Ionisers in the management of bronchial asthma. [Ion generators and bronchial asthma. A double-blind placebo controlled study]. Double blind trial of ionisers in children with asthma sensitive to the house dust mite. A double-blind study of the effectiveness of a high-efficiency particulate air (HEPA) filter in the treatment of patients with perennial allergic rhinitis and asthma. An evaluation of mattress encasings and high efficiency particulate filters on asthma control in the tropics. A randomized, controlled study to evaluate the role of an in-home asthma disease management program provided by respiratory therapists in improving outcomes and reducing the cost of care.
Because of recent interest in the possible benefits to asthmatic patients of negative ion generators and the largely uncontrolled and inconclusive nature of earlier studies a double blind crossover study of this treatment was carried out in 20 subjects with stable asthma over six months. After an initial two week period without an ioniser, active or placebo ionisers were installed in subjects' bedrooms for two eight week periods separated by a four week "washout" period when no ioniser was present. The study was completed by a final four week period when no ioniser was present. Subjects were randomly allocated to receive an active or a placebo ioniser first. Subjects recorded their peak expiratory flow rate (PEFR) twice daily, completed a daily symptom score questionnaire, and noted any treatment they took on a diary card. Recordings were completed throughout the trial. Ion counts and dust concentrations were measured in subjects' bedrooms during the study. Mean ion counts rose considerably when ionisers were activated (p less than 0.001). There were no significant differences in PEFR, symptom score, or consumption of medication between the periods that active ionisers and either no ionisers or placebo ionisers were in operation. This study has failed to show a statistically significant benefit in asthmatic subjects from the use of negative ion generators. In this double blind, placebo-controlled study we examined the value of using a device for ionizing the air in the immediate environment as a therapy for asthma bronchiale. Nineteen adult patients with stable, reversible asthma were randomised to blind treatment with either an active device or an inactive placebo-device. After four weeks treatment the patients were given the alternative device for another period of four weeks. We measured daily peak-flow, symptomscore, use of medicine and spirometry and found no differences between the two periods. Therapy with ionization of the environmental air in patients with bronchial asthma should not be recommended. Manufacturers of ionisers claim many benefits from the use of their devices, including the relief of asthma. Particles removed from the air are likely to include airborne allergens, so ionisers may achieve an effect by reducing the allergen load.
                The effect of ionisers on airborne concentrations of house dust mite allergen Der p I was investigated in a double blind, crossover, placebo controlled trial in the homes of 20 children with allergic asthma. Subjects recorded their peak expiratory flow rate (PEFR) twice daily and completed a daily symptom score and treatment schedule on a diary card for two six week periods, one with an active ioniser and the other with a placed ioniser (randomly allocated) used in the living room and the bedroom.
                Airborne Der p I concentrations fell significantly during the active period compared with the placebo period, but there was no significant change in PEFR, symptom scores, or treatment usage. There was an increase in night time cough which almost reached significance during the active period.
                This study indicates that the use of ionisers cannot be recommended in the homes of asthmatic subjects to improve their symptoms. The significant reduction of airborne allergen concentrations may be of use as part of a multidevice allergen avoidance regimen, but the increase in night time cough requires further study. This study was designed to assess the effectiveness of a high-efficiency particulate air (HEPA) filter in alleviating allergic respiratory symptoms. Thirty-two patients were studied who had symptomatic perennial rhinitis and/or asthma during the fall and winter months and had a positive skin test with house dust or house dust--mite extract. An ENVIRACAIRE room air cleaner was placed in the bedroom for 8 weeks. In a random manner, the active filter was used for 4 weeks and a blank filter for 4 weeks. There was an average 70% reduction in the particulate matter greater than or equal to 0.3 micron with the HEPA filter. In a double-blind design, results were assessed by analysis of the patients' symptom/medication scores and subjective evaluation. For the total study, there was no difference in the total symptom/medication scores or individual symptom scores during the placebo and active-filter periods. Analysis of the last 2 weeks of each filter period in which respiratory infection was absent demonstrated definite differences in total and individual symptoms, suggesting active-filter benefit. Patients' subjective responses also suggested benefit from the filter. The overall impression is that the HEPA filter can reduce allergic respiratory symptoms. The effect of two allergen avoidance modalities, Allergy Control Covers (ACC) and High Efficiency Particulate Filters (HEPA) on asthma control in children were evaluated. This was an open study involving 24 dust mite sensitive asthmatic children. Following a 4 week run-in period, the subjects were randomly allocated to use mattresses fitted with ACC (n = 6), HEPA filters in their bedrooms (n = 12) or act as controls (n = 6) for a study duration of 4 months. Measurements of the major Dermatophagoides spp. mite allergens, Der p 1 and Der f 1, levels in dust samples obtained from mattresses were made at baseline, 1, 2 and 4 months post implementation. Daily symptom scores including morning and evening peak flow readings, and monthly spirometry and exercise bronchoprovocation tests were carried out Our results showed that dust mite allergen levels in mattresses fell at 1 and 2 months post implementation in the ACC group (p<0.05). In contrast, no decrease in allergen levels was seen in the HEPA and control group. At the end of the 16 weeks, only the ACC group showed improvement in FEV1 and reduction in diurnal peak expiratory flow rate (p<0.05). Improvement in mean symptom scores was also observed for both the ACC and HEPA groups, but not the control groups (p<0.05). Although the numbers in this study were small, the results Indicate that the effectiveness on mite exposure barrier covers was short-lived, and the improvement in asthma control though documented was not obvious. Asthma management programs (AMP) may reduce costs and improve outcomes in patients with moderate to severe asthma. However, it is not known which personnel are best able to deliver such interventions and what settings are most effective. The purpose of this study was to compare the effects of an in-home AMP provided by respiratory therapists (RTs) to an AMP provided by nurses (RNs) and to usual care (UC) provided in physician offices or clinics.
                Subjects (age 18-64) who had been admitted to the emergency department (ED) or hospital for acute asthma exacerbation were randomized to three groups: AMP-RT, AMP-RN or UC. The AMP groups received five (5) weekly home visits to provide assessment and instruction; the UC group was instructed to return to their physician for routine follow-up. Outcomes assessed at 6 months included hospitalizations, in patient days, hospitalization cost, ED visits and cost, clinic visits, pulmonary function, symptoms, health related quality of life (HRQOL), asthma episode self-management score (AESM), environmental assessment, and patient satisfaction (PS). Variables were compared using ANOVA with a Neuman-Keuls follow-up for multiple comparisons using an intent-to-treat approach.
                Upon enrollment, (n = 159) there were no differences (p > .05) between groups for age, gender, pulmonary function or HRQOL (SF-36 and St. Georges Respiratory Questionnaire - SGRQ). At 6 months, both AMP groups (AMP-RN n = 54; AMP-RT n = 46) had significantly fewer (p < 0.05) hospitalizations and in-patient days, lower hospitalization costs, and greater HRQOL physical component summary change scores (PCS) and PS than UC (n = 59). AMP-RT also had greater PEFR, SGRQ Total and SGRQ Symptoms change scores when compared to UC and significantly better AESM and PS scores as compared to AMP-RN and UC.
                An in-home asthma management program can be effectively delivered by respiratory therapists and may reduce hospitalizations, in-patient days, cost and improve measures of HRQOL and PS in a population prone to asthma exacerbation.
Based on the evidence currently available from randomised controlled trials, a recommendation cannot be given for the use of room air ionisers to reduce symptoms in patients with chronic asthma.