Phage Therapy of Mycobacterium Infections: Compassionate Use of Phages in 20 Patients With Drug-Resistant Mycobacterial Disease.

BACKGROUND: Nontuberculous Mycobacterium infections, particularly Mycobacterium abscessus, are increasingly common among patients with cystic fibrosis and chronic bronchiectatic lung diseases. Treatment is challenging due to intrinsic antibiotic resistance. Bacteriophage therapy represents a potentially novel approach. Relatively few active lytic phages are available and there is great variation in phage susceptibilities among M. abscessus isolates, requiring personalized phage identification. METHODS: Mycobacterium isolates from 200 culture-positive patients with symptomatic disease were screened for phage susceptibilities. One or more lytic phages were identified for 55 isolates. Phages were administered intravenously, by aerosolization, or both to 20 patients on a compassionate use basis and patients were monitored for adverse reactions, clinical and microbiologic responses, the emergence of phage resistance, and phage neutralization in serum, sputum, or bronchoalveolar lavage fluid. RESULTS: No adverse reactions attributed to therapy were seen in any patient regardless of the pathogen, phages administered, or the route of delivery. Favorable clinical or microbiological responses were observed in 11 patients. Neutralizing antibodies were identified in serum after initiation of phage delivery intravenously in 8 patients, potentially contributing to lack of treatment response in 4 cases, but were not consistently associated with unfavorable responses in others. Eleven patients were treated with only a single phage, and no phage resistance was observed in any of these. CONCLUSIONS: Phage treatment of Mycobacterium infections is challenging due to the limited repertoire of therapeutically useful phages, but favorable clinical outcomes in patients lacking any other treatment options support continued development of adjunctive phage therapy for some mycobacterial infections.

Association of rhinovirus with exacerbations in young children affected by cystic fibrosis: Preliminary data.

Rhinovirus (RV) is a common respiratory viral infection linked to worsening of chronic respiratory diseases including cystic fibrosis (CF) and asthma. RV was tested by RT-PCR in samples (n = 465) collected from the upper (nasal swab, oropharyngeal suction, and sputum) and lower (bronchoalveolar washings) respiratory tract of 110 children with CF. Air samples (n = 52) collected from the operating theatres and outpatient clinics were tested for RV. RV was found in 43% of children <5 years suffering an exacerbation, and 12% of older children (5-17 years). RV particles were detected in the air of clinic rooms. Detection of RV is important in better understanding viral infections in patients with CF.

Prevalence of Malnutrition and Feeding Difficulties in Children With Esophageal Atresia.

OBJECTIVES: Growth and feeding problems have been described in children with esophageal atresia (EA). Ongoing gastrointestinal and respiratory complications such as Gastroesophageal reflux disease, esophageal dysmotility, strictures, and respiratory infections may contribute. The aim of the study was to document the prevalence of malnutrition and feeding difficulties and examine predictive factors, which may influence feeding and growth in children attending a multidisciplinary EA clinic in Sydney, Australia. METHODS: A retrospective review of 75 children, ages 0 to 16 years, who attended a multidisciplinary EA clinic between 2011 and 2014. Data on demographics, comorbidities, nutrition, and mealtime behaviors were collected from their initial clinic appointment. Factors that may affect on growth and mealtime behaviors were identified and analyzed. RESULTS: Nine percent of children were malnourished and 9% were stunted. Infants, children with prior fundoplication, at risk of aspiration, or those who had surgery in the first year of life additional to EA repair were significantly more likely to be malnourished (P < 0.05). Fifty-four percent of children required texture modification at their meals, with parental concern being the most common reason. Younger children were less likely to be eating age-appropriate textures (P = 0.04) which improved after 5 years of age. CONCLUSIONS: Poor growth and inability to manage age-appropriate textures are often present in children with EA, particularly in the younger years. This highlights the need for early intervention in a specialist multidisciplinary EA clinic in which dietetics and speech pathology are available.

Absence of back to school peaks in human rhinovirus detections and respiratory symptoms in a cohort of children with asthma.

Much of what is known about the seasonality of human rhinovirus (hRV) infections has been learned from the study of acute asthma exacerbations presenting to emergency care, including those among children at the start of the school term. Much less is known about the patterns of hRVs in the community. In this study, viruses and day-to-day symptoms of asthma and colds were monitored twice weekly in 67 children with asthma aged 5-12 years, over a 15 month period in Sydney, Australia. Overall hRV was detected in 314/1232 (25.5%) of nasal wash samples and 142/1231 (11.5%) of exhaled breath samples; of these, 231 and 24 respectively were genotyped. HRVs were detected with similar prevalence rate throughout the year, including no peak in hRV prevalence following return to school. No peaks were seen in asthma and cold symptoms using twice-weekly diary records. However, over the same period in the community, there were peaks in asthma emergency visits both at a large local hospital and in state-wide hospitalizations, following both return to school (February) and in late autumn (May) in children of the same age. This study suggests that hRV infections are common throughout the year among children, and differences in virus prevalence alone may not account for peaks in asthma symptoms.

Rhinoviruses significantly affect day-to-day respiratory symptoms of children with asthma.

BACKGROUND: Viruses are frequently associated with acute exacerbations of asthma, but the extent to which they contribute to the level of day-to-day symptom control is less clear. OBJECTIVE: We sought to explore the relationship between viral infections, host and environmental factors, and respiratory symptoms in children. METHODS: Sixty-seven asthmatic children collected samples twice weekly for an average of 10 weeks. These included nasal wash fluid and exhaled breath for PCR-based detection of viral RNA, lung function measurements, and records of medication use and asthma and respiratory symptoms in the previous 3 days. Atopy, mite allergen exposure, and vitamin D levels were also measured. Mixed-model regression analyses were performed. RESULTS: Human rhinoviruses (hRVs) were detected in 25.5% of 1232 nasal samples and 11.5% of breath samples. Non-hRV viruses were detected in less than 3% of samples. hRV in nasal samples was associated with asthma symptoms (cough and phlegm: odds ratio = 2.0; 95% CI = 1.4-2.86, P = .0001; wheeze and chest tightness: odds ratio = 2.34, 95% CI = 1.55-3.52, P < .0001) and with cold symptoms, as reported concurrently with sampling and 3 to 4 days later. No differences were found between the 3 hRV genotypes (hRV-A, hRV-B, and hRV-C) in symptom risk. A history of inhaled corticosteroid use, but not atopic status, mite allergen exposure, or vitamin D levels, modified the association between viruses and asthma symptoms. CONCLUSION: The detection of nasal hRV was associated with a significantly increased risk of day-to-day asthma symptoms in children. Host, virus genotype, and environmental factors each had only a small or no effect on the relationship of viral infections to asthma symptoms.

Mediastinal Nontuberculous Mycobacterial Infection in Children: A Multidisciplinary Approach.

BACKGROUND: Mediastinal infections due to nontuberculous mycobacteria remain an exceedingly rare entity. Most cases in the published literature do not include pediatric patients. Due to their clinical infrequency, poor response to antimicrobial therapy and often precarious anatomical location, the optimal management of these lesions can be challenging. METHODS: Retrospective medical record review of 4 pediatric cases of mediastinal nontuberculous mycobacteria infection was undertaken. Each child presented with nonspecific respiratory symptoms, including significant acute airway obstruction and required a range of investigations to confirm the diagnosis. Nonresponsiveness to conservative measures and antimycobacterial therapy ultimately resulted in surgical intervention to obtain clinical improvement. RESULTS: All 4 children had extensive evaluation and multidisciplinary involvement in otolaryngology, respiratory medicine, pediatric surgery, infectious diseases and cardiothoracic surgery. They all eventually had their disease debulked via thoracotomy in addition to prolonged antimycobacterial therapy, with successful clinical outcomes. CONCLUSIONS: Mediastinal nontuberculous mycobacteria infections in the pediatric population are rare and diagnostically challenging. A high clinical suspicion should be maintained, and multidisciplinary input sought. Targeted surgery with adjuvant medical therapy can reduce disease burden with minimal long-term morbidity.

Early cystic fibrosis lung disease detected by bronchoalveolar lavage and lung clearance index.

RATIONALE: Unrecognized airway infection and inflammation in young children with cystic fibrosis (CF) may lead to irreversible lung disease; therefore early detection and treatment is highly desirable. OBJECTIVES: To determine whether the lung clearance index (LCI) is a sensitive and repeatable noninvasive measure of airway infection and inflammation in newborn-screened children with CF. METHODS: Forty-seven well children with CF (mean age, 1.55 yr) and 25 healthy children (mean age, 1.26 yr) underwent multiple-breath washout testing. LCI within and between-test variability was assessed. Children with CF also had surveillance bronchoalveolar lavage performed. MEASUREMENTS AND MAIN RESULTS: The mean (SD) LCI in healthy children was 6.45 (0.49). The LCI was higher in children with CF (7.21 [0.81]; P < 0.001). The upper limit of normal for the LCI was 7.41. Fifteen (32%) children with CF had an elevated LCI. LCI measurements were repeatable and reproducible. Airway infection was present in 17 (36%) children with CF, including 7 (15%) with Pseudomonas aeruginosa. Polymicrobial growth was associated with worse inflammation. The LCI was higher in children with Pseudomonas (7.92 [1.16]) than in children without Pseudomonas (7.02 [0.56]) (P = 0.038). The LCI correlated with bronchoalveolar lavage IL-8 (R(2) = 0.20, P = 0.004) and neutrophil count (R(2) = 0.21, P = 0.001). An LCI below the upper limit of normality had a high negative predictive value (93%) in excluding Pseudomonas. CONCLUSIONS: The LCI is elevated early in CF, especially in the presence of Pseudomonas and airway inflammation. The LCI is a feasible, repeatable, and sensitive noninvasive marker of lung disease in young children with CF.

Comparing Cytology Brushes for Optimal Human Nasal Epithelial Cell Collection: Implications for Airway Disease Diagnosis and Research.

Primary nasal epithelial cells and culture models are used as important diagnostic, research and drug development tools for several airway diseases. Various instruments have been used for the collection of human nasal epithelial (HNE) cells but no global consensus yet exists regarding the optimal tool. This study compares the efficiency of two cytology brushes (Olympus (2 mm diameter) and Endoscan (8 mm diameter)) in collecting HNE cells. The study involved two phases, with phase one comparing the yield, morphology and cilia beat frequency (CBF) of cells collected from paediatric participants using each of the two brushes. Phase two compared nasal brushing under general anaesthetic and in the awake state, across a wide age range, via the retrospective audit of the use of the Endoscan brush in 145 participants. Results indicated no significant difference in CBF measurements between the two brushes, suggesting that the choice of brush does not compromise diagnostic accuracy. However, the Endoscan brush collected significantly more total and live cells than the Olympus brush, making it a more efficient option. Importantly, the Endoscan brush is more cost-effective, with a notable price difference between the two brushes.

Diet and the gut-lung axis in cystic fibrosis - direct & indirect links.

Cystic fibrosis (CF) is a multisystem, autosomal, recessive disease primarily affecting the lungs, pancreas, gastrointestinal tract, and liver. Whilst there is increasing evidence of a microbial 'gut-lung axis' in chronic respiratory conditions, there has been limited analysis of such a concept in CF. We performed a comprehensive dietary and microbiota analysis to explore the interactions between diet, gastrointestinal microbiota, respiratory microbiota, and clinical outcomes in children with CF. Our results demonstrate significant alterations in intestinal inflammation and respiratory and gastrointestinal microbiota when compared to age and gender matched children without CF. We identified correlations between the gastrointestinal and respiratory microbiota, lung function, CF pulmonary exacerbations and anthropometrics, supporting the concept of an altered gut-lung axis in children with CF. We also identified significant differences in dietary quality with CF children consuming greater relative proportions of total, saturated and trans fats, and less relative proportions of carbohydrates, wholegrains, fiber, insoluble fiber, starch, and resistant starch. Our findings position the CF diet as a potential modulator in gastrointestinal inflammation and the proposed gut-lung axial relationship in CF. The dietary intake of wholegrains, fiber and resistant starch may be protective against intestinal inflammation and should be explored as potential therapeutic adjuvants for children with CF.

The effect of azithromycin on structural lung disease in infants with cystic fibrosis (COMBAT CF): a phase 3, randomised, double-blind, placebo-controlled clinical trial.

BACKGROUND: Structural lung disease and neutrophil-dominated airway inflammation is present from 3 months of age in children diagnosed with cystic fibrosis after newborn screening. We hypothesised that azithromycin, given three times weekly to infants with cystic fibrosis from diagnosis until age 36 months, would reduce the extent of structural lung disease as captured on chest CT scans. METHODS: A phase three, randomised, double-blind, placebo-controlled trial was done at eight paediatric cystic fibrosis centres in Australia and New Zealand. Infants (aged 3-6 months) diagnosed with cystic fibrosis following newborn screening were eligible. Exclusion criteria included prolonged mechanical ventilation in the first 3 months of life, clinically significant medical disease or comorbidities other than cystic fibrosis, or macrolide hypersensitivity. Participants were randomly assigned (1:1) to receive either azithromycin (10 mg/kg bodyweight orally three times per week) or matched placebo until age 36 months. Randomisation was done with a permuted block strategy and an interactive web-based response system, stratified by study site. Unblinding was done once all participants completed the trial. The two primary outcomes were the proportion of children with radiologically defined bronchiectasis, and the percentage of total lung volume affected by disease. Secondary outcomes included clinical outcomes and exploratory outcomes were inflammatory markers. Analyses were done with the intention-to-treat principle. This study is registered at ClinicalTrials.gov (NCT01270074). FINDINGS: Between June 15, 2012, and July 10, 2017, 281 patients were screened, of whom 130 were enrolled, randomly assigned, and received first study dose. 68 participants received azithromycin and 62 received placebo. At 36 months, 88% (n=50) of the azithromycin group and 94% (n=44) of the placebo group had bronchiectasis (odds ratio 0·49, 95% CI 0·12 to 2·00; p=0·32), and total airways disease did not differ between groups (median difference -0·02%, 95% CI -0·59 to 0·56; p=0·96). Secondary outcome results included fewer days in hospital for pulmonary exacerbations (mean difference -6·3, 95% CI -10·5 to -2·1; p=0·0037) and fewer courses of inhaled or oral antibiotics (incidence rate ratio 0·88, 95% CI 0·81 to 0·97; p=0·0088) for those in the azithromycin group. For the preplanned, exploratory analysis, concentrations of airway inflammation were lower for participants receiving azithromycin, including interleukin-8 (median difference -1·2 pg/mL, 95% CI -1·9 to -0·5; p=0·0012) and neutrophil elastase activity (-0·6 µg/mL, -1·1 to -0·2; p=0·0087) at age 36 months, although no difference was noted between the groups for interleukin-8 or neutrophil elastase activity at 12 months. There was no effect of azithromycin on body-mass index at age 36 months (mean difference 0·4, 95% CI -0·1 to 0·9; p=0·12), nor any evidence of pathogen emergence with the use of azithromycin. There were few adverse outcomes with no differences between the treatment groups. INTERPRETATION: Azithromycin treatment from diagnosis of cystic fibrosis did not reduce the extent of structural lung disease at 36 months of age; however, it did reduce airway inflammation, morbidity including pulmonary exacerbations in the first year of life and hospitalisations, and improved some clinical outcomes associated with cystic fibrosis lung disease. Therefore we suggest thrice-weekly azithromycin is a strategy that could be considered for the routine early management of paediatric patients with cystic fibrosis. FUNDING: Cystic Fibrosis Foundation.

Care recommendations for the respiratory complications of esophageal atresia-tracheoesophageal fistula.

Tracheoesophageal fistula (TEF) with esophageal atresia (EA) is a common congenital anomaly that is associated with significant respiratory morbidity throughout life. The objective of this document is to provide a framework for the diagnosis and management of the respiratory complications that are associated with the condition. As there are no randomized controlled studies on the subject, a group of experts used a modification of the Rand Appropriateness Method to describe the various aspects of the condition in terms of their relative importance, and to rate the available diagnostic methods and therapeutic interventions on the basis of their appropriateness and necessity. Specific recommendations were formulated and reported as Level A, B, and C based on whether they were based on "strong", "moderate" or "weak" agreement. The tracheomalacia that exists in the site of the fistula was considered the main abnormality that predisposes to all other respiratory complications due to airway collapse and impaired clearance of secretions. Aspiration due to impaired airway protection reflexes is the main underlying contributing mechanism. Flexible bronchoscopy is the main diagnostic modality, aided by imaging modalities, especially CT scans of the chest. Noninvasive positive airway pressure support, surgical techniques such as tracheopexy and rarely tracheostomy are required for the management of severe tracheomalacia. Regular long-term follow-up by a multidisciplinary team was considered imperative. Specific templates outlining the elements of the clinical respiratory evaluation according to the patients' age were also developed.

Pepsin as a Marker of Reflux Aspiration in Children With Esophageal Atresia: A Pilot Study.

Background: Reflux aspiration secondary to gastroesophageal reflux disease (GERD) is one of the causes of chronic gastrointestinal and respiratory morbidity in children with esophageal atresia (EA). Currently there are no simple, validated non-invasive tests for the diagnosis of reflux aspiration in children. Objectives: The aim of this pilot study was to investigate pepsin detected in exhaled breath condensate (EBC) and saliva as a potential non-invasive marker of reflux aspiration in children with EA. Methods: EBC and saliva samples were prospectively collected from children with EA aged between 5 and 18 years attending a multidisciplinary EA Clinic. Pepsin in the samples was assayed by two methods, a commercial lateral flow device, the Peptest™ and an enzyme-linked immunosorbent assay (ELISA) and correlated with validated gastrointestinal and respiratory symptom questionnaires and objective measures of GERD and respiratory function. Results: EBC were collected from 18 children with EA, 15/18 also provided salivary samples. Pepsin was not detected in any of the EBC samples using the Peptest™ and only 1/14 (7.1%) samples by the ELISA. However, pepsin was detected in 33 and 83% of saliva samples when analyzed with Peptest™ and the ELISA respectively. Salivary pepsin levels were significantly higher in children with reflux symptoms or wheeze. Pepsin was detected by the Peptest™ in the saliva of 5/5 (100%) children with histological evidence of reflux esophagitis compared with 0/2 (0%) in children with normal histology (p = 0.048). Conclusions: Salivary pepsin was detected in a large proportion of children with EA and was significantly associated with GERD symptoms or wheeze. The role of salivary pepsin as a potential non-invasive marker of reflux aspiration in children with EA needs further validation in future studies with larger cohorts.

Distress during airway sampling in children with cystic fibrosis.

BACKGROUND: Oropharyngeal suction and oropharyngeal swab are two methods of obtaining airway samples with similar diagnostic accuracy in children with cystic fibrosis (CF). The primary aim was comparing distress between suctioning and swabbing. A secondary aim was establishing the reliability of the Groningen Distress Rating Scale (GDRS). METHODS: Randomised oropharyngeal suction or swab occurred over two visits. Two physiotherapists and the child's parent rated distress using the GDRS. Heart rate (HR) was also measured. RESULTS: 24 children with CF, mean age of 3 years, participated. Both physiotherapist and parent rating showed significantly higher distress levels during suction than swab. Inter-rater reliability for the GDRS was very good between physiotherapists, and good between physiotherapist and parents. CONCLUSION: The study found that oropharyngeal swab is less distressing in obtaining samples than oropharyngeal suction and that the GDRS was reliable and valid.

Age-related levels of fecal M2-pyruvate kinase in children with cystic fibrosis and healthy children 0 to 10years old.

BACKGROUND: The pathogenesis of gut inflammation, bacterial dysbiosis and increased rates of malignancy in CF is unclear. Fecal M2-pyruvate kinase (M2-PK) is a biomarker indicative of cellular proliferation that may be raised in intestinal malignancy and inflammation. Biomarkers, including M2-PK, may be useful in assessing effects of novel therapies on the gastrointestinal tract. METHODS: M2-PK was measured in stools collected from patients with CF and HC (0-10years). Linear mixed model analysis was used. RESULTS: M2-PK levels did not significantly change in children with CF (36 patients, 77 samples) (P=0.998) or HC (45 patients, 45 samples) (P=0.21), over the age range 0-10years. Patients with CF had elevated M2-PK compared to HC (median [IQR; range]: 10.7 [5.7-28.6; 1.0-239.1] (n=77) vs. 1.0 [1.0-1.0; 1.0-50.0] (n=45) U/mL, respectively; P=0.001). CONCLUSIONS: Fecal M2-PK was elevated in children with CF compared with HC during infancy and throughout childhood suggesting abnormalities in the CF gut exist in early life.

Diagnostic accuracy and distress associated with oropharyngeal suction in cystic fibrosis.

BACKGROUND: Early detection of bacterial pathogens in the lower airway is an important part of managing CF. This study aimed to assess the diagnostic accuracy of oropharyngeal suction (OPS) samples in obtaining airway bacterial cultures in young children with cystic fibrosis (CF), and the level of child distress caused by obtaining OPS samples. METHODS: Young children with CF undergoing broncho-alveolar lavage (BAL) as part of concurrent research or routine annual surveillance were studied. OPS was performed by stimulating a cough and suctioning the back of the oropharynx in the awake child to replicate clinical practice. BAL of the right upper, middle and lingula lobes was then performed. Samples were sent for standard bacterial culture. The child's distress during OPS was rated using the Groningen Distress Scale (1=calm, 2=timid/nervous, 3=serious distress but still under control, 4=serious distress with loss of control, 5=panic). RESULTS: There were 65 paired samples obtained from 39 children (21 boys, mean age on day of first sampling was 34.1months, SD 19.1months). For Pseudomonas aeruginosa, specificity, sensitivity, NPV and PPV with 95% CI were 98% (87-99), 75% (20-96), 98% (91-98) and 60% (15-93%) respectively. In all age groups combined, median level of distress was 3 (IQR 2-4), with distress highest in 2 and 3year olds, with a median of 4 (IQR 3-4). CONCLUSION: OPS has diagnostic utility in determining the absence of organisms in the lower airway, with specificity for P.aeruginosa detection of 98%. However, a positive OPS result is not necessarily a good indicator of lower airway infection. Distress levels were high during OPS, mostly in 2 and 3year olds.

Risk factors for an intensive care unit admission in children with asthma.

An admission to an intensive care unit (ICU) with asthma is a marker of asthma severity and may be a precursor of asthma death. The aim of this study was to investigate risk factors for acute severe asthma needing an ICU admission. We hypothesized that children admitted to the ICU represent a severe phenotype with identifiable premorbid clinical features. The study was case-control in design. One hundred and forty-one children were studied. Seventy children admitted to the ICU and 71 children admitted to the general medical ward served as cases and controls, respectively. Children were aged between 1-16 years. They underwent skin prick allergy testing, and had a nasopharyngeal aspirate and serology performed to screen for respiratory pathogens. Their parents completed an asthma and allergy symptom questionnaire and the Newcastle Asthma Knowledge Questionnaire (NAKQ). On univariate analysis, an admission to the ICU was more likely in children with 1) "frequent episodic" or "persistent" background asthma; 2) three or more previous admissions for asthma; 3) one or more asthma admissions in the previous 12 months; 4) three or more presentations to the Emergency Department (ED) in the preceding 12 months; 5) three or more positive responses on skin prick allergy testing; 6) an elevated IgE level; 7) oxygen saturation on presentation < or =91%; 8) longer duration of asthma; 9) lower level of maternal education; 10) an admission during autumn; 11) three or more siblings; and 12) being prescribed antibiotics. Risk factors that remained significant on multivariate analysis were three or more presentations to the ED in the preceding 12 months (P=0.003), an elevated IgE level (P=0.01), oxygen saturation on presentation < or =91% (P=0.003), and longer asthma duration (P=0.02). ICU patients took longer to see a doctor and to commence oral steroids. No differences were found between cases and controls in the proportion taking preventer therapy (58% vs. 52%), provided with a written asthma action plan (32% vs. 25%), or in whom spirometry or peak flow was measured (28% vs. 42%). However, rates were low in both groups. Parental asthma knowledge was generally poor. This study identified risk factors for an ICU admission in children with asthma. A potentially preventable risk factor is a history of multiple ED presentations in the past year. Specialist referral of children with multiple ED presentations may improve asthma control and reduce the risk of an ICU admission. Background asthma management remains suboptimal in children needing hospitalization.

Refractory otitis media: an unusual presentation of childhood granulomatosis with polyangiitis.

Childhood granulomatosis with polyangiitis (cGPA), previously known as Wegener's granulomatosis, is a rare, potentially fatal necrotizing vasculitis, the symptoms of which overlap with infection. We present a 16-year-old girl who, following 6 months of treatment for persistent middle ear effusion with progressive sensorineural hearing loss, developed rapidly progressing pneumonia, with pleural effusion, and multiple cavitatory lung lesions. Investigations demonstrated high titer c-ANCA and nasal septal biopsy confirmed the diagnosis of cGPA. This case highlights the difficulty in diagnosing cGPA and the potentially life-threatening consequences of failing to do so.