A Survey of Cystic Fibrosis Center Recommendations for Nebulizer Cleaning and Disinfection.

BACKGROUND: Despite advancements in cystic fibrosis (CF) therapeutics, the persistence of chronic infections necessitates continued use of nebulized therapies. Though the Cystic Fibrosis Foundation recommends well-defined cleaning and disinfection of nebulizers to mitigate pathogen exposure risks, discrepancies between Cystic Fibrosis Foundation guidelines, manufacturers' instructions, and variability in center recommendations contribute to confusion and non-standardized practices. METHODS: A digital survey was distributed to directors, associate directors, and care coordinators of CF centers across the United States to investigate the methods, frequency, and educational practices surrounding nebulizer care they provide patients. Responses were analyzed using descriptive techniques and chi-square analyses. RESULTS: Of 855 distributed surveys, 129 respondents provided insights into nebulizer care recommendations. Discrepancies in disinfection frequency were notable, with 18% of respondents recommending disinfecting nebulizers less than daily. Approximately 20% of respondents were unsure if their recommendations aligned with Cystic Fibrosis Foundation guidelines while 73% reported that their recommendations strictly adhered to the published guidelines. Of this 73%, all recommended at least daily cleaning, with 69% specifying cleaning before reuse; and 88% recommended disinfection at least daily, with 36% specifying disinfection before reuse. Only 10% recommended both cleaning and disinfection after every use. Disinfection less than daily was recommended by 11% of the respondents who felt they were strictly following the guidelines. We also highlight respondents who cited barriers to strict adhesion to the published guidelines. CONCLUSIONS: The highlighted variations in CF centers' recommendations for nebulizer care with deviations from Cystic Fibrosis Foundation guidelines underscore the necessity for developing clear and practical guidelines that consider both efficacy and the realities of patient adherence. Collaboration among CF care centers, patients, guideline committees, and other stakeholders is essential to develop recommendations that effectively address the challenges faced by the CF community, ensuring the safe and effective nebulizer use.

An adolescent with Wolfram syndrome and central sleep apnea.

Wolfram syndrome is a rare autosomal recessive disorder affecting approximately 1 in 500,000 individuals. The disorder is most commonly caused by mutations in the WFS1 gene, which encodes an endoplasmic reticulum protein, wolframin, which is thought to protect against endoplasmic reticulum stress-related apoptosis. The major clinical findings of Wolfram syndrome are diabetes mellitus and optic atrophy, both of which usually appear before 16 years of age. Common additional findings include sensorineural hearing impairment, central diabetes insipidus, nonautoimmune hypothyroidism, delayed puberty, neurogenic bladder, cerebellar ataxia, and psychiatric disorders. Central sleep apnea is an uncommon but serious feature of Wolfram syndrome. However, the clinical details of this manifestation have not been documented. Herein, we report an adolescent with recently diagnosed Wolfram syndrome who demonstrated severe central sleep apnea on polysomnography testing. CITATION: Harris JC, Kenkare JD, Schramm CM. An adolescent with Wolfram syndrome and central sleep apnea. J Clin Sleep Med. 2024;20(7):1205-1208.

Bacterial Surface Detachment during Nebulization with Contaminated Reusable Home Nebulizers.

Patients with chronic respiratory diseases use home nebulizers that are often contaminated with pathogenic microbes to deliver aerosolized medications. The conditions under which these microbes leave the surface as bioaerosols during nebulization are not well characterized. The objectives of this study were to (i) determine whether different pathogens detach and disperse from the nebulizer surface during aerosolization and (ii) measure the effects of relative humidity and drying times on bacterial surface detachment and aerosolization. Bacteria were cultured from bioaerosols after Pari LC Plus albuterol nebulization using two different sources, as follows: (i) previously used nebulizers donated by anonymous patients with cystic fibrosis (CF) and (ii) nebulizers inoculated with bacteria isolated from the lungs of CF patients. Fractionated bioaerosols were collected with a Next-Generation Impactor. For a subset of bacteria, surface adherence during rewetting was measured with fluorescence microscopy. Bacteria dispersed from the surface of used CF patient nebulizers during albuterol nebulization. Eighty percent (16/20) of clinical isolates inoculated on the nebulizer in the laboratory formed bioaerosols. Detachment from the plastic surface into the chamber solution predicted bioaerosol production. Increased relative humidity and decreased drying times after inoculation favored bacterial dispersion on aerosols during nebulized therapy. Pathogenic bacteria contaminating nebulizer surfaces detached from the surface as bioaerosols during nebulized therapies, especially under environmental conditions when contaminated nebulizers were dried or stored at high relative humidity. This finding emphasizes the need for appropriate nebulizer cleaning, disinfection, and complete drying during storage and informs environmental conditions that favor bacterial surface detachment during nebulization. IMPORTANCE Studies from around the world have demonstrated that many patients use contaminated nebulizers to deliver medication into their lungs. While it is known that using contaminated medications in a nebulizer can lead to a lung infection, whether bacteria on the surface of a contaminated nebulizer detach as bioaerosols capable of reaching the lung has not been studied. This work demonstrates that a subset of clinical bacteria enter solution from the surface during nebulization and are aerosolized. Environmental conditions of high relative humidity during storage favor dispersion from the surface. We also provide results of an in vitro assay conducted to monitor bacterial surface detachment during multiple cycles of rewetting that correlate with the results of nebulizer/bacterial surface interactions. These studies demonstrate for the first time that pathogenic bacteria on the nebulizer surface pose a risk of bacterial inhalation to patients who use contaminated nebulizers.

Two vs four puffs of albuterol: does dose change bronchodilator response?

BACKGROUND: Reversible obstruction on spirometry may be used to diagnose asthma. As per 2005 American Thoracic Society (ATS) guidelines, our pulmonary center began using 360 µg (four puffs) of albuterol rather than 180 µg (two puffs) to determine reversibility on spirometry starting in 2009. HYPOTHESIS: We hypothesized that fewer patients would respond to two puffs of albuterol than four puffs during spirometric testing. METHODS: We retrospectively reviewed records from new asthmatics seen in Pediatric Pulmonary Clinic from March 2002 to April 2014 who performed reproducible spirometry. Patients were divided into two groups based on whether they had received two or four puffs of albuterol for bronchodilator assessment. A positive bronchodilator response was defined as an increase of ≥12% in forced expiratory volume in one second (FEV1) or ≥25% in forced expiratory flow (FEF25-75%). Data were expressed as percentages and mean ± standard error of the mean values. Chi-squared test and Student's t-test were utilized. RESULTS: Data were collected for 240 patients; 115 patients received two puffs of albuterol and 125 patients received four puffs. There were no significant differences in baseline characteristics between the two groups. There were no differences following two puffs or four puffs in changes in FEV1 (10.0±1.1% vs 10.5±1.1% predicted) or FEF25-75% (30.2±2.9% vs 33.5±2.9% predicted). Moreover, there was no difference in ATS-defined bronchodilator response between the two groups. CONCLUSION: Based on the mean change in FEV1 and overall bronchodilator responsiveness, two puffs of albuterol were not inferior to four puffs in the determination of bronchodilator responsiveness in our pediatric asthmatic patients.

Repeated hot water and steam disinfection of Pari LC Plus® nebulizers alter nebulizer output.

Currently, cystic fibrosis patients require daily nebulized treatments to achieve optimal lung health. Growth of pathogenic bacteria in patient nebulizers is well known, and disinfection guidelines have been established. In this short communication, we sought to discover what effect, if any, repeated nebulization/disinfection cycles had on nebulizer output. We nebulized saline repeatedly after exposure to boiling water, steam, and alcohol disinfection methods. While alcohol disinfection did not affect nebulizer output, boiling water and steam significantly decreased nebulizer output from baseline, 74.1 ±â€¯5.9% (p = 0.022) and steam 63.6 ±â€¯6.5% (p = 0.0048) after 60 cycles respectively. This decrease in nebulizer output could significantly increase the duration of nebulizer treatment time and negatively impact the burden of care on patients with cystic fibrosis.

Early-life antibiotics attenuate regulatory T cell generation and increase the severity of murine house dust mite-induced asthma.

INTRODUCTION: Early-life exposure to antibiotics (ABX) has been linked to increases in asthma severity and prevalence in both children and laboratory animals. We explored the immunologic mechanisms behind this association using a mouse model of house dust mite (HDM)-induced asthma and early-life ABX exposure. METHODS: Mice were exposed to three short courses of ABX following weaning and experimental asthma was thereafter induced. Airway cell counts and differentials; serum immunoglobulin E (IgE); pulmonary function; lung histopathology; pulmonary regulatory T cells (Tregs); and the fecal microbiome were characterized following ABX exposure and induction of experimental asthma. RESULTS: Asthma severity was increased in mice exposed to ABX, including: airway eosinophilia, airway hyper-reactivity, serum HDM-specific IgE, and lung histopathology. ABX treatment led to sharp reduction in fecal microbiome diversity, including the loss of pro-regulatory organisms such as Lachnospira. Pulmonary Tregs were reduced with ABX treatment, and this reduction was directly proportional to diminished microbiome diversity. CONCLUSION: Intermittent exposure to ABX early in life worsened the severity of experimental asthma and reduced pulmonary Tregs; the latter change correlated with decreased microbiome diversity. These data may suggest targets for immunologic or probiotic therapy to counteract the harmful effects of childhood ABX.

Regulation of IgE activity in inhalational tolerance via formation of IgG anti-IgE/IgE immune complexes.

BACKGROUND: Allergic asthma is an inflammatory disorder of the airways that results from inappropriate production of IgE against harmless, environmental antigens. Sequestration of free IgE using humanized IgG anti-IgE is an effective therapy for asthma and other atopic disorders. However, the status of free IgE in subjects who have naturally developed immune tolerance to inhaled antigens has not been well studied. METHODS: C57BL/6 mice were sensitized and challenged with ovalbumin (OVA) for 7 days to induce allergic airway disease (AAD) or 6 weeks to induce a state of local inhalational tolerance (LIT). Serum from AAD or LIT mice, diluted to achieve equivalent levels of total OVA-specific IgE, was used to sensitize rat basophil leukemia cells for allergen-mediated degranulation. Levels of degranulation were measured in relation to serum concentrations of free IgE and IgG anti-IgE/IgE immune complexes. RESULTS: Serum from AAD animals induced a greater degree of basophil degranulation than serum from LIT animals. These results correlated with higher levels of free IgE in AAD animals, whereas LIT mice demonstrated a significant increase in IgG anti-IgE/IgE immune complexes relative to their diseased counterparts. CONCLUSIONS: Sequestration of free IgE by naturally occurring IgG anti-IgE may aid in the development of immune tolerance against inhaled allergens. The decrease in bioavailability of free IgE may, in turn, contribute to the overall reduction of asthma symptoms via a mechanism that mimics the therapeutic effects of humanized IgG anti-IgE.

Ozone disinfection of home nebulizers effectively kills common cystic fibrosis bacterial pathogens.

OBJECTIVE: The Cystic Fibrosis Foundation (CFF) recommends routine nebulizer disinfection for patients but compliance is challenging due to the heavy burden of home care. SoClean® is a user friendly ozone based home disinfection device currently for home respiratory equipment. The objective of this study was to determine whether SoClean® has potential as a disinfection device for families with CF by killing CF associated bacteria without altering nebulizer output. HYPOTHESIS: Ozone based disinfection effectively kills bacterial pathogens inoculated to home nebulizer equipment without gross changes in nebulizer function. STUDY DESIGN: Common bacterial pathogens associated with CF were inoculated onto the PariLC® jet nebulizer and bacterial recovery compared with or without varied ozone exposure. In separate experiments, nebulizer output was estimated after repeated ozone exposure by weighing the nebulizer. RESULTS: Ozone disinfection was time dependent with a 5 min infusion time and 120 min dwell time effectively killing >99.99% bacteria tested including Pseudomonas aeruginosa and Staphylococcus aureus. Over 250 h of repeat ozone exposure did not alter nebulizer output. This suggests SoClean® has potential as a user-friendly disinfection technique for home respiratory equipment.

Clinical Examination Does Not Predict Response to Albuterol in Ventilated Infants With Bronchiolitis.

OBJECTIVE: Bronchiolitis is a common respiratory infection in infants that is sometimes treated with albuterol. Response to albuterol is determined by clinical assessment, but this subjective determination is potentially unreliable. In this study, we compared providers' clinical assessment of response to albuterol with the measurement of response by pulmonary mechanics in intubated, sedated, and ventilated infants. DESIGN: Before and 20 minutes following racemic albuterol therapy, a nurse, respiratory therapist, and physician performed simultaneous examinations and assessed response to albuterol in a population of intubated infants with bronchiolitis. Measurements of ventilator-derived pulmonary mechanics were obtained at these same times. SETTING: This study was conducted in a PICU of a children's hospital. PATIENTS: Seventy-five paired clinical assessments were made in 25 infants who were intubated and mechanically ventilated for severe bronchiolitis. INTERVENTIONS: Pulmonary function measurements and clinical assessments before and after administration of albuterol. MEASUREMENTS AND MAIN RESULTS: Response to albuterol was defined using a threshold of improvement in respiratory system resistance from baseline. Nine children (36%) had greater than 20% change and were deemed responders. Providers' discrimination of response was poor. The positive predictive values of nurses, respiratory therapists, and physicians were 38%, 25%, and 25%, respectively, and the negative predictive values were 67%, 54%, and 59%, respectively. Overall accuracy was 44% for nurses, 40% for respiratory therapists, and 48% for physicians. When comparing separate assessments of wheezing, aeration, and expiratory time, there was poor agreement between groups of providers in all variables (κ < 0.4 for each). CONCLUSIONS: A provider's clinical assessment was not a reliable method for determining response to albuterol in children with bronchiolitis. Without assessment of pulmonary mechanics, caution should be used in classifying children with bronchiolitis as responders to albuterol.

An evaluation strategy for potential QTc prolongation with chronic azithromycin therapy in cystic fibrosis.

Chronic azithromycin therapy is recommended for CF patients with persistent Pseudomonas aeruginosa colonization. Other macrolide antibiotics have been reported to cause QT prolongation, but cardiac effects of azithromycin have not been studied in pediatric populations. We analyzed changes in QTc interval after starting chronic azithromycin in a pediatric CF population. Adolescent males showed increased QTc intervals after initiation of therapy. Given the possible effects of azithromycin on the QTc interval, particularly in patients predisposed to cardiac events, we suggest that the QTc interval of CF patients should be monitored throughout the course of chronic azithromycin.

Cbl-b Deficiency in Mice Results in Exacerbation of Acute and Chronic Stages of Allergic Asthma.

Mice sensitized to ovalbumin (OVA) develop allergic airway disease (AAD) with short-term daily OVA aerosol challenge; inflammation resolves with long-term OVA aerosol exposure, resulting in local inhalational tolerance (LIT). Cbl-b is an E3 ubiquitin ligase involved with CD28 signaling; Cbl-b(-/-) effector T cells are resistant to regulatory T cell-mediated suppression in vitro and in vivo. The present study utilized Cbl-b(-/-) mice to investigate the role of Cbl-b in the development of AAD and LIT. Cbl-b(-/-) mice exhibited increased airway inflammation during AAD, which failed to resolve with long-term OVA aerosol exposure. Exacerbation of inflammation in Cbl-b(-/-) mice correlated with increased proinflammatory cytokine levels and expansion of effector T cells in the BAL during AAD, but did not result in either a modulation of lymphocyte subsets in systemic tissues or in OVA-specific IgE in serum. These results implicate a role for Cbl-b in the resolution of allergic airway inflammation.

Long-Term Exposure to House Dust Mite Leads to the Suppression of Allergic Airway Disease Despite Persistent Lung Inflammation.

BACKGROUND: Allergic asthma is a major cause of worldwide morbidity and results from inadequate immune regulation in response to innocuous, environmental antigens. The need exists to understand the mechanisms that promote nonreactivity to human-relevant allergens such as house dust mite (HDM) in order to develop curative therapies for asthma. The aim of our study was to compare the effects of short-, intermediate- and long-term HDM administration in a murine asthma model and determine the ability of long-term HDM exposure to suppress allergic inflammation. METHODS: C57BL/6 mice were intranasally instilled with HDM for short-term (2 weeks), intermediate-term (5 weeks) and long-term (11 weeks) periods to induce allergic airway disease (AAD). The severity of AAD was compared across all stages of the model via both immunological and pulmonary parameters. RESULTS: Short- and intermediate-term HDM exposure stimulated the development of AAD that included eosinophilia in the bronchoalveolar lavage fluid (BALF), pronounced airway hyperreactivity (AHR) and evidence of lung inflammation. Long-term HDM exposure promoted the suppression of AAD, with a loss of BALF eosinophilia and AHR despite persistent mononuclear inflammation in the lungs. Suppression of AAD with long-term HDM exposure was associated with an increase in both Foxp3+ regulatory T cells and IL-10-positive alveolar macrophages at the site of inflammation. CONCLUSIONS: This model recapitulates the key features of human asthma and may facilitate investigation into the mechanisms that promote immunological tolerance against clinically relevant aeroallergens.

Serial lung magnetic resonance imaging to monitor disease progression in a child with a diffuse alveolar hemorrhage syndrome.

Serial lung magnetic resonance imaging (MRI) was performed in a child with diffuse alveolar hemorrhage (DAH). To minimize radiation exposure with conventional serial chest computerized tomography (CT), serial MRIs of the lungs were used. This effectively monitored her disease process as well as detected acute hemorrhage after 5 years remission.

Regulatory B cells in allergic airways disease and asthma.

B cells have long been known to participate in both innate and adaptive immune responses by contributing to antigen presentation and by producing antigen-specific antibodies. Recent evidence shows that certain B-cell subsets can also inhibit T-cell immune responses. Like regulatory T cells (Treg), these regulatory B cells (Breg) appear to comprise several subpopulations. How Breg cells are generated and how they control immune responses in vivo are just beginning to be elucidated. Here, we provide detailed instructions for the identification, isolation, and functional characterization of Breg cells in a murine model of allergic airway disease.

Transient occult cardiotoxicity in children receiving continuous beta-agonist therapy.

BACKGROUND: Continuous beta-agonist therapy, typically in the form of inhaled albuterol, is the first line therapy for the treatment of acute and severe bronchospasm in children. Although this treatment is commonly used, concerns about cardiotoxicity have been raised. We aimed to investigate the cardiotoxic effects of continuous beta-agonist therapy in children. METHODS: We conducted a retrospective review of children admitted to the intensive care unit (ICU) between May 2008 and April 2009, who were treated with continuous beta-agonist therapy (intravenous and nebulized). RESULTS: Twenty of the 36 children treated with continuous albuterol had repeated serum troponin-T and lactate levels measured. Eleven patients (55%) were also treated with continuous intravenous terbutaline. Elevated levels of troponin-T levels were found in 25% of children, and elevated lactate levels were found in 60%. However, all returned to normal levels within 48 hours of ICU admission, despite continued beta-agonist therapy. No children experienced arrhythmias during therapy. There was no association between intravenous terbutaline use and elevated troponin-T [odds ratio (OR), 1.3; 95% CI, 0.2-10.3] or with elevated serum lactate (OR, 0.6; 95% CI, 0.1-3.7). There was also no association between elevated troponin-T or lactate and ICU or hospital length of stay. CONCLUSIONS: In this small study, a significant proportion of children had elevated serum troponin-T and lactate levels while receiving inhaled continuous beta-agonist therapy, irrespective of intravenous therapy. However, these abnormal values all returned to normal within 48 hours of ICU admission and were not associated with increased duration of hospitalization.

Bromelain Inhibits Allergic Sensitization and Murine Asthma via Modulation of Dendritic Cells.

The incidence of atopic conditions has increased in industrialized countries. Persisting symptoms and concern for drug side-effects lead patients toward adjunctive treatments such as phytotherapy. Previously, we have shown that Bromelain (sBr), a mixture of cysteine proteases from pineapple, Ananas comosus, inhibits ovalbumin (OVA)-induced murine model of allergic airway disease (AAD). However, sBr's effect on development of AAD when treatment is administered throughout OVA-alum sensitization was unknown and is the aim of the present study. C57BL/6J mice were sensitized with OVA/alum and challenged with 7 days OVA aerosol. sBr 6 mg/kg/0.5 ml or PBS vehicle were administered throughout sensitization. Lung, bronchoalveolar lavage (BAL), spleen, and lymph nodes were processed for flow cytometry and OVA-specific IgE was determined via ELISA. sBr treatment throughout OVA-alum sensitization significantly reduced the development of AAD (BAL eosinophils and lymphocytes). OVA-specific IgE and OVA TET(+) cells were decreased. sBr reduced CD11c(+) dendritic cell subsets, and in vitro treatment of DCs significantly reduced CD44, a key receptor in both cell trafficking and activation. sBr was shown to reduce allergic sensitization and the generation of AAD upon antigen challenge. These results provide additional insight into sBr's anti-inflammatory and antiallergic properties and rationale for translation into the clinical arena.

Bromelain limits airway inflammation in an ovalbumin-induced murine model of established asthma.

CONTEXT: Allergic asthma continues to increase despite new pharmacological advances for both acute treatment and chronic-disease management. Asthma is a multifactorial disease process with genetic, allergic, infectious, environmental, and dietary origins. Researchers are investigating the benefits of lifestyle changes and alternative asthma treatments, including the ability of bromelain to inhibit inflammation. Bromelain is a commonly used, proteolytically active pineapple extract. OBJECTIVE: The present study intended to determine the ability of bromelain to reduce the inflammation of preexisting asthma via an ovalbumin (OVA)-induced murine model of allergic airway disease (AAD). DESIGN: The research team designed a study examining the effects of bromelain in a control group of mice that received phosphate buffered saline (PBS) only and in an intervention group that received bromelain in PBS. Setting The study took place in the Department of Immunology at the University of Connecticut's School of Medicine, Farmington. Intervention The research team sensitized female C57BL/6J mice with intraperitoneal OVA/alum and then challenged them with OVA aerosolization for 10 consecutive days. On day 4, the team began administering daily doses of PBS to the control group (n = 10) and bromelain (6mg/kg) in PBS to the bromelain (intervention) group (n = 10). OUTCOME MEASURES: The primary measures included bronchoalveolar lavage (BAL) cellular differential, cellular phenotype via flow cytometry, and lung histology. Additional outcomes included testing for serum cytokines and immunoglobulin. RESULTS: Bromelain treatment of AAD mice (bromelain group) resulted in significant anti-inflammatory activity as indicated by reduced BAL total leukocytes (P < .05), eosinophils (P < .05), and cellular infiltrates via lung pathology (P < .005), as compared to the control group. In addition, bromelain significantly reduced BAL CD4+ and CD8+ T cells without affecting cell numbers in the spleen or hilar lymph node. The study found decreased interleukins IL-4, IL-12, IL-17, as well as IFN-α in the serum of bromelain-treated animals. CONCLUSIONS: The results suggest that bromelain has a therapeutic effect in established AAD, which may translate into an effective adjunctive therapy in patients with similar conditions, such as allergic asthma, who have chosen to initiate treatment after the onset of symptoms.

ß2-adrenergic receptor haplotype linked to intubation and mechanical ventilation in children with asthma.

BACKGROUND AND AIMS: Children with asthma and respiratory failure comprise a small but significant subset of children with acute asthma. In addition to clinical and historical factors that have been associated with respiratory failure, there may also be genetic factors that predispose some asthmatic children to intubation and mechanical ventilation. However, this has not previously been assessed in this population. We hypothesized that genetic polymorphisms of the ß(2)-adrenergic receptor (ADRß(2)) are associated with intubation and mechanical ventilation in children with asthma. MATERIALS AND METHODS: We performed genotyping of the ADRß(2) in a pooled cohort of 104 children admitted to the intensive care unit (ICU) with a severe asthma exacerbation between 2002 and 2008. Genotype of the ADRß(2) was compared with intubation for respiratory failure. RESULTS: At amino acid position 16, 33% (n = 34) of children were homozygous for the glycine allele (Gly16Gly), 15% (n = 16) were homozygous for the arginine allele (Arg16Arg), and 52% (n = 54) were heterozygous (Arg16Gly). At amino acid position 27, 54% (n = 56) of children were homozygous for the glutamine allele (Gln27Gln), 8% (n = 8) were homozygous for the glutamic acid allele (Glu27Glu), and 38% (n = 40) were heterozygous (Gln27Glu). The haplotypes at these positions were Arg16Gly-Gln27Gln (29%, n = 30), Arg16Gly-Gln27Glu (22%, n = 23), Gly16Gly-Gln27Glu (16%, n = 17), Arg16Arg-Gln27Gln (16%, n = 17), Gly16Gly-Gln27Gln (9%, n = 9), and Gly16Gly-Glu27Glu (8%, n = 8). Twelve children in this cohort were intubated for respiratory failure. Intubation was not associated with age, obesity, race/ethnicity, or NHBLI asthma classification. However, children with the Arg16Gly-Gln27Gln haplotype were significantly more likely to be intubated and mechanical ventilated (OR = 4.2; 95% CI = 1.2-14.5; p = .036) than children with other haplotypes of the ADRß(2). When examining the subset of intubated children, those with the Arg16Gly-Gln27Gln haplotype trended towards longer ICU length of stay (329 ± 270 vs. 124 ± 57 hours; p = .09), but this was not statistically significant. CONCLUSIONS: Children with the Arg16Gly-Gln27Gln haplotype of the ADRß(2) were four times more likely to be intubated and mechanically ventilated during severe asthma exacerbations. Genetic factors may influence the development of a more severe asthma phenotype during acute exacerbations.

Pulmonary mechanics following albuterol therapy in mechanically ventilated infants with bronchiolitis.

BACKGROUND AND AIMS: Bronchiolitis is a common cause of critical illness in infants. Inhaled ß(2)-agonist bronchodilators are frequently used as part of treatment, despite unproven effectiveness. The purpose of this study was to describe the physiologic response to these medications in infants intubated and mechanically ventilated for bronchiolitis. MATERIALS AND METHODS: We conducted a prospective trial of albuterol treatment in infants intubated and mechanically ventilated for bronchiolitis. Before and for 30 minutes following inhaled albuterol treatment, sequential assessments of pulmonary mechanics were determined using the interrupter technique on repeated consecutive breaths. RESULTS: Fifty-four infants were enrolled. The median age was 44 days (25-75%; interquartile range (IQR) 29-74 days), mean hospital length of stay (LOS) was 18.3 ± 13.3 days, mean ICU LOS was 11.3 ± 6.4 days, and mean duration of mechanical ventilation was 8.5 ± 3.5 days. Fifty percent (n = 27) of the infants were male, 81% (n = 44) had public insurance, 80% (n = 41) were Caucasian, and 39% (n = 21) were Hispanic. Fourteen of the 54 (26%) had reduction in respiratory system resistance (Rrs) that was more than 30% below baseline, and were defined as responders to albuterol. Response to albuterol was not associated with demographic factors or hospitalization outcomes such as LOS or duration of mechanical ventilation. However, increased Rrs, prematurity, and non-Hispanic ethnicity were associated with increased LOS. CONCLUSIONS: In this population of mechanically ventilated infants with bronchiolitis, relatively few had a reduction in pulmonary resistance in response to inhaled albuterol therapy. This response was not associated with improvements in outcomes.