Abnormal flow conduction through pulmonary arteries is associated with right ventricular volume and function in patients with repaired tetralogy of Fallot: does flow quality affect afterload?

OBJECTIVES: Flow through the proximal pulmonary arteries (PAs) of patients with repaired Tetralogy of Fallot (TOF) is known to be highly disordered and associated with significant regurgitation. The purpose of this study was to evaluate 4D-Flow MRI-derived viscous energy loss [Formula: see text])-as a result of non-efficient flow propagation, and relate this parameter to standard right ventricular (RV) size and function markers in patients with repaired TOF. METHODS: Thirty-five patients with TOF and 14 controls underwent comprehensive 4D-Flow MRI evaluation for qualitative flow analysis and to calculate [Formula: see text] in the main and right pulmonary arteries. Sampled [Formula: see text] indices were correlated with the MRI-derived RV size and functional indices. RESULTS: All patients with TOF exhibited abnormal, supra-physiologic helical/vortical formations in the PAs. Patients with TOF had significantly increased peak systolic [Formula: see text] (8.0 vs 0.5 mW, p < 0.001), time-averaged [Formula: see text] (2.5 vs. 0.2 mW, p < 0.001), and peak systolic [Formula: see text] indexed to stroke volume (0.082 vs. 0.012 mW/mL, p < 0.001). [Formula: see text] indexed to stroke volume correlated with the RV end-diastolic volume (R = 0.68, p < 0.001), end-systolic volume (R = 0.62, p < 0.001), ejection fraction (R = -0.45, p = 0.002), and cardiac index (R = 0.45, p = 0.002). The mean estimated energy loss due to [Formula: see text] with regard to input RV mechanical power was 4.7%. CONCLUSION: This study demonstrates that patients with repaired TOF have highly abnormal flow conduction through the PAs which result into extensive viscous energy loss. This significant flow-mediated energy loss is associated with the RV volume and function, and might represent considerable loss of mechanical power generated by each cardiac cycle. Future studies are required to assess whether the abnormal flow conduction adds to the RV afterload and remodeling. KEY POINTS: • Abnormal flow patterns through proximal pulmonary arteries in patients with TOF are associated with excessive viscous energy loss. • Inefficient flow conduction is associated with the RV dilation and reduced function and might contribute to the RV adaptive remodeling.

Metabolomic profiling demonstrates evidence for kidney and urine metabolic dysregulation in a piglet model of cardiac surgery-induced acute kidney injury.

Acute kidney injury (AKI) is a common cause of morbidity after congenital heart disease surgery. Progress on diagnosis and therapy remains limited, however, in part due to poor mechanistic understanding and a lack of relevant translational models. Metabolomic approaches could help identify novel mechanisms of injury and potential therapeutic targets. In the present study, we used a piglet model of cardiopulmonary bypass with deep hypothermic circulatory arrest (CPB/DHCA) and targeted metabolic profiling of kidney tissue, urine, and serum to evaluate metabolic changes specific to animals with histological acute kidney injury. CPB/DHCA animals with acute kidney injury were compared with those without acute kidney injury and mechanically ventilated controls. Acute kidney injury occurred in 10 of 20 CPB/DHCA animals 4 h after CPB/DHCA and 0 of 7 control animals. Injured kidneys showed a distinct tissue metabolic profile compared with uninjured kidneys (R2 = 0.93, Q2 = 0.53), with evidence of dysregulated tryptophan and purine metabolism. Nine urine metabolites differed significantly in animals with acute kidney injury with a pattern suggestive of increased aerobic glycolysis. Dysregulated metabolites in kidney tissue and urine did not overlap. CPB/DHCA strongly affected the serum metabolic profile, with only one metabolite that differed significantly with acute kidney injury (pyroglutamic acid, a marker of oxidative stress). In conclusion, based on these findings, kidney tryptophan and purine metabolism are candidates for further mechanistic and therapeutic investigation. Urine biomarkers of aerobic glycolysis could help diagnose early acute kidney injury after CPB/DHCA and warrant further evaluation. The serum metabolites measured at this early time point did not strongly differentiate based on acute kidney injury.NEW & NOTEWORTHY This project explored the metabolic underpinnings of postoperative acute kidney injury (AKI) following pediatric cardiac surgery in a translationally relevant large animal model of cardiopulmonary bypass with deep hypothermic circulatory arrest. Here, we present novel evidence for dysregulated tryptophan catabolism and purine catabolism in kidney tissue and increased urinary glycolysis intermediates in animals who developed histological AKI. These pathways represent potential diagnostic and therapeutic targets for postoperative AKI in this high-risk population.

Regional lung metabolic profile in a piglet model of cardiopulmonary bypass with circulatory arrest.

INTRODUCTION: Acute lung injury is common following cardiopulmonary bypass and deep hypothermic circulatory arrest for congenital heart surgery with the most severe injury in the dorsocaudal lung. Metabolomics offers promise in deducing mechanisms of disease states, providing risk stratification, and understanding therapeutic responses in regards to CPB/DHCA related organ injury. OBJECTIVES: Using an infant porcine model, we sought to determine the individual and additive effects of CPB/DHCA and lung region on the metabolic fingerprint, metabolic pathways, and individual metabolites in lung tissue. METHODS: Twenty-seven infant piglets were divided into two groups: mechanical ventilation + CPB/DHCA (n = 20) and mechanical ventilation only (n = 7). Lung tissue was obtained from dorsocaudal and ventral regions. Targeted analysis of 235 metabolites was performed using HPLC/MS-MS. Data was analyzed using Principal Component Analysis (PCA), Partial Least Square Discriminant Analysis (PLS-DA), ANOVA, and pathway analysis. RESULTS: Profound metabolic differences were found in dorsocaudal compared to ventral lung zones by PCA and PLS-DA (R2 = 0.7; Q2 = 0.59; p < 0.0005). While overshadowed by the regional differences, some differences by exposure to CPB/DHCA were seen as well. Seventy-four metabolites differed among groups and pathway analysis revealed 20 differential metabolic pathways. CONCLUSION: Our results demonstrate significant metabolic disturbances between dorsocaudal and ventral lung regions during supine mechanical ventilation with or without CPB/DHCA. CPB/DHCA also leads to metabolic differences and may have additive effects to the regional disturbances. Most pathways driving this pathology are involved in energy metabolism and the metabolism of amino acids, carbohydrates, and reduction-oxidation pathways.

Selected 2020 Highlights in Congenital Cardiac Anesthesia.

This article is a review of the highlights of pertinent literature published during the 12 months of 2020 that are of interest to the congenital cardiac anesthesiologist. After a search of the US National Library of Medicine's PubMed database, several topics emerged for which significant contributions were made in 2020. The authors of the present article considered the following topics noteworthy to be included in this review: pediatric cardiac care in the coronavirus disease 2019 era, the use of mechanical circulatory support in coronavirus disease 2019-related multisystem inflammatory syndrome in children, transfusion and coagulation management in children undergoing congenital heart surgery, and pulmonary vein stenosis.

Update on Congenital Diaphragmatic Hernia.

Congenital diaphragmatic hernia (CDH) is a rare developmental defect of the diaphragm, characterized by herniation of abdominal contents into the chest that results in varying degrees of pulmonary hypoplasia and pulmonary hypertension (PH). Significant advances in the prenatal diagnosis and identification of prognostic factors have resulted in the continued refinement of the approach to fetal therapies for CDH. Postnatally, protocolized approaches to lung-protective ventilation, nutrition, prevention of infection, and early aggressive management of PH have led to improved outcomes in infants with CDH. Advances in our understanding of the associated left ventricular (LV) hypoplasia and myocardial dysfunction in infants with severe CDH have allowed for the optimization of hemodynamics and management of PH. This article provides a comprehensive review of CDH for the anesthesiologist, focusing on the complex pathophysiology, advances in prenatal diagnosis, fetal interventions, and optimal postnatal management of CDH.

Perioperative Management of Children on Ketogenic Dietary Therapies.

Ketogenic diet therapy (KDT) is an effective treatment modality for children with drug-resistant epilepsy and certain other metabolic and neurologic disorders. With a resurgence of interest in KDT, pediatric anesthesiologists are increasingly encountering children on KDT for a variety of surgical and medical procedures. Maintenance of ketosis is critical throughout the perioperative period, and if not managed appropriately, these patients are at an increased risk of seizures. This review article provides an overview of the clinical indications, contraindications, proposed anticonvulsant mechanisms, initiation, and monitoring of children on KDTs. Recommendations for the perioperative anesthetic management of children on KDT are summarized. A comprehensive table listing the carbohydrate content of common anesthetic drugs is also included.

Anesthetic Implications of the New Guidelines for Button Battery Ingestion in Children.

Button battery ingestions result in significant morbidity and mortality in children-before, during, and even after removal. The injuries created by a button battery lodged in the esophagus develop rapidly and can be severe. The current of the button battery, conducted through saliva and the tissue drives a highly alkaline caustic injury, leading to liquefactive tissue necrosis. In June 2018, new guidelines were released from the National Capital Poison Center, which include the use of preoperative protective, pH-neutralizing and viscous barrier interventions with honey and/or sucralfate administered within 12 h of ingestion. In addition, the use of postremoval irrigation of the esophagus with 50-150 mL 0.25% acetic acid is done in the operating room to help neutralize the site of tissue injury. Given that anesthesiologists play an important role in the management of esophageal foreign body removal, the entire specialty needs to be aware of the supporting data behind this and general perioperative considerations for management and potential complications of button battery ingestion.

Achieving Sustainability in Reducing Unplanned Extubations in a Pediatric Cardiac ICU.

OBJECTIVES: To determine the incidence of unplanned extubations in a pediatric cardiac ICU in order to prove sustainability of our previously implemented quality improvement initiative. Additionally, we sought to identify risk factors associated with unplanned extubations as well as review the overall outcome of this patient population. DESIGN: Retrospective chart review. SETTING: Pediatric cardiac ICU at Children's Hospital of Colorado on the Anschutz Medical Center of the University of Colorado. PATIENTS: Intubated and mechanically ventilated patients in the cardiac ICU from July 2011 to December 2017. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 2,612 hospitalizations for 2,067 patients were supported with mechanical ventilation. Forty-five patients had 49 episodes of unplanned extubations (four patients > 1 unplanned extubation). The average unplanned extubation rate per 100 ventilator days was 0.4. Patients who had an unplanned extubation were younger (0.09 vs 5.45 mo; p < 0.001), weighed less (unplanned extubation median weight of 3.0 kg [interquartile range, 2.5-4.5 kg] vs control median weight of 6.0 kg [interquartile range, 3.5-13.9 kg]) (p < 0.001), and had a longer length of mechanical ventilation (8 vs 2 d; p < 0.001). Patients who had an unplanned extubation were more likely to require cardiopulmonary resuscitation during their hospital stay (54% vs 18%; p < 0.001) and had a higher likelihood of in-hospital mortality (15% vs 7%; p = 0.001). There was a significant difference in surgical acuity as denoted by The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery score and patients with an unplanned extubation had a higher Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery category (p = 0.019). Contributing factors associated with unplanned extubation were poor endotracheal tube tape integrity, inadequate tube securement, and/or inadequate sedation. A low rate of unplanned extubation was maintained even in the setting of increasing patient complexity and an increase in patient volume. CONCLUSIONS: A low rate of unplanned extubation is sustainable even in the setting of increased patient volume and acuity. Additionally, early identification of patients at higher risk of unplanned extubation may also contribute to decreasing the incidence of unplanned extubation.

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.

Bilateral suprazygomatic maxillary nerve blocks vs. infraorbital and palatine nerve blocks in cleft lip and palate repair: A double-blind, randomised study.

BACKGROUND: Cleft defects are common craniofacial malformations which require early surgical repair. These patients are at high risk of postoperative airway obstruction and respiratory failure. Cleft surgery may require high doses of opioids which may contribute to these complications. OBJECTIVES: To compare the effectiveness of proximal and distal approaches to blocking the maxillary nerve in patients undergoing cleft lip or cleft palate surgery. DESIGN: Randomised, controlled and double-blind study. SETTING: The current study was carried out in Guwahati (Assam, India) between April 2014 and June 2014. PATIENTS: A total of 114 patients older than 6 months who underwent cleft lip or cleft palate surgery were included. Exclusion criteria included coagulation disorders, peripheral neuropathy or chronic pain syndrome, infection in the puncture site, allergy to local anaesthetics, lack of consent and language problems or other barriers that could impede the assessment of postoperative pain. INTERVENTIONS: Patients were randomly assigned to one of two groups: proximal group (bilateral suprazygomatic maxillary nerve blocks) and distal group (bilateral infraorbital nerve blocks for cleft lip repair and bilateral greater and lesser palatine nerve blocks and nasopalatine nerve block for cleft palate surgery). MAIN OUTCOME MEASURE: The primary endpoint was the percentage of patients requiring extra doses of opioids. Secondary endpoints included pain scores, respiratory and nerve block-related complications during the first 24 h. RESULTS: In the intra-operative period, there was a significant reduction of nalbuphine consumption in the proximal group (9.1 vs. 25.4%, P = 0.02). The percentage of patients requiring intra-operative fentanyl was lower in the proximal group (16.4 vs. 30.5%, P = 0.07). There were no differences in either postoperative pain scores or in postoperative complications. No technical failure or block-related complications were reported. CONCLUSION: Bilateral suprazygomatic maxillary nerve block is an effective and safe alternative to the traditional peripheral nerve blocks for cleft lip and cleft palate surgery, in a mixed paediatric and adult population.

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.

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.

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.

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.