Weaning strategies for children on home invasive mechanical ventilation.

Children who require home mechanical ventilation (HMV) with an artificial airway or invasive mechanical ventilation (HMV) have a possibility of successful weaning due to the potential of compensatory lung growth. Internationally accepted guidelines on how to wean from HMV in children is not available, we summarize the weaning strategies from the literature reviews combined with our 27-year experience in the Pediatric Home Respiratory Care program at the tertiary care center in Thailand. The readiness to wean is considered in patients with hemodynamic stability, having effective cough measured by maximal inspiratory pressure, requiring a fraction of inspired oxygen (FiO2) < 40%, positive end expiratory pressure <5 cmH2O, and acceptable arterial blood gases. The strategies of weaning is start weaning during the daytime while the child is awake and close monitoring is feasible. Disconnect time is gradually increased through naps and sleeping hours. Weaning from the conventional mechanical ventilator to Bilevel PAP or CPAP are optional. Factors affected the successful weaning are mainly the underlying diseases, complications, growth and development, caregivers, and resources. Weaning should be stopped during acute illness or increased work of breathing. The readiness for decannulation could be determined by using the speaking devices, tracheostomy capping, and measurement of end-expiratory pressure. Polysomnography and airway evaluation by bronchoscopy are recommended before decannulation. Weaning when the child is ready is crucial because living with HMV can be challenging and stressful. Failure to remove a tracheostomy when indicated can result in delayed speech, social problems as well as risk for infection.

Nasal Suctioning Therapy Among Infants With Bronchiolitis Discharged Home From the Emergency Department: A Randomized Clinical Trial.

Importance: Although nasal suctioning is the most frequently used supportive management for bronchiolitis, its benefit remains unknown. Objective: To evaluate the effectiveness of enhanced vs minimal nasal suctioning in treating infants with bronchiolitis after discharge from the emergency department (ED). Design, Setting, and Participants: This single-blind, parallel-group, randomized clinical trial was conducted from March 6, 2020, to December 15, 2022, at 4 tertiary-care Canadian pediatric EDs. Participants included otherwise healthy infants aged 1 to 11 months with a diagnosis of bronchiolitis who were discharged home from the ED. Interventions: Participants were randomized to minimal suctioning via bulb or enhanced suctioning via a battery-operated device before feeding for 72 hours. Main Outcomes and Measures: The primary outcome was additional resource use, a composite of unscheduled revisits for bronchiolitis or use of additional suctioning devices for feeding and/or breathing concerns. Secondary outcomes included health care utilization, feeding and sleeping adequacy, and satisfaction. Results: Of 884 screened patients, 352 were excluded for criteria, 79 declined participation, 81 were otherwise excluded, 372 were randomized (185 to the minimal suction group and 187 to the enhanced suction group), and 367 (median [IQR] age, 4 [2-6] months; 221 boys [60.2%]) completed the trial (184 in the minimal suction and 183 in the enhanced suction group). Additional resource use occurred for 68 of 184 minimal suction participants (37.0%) vs 48 of 183 enhanced suction participants (26.2%) (absolute risk difference, 0.11; 95% CI, 0.01 to 0.20; P = .03). Unscheduled revisits occurred for 47 of 184 minimal suction participants (25.5%) vs 40 of 183 enhanced suction participants (21.9%) (absolute risk difference, 0.04; 95% CI, -0.05 to 0.12; P = .46). A total of 33 of 184 parents in the minimal suction group (17.9%) used additional suctioning devices vs 11 of 183 parents in the enhanced suction group (6.0%) (absolute risk difference, 0.12; 95% CI, 0.05 to 0.19; P < .001). No significant between-group differences were observed for all bronchiolitis revisits (absolute risk difference, 0.07; 95% CI, -0.02 to 0.16; P = .15), ED revisits (absolute risk difference, 0.04; 95% CI, -0.03 to 0.12; P = .30), parental care satisfaction (absolute risk difference, -0.02; 95% CI, -0.10 to 0.06; P = .70), and changes from baseline to 72 hours in normal feeding (difference in differences, 0.03; 95% CI, -0.10 to 0.17; P = .62), normal sleeping (difference in differences, 0.05; 95% CI, -0.08 to 0.18; P = .47), or normal parental sleeping (difference in differences, 0.10; 95% CI, -0.02 to 0.23; P = .09). Parents in the minimal suction group were less satisfied with the assigned device (62 of 184 [33.7%]) than parents in the enhanced suction group (145 of 183 [79.2%]) (risk difference, 0.45; 95% CI, 0.36 to 0.54; P < .001). Conclusions and Relevance: Compared with minimal suctioning, enhanced suctioning after ED discharge with bronchiolitis did not alter the disease course because there were no group differences in revisits or feeding and sleeping adequacy. Minimal suctioning resulted in higher use of nonassigned suctioning devices and lower parental satisfaction with the assigned device. Trial Registration: ClinicalTrials.gov Identifier: NCT03361371.

European Respiratory Society/American Thoracic Society technical statement: standardisation of the measurement of lung volumes, 2023 update.

This document updates the 2005 European Respiratory Society (ERS) and American Thoracic Society (ATS) technical standard for the measurement of lung volumes. The 2005 document integrated the recommendations of an ATS/ERS task force with those from an earlier National Heart, Lung, and Blood Institute workshop that led to the publication of background papers between 1995 and 1999 and a consensus workshop report with more in-depth descriptions and discussion. Advancements in hardware and software, new research and emerging approaches have necessitated an update to the 2005 technical standard to guide laboratory directors, physiologists, operators, pulmonologists and manufacturers. Key updates include standardisation of linked spirometry, new equipment quality control and validation recommendations, generalisation of the multiple breath washout concept beyond nitrogen, a new acceptability and grading system with addition of example tracings, and a brief review of imaging and other new techniques to measure lung volumes. Future directions and key research questions are also noted.

International consensus on lung function testing during the COVID-19 pandemic and beyond.

Coronavirus disease 2019 (COVID-19) has negatively affected the delivery of respiratory diagnostic services across the world due to the potential risk of disease transmission during lung function testing. Community prevalence, reoccurrence of COVID-19 surges and the emergence of different variants of SARS-CoV-2 have impeded attempts to restore services. Finding consensus on how to deliver safe lung function services for both patients attending and for staff performing the tests are of paramount importance. This international statement presents the consensus opinion of 23 experts in the field of lung function and respiratory physiology balanced with evidence from the reviewed literature. It describes a robust roadmap for restoration and continuity of lung function testing services during the COVID-19 pandemic and beyond. Important strategies presented in this consensus statement relate to the patient journey when attending for lung function tests. We discuss appointment preparation, operational and environmental issues, testing room requirements including mitigation strategies for transmission risk, requirement for improved ventilation, maintaining physical distance and use of personal protection equipment. We also provide consensus opinion on precautions relating to specific tests, filters, management of special patient groups and alternative options to testing in hospitals. The pandemic has highlighted how vulnerable lung function services are and forces us to re-think how long-term mitigation strategies can protect our services during this and any possible future pandemic. This statement aspires to address the safety concerns that exist and provide strategies to make lung function tests and the testing environment safer when tests are required.

Association Between Intravenous Magnesium Therapy in the Emergency Department and Subsequent Hospitalization Among Pediatric Patients With Refractory Acute Asthma: Secondary Analysis of a Randomized Clinical Trial.

Importance: Despite guidelines recommending administration of intravenous (IV) magnesium sulfate for refractory pediatric asthma, the number of asthma-related hospitalizations has remained stable, and IV magnesium therapy is independently associated with hospitalization. Objective: To examine the association between IV magnesium therapy administered in the emergency department (ED) and subsequent hospitalization among pediatric patients with refractory acute asthma after adjustment for patient-level variables. Design, Setting, and Participants: This post hoc secondary analysis of a double-blind randomized clinical trial of children with acute asthma treated from September 26, 2011, to November 19, 2019, at 7 Canadian tertiary care pediatric EDs was conducted between September and November 2020. In the randomized clinical trial, 816 otherwise healthy children aged 2 to 17 years with Pediatric Respiratory Assessment Measure (PRAM) scores of 5 points or higher after initial therapy with systemic corticosteroids and inhaled albuterol with ipratropium bromide were randomly assigned to 3 nebulized treatments of albuterol plus either magnesium sulfate or 5.5% saline placebo. Exposures: Intravenous magnesium sulfate therapy (40-75 mg/kg). Main Outcomes and Measures: The association between IV magnesium therapy in the ED and subsequent hospitalization for asthma was assessed using multivariable logistic regression analysis. Analyses were adjusted for year epoch at enrollment, receipt of IV magnesium, PRAM score after initial therapy and at ED disposition, age, sex, duration of respiratory distress, previous intensive care unit admission for asthma, hospitalizations for asthma within the past year, atopy, and receipt of oral corticosteroids within 48 hours before arrival in the ED, nebulized magnesium, and additional albuterol after inhaled magnesium or placebo, with site as a random effect. Results: Among the 816 participants, the median age was 5 years (interquartile range, 3-7 years), 517 (63.4%) were boys, and 364 (44.6%) were hospitalized. A total of 215 children (26.3%) received IV magnesium, and 190 (88.4%) of these children were hospitalized compared with 174 of 601 children (29.0%) who did not receive IV magnesium. Multivariable factors associated with hospitalization were IV magnesium receipt from 2011 to 2016 (odds ratio [OR], 22.67; 95% CI, 6.26-82.06; P < .001) and from 2017 to 2019 (OR, 4.19; 95% CI, 1.99-8.86; P < .001), use of additional albuterol (OR, 5.94; 95% CI, 3.52-10.01; P < .001), and increase in PRAM score at disposition (per 1-U increase: OR, 2.24; 95% CI, 1.89-2.65; P < .001). In children with a disposition PRAM score of 3 or lower, receipt of IV magnesium therapy was associated with hospitalization (OR, 8.52; 95% CI, 2.96-24.41; P < .001). Conclusions and Relevance: After adjustment for patient-level characteristics, receipt of IV magnesium therapy after initial asthma treatment in the ED was associated with subsequent hospitalization. This association also existed among children with mild asthma at ED disposition. Evidence of a benefit of IV magnesium regarding hospitalization may clarify its use in the treatment of refractory pediatric asthma. Trial registration: ClinicalTrials.gov: NCT01429415.

Humidified and Heated Cascade Impactor for Aerosol Sizing.

Aerosol sizing is generally measured at ambient air but human airways have different temperature (37°C) and relative humidity (100%) which can affect particle size in airways and consequently deposition prediction. This work aimed to develop and evaluate a new method using cascade impactor to measure particle size at human physiological temperature and humidity (HPTH) taking into account ambient air conditions. A heated and humidified trachea was built and a cascade impactor was heated to 37°C and humidified inside. Four medical aerosols [jet nebulizer, mesh nebulizer, Presurized Metered Dose Inhaler (pMDI), and Dry Powder Inhaler (DPI)] under ambient conditions and at HPTH were tested. MMAD was lower at HPTH for the two nebulizers; it was similar at ambient conditions and HPTH for pMDI, and the mass of particles smaller than 5 µm decreased for DPI at HPTH (51.9 vs. 82.8 µg/puff). In conclusion, we developed a new method to measure particle size at HPTH affecting deposition prediction with relevance. In vivo studies are required to evaluate the interest of this new model to improve the precision of deposition prediction.

Effect of Nebulized Magnesium vs Placebo Added to Albuterol on Hospitalization Among Children With Refractory Acute Asthma Treated in the Emergency Department: A Randomized Clinical Trial.

Importance: While intravenous magnesium decreases hospitalizations in refractory pediatric acute asthma, it is variably used because of invasiveness and safety concerns. The benefit of nebulized magnesium to prevent hospitalization is unknown. Objective: To evaluate the effectiveness of nebulized magnesium in children with acute asthma remaining in moderate or severe respiratory distress after initial therapy. Design, Setting, and Participants: A randomized double-blind parallel-group clinical trial from September 26, 2011, to November 19, 2019, in 7 tertiary-care pediatric emergency departments in Canada. The participants were otherwise healthy children aged 2 to 17 years with moderate to severe asthma defined by a Pediatric Respiratory Assessment Measure (PRAM) score of 5 or greater (on a 12-point scale) after a 1-hour treatment with an oral corticosteroid and 3 inhaled albuterol and ipratropium treatments. Of 5846 screened patients, 4332 were excluded for criteria, 273 declined participation, 423 otherwise excluded, 818 randomized, and 816 analyzed. Interventions: Participants were randomized to 3 nebulized albuterol treatments with either magnesium sulfate (n = 410) or 5.5% saline placebo (n = 408). Main Outcomes and Measures: The primary outcome was hospitalization for asthma within 24 hours. Secondary outcomes included PRAM score; respiratory rate; oxygen saturation at 60, 120, 180, and 240 minutes; blood pressure at 20, 40, 60, 120, 180, and 240 minutes; and albuterol treatments within 240 minutes. Results: Among 818 randomized patients (median age, 5 years; 63% males), 816 completed the trial (409 received magnesium; 407, placebo). A total of 178 of the 409 children who received magnesium (43.5%) were hospitalized vs 194 of the 407 who received placebo (47.7%) (difference, -4.2%; absolute risk difference 95% [exact] CI, -11% to 2.8%]; P = .26). There were no significant between-group differences in changes from baseline to 240 minutes in PRAM score (difference of changes, 0.14 points [95% CI, -0.23 to 0.50]; P = .46); respiratory rate (0.17 breaths/min [95% CI, -1.32 to 1.67]; P = .82); oxygen saturation (-0.04% [95% CI, -0.53% to 0.46%]; P = .88); systolic blood pressure (0.78 mm Hg [95% CI, -1.48 to 3.03]; P = .50); or mean number of additional albuterol treatments (magnesium: 1.49, placebo: 1.59; risk ratio, 0.94 [95% CI, 0.79 to 1.11]; P = .47). Nausea/vomiting or sore throat/nose occurred in 17 of the 409 children who received magnesium (4%) and 5 of the 407 who received placebo (1%). Conclusions and Relevance: Among children with refractory acute asthma in the emergency department, nebulized magnesium with albuterol, compared with placebo with albuterol, did not significantly decrease the hospitalization rate for asthma within 24 hours. The findings do not support use of nebulized magnesium with albuterol among children with refractory acute asthma. Trial Registration: ClinicalTrials.gov Identifier: NCT01429415.

ERS technical standard on bronchial challenge testing: pathophysiology and methodology of indirect airway challenge testing.

Recently, this international task force reported the general considerations for bronchial challenge testing and the performance of the methacholine challenge test, a "direct" airway challenge test. Here, the task force provides an updated description of the pathophysiology and the methods to conduct indirect challenge tests. Because indirect challenge tests trigger airway narrowing through the activation of endogenous pathways that are involved in asthma, indirect challenge tests tend to be specific for asthma and reveal much about the biology of asthma, but may be less sensitive than direct tests for the detection of airway hyperresponsiveness. We provide recommendations for the conduct and interpretation of hyperpnoea challenge tests such as dry air exercise challenge and eucapnic voluntary hyperpnoea that provide a single strong stimulus for airway narrowing. This technical standard expands the recommendations to additional indirect tests such as hypertonic saline, mannitol and adenosine challenge that are incremental tests, but still retain characteristics of other indirect challenges. Assessment of airway hyperresponsiveness, with direct and indirect tests, are valuable tools to understand and to monitor airway function and to characterise the underlying asthma phenotype to guide therapy. The tests should be interpreted within the context of the clinical features of asthma.

Does Size Matter When Calculating the "Correct" Tidal Volume for Pediatric Mechanical Ventilation?: A Hypothesis Based on FVC.

BACKGROUND: Tidal volumes standardized to predicted body weight are recommended for adult mechanical ventilation, but children are frequently ventilated by using measured body weight. The goal of this study was to examine the difference in FVC (in milliliters per kilogram [mL/kg]) by using measured body weight compared with predicted body weight in children. METHODS: This retrospective analysis included outpatient pulmonary function tests (PFTs) from two datasets. Dataset one included 6- to 19-year-old patients undergoing PFTs from the nationally representative Canadian Health Measures Survey. Dataset two included 6- to 20-year-old patients undergoing PFTs at a freestanding children's hospital. FVC mL/kg values were analyzed against BMI z scores to show changes in FVC vs BMI between measured and predicted weight. RESULTS: Dataset one included 5,394 PFTs from the Canadian survey. FVC from measured weight decreased as the BMI z score group increased. The median FVC from measured weight was 81.4 mL/kg in the lowest BMI z score group and 51.7 mL/kg in the highest BMI z score group. FVC from predicted weight increased slightly with increasing BMI z score group. Dataset two included 8,472 patient PFTs from clinical measurement. A decline in median FVC from measured weight (from 69.4 to 37.6 mL/kg) as BMI z score group increased was also seen. CONCLUSIONS: FVC differs significantly when standardizing to measured weight vs predicted weight. Obese children have lung volumes reflecting their predicted body weight from height. Children with low or normal BMI have lung volumes reflecting measured body weight. These findings suggest that targeting tidal volume by using the lower of measured and predicted body weights would be the most lung-protective strategy.

Transducing Airway Basal Cells with a Helper-Dependent Adenoviral Vector for Lung Gene Therapy.

A major challenge in developing gene-based therapies for airway diseases such as cystic fibrosis (CF) is sustaining therapeutic levels of transgene expression over time. This is largely due to airway epithelial cell turnover and the host immunogenicity to gene delivery vectors. Modern gene editing tools and delivery vehicles hold great potential for overcoming this challenge. There is currently not much known about how to deliver genes into airway stem cells, of which basal cells are the major type in human airways. In this study, helper-dependent adenoviral (HD-Ad) vectors were delivered to mouse and pig airways via intranasal delivery, and direct bronchoscopic instillation, respectively. Vector transduction was assessed by immunostaining of lung tissue sections, which revealed that airway basal cells of mice and pigs can be targeted in vivo. In addition, efficient transduction of primary human airway basal cells was verified with an HD-Ad vector expressing green fluorescent protein. Furthermore, we successfully delivered the human CFTR gene to airway basal cells from CF patients, and demonstrated restoration of CFTR channel activity following cell differentiation in air-liquid interface culture. Our results provide a strong rationale for utilizing HD-Ad vectors to target airway basal cells for permanent gene correction of genetic airway diseases.

Recommendations for a Standardized Pulmonary Function Report. An Official American Thoracic Society Technical Statement.

BACKGROUND: The American Thoracic Society committee on Proficiency Standards for Pulmonary Function Laboratories has recognized the need for a standardized reporting format for pulmonary function tests. Although prior documents have offered guidance on the reporting of test data, there is considerable variability in how these results are presented to end users, leading to potential confusion and miscommunication. METHODS: A project task force, consisting of the committee as a whole, was approved to develop a new Technical Standard on reporting pulmonary function test results. Three working groups addressed the presentation format, the reference data supporting interpretation of results, and a system for grading quality of test efforts. Each group reviewed relevant literature and wrote drafts that were merged into the final document. RESULTS: This document presents a reporting format in test-specific units for spirometry, lung volumes, and diffusing capacity that can be assembled into a report appropriate for a laboratory's practice. Recommended reference sources are updated with data for spirometry and diffusing capacity published since prior documents. A grading system is presented to encourage uniformity in the important function of test quality assessment. CONCLUSIONS: The committee believes that wide adoption of these formats and their underlying principles by equipment manufacturers and pulmonary function laboratories can improve the interpretation, communication, and understanding of test results.

ERS technical standard on bronchial challenge testing: general considerations and performance of methacholine challenge tests.

This international task force report updates general considerations for bronchial challenge testing and the performance of the methacholine challenge test. There are notable changes from prior recommendations in order to accommodate newer delivery devices. Rather than basing the test result upon a methacholine concentration (provocative concentration (PC20) causing a 20% fall in forced expiratory volume in 1 s (FEV1)), the new recommendations base the result upon the delivered dose of methacholine causing a 20% fall in FEV1 (provocative dose (PD20)). This end-point allows comparable results from different devices or protocols, thus any suitable nebuliser or dosimeter may be used, so long as the delivery characteristics are known. Inhalation may be by tidal breathing using a breath-actuated or continuous nebuliser for 1 min (or more), or by a dosimeter with a suitable breath count. Tests requiring maximal inhalations to total lung capacity are not recommended because the bronchoprotective effect of a deep breath reduces the sensitivity of the test.

Magnesium nebulization utilization in management of pediatric asthma (MagNUM PA) trial: study protocol for a randomized controlled trial.

BACKGROUND: Up to 30 % of children with acute asthma are refractory to initial therapy, and 84 % of this subpopulation needs hospitalization. Finding safe, noninvasive, and effective strategies to treat this high-risk group would substantially decrease hospitalizations, healthcare costs, and the psycho-social burden of the disease. Whereas intravenous magnesium (Mg) is effective in severe refractory asthma, its use is sporadic due to safety concerns, with the main treatment goal being to prevent intensive care unit admission. In contrast, nebulized Mg is noninvasive, allows higher pulmonary drug concentrations, and has a much higher safety potential due to the lower rate of systemic delivery. Previous studies of inhaled Mg show disparate results due to the use of unknown/inefficient delivery methods and other methodological flaws. METHODS/DESIGN: The study is a randomized double-blind controlled trial in seven Canadian pediatric Emergency Departments (two-center pilot 2011 to 2014, Canada-wide November 2014 to December 2017). The trial will include 816 otherwise healthy children who are 2 to 17 years old, having had at least one previous wheezing episode, have received systemic corticosteroids, and have a Pediatric Respiratory Assessment Measure (PRAM) ≥ 5 points after three salbutamol and ipratropium treatments for a current acute asthma exacerbation. Eligible consenting children will receive three experimental treatments of nebulized salbutamol with either 600 mg of Mg sulfate or placebo 20 min apart, using an Aeroneb Go nebulizer, which has been shown to maximize pulmonary delivery while maintaining safety. The primary outcome is hospitalization within 24 h of the start of the experimental therapy for persistent respiratory distress or supplemental oxygen. Secondary outcomes include all-cause hospitalization within 24 h, PRAM, vital signs, number of bronchodilator treatments by 240 min, and the association between the difference in the primary outcome between the groups, age, gender, baseline PRAM, atopy, and "viral induced wheeze" phenotype (Fig. 1). DISCUSSION: If effective, inhaled Mg may represent an effective strategy to minimize morbidity in pediatric refractory acute asthma. Unlike previous works, this trial targets nonresponders to optimized initial therapy who are the most likely to benefit from inhaled Mg. Future dissemination of results will include knowledge translation, incorporation into a Cochrane Review, presentation at scientific meetings, and a peer-reviewed publication. TRIAL REGISTRATION: NCTO1429415 , registered 2 September 2011.

Reference Equations for Spirometry in the Canadian Population.

RATIONALE: Spirometry plays a major role in the diagnosis and assessment of severity of lung disease. Determining which lung function values are normal and which are below the lower limit of normal depends on reference equations derived from an appropriate population. OBJECTIVES: The purpose of this study was to derive spirometric reference equations for the Canadian population. METHODS: The Canadian Health Measures Survey consisted of a respiratory questionnaire, urinary cotinine measurements, and spirometry performed in the sitting position with rigorous quality control standards. Of the 16,606 respondents between 6 and 79 years of age, 11,145 were eliminated for positive responses to the respiratory questionnaire, tobacco exposure, or inability to provide high-quality spirograms. Of the remaining 5,461, roughly half were less than 18 years of age. Quantile regression was used to derive predictive (median) and lower limit of normal equations for males and females for FEV1, FVC, and FEV1/FVC ratio for those with ages greater and less than 18 years. MEASUREMENTS AND MAIN RESULTS: The resulting equations were compared with those from the Global Lung Initiative (GLI) and National Health and Nutrition Examination Survey (NHANES) III by using an ideal subject on the 50th percentile for height and between the ages of 6 and 79 years; the comparison showed minor and inconsistent discrepancies among the predictive equations. A plot of residuals (predicted minus measured value for each subject) suggested a marginally better fit compared with the GLI and NHANES III equations, although differences among the equations were small and unlikely to have any clinical significance. CONCLUSIONS: This study provides spirometric reference equations for the Canadian population that were measured under the recommended clinical conditions and with rigorous quality control.

Effect of Oxygen Desaturations on Subsequent Medical Visits in Infants Discharged From the Emergency Department With Bronchiolitis.

IMPORTANCE: Reliance on pulse oximetry has been associated with increased hospitalizations, prolonged hospital stay, and escalation of care. OBJECTIVE: To examine whether there is a difference in the proportion of unscheduled medical visits within 72 hours of emergency department discharge in infants with bronchiolitis who have oxygen desaturations to lower than 90% for at least 1 minute during home oximetry monitoring vs those without desaturations. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study conducted from February 6, 2008, to April 30, 2013, at a tertiary care pediatric emergency department in Toronto, Ontario, Canada, among 118 otherwise healthy infants aged 6 weeks to 12 months discharged home from the emergency department with a diagnosis of acute bronchiolitis. MAIN OUTCOMES AND MEASURES: The primary outcome was unscheduled medical visits for bronchiolitis, including a visit to any health care professional due to concerns about respiratory symptoms, within 72 hours of discharge in infants with and without desaturations. Secondary outcomes included examination of the severity and duration of the desaturations, delayed hospitalizations within 72 hours of discharge, and the effect of activity on desaturations. RESULTS: A total of 118 infants were included (mean [SD] age, 4.5 [2.1] months; 69 male [58%]). During a mean (SD) monitoring period of 19 hours 57 minutes (10 hours 37 minutes), 75 of 118 infants (64%) had at least 1 desaturation event (median continuous duration, 3 minutes 22 seconds; interquartile range, 1 minute 54 seconds to 8 minutes 50 seconds). Among the 118 infants, 59 (50%) had at least 3 desaturations, 12 (10%) had desaturation for more than 10% of the monitored time, and 51 (43%) had desaturations lasting 3 or more minutes continuously. Of the 75 infants who had desaturations, 59 (79%) had desaturation to 80% or less for at least 1 minute and 29 (39%) had desaturation to 70% or less for at least 1 minute. Of the 75 infants with desaturations, 18 (24%) had an unscheduled visit for bronchiolitis as compared with 11 of the 43 infants without desaturation (26%) (difference, -1.6%; 95% CI, -0.15 to ∞; P = .66). One of the 75 infants with desaturations (1%) and 2 of the 43 infants without desaturations (5%) were hospitalized within 72 hours (difference, -3.3%; 95% CI, -0.04 to 0.10; P = .27). Among the 62 infants with desaturations who had diary information, 48 (77%) experienced them during sleep or while feeding. CONCLUSIONS AND RELEVANCE: The majority of infants with mild bronchiolitis experienced recurrent or sustained desaturations after discharge home. Children with and without desaturations had comparable rates of return for care, with no difference in unscheduled return medical visits and delayed hospitalizations.

Delivery of Epinephrine in the Vapor Phase for the Treatment of Croup.

OBJECTIVES: The Vapotherm system delivers high humidity to the airway of patients by using semipermeable tubules where heated liquid water is in contact with air. The humidified air is conducted to the patient via a heated tube. Preliminary clinical observations in infants with croup suggested that epinephrine added to the water supplying the humidity was delivered successfully in the vapor phase. The purpose of this study was to evaluate the efficiency of the delivery of epinephrine in the vapor phase and to develop the feasibility criteria for a clinical pilot study. DESIGN: Thirty milligrams of epinephrine in a 1-L bag of sterile water was used as the humidification source for a Vapotherm 2000i. The output of the heated circuit was condensed and collected into a small Erlenmeyer flask via a metal coil while the whole collection system was submerged in an ice slurry to maintain the outflow temperature from the flask between 0°C and 2°C. The in vitro system was tested at 40°C with flows of 5, 10, and 15 L/min and L-epinephrine concentrations of 15, 30, and 60 mg/L. Each test was duplicated at each of the six conditions. SETTING: Academic children's hospital research laboratory. PATIENTS: None. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The system recovered more than 90% of the water vapor from the fully saturated air at 40°C. The epinephrine concentration recovery quantified by ultraviolet-visible spectrophotometry was 23.9% (27.5-20.4%) (mean and range) of the initial concentration. At flows of 5, 10, and 15 L/min, the delivery of epinephrine would be 1.8, 3.6, and 4.2 µg/min, respectively, which is in the therapeutic range used for parenteral infusion in young children. CONCLUSIONS: The Vapotherm system can be used to deliver epinephrine in pharmacological doses to the respiratory system as a vapor and thus as an alternative to droplets by conventional nebulization.