Impact of respiratory illness on expiratory flow rates in normal, asthmatic, and allergic children

Pulmonary function in cannabis users: Support for a clinical trial of the vaporizer

BACKGROUND

Debates about cannabis policy often mention respiratory symptoms as a negative consequence of use. The cannabis vaporizer, a machine that heats the plant to release cannabinoids in a mist without smoke and other respiratory irritants, appears to have the potential to minimize respiratory complaints.

METHODS

Twenty frequent cannabis users (uninterested in treatment) reporting at least two respiratory symptoms completed subjective ratings of respiratory symptoms and spirometry measures prior to and following 1 month's use of a cannabis vaporizer in a pre/post-design. Outcome measures included self-reported severity of nine respiratory symptoms as well as spirometry measures, including the maximum amount of air exhaled in 1s (forced expiratory volume; FEV1) and maximum total lung volume (forced vital capacity; FVC).

RESULTS

The 12 participants who did not develop a respiratory illness during the trial significantly improved respiratory symptoms (t(11)=6.22, p=0.000065, d=3.75) and FVC, t(11)=2.90, p=0.007, d=1.75. FEV1 improved but not significantly t(11)=1.77, p=0.053, d=1.07.

CONCLUSIONS

These preliminary data reveal meaningful improvements in respiratory function, suggesting that a randomized clinical trial of the cannabis vaporizer is warranted. The vaporizer has potential for the administration of medical cannabis and as a harm reduction technique.

[Involvement of distal airways in asthma: lessons from pediatric cohorts]

INTRODUCTION

Prospective studies of paediatric cohorts contribute to our knowledge of changes in pulmonary function in children with asthma.

STATE OF THE ART

Asthma is associated with a significant impairment of the distal airways which is more pronounced when asthma has started early, before 5 years of age, or when asthma is persistent. In utero exposure to tobacco smoke allergenic sensitization and persistent bronchial hyperresponsiveness are the main factors associated with an unfavourable respiratory function outcome. This impairment may persist despite the disappearance of symptoms. Distal airway alterations are also poorly responsive to conventional inhaled corticosteroid therapy. This could be due to early remodelling phenomenon or non-optimal deposition of the drugs on distal airways.

PERSPECTIVES AND CONCLUSIONS

The medium and long term clinical implications of distal airway involvement in paediatric asthma and the impact of treatment need to be evaluated.

[Respiratory dynamics measurements in children with four to ten years of age]

BACKGROUND

respiratory dynamics measurements are frequently used in the speech-language pathology practice, but few are the scientific data for children.

AIM

to study the respiratory dynamics in children with nasal breathing.

METHOD

the study was performed with a stratified random sample of 106 nasal breathing children, male and female, from schools of the city of Marília-SP, with ages between four and ten years. The following measurements were obtained: vital capacity (VC) in both standing and sitting positions, with and without nasal occlusion; maximum phonation time (MPT) of sustained vowels and consonants and also of speech when counting numbers.

RESULTS

the mean values for VC in the standing position with and without nasal occlusion were of 1515.56ml and 1538.67ml respectively and for the sitting position of 1524ml and 1539.15ml respectively. MPT of vowels in seconds were: /a/ = 8.32, /i/ = 8.61 and /ul = 8.42; of consonants: /s/ = 6.64 and /z/ = 7.65; and when counting numbers: 7.76. It was observed that the mean values of these measurements progressively increased according to age. There was a statistically significant difference (p<0.05) not only for the MPT of vowels but also for the MPT of consonants in older children, i.e. between 4 and 10 year olds, 4 and 9 year olds and 4 and 8 year olds. There was no significant statistical difference for the VC values in consecutive age groups. There was a strong association between VC and the child's physical development.

CONCLUSION

this study presented respiratory dynamics measurements in children that can be used for the spech-language diagnosis and therapy. Other studies should be developed in order to bring additional information on the subject.

Evaluation of severity of bronchial asthma through an exercise bronchial challenge

Optimum treatment of bronchial asthma requires accurate diagnosis and severity classification. We studied the use of an exercise bronchial challenge in the asthmatic patient as a diagnostic tool. An exercise bronchial challenge test was carried out in 431 asthmatic children and 114 children without a history of asthma in a moderate-altitude environment (2,230 m above sea level/7,314 feet above sea level). Values of peak expiratory flow (baseline and maximum fall) were analyzed through time in each asthma severity group (intermittent, mild persistent, moderate persistent, severe persistent, and nonasthmatic controls). There was a significant difference among responses of asthma severity groups for almost all variables. No difference was found between nonasthmatic and intermittent groups who had similar behavior, except in bronchodilator response. An exercise bronchial challenge helps classify a patient according to asthma severity; it is easy to reproduce and does not require expensive equipment. It allows diagnosing and classifying asthma severity easily and supplementing the clinical evaluation. Based on our results, we propose a fall of PEF >or= 11% as new cutoff point for making a diagnosis of persistent bronchial asthma. A fall of 11-25% indicates mild persistent asthma; from 25-50%, moderate persistent asthma; and a bigger fall, severe persistent asthma.

[The role of the small airways in childhood asthma]

INTRODUCTION

Asthma, the most common chronic disease in paediatrics, is characterised by an inflammatory process involving the proximal and distal airways, with remodelling of the airways and changes in respiratory function.

STATE OF THE ART

Recent studies in children have provided evidence of damage to the small airways identical to that occurring in adults. In fact inflammatory cells as well as structural alterations of the airways have been found in both bronchial biopsies and broncho-alveolar lavage fluid in infants and young children. At the functional level this damage is manifest by a reduction in maximum expiratory flow rates between 25-75% of the vital capacity. It also shows itself by the demonstration of thick walled bronchi and hypodense bands on the high resolution CT scan. It appears that conventional inhaled treatments have no effect on the small airways. Finally the main prognostic factors for this distal damage are respiratory infections and exposure to tobacco in utero.

PERSPECTIVES

Damage to the small airways in childhood asthma indicates the need for new therapies aimed at this part of the respiratory system.

CONCLUSION

Inflammation and remodelling of the small airways develops early in an asthmatic child whose respiratory system is growing rapidly and persists throughout life.

Breathless in Los Angeles: the exhausting search for clean air

Population growth and the proliferation of roadways in Southern California have facilitated a glut of mobile air pollution sources (cars and trucks), resulting in substantial atmospheric pollution. Despite successful efforts over the past 40 years to reduce pollution, an alarming set of health effects attributable to air pollution have been described in Southern California. The Children's Health Study indicates that reduced lung function growth, increased school absences, asthma exacerbation, and new-onset asthma are occurring at current levels of air pollution, with sizable economic consequences. We describe these findings and urge a more aggressive effort to reduce air pollution exposures to protect our children's health. Lessons from this "case study" have national implications.