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.

Pulmonary artery sling: An overview.

Pulmonary artery sling is a rare childhood vascular tracheobronchial compression syndrome that is frequently associated with tracheal stenosis. Consequently, neonates or infants may present with critical airway obstruction if there is long segment airway narrowing and complete rings. Rapid diagnosis of this cardiac vascular malformation and evaluation of the extent and severity of airway involvement is essential to plan surgery, typically a slide tracheoplasty to relieve critical airway obstruction. Long term outcome can be excellent following surgical repair of the stenosed airway and reimplantation of the left pulmonary artery. In this review we focus on the embryology, diagnostic workup, airway investigations and management for this rare but challenging congenital condition.

Long term outcome of babies with pulmonary hypertension.

Neonatal pulmonary hypertension (PH) is associated with many severe congenital abnormalities (congenital diaphragmatic hernia) or acquired cardiorespiratory diseases such as pneumonia, meconium aspiration and bronchopulmonary dysplasia (BPD). If no cause is found it may be labelled idiopathic persistent pulmonary hypertension of the newborn. Although PH may result in life threatening hypoxia and circulatory failure, in the majority of cases, it resolves in the neonatal period following treatment of the underlying cause. However, in some cases, neonatal PH progresses into infancy and childhood where symptoms include failure to thrive and eventually right heart failure or death if left untreated. This chronic condition is termed pulmonary vascular hypertensive disease (PHVD). Although classification and diagnostic criteria have only recently been proposed for pediatric PHVD, little is known about the pathophysiology of chronic neonatal PH, or why pulmonary vascular resistance may remain elevated well beyond infancy. This review explores the many factors involved in chronic PH and what implications this may have on long term outcome when the disease progresses beyond the neonatal period.

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.

Application of the Boston Technical Performance Score to intraoperative echocardiography.

BACKGROUND: The Technical Performance Score (TPS) developed by Boston Children's Hospital showed surgical outcomes correlate with adequacy of technical repair when implemented on pre-discharge echocardiograms. We applied this scoring system to intraoperative imaging in a tertiary UK congenital heart surgical centre. METHODS: After a period of training, intraoperative TPS (epicardial and/or transesophageal echocardiography) was instituted. TPS was used to inform intraoperative discussions and recorded on a custom-made database using the previously published scoring system. After a year, we reviewed the feasibility, results and relationship between the TPS and mortality, extubation time and length of stay. RESULTS: From 01 September 2015 to 04 July 2016, there were 272 TPS procedures in 251 operations with 208 TPS recorded. Seven patients had surgery with no documented TPS, three had operations with no current TPS score template available. Patients left the operating theatre with TPS optimal in 156 (75%), adequate 34 (16%) and inadequate 18 (9%). Of those with an optimal score on leaving theatre, ten had more than one period of cardiopulmonary bypass. All four deaths <30 days after surgery (1.9%) had optimal TPS. There was a statistically significant difference in extubation times in the RACHS category 4 patients (3 days vs 5 days, P < 0.05) and in PICU and total length of stay in the RACHS category three patients (2 and 8 days vs 12.5 and 21.5 days respectively) if leaving theatre with an inadequate result. CONCLUSIONS: Application of intraoperative TPS is feasible and provides a way of objectively recording intraoperative imaging assessment of surgery. An 'inadequate' TPS did not predict mortality but correlated with a longer ventilation time and longer length of stay compared to those with optimal or adequate scores.

Prenatal diagnosis and clinical implications of an apparently isolated right aortic arch.

OBJECTIVE: To define the associations of a prenatally diagnosed, apparently isolated right aortic arch (RAA) with chromosomal or genetic abnormalities and tracheal compression. METHODS: This was a retrospective study of apparently isolated RAA assessed by fetal cardiologists and fetal medicine specialists at Kings College Hospital, London between 2000 and 2017. RESULTS: The search identified 138 cases of apparently isolated RAA. Invasive testing was performed in 75, and chromosomal or genetic anomalies were identified in 16 (22%), and the most common was 22q11 microdeletion. An aberrant left subclavian artery was seen in 51% of cases. Symptoms of a vascular ring were present in 24 of 97 (25%) children who were reviewed after birth. Bronchoscopy was performed in 33 children, and significant tracheal compression was diagnosed in 28, including 18 of 19 symptomatic and 10 of 14 asymptomatic children. CONCLUSIONS: An apparently isolated RAA is associated with a high incidence of chromosomal or genetic abnormalities and a high incidence of tracheal compression in symptomatic and asymptomatic patients. Prenatal counselling for genetic associations and postnatal airway assessment in the context of the vascular anatomy is recommended.

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.

Safe implementation of standard concentration infusions in paediatric intensive care.

OBJECTIVE: To evaluate safety, following introduction of standard concentrations of morphine infusions in paediatric critical care. METHODS: Implementation: A multidisciplinary team was convened, and several workstreams designated, including derivation of concentrations, manufacturing, supply, prescribing, administration using smart pump technology, training and evaluation. Safety Evaluation: Retrieval of all existing data on medication errors linked to morphine use using our hospital incident reporting system and risk assessment of errors in relation to standard concentration implementation. KEY FINDINGS: The pilot identified several areas for improvement, stock control, reasons for reverting from standard to variable concentrations and sources of error. Improvements included the following: refining morphine concentrations and weight limits for bands, pump reprogramming and education. Long-term Safety: Over an 8-year period, 126 morphine-related incidents occurred (two-thirds in the 3 years around introduction). Of note, 67% (85/126) resulted in no patient harm; the remainder 33% resulted in low harm. Analysis of administration errors revealed that up to 70% could be eliminated by refining technology to include bar coding. These included the following: wrong syringe selection (24%), wrong pump mode (28%) and wrong patient weight inputted (18%). CONCLUSION: Introduction of standard infusions is safe and effective. We are exploring ways to further refine safety and extending to other drugs.

Critical airway obstruction in apparently asymptomatic neonates.

Central airway obstruction (trachea and major bronchi) in neonates can be caused by malacia, stenosis, or compression by masses or vascular structures. These abnormalities may be present in the neonatal period but are typically not detected until at least 6 months of age. We present four patients (1.6-4.1 kg, 32-41 weeks gestation) with nonspecific symptoms (e.g., poor weight gain, difficulty weaning from CPAP) who underwent bronchoscopy in the neonatal period. Critical airway obstruction (>90%) was identified in these relatively asymptomatic neonates. We suggest a low threshold for investigation with bronchoscopy in high-risk neonates. Pediatr Pulmonol. 2017;52:E15-E17. © 2016 Wiley Periodicals, Inc.

Treatment of severe tracheobronchomalacia: Ten-year experience.

INTRODUCTION: Paediatric tracheobronchomalacia is a rare but potentially serious condition. Severe tracheobronchomalacia requires intervention or operation. This is an evaluation of a ten-year experience at an institution. METHODS: In this retrospective study all patients were included that required an intervention for severe tracheobronchomalacia from 2003 to 2012. Symptoms, aetiology, comorbidities, localisation of the malacia, age at diagnosis, therapeutic measures and associated complications were evaluated. RESULTS: Forty-four patients with severe tracheobronchomalacia underwent intervention/operation. The predominant aetiology was vascular compression in 48%. The majority of patients had complex comorbidities, most importantly cardiac pathology in 66%. The median age at diagnosis was 3 months. A total of 17 aortopexies, 21 tracheostomies and 25 stent placements were performed. The mean follow-up was 2.6 years. Severe complications occurred in 12 patients. The most common complications were stent obstruction/fracture and tracheostomy tube obstruction. CONCLUSION: The management of severe tracheobronchomalacia is complex and the population of patients is very heterogeneous. Therefore the treatment has to be adapted for each patient individually. The decision strategies are discussed in this article. The surgical techniques for placement and safe removal of expandable bare metallic stents employed in our institution are presented. A multidisciplinary team of ENT surgeons, Intensivists, Cardiologists and Cardiac surgeons is of great importance.

Predicting fluid responsiveness in 100 critically ill children: the effect of baseline contractility.

PURPOSE: Fluid overload is a risk factor for poor outcome in intensive care; thus volume loading should be tailored towards patients who are likely to increase stroke volume. We aimed to evaluate the paediatric predictive ability (stroke volume increase of at least 15 % after fluid bolus) of novel and established volumetric and dynamic haemodynamic variables, and assess the influence of baseline contractility on response. METHODS: We assessed 142 volume loading episodes (10 ml/kg crystalloid) in 100 critically ill ventilated children, median (interquartile) weight 10 (5.6-15) kg. Eight advanced haemodynamic variables were assessed using two commercially available devices. Systemic ventricular contractility was measured as the maximum rate of systolic arterial pressure rise. RESULTS: Overall, predictive ability was poor, with volumetric variables performing better than dynamic (area under receiver operating characteristic curves ranged from 0.53 to 0.67). The best predictor was total end-diastolic volume index; however, this did not increase in a consistent way with volume loading, with change post volume being weakly related to baseline values (r = -0.19, p = 0.02). A multivariable model quantified the importance of contractility in stroke volume response. Children with high baseline contractility (≥75th centile) typically achieved a positive stroke volume response when end-diastolic volume values changed by 10-15 ml/m(2.6), whereas patients with low contractility (≤25th centile) typically required end-diastolic volume increases of 35-40 ml/m(2.6). CONCLUSIONS: Current paediatric predictors of volume response perform poorly; prediction may be improved if baseline contractility is taken into account.

Unplanned extubation in a paediatric intensive care unit: prospective cohort study.

PURPOSE: Unplanned extubation (UE) is an important paediatric intensive care unit (PICU) quality indicator. Studies on UE have been modest in size, with accurate UE rate calculation potentially hampered by ventilation episodes recorded in calendar days. We wished to document UE rates, outcomes, associated factors and quantify error when calendar days rather than exact timings are used. METHODS: We recorded prospectively all UE episodes and potential associated factors in our 20-bed PICU for 12,533 admissions (2000-2013). Ventilation episodes were recorded to the minute, with non-invasive and tracheostomy ventilation excluded. Analysis utilised multilevel mixed-effects Poisson regression, adjusting for multiple ventilation episodes in the same patient. RESULTS: Overall, 243 UEs occurred within 14,141 ventilation episodes (31,564 intubated days), giving a UE rate of 0.77 (95% CI 0.67-0.87) episodes per 100 intubated days. If calendar ventilation days were used, the yearly UE rate was underestimated by 27-35%. UE rates decreased with time, by approximately 0.05/100 intubated days each year. Associations with UE incidence rate included patient age, source of admission, disease severity and diagnostic category, with nasal tubes decreasing the risk. Although UE versus planned extubation was associated with a higher re-intubation rate (43 versus 8%) and longer median PICU stay (4.6 versus 2.6 days, p < 0.001), mortality between the two groups did not differ (3.0 versus 5.1%, p = 0.18). CONCLUSIONS: This study provides contemporaneous UE rates for benchmarking. Recording ventilation in calendar days underestimates UE rate. Several factors associated with UE may serve as a focus of quality improvement.

Neonatal decompensation before surgery in hypoplastic left heart syndrome: a case control study.

OBJECTIVE: Prior to Norwood 1 surgery, neonates with hypoplastic left heart syndrome (HLHS) are at risk of decompensation from systemic underperfusion secondary to pulmonary overcirculation. We examined whether preoperative temporal profiles of physiological and laboratory variables differed between neonates who did and did not decompensate preoperatively. DESIGN: Case control study. SETTING: Paediatric Intensive Care Unit, 2002-2013. PATIENTS: Eighty-five neonates with HLHS, matched by birth weight and admission date. MEASUREMENTS: Decompensation was defined as the need for emergency intubation and ventilation due to clinically diagnosed impaired systemic oxygen delivery. The end point was time of decompensation (cases, n=33) or discharge for surgery (controls, n=52). Variable trajectories were modelled non-linearly using generalised estimating equations. RESULTS: Decompensation occurred on median (IQR) day 3 (2-4) of life in cases, with surgery occurring on day 4 (3-7) in controls. Oxygen saturation and blood pressure trajectories were identical between groups (p>0.2). Heart and respiratory rates increased with time overall, but significantly faster in cases than controls; by an average of 4.0 bpm/day versus 1.4 bpm/day (p=0.002) and 5.3 respirations/minute/day versus 1.5 respirations/minute/day, respectively, (p=0.003). Although metabolic blood gas components began to decline subtly 24 h before clinical decompensation, they remained in the normal range for much of this period. CONCLUSIONS: Heart and respiratory rates, and metabolic acid base trajectories show subtle differences prior to decompensation in neonates with HLHS. These findings highlight the importance of evaluating rates of change rather than absolute values of physiological and laboratory variables.

Stenting the atrial septum: a hybrid approach guided solely by echocardiography.

Stenting the atrial septum to achieve decompression of the atrium is well described and commonly performed via a percutaneous catheter approach under combined fluoroscopic and echocardiographic guidance. We describe two successful cases of a hybrid approach to atrial stenting under echocardiographic guidance alone, as a viable alternative approach.

Levomepromazine for difficult sedation in pediatric intensive care.

Sedation and analgesia using opioids and benzodiazepines is frequently required in critically ill children to minimize pain and anxiety. In some patients, difficult sedation occurs when tolerance or unacceptable side effects limit the efficacy of conventional analgo-sedative treatment. We describe seven patients (age range 1 to 17 yr) where difficult sedation was successfully managed with enteral levomepromazine (LMZ). LMZ is a neuroleptic antipsychotic agent that exhibits potent analgo-sedative properties without respiratory depression, through non-opioid and non-benzodiazepine pathways. We describe its use in our pediatric intensive care unit to control agitation in patients with known behavioral disorders who frequently pose a significant sedation challenge. We also illustrate its successful use in cases of withdrawal syndrome and delirium, and discuss the association of fever and its distinction from neuroleptic malignant syndrome in two patients. LMZ should be considered as a useful sedative in critically ill children where difficult sedation occurs and conventional agents are exhausted.

Mechanisms of ventilator dependence in children with neuromuscular and respiratory control disorders identified by monitoring diaphragm electrical activity.

OBJECTIVES: To report on the monitoring of diaphragm electrical activity (Edi) using neurally adjusted ventilator assist (NAVA) technology to investigate the mechanisms of ventilator dependence in children with neuromuscular and respiratory control disorders. PATIENTS AND METHODS: Using NAVA technology, electrical activity of the diaphragm (Edi) was monitored at the lowest achievable level of respiratory support in six ventilator-dependent patients with neuromuscular and respiratory control disorders, aged 6 weeks to 12 years, admitted to a tertiary paediatric intensive care unit between 2009 and 2011. RESULTS: Edi monitoring identified markedly abnormal respiratory dynamic patterns that were not always apparent clinically. These were associated with disorders of central respiratory control, muscle weakness and diaphragm pathology. CONCLUSIONS: Edi monitoring using NAVA technology is a valuable, minimally invasive, diagnostic adjunct in children with neuromuscular and respiratory control disorders who are ventilator-dependent.