Single-center review on safety of biodegradable airway stenting in pediatric population.

BACKGROUND: Tracheobronchomalacia (TBM) and airway stenosis are recognized etiologies of airway obstruction among children. Their management is often challenging, requiring multiple interventions and prolonged respiratory support with associated long-term morbidity. Metallic or silicone stents have been used with mixed success and high complication rates. More recently biodegradable Ella stents (BES) provided an attractive interventional option. OBJECTIVES: We report our experience in the treatment of TBM and vascular airway compression using BES. We deliberately downsized them to minimize intraluminal granulation tissue formation. MATERIALS AND METHODS: Retrospective study over an 8-year period between November 2012 and December 2020 of pediatric patients with severe airway obstruction requiring airway stenting for extubation failure, malacic death spells, recurrent chest infections, or lung collapse. RESULTS: Thirty-three patients (5 tracheal and 28 bronchial diseases) required 55 BES during the study period. The smallest patient weighed 1.8 kg. Median age of patient at first stent implantation was 13.1 months (IQR 4.9-58.3). The majority of the bronchial stents were in the left main bronchus (93%), of which 57% for vascular compression. Repeat stents were used in 19 patients (57.7%), with a range of two to four times. We did not experience erosion, infection, or obstructive granuloma needing removal by forceps or lasering. Three stent grid occluded with secretions needing bronchoscopic lavage. Stent migration occurred in three patients. CONCLUSIONS: BES holds promise as a treatment option with low rate of adverse effects for a specific subset of pediatric patients with airway malacia or vascular compression. Further studies are warranted.

Impact on the trachea in children with prenatally diagnosed vascular ring formed by a right aortic arch.

OBJECTIVE: There has been a rise in the prenatal detection of right sided aortic arch (RAA). When associated with a left-sided arterial duct (LD), this forms a vascular ring encircling the trachea. Infants may have symptoms or signs suggestive of tracheoesophageal compression but many are asymptomatic. The objective of this study was to investigate the relationship between symptoms and severity of tracheobronchial compression assessed by bronchoscopy. METHODS: Retrospective review of all cases of prenatally diagnosed RAA-LD in the absence of associated congenital heart disease at Evelina London Children's Hospital and Kings College Hospital over a 4-year period between April 2015-2019. Clinical records, fetal echocardiograms, and free-breathing flexible bronchoscopy (FB) data were reviewed. RESULTS: One hundred and twelve cases of isolated RAA-LD were identified of whom 82 cases (73%) underwent FB. FB was performed median age of 11 months (range 1-36 months), no complications occurred. Aberrant left subclavian artery (ALSA) was present in 86% (96/112) and mirror image branching (MIB) in 13% (15/112). 34/112 (30%) reported symptoms during follow-up. 36/77 (47%) with ALSA who underwent FB showed moderate-severe compression mostly at distal tracheal and carinal level of whom 38% had parent-reported symptoms. Moderate-severe compression was seen in 3/5 (60%) with MIB mostly at mid tracheal level; 3 were symptomatic but only 2 had tracheal compression. In total 36% (18/50) of investigated asymptomatic patients showed moderate-severe compression. Respiratory symptoms were poorly predictive of moderate-severe tracheal compression (positive predictive value 66%, negative predictive value 64%). CONCLUSION: The absence of symptoms did not exclude significant tracheal compression. The anatomical effect of the vascular ring is under appreciated when symptoms alone are used as a marker of tracheal compression.

Catheter directed thrombolysis for a pulmonary arterial thrombus on VA ECMO in a child - a case report.

INTRODUCTION: Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) as a bridge to cardiac transplantation is considered a high risk support strategy in the paediatric population. METHODS: We describe the case of a 12 year old boy who required V-A ECMO support for rapidly deteriorating cardiomyopathy and developed a massive pulmonary embolus (PE) peri-cannulation. Subsequent investigations were also positive for heparin induced thrombocytopenia. RESULTS: We elected to treat the PE with ultrasound accelerated catheter directed thrombolysis using the advantages of this minimally invasive targeted method to try and resolve the PE and avoid a cerebral haemorrhage, both of which would have taken the patient off the urgent transplant list. CONCLUSION: The PE resolved in 24 h and he went on to receive a cardiac transplant and have a favourable outcome.

The Infant KIdney Dialysis and Utrafiltration (I-KID) Study: A Stepped-Wedge Cluster-Randomized Study in Infants, Comparing Peritoneal Dialysis, Continuous Venovenous Hemofiltration, and Newcastle Infant Dialysis Ultrafiltration System, a Novel Infant Hemodialysis Device.

OBJECTIVES: Renal replacement therapy (RRT) options are limited for small babies because of lack of available technology. We investigated the precision of ultrafiltration, biochemical clearances, clinical efficacy, outcomes, and safety profile for a novel non-Conformité Européenne-marked hemodialysis device for babies under 8 kg, the Newcastle Infant Dialysis Ultrafiltration System (NIDUS), compared with the current options of peritoneal dialysis (PD) or continuous venovenous hemofiltration (CVVH). DESIGN: Nonblinded cluster-randomized cross-sectional stepped-wedge design with four periods, three sequences, and two clusters per sequence. SETTING: Clusters were six U.K. PICUs. PATIENTS: Babies less than 8 kg requiring RRT for fluid overload or biochemical disturbance. INTERVENTIONS: In controls, RRT was delivered by PD or CVVH, and in interventions, NIDUS was used. The primary outcome was precision of ultrafiltration compared with prescription; secondary outcomes included biochemical clearances. MEASUREMENTS AND MAIN RESULTS: At closure, 97 participants were recruited from the six PICUs (62 control and 35 intervention). The primary outcome, obtained from 62 control and 21 intervention patients, showed that ultrafiltration with NIDUS was closer to that prescribed than with control: sd controls, 18.75, intervention, 2.95 (mL/hr); adjusted ratio, 0.13; 95% CI, 0.03-0.71; p = 0.018. Creatinine clearance was smallest and least variable for PD (mean, sd ) = (0.08, 0.03) mL/min/kg, larger for NIDUS (0.46, 0.30), and largest for CVVH (1.20, 0.72). Adverse events were reported in all groups. In this critically ill population with multiple organ failure, mortality was lowest for PD and highest for CVVH, with NIDUS in between. CONCLUSIONS: NIDUS delivers accurate, controllable fluid removal and adequate clearances, indicating that it has important potential alongside other modalities for infant RRT.

In vitro measurements of ultrafiltration precision in hemofiltration and hemodialysis devices used in infants.

BACKGROUND: To determine in vitro whether infant hemofiltration and hemodialysis devices can reliably deliver precise ultrafiltration (UF) control. METHODS: We tested the Prismaflex, Aquarius and NIDUS devices which have different circuit types, by in vitro testing with a bag of saline set up as a dummy patient, and monitoring fluid shifts by precise weighing. We looked for differences between the UF rates set and achieved and between the UF result the device displays to the clinician and the true volumes removed, which may lead to clinical errors. We performed short studies at UF settings of zero and 40 ml/h, and with and without simulating poor withdrawal and return lines, and simulated a 4-h treatment session. RESULTS: The Prismaflex setting vs actual errors and display vs actual errors had wide variances, with SDs of 4.1 and 14.0 ml by 15 min, respectively, at both zero and 40 ml/h UF settings. The Aquarius values were wider at 17.3 and 30.3 ml, respectively. For the NIDUS, the mean UF errors were close to zero, and the variances were 0.17 ml. Stop-alarms induced by an obstructed line produced extra UF errors of up to 0.2 ml. A limitation was that we used crystalloid and not colloid for these tests. CONCLUSIONS: Hemotherapy devices with conventional circuits available in the UK do not regulate UF control sufficiently well to recommend for use in small infants, but the NIDUS volumetrically controlled circuit does. All hemotherapy devices intended for small infants should be tested for UF precision. We were unable to test the CARPEDIEM or Aquadex devices. A higher resolution version of the Graphical abstract is available as Supplementary information.

Contemporary surgical outcome and symptomatic relief following vascular ring surgery in children: effect of prenatal diagnosis.

OBJECTIVES: Our goal was to describe postoperative complications and outcomes in a large contemporary cohort of children with an isolated double aortic arch (DAA) or a right aortic arch (RAA) with left arterial ligament and to assess the impact of foetal diagnosis on outcomes. METHODS: We performed a retrospective analysis of all patients who underwent surgery for DAA or RAA with left arterial ligament between 2005 and 2019. RESULTS: A total of 132 children were operated on for a DAA (n = 77) or a RAA (n = 55). Prenatal diagnosis was made in 100/132 (75.8%). Median age at surgery for DAA was 5.0 (1.7-13.3) months and for RAA was 13.9 (6.4-20.1) months. There was no difference in the age at surgery between the prenatal and postnatal cases (8.6 [4.0-15.6] vs 5.4 months [1.8-17.7]; P = 0.37). No surgical deaths occurred. Vocal cord palsy was the most common complication, occurring in 12/132 (9%): of these, 11 resolved spontaneously and 1 required a temporary tracheostomy. Logistic regression demonstrated that older age at operation was the only predictor for a postoperative complication (P = 0.02). Overall, 21/67 (31%) of prenatally detected, symptomatic cases reported residual symptoms/signs 1 year after surgery compared to 18/28 (64%) of postnatally detected cases. Postnatal diagnosis was associated with persistent postoperative symptoms/signs [P = 0.006, odds ratio = 3.9 (95% confidence interval 1.5-9.4)]. CONCLUSIONS: Surgery to relieve a vascular ring resolves trache-oesophageal compressive symptoms in most cases, but parents/patients should be aware that symptoms/signs may persist in the first postoperative year despite effective release of the vascular ring. Earlier surgery and prenatal diagnosis may improve outcomes.

Multisite Veno-Venous Cannulation for Neonates and Nonambulatory Children.

OBJECTIVES: Neonates with respiratory failure are ideally supported with veno-venous rather than veno-arterial extracorporeal membrane oxygenation due to the reduced rate of neurologic complications. However, the proportion of neonates supported with veno-venous extracorporeal membrane oxygenation is declining. We report multisite veno-venous extracorporeal membrane oxygenation, accessing the neck, returning to the inferior vena cava via the common femoral vein in neonates and children less than 10 kg. DESIGN: Retrospective case series with 1 year minimum follow-up. PATIENTS: Patients less than 10 kg supported with veno-venous extracorporeal membrane oxygenation accessing the jugular and returning to the femoral vein. SETTING: A 30-bed pediatric intensive care delivering extracorporeal membrane oxygenation to approximately 20 children annually. INTERVENTIONS: Veno-venous extracorporeal membrane oxygenation accessing the jugular and returning to the femoral vein was delivered using two single lumen cannulae. MEASUREMENTS AND MAIN RESULTS: January 2015 to August 2019, 11 patients underwent veno-venous extracorporeal membrane oxygenation accessing the jugular and returning to the femoral vein with median weight of 3.6 kg (interquartile range 2.8-6.1 kg), and median corrected gestational age of 13 days (interquartile range, 2-175 d). The smallest patient weighed 2.1 kg. Seven patients had comorbidities. Extracorporeal membrane oxygenation was technically successful in all patients with median flows of 126 mL/kg/min (interquartile range, 120-138 mL/kg/min) and median arterial oxygenation saturation of 94% (interquartile range, 91-98%) at 24 hours. Nine survived to home discharge, and two were palliated. Common femoral vein occlusion was observed in all patients on ultrasound post decannulation. There was no clinical or functional deficit in the cannulated limb at follow-up, a minimum of 1 year post extracorporeal membrane oxygenation. CONCLUSIONS: Veno-venous extracorporeal membrane oxygenation accessing the jugular and returning to the femoral vein was performed safely in patients under 10 kg with the smallest patient weighing 2.1 kg. Although occlusion of the common femoral vein was observed in patients post decannulation, subsequent follow-up demonstrated no clinical implications. We challenge current practice that veno-venous extracorporeal membrane oxygenation accessing the jugular and returning to the femoral vein cannot be performed in nonambulatory patients and suggest that this strategy is preferred over veno-arterial extracorporeal membrane oxygenation in infants requiring extracorporeal membrane oxygenation for respiratory failure.

Postnatal impact of a prenatally diagnosed double aortic arch.

BACKGROUND: A double aortic arch (DAA) is increasingly identified before birth; however, there are no published data describing the postnatal outcome of a large prenatal cohort. OBJECTIVE: To describe the associations, symptoms and impact of prenatally diagnosed DAA. METHODS: Retrospective review of consecutive cases seen at two fetal cardiology units from 2014 to 2019. Clinical records including symptoms and assessment of tracheobronchial compression using flexible bronchoscopy were reviewed. Moderate-severe tracheal compression was defined as >75% occlusion of the lumen. RESULTS: There were 50 cases identified prenatally and 48 with postnatal follow-up. Array comparative genomic hybridisation (aCGH) was abnormal in 2/50 (4%), aCGH was normal in 33/50 (66%) and of those reviewed after birth, 13 were phenotypically normal. After birth, there was a complete DAA with patency of both arches in 8/48 (17%) and in 40/48 (83%) there was a segment of the left arch which was a non-patent, ligamentous connection.Stridor was present in 6/48 (13%) on the day of birth. Tracheo-oesophageal compressive symptoms/signs were present in 31/48 (65%) patients at median age of 59 days (IQR 9-182 days). Tracheal/carinal compression was present in 40/45 (88%) cases. Seven of 17 (41%) asymptomatic cases demonstrated moderate-severe tracheal compression. All morphologies of DAA caused symptoms and morphology type was not predictive of significant tracheal compression (p=0.3). CONCLUSIONS: Genetic testing should be offered following detection of double aortic arch. Early signs of tracheal compression are common and therefore delivery where onsite neonatal support is available is recommended. Significant tracheal compression may be present even in the absence of symptoms.

Individualized, Intraoperative Dosing of Fibrinogen Concentrate for the Prevention of Bleeding in Neonatal and Infant Cardiac Surgery Using Cardiopulmonary Bypass (FIBCON): A Phase 1b/2a Randomized Controlled Trial.

BACKGROUND: Mediastinal bleeding is common following pediatric cardiopulmonary bypass surgery for congenital heart disease. Fibrinogen concentrate (FC) represents a potential therapy for preventing bleeding. METHODS: We performed a single-center, phase 1b/2a, randomized controlled trial on infants 2.5 to 12 kg undergoing cardiopulmonary bypass surgery, aimed at (1) demonstrating the feasibility of an intraoperative point-of-care test, rotational thromboelastometry, to screen out patients at low risk of postoperative bleeding and then guide individualized FC dosing in high-risk patients and (2) determining the dose, safety, and efficacy of intraoperative FC supplementation. Screening occurred intraoperatively 1-hour before bypass separation using the rotational thromboelastometry variable fibrinogen thromboelastometry maximum clot firmness (FibTEM-MCF; fibrinogen contribution to clot firmness). If FibTEM-MCF ≥7 mm, patients entered the monitoring cohort. If FibTEM-MCF ≤6 mm, patients were randomized to receive FC/placebo (2:1 ratio). Individualized FC dose calculation included weight, bypass circuit volume, hematocrit, and intraoperative measured and desired FibTEM-MCF. The coprimary outcomes, measured 5 minutes post-FC administration were FibTEM-MCF (desired range, 8-13 mm) and fibrinogen levels (desired range, 1.5-2.5 g/L). Secondary outcomes were thrombosis and thrombosis-related major complications and postoperative 24-hour mediastinal blood loss. RESULTS: We enrolled 111 patients (cohort, n=21; FC, n=60; placebo, n=30); mean (SD) age, 6.4 months (5.8); weight, 5.9 kg (2.0). Intraoperative rotational thromboelastometry screening effectively excluded low-risk patients, in that none in the cohort arm (FibTEM-MCF, ≥7 mm) demonstrated clinically significant early postoperative bleeding (>10 mL/kg per 4 hours). Among randomized patients, the median (range) FC administered dose was 114 mg/kg (51-218). Fibrinogen levels increased from a mean (SD) of 0.91 (0.22) to 1.7 g/L (0.41). The postdose fibrinogen range was 1.2 to 3.3 g/L (72% within the desired range). The corresponding FibTEM-MCF values were as follows: pre-dose, 5.3 mm (1.9); post-dose, 13 mm (3.2). Ten patients (8 FC and 2 placebo) exhibited 12 possible thromboses; none were clearly related to FC. There was an overall difference in mean (SD) 24-hour mediastinal drain loss: cohort, 12.6 mL/kg (6.4); FC, 11.6 mL/kg (5.2); placebo, 17.1 mL/kg (14.3; ANOVA P=0.02). CONCLUSIONS: Intraoperative, individualized dosing of FC appears feasible. The need for individualized dosing is supported by the finding that a 4-fold variation in FC dose is required to achieve therapeutic fibrinogen levels. Registration: URL: https://eudract.ema.europa.eu/; Unique identifier: 2013-003532-68. URL: https://www.isrctn.com/; Unique identifier: 50553029.

Factors Behind Decline of Venovenous Extracorporeal Membrane Oxygenation to Support Neonatal Respiratory Failure.

OBJECTIVES: Neonates with respiratory failure are ideally supported with venovenous rather than venoarterial extracorporeal membrane oxygenation due to the reduced rate of neurologic complications. However, the proportion of neonates supported with venovenous extracorporeal membrane oxygenation is declining. We aimed to explore the factors behind this decline. DESIGN: We conducted a survey in order to understand current practice across the United Kingdom, exploring barriers to neonatal venovenous extracorporeal membrane oxygenation in addition to collecting U.K.-wide retrospective data from 2000 onwards. PATIENTS: Neonates with respiratory failure supported with extracorporeal membrane oxygenation in the United Kingdom. SETTING: All 11 pediatric U.K. extracorporeal membrane oxygenation centers provided data. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The percentage of neonates with respiratory failure supported with venovenous extracorporeal membrane oxygenation has declined from 58% to 16% over the last decade, reflected internationally with a decrease of 1.3% per year. Nine extracorporeal membrane oxygenation centers are able to offer pediatric venovenous extracorporeal membrane oxygenation, but only four offer neonatal venovenous extracorporeal membrane oxygenation. Of those able to provide neonatal venovenous extracorporeal membrane oxygenation, three centers use dual lumen cannulae and one uses neonatal multisite cannulation. The most frequently cited barriers to neonatal venovenous extracorporeal membrane oxygenation were the lack of availability of a suitable dual lumen cannula with concerns of cardiac perforation and challenges of multisite cannulation due to small caliber femoral veins. CONCLUSIONS: The majority of U.K. centers are unable to provide venovenous extracorporeal membrane oxygenation for neonates due to concerns with availability and suitability of dual lumen cannulae. An alternative to be considered is the use of multisite cannulation, which has been used historically and is currently being used in centers internationally and in the United Kingdom.

Biodegradable Stents for the Relief of Vascular Bronchial Compression in Children With Left Atrial Enlargement.

BACKGROUND: We report our experience of the biodegradable polydioxanone stent in cases of bronchial compression by a dilated left atrium in children with heart disease. METHODS: Eight custom-made biodegradable stents were inserted into the left main bronchus in 5 patients diagnosed with critical airway compression. Four of the 5 patients were ventilator-dependent with significant cardiac morbidity. RESULTS: Stents were inserted without complication under fluoroscopic guidance. All experienced improvement in symptoms over time. In 3 patients, repeat bronchial stenting was performed where stent degradation was associated with recurrence of vascular airway compression and symptoms. No stents migrated nor was there evidence of bronchial or vascular erosion. There was 1 death, unrelated to the stent, and all remaining survivors were well at a 2-year follow-up. CONCLUSION: The use of the polydioxanone biodegradable stent appeared safe in this cohort of critically ill patients with vascular bronchial compression. There use may aid weaning from mechanical ventilation and support eventual cardiac recovery.

Correlation of Symptoms with Bronchoscopic Findings in Children with a Prenatal Diagnosis of a Right Aortic Arch and Left Arterial Duct.

A right aortic arch (RAA) with a left arterial duct (LAD) together encircle the trachea and have the potential to cause tracheobronchial compression and published guidelines recommend bronchoscopy in symptomatic patients. The aim of the study was to describe the incidence of tracheal compression in a cohort of prenatally diagnosed RAA and LAD. Retrospective review of clinical course and imaging of prenatal cases of RAA and LAD assessed with flexible bronchoscopy over an 11-year period. 34 cases of prenatally diagnosed RAA with LAD underwent bronchoscopy at median age of 9 months (range 0.4-123) of whom 11 had respiratory symptoms and 23 were asymptomatic. In the neonatal period, three cases demonstrated respiratory symptoms. An aberrant left subclavian artery (ALSA) was identified in 29 cases. Pulsatile tracheal compression was identified in 32/34 (94%) cases and two cases showed normal tracheal appearances. Significant tracheal compression (> 70% occlusion) was present in 25/34 (74%) cases of which 16 were asymptomatic. Significant carinal compression (> 70% occlusion) was identified in 14/34 (42%) cases, an ALSA was observed in 13/14. Surgical relief of a vascular ring has been performed in 27 (79%) cases at a median age of 15 months (range 0.6-128 months). At surgery, a fibrous remnant of an atretic left aortic arch was identified in 11/27 (41%) cases. Significant tracheal compression may be present in infants even without symptoms. If early relief of airway compression is to be achieved to promote normal development of tracheal cartilage, early bronchoscopy should be considered.

Case-based discussion from the neonatal intensive care unit: a case of an intentional oesophageal intubation.

Tracheal agenesis (TA) is a rare congenital defect consisting of complete or partial absence of the trachea below the larynx. Antenatal diagnosis is challenging, and most cases are detected in the postnatal period. Airway management of such cases, particularly in the absence of antenatal diagnosis, can be challenging. Various methods of management have been described but with limited success, and overall prognosis remains very poor. We present an unexpected case of TA, highlighting management issues and diagnostic methods.

Microbial Community Composition and Extracellular Enzyme Activities Associated with Juncus roemerianus and Spartina alterniflora Vegetated Sediments in Louisiana Saltmarshes.

Saltmarshes are typically dominated by perennial grasses with large underground rhizome systems that can change local sediment conditions and be important in shaping the sediment microbial community. Factors such as salinity that control plant zonation in saltmarshes are also likely to influence the microbial community, but little is known as to whether microbial communities share distribution patterns with plants in these systems. To determine the extent to which microbial assemblages are influenced by saltmarsh plant communities, as well as to examine patterns in microbial community structure at local and regional scales, we sampled sediments at three saltmarshes in Louisiana, USA. All three systems exhibit a patchy distribution of Juncus roemerianus stands within a Spartina alterniflora marsh. Sediment samples were collected from the interior of several J. roemerianus stands as well as from the S. alterniflora matrix. Samples were assayed for extracellular enzyme activity and DNA extracted to determine microbial community composition. Denaturing gradient gel electrophoresis of rRNA gene fragments was used to determine regional patterns in bacterial, archaeal, and fungal assemblages, while Illumina sequencing was used to examine local, vegetation-driven, patterns in community structure at one site. Both enzyme activity and microbial community structure were primarily influenced by regional site. Within individual saltmarshes, bacterial and archaeal communities differed between J. roemerianus and S. alterniflora vegetated sediments, while fungal communities did not. These results highlight the importance of the plant community in shaping the sediment microbial community in saltmarshes but also demonstrate that regional scale factors are at least as important.

The role and scope of retrieval nurse practitioners in the UK.

BACKGROUND: The first independent paediatric retrieval nurse practitioners (RNP) in the UK and Europe were appointed in 2006 in one hospital Trust. Since then, many have been appointed around the UK but the range of responsibility and scope of the role is unknown as well as possible geographical variability. AIM: The aim of this paper is to explore the role and scope of paediatric retrieval nurse practitioners in the United Kingdom (UK). METHOD: A two part questionnaire was sent to all RNPs identified by the regional retrieval/transport centres. Information was sought about the role and scope of RNPs and how the role may have changed since appointment. RNPs were asked to self-assess their own ability in a variety of technical and leadership skills. CONCLUSION: The majority of respondents felt their role had expanded since appointment. RNPs reported that they would now lead the team for any critically ill infant or child where previously they were retrieving stable or high dependency patients. Other expansions of their role included being on a middle grade tier of the medical rota, asked to undertake aeromedical transfers, providing the withdrawal of care at referring centres and non-medical independent prescribing. RELEVANCE TO PRACTICE: This survey has revealed the changing role and scope of RNPs in the UK but most importantly, the increased responsibility of the roles. Over 80% of RNPs rated their leadership skills between proficient and expert on Benner's Novice to Expert Continuum (Benner, 1984).