantage of producing deeper compressions than the one-hand technique, but it is accompanied by more frequent residual leaning. For the one-hand techniques, the right and left hand produced chest compressions of similar quality.

[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.

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.

All this monitoring…what's necessary, what's not?

The goal of perioperative monitoring is to aid the clinician in optimizing care to achieve the best possible survival with the lowest possible morbidity. Ideally, we would like to have monitoring that can rapidly and accurately identify perturbations in circulatory well-being that would permit timely intervention and allow for restoration before the patient is damaged. The evidence to support the use of our standard monitoring strategies (continuous electrocardiography, blood pressure, central venous pressure, oxygen saturation and capnography) is based on expert opinion, case series, or at best observational studies. While these monitoring parameters will identify life-threatening events, they provide no direct information concerning the oxygen economy of the patient. Nevertheless, they are mandated by professional societies representing specialists in cardiac disease, critical care, and anesthesiology. Additional non-routine monitoring strategies that provide data concerning the body's oxygen economy, such as venous saturation monitoring and near infrared spectroscopy, have shown promise in prospective observational studies in managing these complex groups of patients. Ideally, high-level evidence would be required before adopting these newer strategies, but in the absence of new funding sources and the challenges of the wide variation in practice patterns between centers, this seems unlikely. The evidence supporting the current standard perioperative monitoring strategies will be reviewed. In addition, evidence supporting non-routine monitoring strategies will be reviewed and their potential for added benefit assessed.

D-transposition of the great arteries: the current era of the arterial switch operation

This paper aims to update clinicians on "hot topics" in the management of patients with D-loop transposition of the great arteries (D-TGA) in the current surgical era. The arterial switch operation (ASO) has replaced atrial switch procedures for D-TGA, and 90% of patients now reach adulthood. The Adult Congenital and Pediatric Cardiology Council of the American College of Cardiology assembled a team of experts to summarize current knowledge on genetics, pre-natal diagnosis, surgical timing, balloon atrial septostomy, prostaglandin E1 therapy, intraoperative techniques, imaging, coronary obstruction, arrhythmias, sudden death, neoaortic regurgitation and dilation, neurodevelopmental (ND) issues, and lifelong care of D-TGA patients. In simple D-TGA: 1) familial recurrence risk is low; 2) children diagnosed pre-natally have improved cognitive skills compared with those diagnosed post-natally; 3) echocardiography helps to identify risk factors; 4) routine use of BAS and prostaglandin E1 may not be indicated in all cases; 5) early ASO improves outcomes and reduces costs with a low mortality; 6) single or intramural coronary arteries remain risk factors; 7) post-ASO arrhythmias and cardiac dysfunction should raise suspicion of coronary insufficiency; 8) coronary insufficiency and arrhythmias are rare but are associated with sudden death; 9) early- and late-onset ND abnormalities are common; 10) aortic regurgitation and aortic root dilation are well tolerated; and 11) the aging ASO patient may benefit from "exercise-prescription" rather than restriction. Significant strides have been made in understanding risk factors for cardiac, ND, and other important clinical outcomes after ASO.

Study protocol for the PHANTOM study: prehospital assessment of noninvasive tissue oximetry monitoring

BACKGROUND

Traumatic brain injury is a major cause of mortality and morbidity worldwide. It can be worsened by secondary injury particularly with hypoxia or hypotension. Current prehospital guidelines emphasise regular measurement of peripheral oxygen saturation and blood pressure but there is no monitor in use to provide direct information relating to blood flow or oxygen delivery to the brain tissue. This prospective cohort study will assess the utility of near-infrared spectroscopy monitoring in prehospital medicine in demonstrating injury, pathophysiology and associations with long-term functional outcomes.

METHODS/DESIGN

A prospective cohort study will be conducted in prehospital services where physician/paramedic teams respond rapidly to patients suffering significant traumatic injuries. A study observer accompanying the clinical team will apply non-invasive near-infrared spectroscopy tissue oximetry using a Nonin EQUANOX 7610 Regional Oximetry monitor (TM Nonin Medical, Inc.). This will be applied to patients with traumatic injuries less than 30 minutes old requiring transport. Measurements will be taken at two sites on the forehead and one on the forearm. Clinical teams will be blinded to all monitoring values. Near-infrared spectroscopy tissue oximetry parameters of oxyhaemoglobin%, deoxyhaemoglobin%, total tissue haemoglobin index and regional oxygen saturation will be recorded. Separate statistical analysis relating to time spent with cerebral regional oxygen saturation values < 45% and time series analysis will be performed to demonstrate associations with acute phase outcomes including injuries seen on cerebral imaging, and long-term functional outcomes measured by Glasgow Outcome Score and Extended Glasgow Outcome Score will then be undertaken.

DISCUSSION

This prospective cohort study will demonstrate associations evident from the earliest stages of prehospital treatment between near-infrared spectroscopy tissue oximetry values and both acute and long-term outcomes of patients suffering traumatic injuries. This may provide the basis for future interventional studies utilising near-infrared spectroscopy tissue oximetry to guide prehospital trauma care.

TRIAL REGISTRATION

This trial is registered with the Australian and New Zealand Clinical Trials Registry. The registration number is ACTRN12611001124921 .

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.

Cerebral blood flow velocity and neurodevelopmental outcome in infants undergoing surgery for congenital heart disease

BACKGROUND

Cerebral blood flow velocity (CBFV) measured by transcranial Doppler sonography has provided information on cerebral perfusion in patients undergoing infant heart surgery, but no studies have reported a relationship to early postoperative and long-term neurodevelopmental outcomes.

METHODS

CBFV was measured in infants undergoing biventricular repair without aortic arch reconstruction as part of a trial of hemodilution during cardiopulmonary bypass (CPB); CBFV (Vm, mean; Vs, systolic; Vd, end-diastolic) in the middle cerebral artery and change in Vm (rVm) were measured intraoperatively and up to 18 hours post-CPB. Neurodevelopmental outcomes, measured at 1 year of age, included the psychomotor development index (PDI) and mental development index (MDI) of the Bayley Scales of Infant Development-II.

RESULTS

CBFV was measured in 100 infants; 43 with D-transposition of the great arteries, 36 with tetralogy of Fallot, and 21 with ventricular septal defects. Lower Vm, Vs, Vd, and rVm at 18 hours post-CPB were independently related to longer intensive care unit duration of stay (p<0.05). In the 85 patients who returned for neurodevelopmental testing, lower Vm, Vs, Vd, and rVm at 18 hours post-CPB were independently associated with lower PDI (p<0.05) and MDI (p<0.05, except Vs: p=0.06) scores. Higher Vs and rVm at 18 hours post-CPB were independently associated with increased incidence of brain injury on magnetic resonance imaging in 39 patients.

CONCLUSIONS

Postoperative CBFV after biventricular repair is related to early postoperative and neurodevelopmental outcomes at 1 year of age, possibly indicating that low CBFV is a marker of suboptimal postoperative hemodynamics and cerebral perfusion.

Effect of cerebral circulatory arrest on cerebral near-infrared spectroscopy in pediatric patients

BACKGROUND/AIMS

The aim was to investigate whether cerebral transcutaneous near-infrared spectroscopy (NIRS) or two-site NIRS is a suitable monitoring tool to detect or confirm a cerebral circulatory arrest in pediatric intensive care unit (PICU) patients.

METHODS

Prospective single-center pediatric observational study. Simultaneous NIRS measurements over forehead (cNIRS, crS02) and kidney (rNIRS, rrSO2), at the same time, the cardiac output were determined by transthoracic echocardiography. Area under the curve (AUC) in the receiver-operating curve (ROC) was analyzed for NIRS regarding cerebral circulatory arrest.

RESULTS

There were two groups of patients (weight 2.1-73 kg): Group A: patients with intact cerebral perfusion (n = 36). Group B: patients with cerebral circulatory arrest (n = 8) proven by Doppler ultrasound scan or perfusion scintigraphy. There was no difference in cardiac output between the groups. PICU mortality for Group A was 3/36 (8.3%), for Group B 8/8, (100%). Mean cNIRS values were significantly higher with 68.92 (SEM = 2.54, SD = 15.25) in Group A compared with 34.63 (SEM = 5.36, SD = 15.15) in Group B (P < 0.001). ROC analysis for cNIRS detecting cerebral circulatory arrest was significant (AUC 0.948, 95% confidence interval 0.876-1.000, SE = 0.037, P < 0.001). Discrimination was optimal at 46 for cNIRS, at 36.5 for the difference rNIRS-cNIRS and at 0.5646 for the quotient cNIRS/rNIRS. The probability of a cerebral circulatory arrest was 77.8% (cNIRS) and 87.5% (combinations of cNIRS and rNIRS) at these cutoffs.

CONCLUSIONS

cNIRS did detect cerebral circulatory arrest with high sensitivity. Specificity was, however, not high enough to confirm a cerebral circulatory arrest.

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.