Arginine-NO metabolites are associated with morbidity in single ventricle infants undergoing stage 2 palliation.

BACKGROUND: Infants with single ventricle heart disease (SVHD) suffer morbidity from insufficient pulmonary blood flow, which may be related to impaired arginine metabolism. No prior study has reported quantitative mapping of arginine metabolites to evaluate the relationship between circulating metabolite levels and outcomes. METHODS: Prospective cohort study of 75 SVHD cases peri-Stage 2 and 50 healthy controls. We targeted pre- and post-op absolute serum quantification of 9 key members of the arginine metabolism pathway by tandem mass spectrometry. Primary outcomes were length of stay (LOS) and post-Stage 2 hypoxemia. RESULTS: Pre-op cases showed alteration in 6 metabolites including decreased arginine and increased asymmetric dimethyl arginine (ADMA) levels compared to controls. Post-op cases demonstrated decreased arginine and citrulline levels persisting through 48 h. Adjusting for clinical variables, lower pre-op and 2 h post-op concentrations of multiple metabolites, including arginine and citrulline, were associated with longer post-op LOS (p < 0.01). Increased ADMA at 24 h was associated with greater post-op hypoxemia burden (p < 0.05). CONCLUSION: Arginine metabolism is impaired in interstage SVHD infants and is further deranged following Stage 2 palliation. Patients with greater metabolite alterations experience greater post-op morbidity. Decreased arginine metabolism may be an important driver of pathology in SVHD. IMPACT: Interstage infants with SVHD have significantly altered arginine-nitric oxide metabolism compared to healthy children with deficiency of multiple pathway intermediates persisting through 48 h post-Stage 2 palliation. After controlling for clinical covariates and classic catheterization-derived predictors of Stage 2 readiness, both lower pre-operation and lower post-operation circulating metabolite levels were associated with longer post-Stage 2 LOS while increased post-Stage 2 ADMA concentration was associated with greater post-op hypoxemia. Arginine metabolism mapping offers potential for development using personalized medicine strategies as a biomarker of Stage 2 readiness and therapeutic target to improve pulmonary vascular health in infants with SVHD.

A novel, cassette-based nitric oxide delivery system with an advanced feedback control algorithm accurately delivers nitric oxide via the anesthesia machine independent of fresh gas flow rate and volatile anesthetic agent.

Nitric oxide (NO), a selective pulmonary vasodilator, can be delivered via conventional ICU and anesthesia machine ventilators. Anesthesia machines are designed for rebreathing of circulating gases, reducing volatile anesthetic agent quantity used. Current cylinder- and ionizing-based NO delivery technologies use breathing circuit flow to determine NO delivery and do not account for recirculated gases; therefore, they cannot accurately dose NO at FGF below patient minute ventilation (MV). A novel, cassette-based NO delivery system (GENOSYL® DS, Vero Biotech Inc.) uses measured NO concentration in the breathing circuit as an input to an advanced feedback control algorithm, providing accurate NO delivery regardless of FGF and recirculation of gases. This study evaluated GENOSYL® DS accuracy with different anesthesia machines, ventilation parameters, FGFs, and volatile anesthetics. GENOSYL® DS was tested with GE Aisys and Dräger Fabius anesthesia machines to determine NO dose accuracy with FGF < patient MV, and with a Getinge Flow-i anesthesia machine to determine NO dose accuracy when delivering various volatile anesthetic agents. Neonatal and adult mechanical ventilation parameters and circuits were used. GENOSYL® DS maintained accurate NO delivery with all three anesthesia machines, at low FGF with recirculation of gases, and with all volatile anesthetic agents at different concentrations. Measured NO2 levels remained acceptable at ≤ 1 ppm with set NO dose ≤ 40 ppm. GENOSYL® DS, with its advanced feedback control algorithm, is the only NO delivery system capable of accurately dosing NO with anesthesia machines with rebreathing ventilation parameters (FGF < MV) regardless of anesthetic agent.

The Practice of Pediatric Cardiac Anesthesiology in the United States.

BACKGROUND: With advances in surgical and catheter-based interventions and technologies in patients with congenital heart disease (CHD), the practice of pediatric cardiac anesthesiology has evolved in parallel with pediatric cardiac surgery and pediatric cardiology as a distinct subspecialty over the past 80 years. To date, there has not been an analysis of the distribution of pediatric cardiac anesthesiologists relative to cardiac and noncardiac procedures in the pediatric population. The primary aim is to report the results of a survey and its subsequent analysis to describe the distribution of pediatric cardiac anesthesiologists relative to pediatric cardiac procedures that include surgical interventions, cardiac catheterization procedures, imaging studies (echocardiography, magnetic resonance, computed tomography, positron emission tomography), and noncardiac procedures. METHODS: A survey developed in Research Electronic Data Capture (REDcap) was sent to the identifiable division chiefs/cardiac directors of 113 pediatric cardiac anesthesia programs in the United States. Data regarding cardiac surgical patients and procedures were collected from the Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHD). RESULTS: This analysis reveals that only 38% (117 of 307) of pediatric cardiac anesthesiologists caring for patients with CHD pursued additional training in pediatric cardiac anesthesiology, while 44% (136 of 307) have gained experience during their clinical practice. Other providers have pursued different training pathways such as adult cardiac anesthesiology or pediatric critical care. Based on this survey, pediatric cardiac anesthesiologists devote 35% (interquartile range [IQR], 20%-50%) of clinical time to the care of patients in the cardiac operating room, 25% (20%-35%) of time to the care of patients in the cardiac catheterization laboratory, 10% (5%-10%) to patient care in imaging locations, and 15% covering general pediatric, adult, or cardiac patients undergoing noncardiac procedures. Attempts to actively recruit pediatric cardiac anesthesiologists were reported by 49.2% (29 of 59) of the institutions surveyed. Impending retirement of staff was anticipated in 17% (10 of 59) of the institutions, while loss of staff to relocation was anticipated in 3.4% (2 of 59) of institutions. Thirty-seven percent of institutions reported that they anticipated no immediate changes in current staffing levels. CONCLUSIONS: The majority of currently practicing pediatric cardiac anesthesiologists have not completed a fellowship training in the subspecialty. There is, and will continue to be, a need for subspecialty training to meet increasing demand for services especially with increase survival of this patient population and to replace retiring members of the workforce.

Serum metabolic profile of postoperative acute kidney injury following infant cardiac surgery with cardiopulmonary bypass.

BACKGROUND: We sought to determine differences in the circulating metabolic profile of infants with or without acute kidney injury (AKI) following cardiothoracic surgery with cardiopulmonary bypass (CPB). METHODS: We performed a secondary analysis of preoperative and 24-h postoperative serum samples from infants ≤ 120 days old undergoing CPB. Metabolic profiling of the serum samples was performed by targeted analysis of 165 serum metabolites via tandem mass spectrometry. We then compared infants who did or did not develop AKI in the first 72 h postoperatively to determine global differences in the preoperative and 24-h metabolic profiles in addition to specific differences in individual metabolites. RESULTS: A total of 57 infants were included in the study. Six infants (11%) developed KDIGO stage 2/3 AKI and 13 (23%) developed stage 1 AKI. The preoperative metabolic profile did not differentiate between infants with or without AKI. Infants with severe AKI could be moderately distinguished from infants without AKI by their 24-h metabolic profile, while infants with stage 1 AKI segregated into two groups, overlapping with either the no AKI or severe AKI groups. Differences in these 24-h metabolic profiles were driven by 21 metabolites significant at an adjusted false discovery rate of < 0.05. Prominently altered pathways include purine, methionine, and kynurenine/nicotinamide metabolism. CONCLUSION: Moderate-to-severe AKI after infant cardiac surgery is associated with changes in the serum metabolome, including prominent changes to purine, methionine, and kynurenine/nicotinamide metabolism. A portion of infants with mild AKI demonstrated similar metabolic changes, suggesting a potential role for metabolic analysis in the evaluation of lower stage injury.

Use of compressed sensing to reduce scan time and breath-holding for cardiac cine balanced steady-state free precession magnetic resonance imaging in children and young adults.

BACKGROUND: Conventional pediatric volumetric MRI acquisitions of a short-axis stack typically require multiple breath-holds under anesthesia. OBJECTIVE: Here, we aimed to validate a vendor-optimized compressed-sensing approach to reduce scan time during short-axis balanced steady-state free precession (bSSFP) cine imaging. MATERIALS AND METHODS: Imaging was performed in 28 patients (16±9 years) in this study on a commercial 3-tesla (T) scanner using retrospective electrocardiogram-gated cine bSSFP. Cine short-axis images covering both ventricles were acquired with conventional parallel imaging and a vendor-optimized parallel imaging/compressed-sensing approach. Qualitative Likert scoring for blood-myocardial contrast, edge definition, and presence of artifact was performed by two experienced radiologists. Quantitative comparisons were performed including biventricular size and function. A paired t-test was used to detect significant differences (P<0.05). RESULTS: Scan duration was 7±2 s/slice for conventional imaging (147±33 s total) vs. 4±2 s/slice for compressed sensing (83±28 s total). No significant differences were found with qualitative image scores for blood-myocardial contrast, edge definition, and presence of artifact. No significant differences were found in volumetric analysis between the two sequences. The number of breath-holds was 10±4 for conventional imaging and 5±3 for compressed sensing. CONCLUSION: Compressed sensing allowed for a 50% reduction in the number of breath-holds and a 43% reduction in the total scan time without differences in the qualitative or quantitative measurements as compared to the conventional technique.

Activation of kynurenine pathway of tryptophan metabolism after infant cardiac surgery with cardiopulmonary bypass: a prospective cohort study.

BACKGROUND: Serum kynurenic acid is associated with poor outcomes after infant cardiopulmonary bypass (CPB), but comprehensive mapping of the kynurenine pathway (KP) after CPB has yet to be performed. AIMS: To map changes in the KP induced by infant CPB. METHODS: Compared changes in serum KP metabolites through 48hrs post-op with liquid-chromatography-tandem mass spectrometry. RESULTS: Infant CPB results in marked increase in proximal, but not distal metabolites of the KP. CONCLUSIONS: Infant CPB leads to accumulation of circulating KP metabolites, which have important neurologic and immunologic activities. Thus, further exploration of the KP is warranted in these high-risk infants.

Williams syndrome.

Williams syndrome affects approximately one in 10 000 people and is caused by the deletion of genes on chromosome 7q11.23 which code for elastin. The phenotypic appearance of people with Williams syndrome is well characterized, but there continues to be new genetic and therapeutic discoveries. Patients with Williams syndrome have increased morbidity and mortality under sedation and anesthesia, largely as a result of cardiovascular abnormalities. This review article focuses on new information about Williams syndrome and outlines a structured approach to patients with Williams syndrome in the perioperative period.

Vascular anatomical considerations and clinical decision making during insertion of the Avalon® Elite Dual Lumen single-site veno-venous ECMO cannula in children weighing less than 20 kg.

The correct selection and placement of a single-site Avalon® Elite Dual Lumen Cannula for veno-venous extracorporeal membrane oxygenation (ECMO) in children weighing less than 20 kg is dependent on both the mechanical characteristics of the catheter, including length and diameter, as well as the unique vascular anatomic considerations of the patient. This manuscript describes the development of a clinical strategy, over a four-year period from 2012-2016, for cannula selection to reduce the risk of migration and malposition in 20 critically ill children weighing less than 20 kg who presented for veno-venous ECMO.

Consensus Statement by the Congenital Cardiac Anesthesia Society: Milestones for the Pediatric Cardiac Anesthesia Fellowship.

Pediatric cardiac anesthesiology has evolved as a subspecialty of both pediatric and cardiac anesthesiology and is devoted to caring for individuals with congenital heart disease ranging in age from neonates to adults. Training in pediatric cardiac anesthesia is a second-year fellowship with variability in both training duration and content and is not accredited by the Accreditation Council on Graduate Medical Education. Consequently, in this article and based on the Accreditation Council on Graduate Medical Education Milestones Model, an expert panel of the Congenital Cardiac Anesthesia Society, a section of the Society of Pediatric Anesthesiology, defines 18 milestones as competency-based developmental outcomes for training in the pediatric cardiac anesthesia fellowship.

Morphine Pharmacokinetics in Children With Down Syndrome Following Cardiac Surgery.

OBJECTIVES: To assess if morphine pharmacokinetics are different in children with Down syndrome when compared with children without Down syndrome. DESIGN: Prospective single-center study including subjects with Down syndrome undergoing cardiac surgery (neonate to 18 yr old) matched by age and cardiac lesion with non-Down syndrome controls. Subjects were placed on a postoperative morphine infusion that was adjusted as clinically necessary, and blood was sampled to measure morphine and its metabolites concentrations. Morphine bolus dosing was used as needed, and total dose was tracked. Infusions were continued for 24 hours or until patients were extubated, whichever came first. Postinfusion, blood samples were continued for 24 hours for further evaluation of kinetics. If patients continued to require opioid, a nonmorphine alternative was used. Morphine concentrations were determined using a unique validated liquid chromatography tandem-mass spectrometry assay using dried blood spotting as opposed to large whole blood samples. Morphine concentration versus time data was modeled using population pharmacokinetics. SETTING: A 16-bed cardiac ICU at an university-affiliated hospital. PATIENTS: Forty-two patients (20 Down syndrome, 22 controls) were enrolled. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The pharmacokinetics of morphine in pediatric patients with and without Down syndrome following cardiac surgery were analyzed. No significant difference was found in the patient characteristics or variables assessed including morphine total dose or time on infusion. Time mechanically ventilated was longer in children with Down syndrome, and regarding morphine pharmacokinetics, the covariates analyzed were age, weight, presence of Down syndrome, and gender. Only age was found to be significant. CONCLUSIONS: This study did not detect a significant difference in morphine pharmacokinetics between Down syndrome and non-Down syndrome children with congenital heart disease.

The anesthetic management of button battery ingestion in children.

PURPOSE: Injuries related to button battery ingestion are common in children. This review provides an outline of the epidemiology, pathophysiology, management, and anesthetic implications in children who have ingested a button battery. SOURCE: A literature search was conducted in the United States National Library of Medicine PubMed database using the terms "button battery ingestion" and "children' and "removal" and "surgery" and "anesthesia". Ninety-six articles published in English were found from 1983-2017, and 62 of these articles were incorporated into this review. Additionally, the Internet was searched with the terms "button battery ingestion and children" to identify further entities, organizations, and resources affiliated with button battery ingestion in children. These additional sources were studied and included in this review. PRINCIPAL FINDINGS: Button batteries are ubiquitous in homes and electronic devices. Since 2006, larger-diameter and higher-voltage batteries have become available. These are more likely to become impacted in the esophagus after ingestion and lead to an increase in severe morbidity and mortality due to caustic tissue injury. Children at the highest risk for complications are those under six years of age who have ingested batteries > 20 mm in diameter and sustain prolonged esophageal impaction at the level of the aortic arch with the negative pole oriented anteriorly. CONCLUSION: Anesthesiologists need to know about the epidemiology, pathophysiology, complications, and anesthetic management of children who have ingested button batteries.

Alkaline Phosphatase in Infant Cardiopulmonary Bypass: Kinetics and Relationship to Organ Injury and Major Cardiovascular Events.

OBJECTIVES: To determine the kinetics of alkaline phosphatase (AP) activity and concentration after infant cardiopulmonary bypass, including isoform-specific changes, and to measure the association between postoperative AP activity and major postoperative cardiovascular events, organ injury/dysfunction, and postoperative support requirements STUDY DESIGN: Prospective cohort study of 120 infants ≤120 days of age undergoing cardiopulmonary bypass. AP total and isoform-specific activity was assessed at 6 time points (preoperation, rewarming, 6, 24, 48, and 72 hours postoperation). Low AP activity was defined as ≤80 U/L. AP concentrations and biomarkers of organ injury/dysfunction were collected through 24 hours postoperation. Major cardiovascular events were defined as cardiac arrest, mechanical circulatory support, or death. RESULTS: AP activity loss occurred primarily during the operation (median decrease 89 U/L; P < .0001) secondary to decreased bone and liver 2 isoforms. Activity declined through 24 hours in 27% of patients. AP activity strongly correlated with serum concentration (r = 0.87-0.91; P < .0001). Persistent low AP activity at 72 hours was associated independently with occurrence of a major cardiac event (OR 5.6; P < .05). Early AP activity was associated independently with subsequent vasoactive-inotropic score (P < .001), peak lactate (P < .0001), peak creatinine (P < .0005), N-terminal pro-brain natriuretic peptide (P < .05), and intestinal fatty acid binding protein (P < .005). CONCLUSIONS: AP activity decreases during infant cardiopulmonary bypass and may continue to decrease for 24 hours. Activity loss is secondary to decreased bone and liver 2 isoform concentrations. Early low AP activity is associated independently with subsequent postoperative support and organ injury/dysfunction, and persistence of AP activity ≤80 U/L at 72 hours is associated independently with increased odds of major cardiovascular events.

Outstanding contribution to pediatric anesthesiology: An interview with Dr. Robert H. Friesen.

Dr. Robert H. Friesen, (1946-) Professor of Anesthesiology, Children's Hospital Colorado, University of Colorado, Anschutz Medical Campus, has played a pivotal and pioneering role in the development of pediatric and congenital cardiac anesthesiology. His transformative research included the study of the hemodynamic effects of inhalational and intravenous anesthetic agents in the newborn and the effects of anesthetic agents on pulmonary vascular resistance in patients with pulmonary hypertension. As a model clinician-scientist, educator, and administrator, he changed the practice of pediatric anesthesia and shaped the careers of hundreds of physicians-in-training, imbuing them with his core values of honesty, integrity, and responsibility. Based on a series of interviews with Dr. Friesen, this article reviews a career that advanced pediatric and congenital cardiac anesthesia during the formative years of the specialties.

The 2017 Seventh World Congress of Pediatric Cardiology & Cardiac Surgery: week in review: congenital cardiac anaesthesia.

The seventh meeting of the World Congress of Pediatric Cardiology and Cardiac Surgery was an opportunity for healthcare professionals from around the world to meet and discuss current issues affecting patients with acquired and CHD. A dedicated anaesthesia track facilitated the exchange of ideas and fostered many new friendships. This review highlights the congenital cardiac anaesthesia track and the involvement of the Congenital Cardiac Anesthesia Society in the congress.

Retrospective analysis of eliminating modified ultrafiltration after pediatric cardiopulmonary bypass.

Modified ultrafiltration (MUF) is a technique which is commonly used immediately post-cardiopulmonary bypass (CPB) for open heart surgery in children. There are many advantages of MUF, but there are also a number of less reported disadvantages. At our institution, after considering all of the available data, a decision was made to no longer perform MUF. The primary motivation being the simplified and miniaturized CPB circuit would reduce hemodilution, decrease our likelihood of reaching our transfusion trigger during CPB and, potentially, improve safety. This study reports the before and after data from this practice change. A total of 160 patients less than 8kg were studied over 38 months and divided into neonatal and pediatric cohorts. Parameters reported in this study include: demographics, hematocrit, blood product transfusion, hemostasis, hemodynamics and outcomes. Although retrospective, our analysis supports an advantage of preventing hemodilution (via circuit miniaturization) versus reversing hemodilution (via MUF) at our institution with the patient population we examined.

The Perioperative Use of Dexmedetomidine in Pediatric Patients with Congenital Heart Disease: An Analysis from the Congenital Cardiac Anesthesia Society-Society of Thoracic Surgeons Congenital Heart Disease Database.

BACKGROUND: Dexmedetomidine is a selective α-2 receptor agonist with a sedative and cardiopulmonary profile that makes it an attractive anesthetic for pediatric patients with congenital heart disease (CHD). Although several smaller, single-center studies suggest that dexmedetomidine use is gaining traction in the perioperative setting in children with CHD, there are limited multicenter data, with little understanding of the variation in use across age ranges, procedural complexity, and centers. The aim of this study was to use the Congenital Cardiac Anesthesia Society-Society of Thoracic Surgeons (CCAS-STS) registry to describe patient- and center-level variability in the use of dexmedetomidine in the perioperative setting in children with heart disease. METHODS: To describe the use of dexmedetomidine in patients for CHD surgery, we analyzed all index cardiopulmonary bypass operations entered in the CCAS-STS database from 2010 to 2013. Patient and operative characteristics were compared between those who received intraoperative dexmedetomidine and those who did not. Selective outcomes associated with dexmedetomidine use were also described. RESULTS: Of the 12,142 operations studied, 3600 (29.6%) received perioperative dexmedetomidine (DEX) and 8542 did not receive the drug (NoDEX). Patient characteristics were different between the 2 groups with the DEX group generally exhibiting both lower patient and procedural risk factors. Patients who received dexmedetomidine were more likely to have a lower level of Society of Thoracic Surgeons mortality complexity than patient who did not receive it. Consistent with their overall lower risk profile, children in the DEX group also demonstrated improved outcomes compared with patients who did not receive dexmedetomidine. CONCLUSIONS: We described the growing use of dexmedetomidine in children anesthetized for surgical repair of CHD. Dexmedetomidine appears to be preferentially given to older and larger children who are undergoing less complex CHD surgery. We believe that the data provided in this study are the largest investigating the use of an anesthetic drug in CHD patients. It is also the first analysis of the anesthesia data in the CCAS-STS Congenital Heart Disease database.