Volatile gas scavenging in the paediatric intensive care unit: Occupational health and safety assessment.

Introduction: The use of volatile anesthetic agents in the paediatric intensive care unit (PICU) is experiencing increased interest since the availability of the miniature vapourizing device. However, the effectiveness of scavenging systems in the presence of humidifiers in the ventilator circuit is unknown. Approach Methods: We performed a bench study to evaluate the effectiveness of the Deltasorb® scavenging system in the presence of isoflurane and active humidity by simulating both infant and child ventilator test settings. A total of four ventilators were set to ventilate test lungs, all with active humidity and a Deltasorb scavenging canister collecting exhaled ventilation gas. Two ventilators also had isoflurane delivered using the Anesthesia Conserving Device- small (ACD®-S) on the inspiratory limb (also called alternative ventilator configuration). We performed instantaneous measurements of isoflurane and continuous sampling with passive badges to measure average environmental exposure over a test period of 6.5 hours. Scavenging canisters were returned to the company, where desorption analysis showed the volume of water and isoflurane captured in each canister. Findings: Both instantaneous point sampling and diffusive sampling results were below the occupational exposure limit confirming safety. The canisters collected both isoflurane and a portion of the water vapour delivered; the percentage of captured water and isoflurane collected in infants was higher than the child ventilator test settings. Practice implications Conclusion: The tested scavenging configuration was effective in maintaining a safe working environment with active humidity and inspiratory limb (alternative) ventilator configuration of the the miniature vapourizing device.

Pediatric Esophageal Button Battery Protocol Reduces Time From Presentation to Removal.

OBJECTIVE: Evaluate implementation of an institutional protocol to reduce the time to removal of esophageal button battery (BB) and increase use of mitigation strategies. METHODS: We developed a protocol for esophageal BB management [Zakai's Protocol (ZP)]. All cases of esophageal BB impaction managed at a tertiary care center before and after implementation from 2011 to 2023 were reviewed. Time to BB removal, adherence to critical steps, and use of mitigation strategies (honey/sucralfate, acetic acid) were evaluated. RESULTS: Fifty-one patients (38 pre-ZP, 13 post-ZP) were included. Median age was 2.3 years (IQR 1.3-3.4). After implementation, the time from arrival at the institution to arrival in the operating room (OR) reduced by 4.2 h [4.6 h (IQR 3.9-6.5) to 0.4 h (IQR 0.3-0.6), p < 0.001] and there was improvement in all management steps. The number of referrals direct to otolaryngology increased from 51% to 92%, arrival notification increased from 86% to 100%, avoidance of second x-ray increased from 63% to 100%, and direct transfer to OR increased from 92% to 100%. Adherence to mitigation strategies such as preoperative administration of honey or sucralfate increased from 0% to 38%, intraoperative use of acetic acid from 3% to 77%, and nasogastric tube insertion from 53% to 92%. CONCLUSION: Implementation of ZP substantially reduced the time to BB removal and the use of mitigation strategies in our tertiary care institution. Additional strategies focused on prevention of BB ingestion, and shortening the transfer time to the tertiary care hospital are required to prevent erosive complications. LEVEL OF EVIDENCE: Level 3 Case-series Laryngoscope, 2024.

Percutaneous tracheostomy in the pediatric population: A systematic review.

OBJECTIVE: Percutaneous tracheostomy is routinely performed in adult patients but is seldomly used in the pediatric population due to concerns regarding safety and limited available evidence. This study aims to consolidate the current literature on percutaneous tracheostomy in the pediatric population. METHODS: A systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted. MEDLINE, EMBASE, CINAHL, and Web of Science were searched for studies on pediatric percutaneous tracheostomy (age ≤18). The Joanna Briggs Institute and ROBINS-I tools were used for quality appraisal. RESULTS: Twenty-one articles were included resulting in 143 patients. Patient age ranged from 2 days to 17 years, with the largest subpopulation of patients (n = 57, 40 %) being adolescents (age between 12 and 17 years old). Main indications for percutaneous tracheostomy included prolonged ventilation (n = 6), respiratory insufficiency (n = 5), and upper airway obstruction (n = 5). One-third (n = 47) of percutaneous tracheostomies were completed at the bedside in an intensive care unit. Select studies reported on surgical time and time from intubation to tracheostomy with a mean of 13.8 (SD = 7.8) minutes (n = 27) and 8.9 (SD = 2.8) days (n = 35), respectively. Major postoperative complications included tracheoesophageal fistula (n = 4, 2.8 %) and pneumothorax (n = 3, 2.1 %). There were four conversions to open tracheostomy. CONCLUSION: Percutaneous tracheostomy had a similar risk of complications to open surgical tracheostomy in children and adolescents and can be performed at the bedside in a select group of patients if necessary. However, we feel that consideration must be given to the varying anatomical considerations in children and adolescents compared with adults, and therefore suggest that this procedure be reserved for adolescent patients with a thin body habitus and clearly demarcated and palpable anatomical landmarks who require a tracheostomy. When performed, we strongly support using endoscopic guidance and a surgeon who has the ability to convert to an open tracheostomy if required.

Adenotonsillectomy for obstructive sleep apnea in children with cerebral palsy: Risks and benefits.

OBJECTIVES: To determine outcomes following adenotonsillectomy for obstructive sleep apnea (OSA) and the impact of motor and swallowing impairment on respiratory complications in children with Cerebral Palsy (CP). METHODS: A retrospective review of children with CP and sleep disordered breathing (SDB) who underwent adenotonsillectomy (2003-2021) was performed. Children with CP were age-matched to children without CP. Motor and swallowing function was assessed using the Gross Motor Functional Classification System (GMFCS) and the Eating and Drinking Ability Classification System (EDACS). The primary outcome was postoperative obstructive apnea-hypopnea index (OAHI). Secondary outcomes were cure rate, complications, and need for additional interventions. RESULTS: Ninety-seven children with CP were assessed for SDB, and 74 underwent polysomnography. Moderate or severe OSA was found in 49% (36/74). Adenotonsillectomy was performed in 30% (29/97). All children who underwent adenotonsillectomy experienced an initial reduction in OAHI (31.7/h to 2.9/h, p < 0.0001). Children with CP were less likely to achieve an OAHI<1 compared with children without CP (62.5% vs 81.8%, p = 0.23). Children with CP had more postoperative complications (43.5% vs. 8.7%) and greater odds of respiratory complications compared with children without CP (OR 8.9 95% CI 2.1-37.9). Children with CP and a GMFCS score of 5 and EDACS score between 3 and 5 had more respiratory complications post-adenotonsillectomy compared to those with GMFCS<5 (p = 0.002) and EDACS<3 (p = 0.031). CONCLUSION: Children with CP had an improved OAHI initially following adenotonsillectomy but had higher rates of post-adenotonsillectomy complications. Respiratory complications after adenotonsillectomy were more common in children with motor and swallowing impairment. Findings may provide better preoperative planning for caregivers.

The care of critically ill adults with COVID-19 in Ontario pediatric intensive care units.

PURPOSE: To describe and review the experience of two pediatric intensive care units (PICUs) in Ontario, Canada, adapting and providing care to critically ill adults during the COVID-19 pandemic. CLINICAL FEATURES: At a time of extreme pressure to adult intensive care unit (ICU) capacity, two PICUs provided care to critically ill adults with COVID-19 pneumonia. Substantial yet rapid planning was required to facilitate safe delivery of critical care to adult patients while maintaining PICU services, including thoughtful development of care pathways and patient selection. To prepare clinical staff, several communication strategies, knowledge translation, skill consolidation, and system-adaptation mechanisms were developed. There was iterative adaptation of operational processes, including staffing models, specialist consultation, and the pharmacy. Care provided by the interprofessional teams was reoriented as appropriate to the needs of critically ill adults in close collaboration with adult ICU teams. Forty-one adults were admitted to the two PICUs over a 12-week period. In total, 36 patients (88%) received invasive ventilation, eight patients (20%) were supported with venovenous extracorporeal membrane oxygenation, and six patients (15%) received continuous renal replacement therapy. Four died in the PICU during this period. Feedback from staff included anxiety around reorienting practice to the care of critically ill adults, physical exhaustion, and psychological distress. Importantly, staff also reported a renewed sense of purpose with participation in the program. CONCLUSION: Though challenging, the experience has provided opportunity to enhance collaboration with partner institutions and improve the care of older children and adolescents in the PICU.

RéSUMé: OBJECTIF: Nous avions pour objectif de décrire et examiner l'expérience de deux unités de soins intensifs pédiatriques (USIP) en Ontario, au Canada, qui se sont adaptées et ont fourni des soins aux adultes gravement malades pendant la pandémie de COVID-19. CARACTéRISTIQUES CLINIQUES: À l'époque où la capacité des unités de soins intensifs (USI) pour adultes était extrêmement sollicitée, deux USIP ont prodigué des soins à des adultes gravement malades souffrant de pneumonie liée à la COVID-19. Une planification substantielle mais rapide a été nécessaire pour faciliter la prestation sécuritaire de soins intensifs à une patientèle adulte tout en maintenant les services de l'USIP, y compris l'élaboration réfléchie des trajectoires de soins et la sélection de la patientèle. Pour préparer le personnel clinique, plusieurs stratégies de communication, d'application des connaissances, de consolidation des compétences et de mécanismes d'adaptation du système ont été élaborées. Il y a eu une adaptation progressive des processus opérationnels, y compris des modèles de dotation, des consultations de spécialistes et de la pharmacie. Les soins fournis par les équipes interprofessionnelles ont été réorientés en fonction des besoins des adultes gravement malades en étroite collaboration avec les équipes adultes de soins intensifs. Quarante et une personnes adultes ont été admises dans les deux unités de soins intensifs pédiatriques sur une période de 12 semaines. Au total, 36 adultes (88 %) ont bénéficié d'une ventilation invasive, huit personnes (20 %) ont reçu une oxygénation par membrane extracorporelle veino-veineuse, et six (15 %) ont reçu un traitement substitutif de l'insuffisance rénale en continu. Quatre personnes sont décédées à l'USIP au cours de cette période. Les commentaires du personnel comprenaient de l'anxiété liée à la réorientation de leur pratique vers des soins à des adultes gravement malades, l'épuisement physique et la détresse psychologique. Fait important, le personnel a également signalé un regain de motivation lié à la participation de leur USIP à ce programme. CONCLUSION: Bien que difficile, l'expérience a permis d'améliorer la collaboration avec les établissements partenaires et d'améliorer les soins aux enfants plus âgé·es et aux adolescent·es de l'USIP.

A brain-based definition of death and criteria for its determination after arrest of circulation or neurologic function in Canada: a 2023 clinical practice guideline.

This 2023 Clinical Practice Guideline provides the biomedical definition of death based on permanent cessation of brain function that applies to all persons, as well as recommendations for death determination by circulatory criteria for potential organ donors and death determination by neurologic criteria for all mechanically ventilated patients regardless of organ donation potential. This Guideline is endorsed by the Canadian Critical Care Society, the Canadian Medical Association, the Canadian Association of Critical Care Nurses, Canadian Anesthesiologists' Society, the Canadian Neurological Sciences Federation (representing the Canadian Neurological Society, Canadian Neurosurgical Society, Canadian Society of Clinical Neurophysiologists, Canadian Association of Child Neurology, Canadian Society of Neuroradiology, and Canadian Stroke Consortium), Canadian Blood Services, the Canadian Donation and Transplantation Research Program, the Canadian Association of Emergency Physicians, the Nurse Practitioners Association of Canada, and the Canadian Cardiovascular Critical Care Society.

RéSUMé: Ces Lignes directrices de pratique clinique 2023 Lignes directrices de pratique clinique dicale du décès basée sur l'arrêt permanent de la fonction cérébrale qui s'applique à toute personne, ainsi que des recommandations pour la détermination du décès par des critères circulatoires pour des donneurs d'organes potentiels et des recommandations pour la détermination du décès par des critères neurologiques pour tous les patients sous ventilation mécanique, indépendamment de leur potentiel de donneur d'organes. Les présentes Lignes directrices sont approuvées par la Société canadienne de soins intensifs, l'Association médicale canadienne, l'Association canadienne des infirmiers/infirmières en soins intensifs, la Société canadienne des anesthésiologistes, la Fédération des sciences neurologiques du Canada (représentant la Société canadienne de neurologie, la Société canadienne de neurochirurgie, la Société canadienne de neurophysiologie clinique, l'Association canadienne de neurologie pédiatrique, la Société canadienne de neuroradiologie et le Consortium neurovasculaire canadien), la Société canadienne du sang, le Programme de recherche en don et transplantation du Canada, l'Association canadienne des médecins d'urgence, l'Association des infirmières et infirmiers praticiens du Canada, et la Société canadienne de soins intensifs cardiovasculaires (CANCARE) et la Société canadienne de pédiatrie.

Ancillary radionuclide perfusion studies in the determination of death by neurologic criteria: methods, interpretation, and lexicon-a user guide for the clinician.

Radionuclide perfusion studies have an established ancillary role in determination of death by neurologic criteria (DNC). While critically important, these examinations are not well understood by individuals outside of the imaging specialties. The purpose of this review is to clarify relevant concepts and nomenclature and provide a lexicon of relevant terminology of value to non-nuclear medicine practitioners who wish to better understand these examinations. Radionuclides were first employed to evaluate cerebral blood flow in 1969. Radionuclide DNC examinations that use lipophobic radiopharmaceuticals (RPs) entail a flow phase followed immediately by blood pool images. On flow imaging, presence of intracranial activity within the arterial vasculature is scrutinized following arrival of the RP bolus into the neck. Lipophilic RPs designed for functional brain imaging were introduced to nuclear medicine in the 1980s and were engineered to cross the blood-brain-barrier and be retained in the parenchyma. The lipophilic RP 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO) was first used as an ancillary investigation in DNC in 1986. Examinations using lipophilic RPs entail both flow and parenchymal phase images. According to some guidelines, parenchymal phase uptake should be assessed by tomographic imaging, while other investigators consider simple planar imaging sufficient. Findings of perfusion on either the flow or parenchymal phase of the examination effectively precludes DNC. If the flow phase is omitted or somehow compromised, the parenchymal phase remains sufficient for DNC. A priori, parenchymal phase imaging is superior to flow phase imaging for several reasons and lipophilic RPs are favoured over lipophobic RPs in that both flow and parenchymal phase imaging are performed. Disadvantages of lipophilic RPs are increased cost and the need to procure them from a central laboratory, which can prove difficult, especially outside usual working hours. According to most current guidelines, both lipophilic and lipophobic RP categories are acceptable for use in ancillary investigations in DNC, with a growing overt preference for studies using the lipophilic RPs based on their ability to capture the parenchymal phase. The new adult and pediatric Canadian recommendations favour use of lipophilic RPs to variable degrees, specifically 99mTc-HMPAO, the lipophilic moiety which has undergone the greatest validation. Although ancillary use of radiopharmaceuticals is quite settled in multiple DNC guidelines and best practices, several areas of further research remain open to investigation. Examens auxiliaires de perfusion nucléaire pour la détermination du décès selon des critères neurologiques : méthodes, interprétation et lexique-un guide de l'utilisateur à l'intention du clinicien.

RéSUMé: Les examens de la perfusion nucléaire jouent un rôle auxiliaire bien établi dans la détermination du décès selon des critères neurologiques (DCN). Bien qu'ils soient d'une importance cruciale, ces examens ne sont pas bien compris par les personnes en dehors des spécialités d'imagerie. Le but de cette revue est de clarifier les concepts et la nomenclature pertinents et de fournir un lexique de terminologie pertinente utile aux praticiens non spécialisés en médecine nucléaire qui souhaitent mieux comprendre ces examens. Les radionucléides ont été utilisés pour la première fois pour évaluer la circulation sanguine cérébrale en 1969. Les examens de DCN par radionucléides qui utilisent des produits radiopharmaceutiques (RP) lipophobes impliquent une phase de circulation suivie immédiatement d'images de pool sanguin. Sur l'imagerie en circulation, la présence d'une activité intracrânienne dans le système vasculaire artériel est examinée après l'arrivée du bolus de RP dans le cou. Les RP lipophiles conçus pour l'imagerie cérébrale fonctionnelle ont été introduits en médecine nucléaire dans les années 1980 et ont été conçus pour franchir la barrière hémato-encéphalique et être retenus dans le parenchyme. Le RP lipophile 99mTc-hexaméthylpropylèneamine-oxime (99mTc-HMPAO) a été utilisé pour la première fois comme examen auxiliaire pour le DCN en 1986. Les examens utilisant des RP lipophiles impliquent à la fois des images de circulation et de phase parenchymateuse. Selon certaines lignes directrices, l'absorption durant la phase parenchymateuse devrait être évaluée par imagerie tomographique, tandis que d'autres chercheurs considèrent qu'une imagerie planaire simple suffit. Les résultats de perfusion sur la phase de circulation ou la phase parenchymateuse de l'examen excluent effectivement un DCN. Si la phase de circulation est omise ou compromise d'une manière ou d'une autre, la phase parenchymateuse reste suffisante pour établir un DCN. A priori, l'imagerie en phase parenchymateuse est supérieure à l'imagerie en phase de circulation pour plusieurs raisons et les RP lipophiles sont privilégiés par rapport aux RP lipophobes parce que l'imagerie en circulation et en phase parenchymateuse sont toutes deux réalisées. Les inconvénients des RP lipophiles sont l'augmentation des coûts et la nécessité de les obtenir auprès d'un laboratoire central, ce qui peut s'avérer difficile, surtout en dehors des heures de travail habituelles. Selon la plupart des lignes directrices actuelles, les catégories de RP lipophiles et lipophobes sont toutes deux acceptables pour une utilisation dans les examens auxiliaires pour un DCN, avec une préférence manifeste croissante pour les études utilisant les RP lipophiles en fonction de leur capacité à capturer la phase parenchymateuse. Les nouvelles recommandations canadiennes pour adultes et enfants privilégient l'utilisation de RP lipophiles à des degrés variables, en particulier le 99mTc-HMPAO, le fragment lipophile qui a subi la plus grande validation. Bien que l'utilisation auxiliaire des produits radiopharmaceutiques soit tout à fait établie dans de multiples lignes directrices et meilleures pratiques de DCN, plusieurs domaines de recherche supplémentaires restent ouverts à l'étude.

Ancillary investigations for death determination in infants and children: a systematic review and meta-analysis.

PURPOSE: We performed a systematic review and meta-analysis to determine the diagnostic test accuracy of ancillary investigations for declaration of death by neurologic criteria (DNC) in infants and children. SOURCE: We searched MEDLINE, EMBASE, Web of Science, and Cochrane databases from their inception to June 2021 for relevant randomized controlled trials, observational studies, and abstracts published in the last three years. We identified relevant studies using Preferred Reporting Items for Systematic Reviews and Meta-Analysis methodology and a two-stage review. We assessed the risk of bias using the QUADAS-2 tool, and applied Grading of Recommendations Assessment, Development, and Evaluation methodology to determine the certainty of evidence. A fixed-effects model was used to meta-analyze pooled sensitivity and specificity data for each ancillary investigation with at least two studies. PRINCIPAL FINDINGS: Thirty-nine eligible manuscripts assessing 18 unique ancillary investigations (n = 866) were identified. The sensitivity and specificity ranged from 0.00 to 1.00 and 0.50 to 1.00, respectively. The quality of evidence was low to very low for all ancillary investigations, with the exception of radionuclide dynamic flow studies for which it was graded as moderate. Radionuclide scintigraphy using the lipophilic radiopharmaceutical 99mTc-hexamethylpropyleneamine oxime (HMPAO) with or without tomographic imaging were the most accurate ancillary investigations with a combined sensitivity of 0.99 (95% highest density interval [HDI], 0.89 to 1.00) and specificity of 0.97 (95% HDI, 0.65 to 1.00). CONCLUSION: The ancillary investigation for DNC in infants and children with the greatest accuracy appears to be radionuclide scintigraphy using HMPAO with or without tomographic imaging; however, the certainty of the evidence is low. Nonimaging modalities performed at the bedside require further investigation. STUDY REGISTRATION: PROSPERO (CRD42021278788); registered 16 October 2021.

RéSUMé: OBJECTIF: Nous avons réalisé une revue systématique et une méta-analyse pour déterminer la précision des tests diagnostiques des examens auxiliaires pour la déclaration du décès selon des critères neurologiques (DCN) chez les nourrissons et les enfants. SOURCES: Nous avons effectué des recherches dans les bases de données MEDLINE, EMBASE, Web of Science et Cochrane de leur création jusqu'en juin 2021 pour trouver des études randomisées contrôlées, des études observationnelles et des résumés pertinents publiés au cours des trois dernières années. Nous avons identifié les études pertinentes utilisant la méthodologie PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) et une revue en deux étapes. Nous avons évalué le risque de biais en utilisant l'outil QUADAS-2 et appliqué la méthodologie GRADE (Grading of Recommendations Assessment, Development and Evaluation) afin d'évaluer la certitude des données probantes. Un modèle à effets fixes a été utilisé pour méta-analyser les données de sensibilité et de spécificité regroupées pour chaque examen auxiliaire avec au moins deux études. CONSTATATIONS PRINCIPALES: Trente-neuf manuscrits admissibles évaluant 18 examens auxiliaires uniques (n = 866) ont été identifiés. La sensibilité et la spécificité variaient de 0,00 à 1,00 et de 0,50 à 1,00, respectivement. La qualité des données probantes était faible à très faible pour tous les examens auxiliaires, à l'exception des études de circulation nucléaire dynamique, pour lesquelles elle a été classée comme modérée. La scintigraphie nucléaire à l'aide du produit radiopharmaceutique lipophile 99mTc- hexa-méthyl-propylène amine oxime (HMPAO) avec ou sans imagerie tomographique était à la base des examens auxiliaires les plus précis, avec une sensibilité combinée de 0,99 (intervalle de densité le plus élevé [IDE] à 95 %, 0,89 à 1,00) et une spécificité de 0,97 (IDE à 95 %, 0,65 à 1,00). CONCLUSION: L'examen auxiliaire pour un DCN chez les nourrissons et les enfants offrant la plus grande précision semble être la scintigraphie nucléaire utilisant le HMPAO avec ou sans imagerie tomographique; cependant, la certitude des données probantes est faible. Les modalités sans imagerie réalisées au chevet du patient nécessitent un examen plus approfondi. Enregistrement de l'étude: PROSPERO (CRD42021278788); enregistrée le 16 octobre 2021.

Vascular Complications in Children Following Button Battery Ingestions: A Systematic Review.

CONTEXT: Children presenting to health care facilities with button battery (BB) impaction. OBJECTIVES: To describe characteristics of children with vascular complications after BB impaction, as well as associated outcomes. DATA SOURCES: National Capital Poison Center registry and PubMed database from inception to December 2021. STUDY SELECTION: All reports describing children aged <18 years with vascular, esophageal, or airway complications after BB ingestion. DATA EXTRACTION: We extracted characteristics including date of publication, age and sex of child, battery type and size, duration and location of impaction, complications, subsequent interventions, and interval between battery removal and death. RESULTS: A total of 361 cases involved severe complications or death after BB ingestion (321 cases from the National Capital Poison Center registry database, 40 additional cases from PubMed). Nineteen percent (69 of 361) were fatal and 14% (51 of 361) involved vascular injuries. Three-quarters (75%) of vascular complications were aorto-esophageal fistulae and 82% of vascular injuries were not survivable. Fatal vascular cases had significantly longer median impaction time (96 hours versus 144 hours, P <.05) and a wider range of presenting features than survivors. LIMITATIONS: The total number of cases with vascular complications was small, data reported varied between cases, and no data were available on overall exposure. Long-term morbidity data were not available for the survivors. CONCLUSIONS: Prolonged BB impaction is a risk factor for vascular complications and death. A high index of suspicion is required for children representing with hematemesis after BB impaction, with prompt transfer to a tertiary center because vascular surgical intervention may offer a chance of survival.

Button battery taping prevents oesophageal injury.

AIM: Most button battery (BB) ingestions in children are unwitnessed leading to prolonged exposures and severe complications. One third of ingestions occur from free BB, that are stored or awaiting disposal. Recommendations have been made to cover the terminals of discarded BB with adhesive tape; however, it is unclear if this practice prevents injury. Our aim was to determine if tape could prevent oesophageal injury in a cadaveric porcine model. METHODS: Electrical, masking, packing and duct tape were compared. One BB was left untaped. Taped BBs were placed in a cadaveric porcine oesophagus controlled for temperature and humidification. Specimens were assessed at 0, 0.5, and hourly for 6 h by visual inspection, temperature and pH. BB voltage was measured before and after testing. All tests were repeated in triplicate. RESULTS: Oesophageal specimens demonstrated burn prevention in the packing and duct tape trials. Burns were seen in 2/3 trials with electrical tape and 3/3 trials with masking tape. pH remained neutral throughout the study for all packing and duct tape specimens. pH remained neutral initially for masking tape but increased rapidly to 12 by 2 h. There was no change in battery voltage for the packing tape and duct tape trials. There was a 16.3% reduction in voltage for masking tape which was similar to controls. CONCLUSIONS: Taping BB with packing tape and duct tape prevented oesophageal burns. This may provide a novel method of burn prevention for loose BB intended for disposal.

Identifying and Treating Severe Bone Marrow Necrosis and Fat Embolism Syndrome in Pediatric Patients With Sickle Cell Disease: A Case Report.

Fat embolism syndrome after bone marrow necrosis is an extremely rare complication in sickle cell disease associated with significant morbidity and mortality. A high index of suspicion is required for diagnosis. This case report will assist pediatric clinicians and hematologists to recognize this severe complication in patients with sickle cell disease and to promptly initiate treatment. Red flags include severe bone pain, respiratory distress, neurological impairment, decreasing platelet count, peripheral leukocyte left shift, elevated nucleated red blood cells, and significant elevation in plasma ferritin and lactate dehydrogenase. We report a pediatric patient who was diagnosed early, received urgent red cell exchange transfusion and plasma exchange, and ultimately survived this devastating complication.

Risks and Benefits of Adenotonsillectomy in Children With Cerebral Palsy With Obstructive Sleep Apnea: A Systematic Review.

OBJECTIVES/HYPOTHESIS: Assess the risks and benefits of adenotonsillectomy (AT) for obstructive sleep apnea (OSA) in children with cerebral palsy (CP). STUDY DESIGN: Systematic review. METHODS: We conducted a systematic review of Medline, Embase, and Cochrane Central Registry from 1946 to 2021. Broad search concepts included cerebral palsy, pediatric, tonsillectomy/adenoidectomy, and sleep. Additional articles were identified by searching reference lists. Studies on the safety and efficacy of AT for OSA management in children with CP were included. RESULTS: Fifteen articles met inclusion criteria. Articles were classified into one or more of four themes: intraoperative risk (n = 1), postoperative risk (n = 3), postoperative care requirements (n = 6), and surgical outcomes (n = 7). No intraoperative anesthetic complications were reported. Postoperatively, respiratory complications including pneumonia were common and necessitated additional airway management. Following AT, children with CP required close postoperative observation, experienced increased lengths of stay, and had increased odds of unplanned intensive care unit (ICU) admission. Benefits following AT were improvement in OSA as measured by a reduction in obstructive apnea-hypopnea index (OAHI) as well as improved quality of life in some; however, many patients went on to require tracheostomy due to persistent OSA. CONCLUSIONS: Children with CP who undergo AT have a significant risk of developing a postoperative respiratory complication. Realistic counseling of families around increased perioperative risks in this population is imperative and close postoperative monitoring is critical. Many children will obtain a reduction in OAHI, but additional surgical management is often required, including tracheostomy. Further research is needed to determine the best management strategy for OSA in children with CP. Laryngoscope, 132:687-694, 2022.

Length and amino acid sequence of peptides substituted for the 5-HT3A receptor M3M4 loop may affect channel expression and desensitization.

5-HT3A receptors are pentameric neurotransmitter-gated ion channels in the Cys-loop receptor family. Each subunit contains an extracellular domain, four transmembrane segments (M1, M2, M3, M4) and a 115 residue intracellular loop between M3 and M4. In contrast, the M3M4 loop in prokaryotic homologues is <15 residues. To investigate the limits of M3M4 loop length and composition on channel function we replaced the 5-HT3A M3M4 loop with two to seven alanine residues (5-HT3A-A(n = 2-7)). Mutants were expressed in Xenopus laevis oocytes and characterized using two electrode voltage clamp recording. All mutants were functional. The 5-HT EC(50)'s were at most 5-fold greater than wild-type (WT). The desensitization rate differed significantly among the mutants. Desensitization rates for 5-HT3A-A(2), 5-HT3A-A(4), 5-HT3A-A(6), and 5-HT3A-A(7) were similar to WT. In contrast, 5-HT3A-A(3) and 5-HT3A-A(5) had desensitization rates at least an order of magnitude faster than WT. The one Ala loop construct, 5-HT3A-A(1), entered a non-functional state from which it did not recover after the first 5-HT application. These results suggest that the large M3M4 loop of eukaryotic Cys-loop channels is not required for receptor assembly or function. However, loop length and amino acid composition can effect channel expression and desensitization. We infer that the cytoplasmic ends of the M3 and M4 segments may undergo conformational changes during channel gating and desensitization and/or the loop may influence the position and mobility of these segments as they undergo gating-induced conformational changes. Altering structure or conformational mobility of the cytoplasmic ends of M3 and M4 may be the basis by which phosphorylation or protein binding to the cytoplasmic loop alters channel function.

5-HT3 receptor ion size selectivity is a property of the transmembrane channel, not the cytoplasmic vestibule portals.

5-HT3A receptors select among permeant ions based on size and charge. The membrane-associated (MA) helix lines the portals into the channel's cytoplasmic vestibule in the 4-Å resolution structure of the homologous acetylcholine receptor. 5-HT3A MA helix residues are important determinants of single-channel conductance. It is unknown whether the portals into the cytoplasmic vestibule also determine the size selectivity of permeant ions. We sought to determine whether the portals form the size selectivity filter. Recently, we showed that channels functioned when the entire 5-HT3A M3-M4 loop was replaced by the heptapeptide M3-M4 loop sequence from GLIC, a bacterial Cys-loop neurotransmitter gated ion channel homologue from Gloebacter violaceus. We used homomeric 5-HT3A receptors with either a wild-type (WT) M3-M4 loop or the chimeric heptapeptide (5-HT3A-glvM3M4) loop, i.e., with or without portals. In Na(+)-containing buffer, the WT receptor current-voltage relationship was inwardly rectifying. In contrast, the 5-HT3A-glvM3M4 construct had a negative slope conductance region at voltages less than -80 mV. Glutamine substitution for the heptapeptide M3-M4 loop arginine eliminated the negative slope conductance region. We measured the relative permeabilities and conductances of a series of inorganic and organic cations ranging from 0.9 to 4.5 Å in radius (Li(+), Na(+), ammonium, methylammonium, ethanolammonium, 2-methylethanolammonium, dimethylammonium, diethanolammonium, tetramethylammonium, choline, tris [hydroxymethyl] aminomethane, and N-methyl-d-glucamine). Both constructs had measurable conductances with Li(+), ammonium, and methylammonium (size range of 0.9-1.8-Å radius). Many of the organic cations >2.4 Å acted as competitive antagonists complicating measurement of conductance ratios. Analysis of the permeability ratios by excluded volume theory indicates that the minimal pore radius for 5-HT3A and 5-HT3-glvM3M4 receptors was similar, ∼ 5 Å. We infer that the 5-HT3A size selectivity filter is located in the transmembrane channel and not in the portals into the cytoplasmic vestibule. Thus, the determinants of size selectivity and conductance are located in physically distinct regions of the channel protein.