The salt output of a nebulizer--a comparison between two nebulizer types.
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The output of a nebulizer is generally defined as its weight loss during 1 min of nebulization. This mass output includes the weight loss due to evaporation of the solution required to moisten the dry air that is fed through the nebulizer. In order to compare results obtained from studies using different nebulizers we introduce the salt output as the amount of the solution that actually leaves the liquid phase as droplets and not by evaporation. The performance characteristics of a standard jet nebulizer (MA2) and a Sidestream jet neublizer were compared. Mass output was determined at different methacholine concentrations. Salt output was assessed by analysing the remaining salt in the nebulizers after 1 min of nebulization. Overall system performance in terms of forced expiratory volume in 1 sec (FEV1) reduction after 1 min of exposure to individually selected concentrations of methacholine were studied in 15 healthy, non-smoking subjects. Both nebulizer types showed a moderate linear increase of mass output with methacholine concentration. The efficiency coefficient, the quotient between salt output and mass output, was found to be 0.93 and 0.75 for the MA2 and Sidestream nebulizer respectively. These findings were explained by differences in airflow through, and temperature inside, the nebulizers. The salt output of the nebulizers proved to be better correlated to the FEV1-reduction following methacholine inhalation than did the mass output. The relative amount of the salt output that adhered to the acrylic walls of the Sidestream nebulizer drying tower was found to be 9%. We conclude that it is more appropriate to use salt output than mass output as a nebulizer performance descriptor. The study also shows the importance of determining nebulizer system performance under conditions as similar to true provocations as possible. (+info)
Improving patient compliance with asthma therapy.
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Patients fail to comply with asthma medication for a variety of reasons. These range from physical inability to use an inhaler, through simple forgetfulness, to a conscious decision not to use medication as prescribed due to internal or cultural health beliefs or socioeconomic factors. In some patients, poor self-care because of deep-rooted psychological factors (i.e. factors of which patients have only limited awareness) can affect compliance. Poor doctor-patient communication can be the cause in many other individuals. Thus, there is no single solution that will improve compliance in all patients. Simplifying the regimen or providing memory aids will be sufficient for some patients, while education or psychological counselling will be more appropriate for others. Doctors can also use a range of communication skills to improve the way in which they present information, motivate patients and reinforce progress. These approaches, plus respect for patients' health beliefs and involving them in treatment decisions, can help foster an atmosphere of mutual responsibility and concordance over medicine taking. (+info)
The relative bioavailability of salbutamol to the lung using urinary excretion following inhalation from a novel dry powder inhaler: the effect of inhalation rate and formulation.
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Each dry powder inhaler has a different resistance so that a respirable dose can be generated from the formulation by the patient's inspiratory effort. It is important to recognize that this effect is achievable. The inspiratory flow characteristics of asthmatics inhaling through a Clickhaler were determined. In a separate study 10 volunteers inhaled separate 2 x 100 microg salbutamol doses from a Clickhaler (ML Laboratories plc U.K.). Two different formulations (one with a high and one with a low respirable fraction) were each inhaled using an inspiratory flow of 30 and 60 l min(-1). A urine sample was collected 30 min post inhalation and then pooled for the next 24 h. The mean (SD) inhalation rate of 24 asthmatics when they inhaled from a Clickhaler was 37.3 (14.6) l min(-1). The mean (SD) urinary salbutamol excretion during the first 30 min, by the volunteers, using the high respirable dose formulation at 30 and 60 l min(-1) was 5.59 (1.87) and 4.62 (1.49) microg respectively (P<0.01). Similar values using the low respirable dose formulation were 4.84 (1.58) and 3.86 (2.14) microg. There was no significant difference between the amounts excreted in the 24 h post-dose. The different 30-min urinary excretions following inhalation of the two formulations suggest a link between the relative bioavailability of salbutamol to the lung and the respirable dose, and that a slow inhalation rate should be used when using a Clickhaler. The patient study shows that this rate is achieved by most asthmatics without further training. (+info)
Effect of nebulized morphine in cancer patients with dyspnea: a pilot study.
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BACKGROUND: It is known that opioids may decrease subjective dyspnea. The recent finding that opioid binding sites are present in the peripheral bronchus supports the possibility of a local action of opioids. However, the clinical benefit of nebulized morphine is controversial. The purpose of this study was to confirm the feasibility of nebulized morphine and to evaluate its clinical benefits. PATIENTS AND METHODS: Fifteen cancer patients with dyspnea in the Thoracic Oncology Division and Palliative Care Unit in the National Cancer Center Hospital East were given 20 mg of morphine hydrochloride dissolved in 5 ml of normal saline through an ultranebulizer. The subjective effects were evaluated using a visual analog scale (VAS) immediately before and 60 min after inhalation. Respiratory rate (RR), hemoglobin oxygen saturation (SpO2) and blood pressure also were measured twice at these two time points. A questionnaire about adverse reactions was included. RESULTS: No major adverse reactions such as respiratory depression, sleepiness, nausea or vomiting were observed. VAS was significantly decreased after nebulization (p = 0.005) without any significant change in RR or SpO2. In eight of 15 patients, dyspnea was improved as measured by a decrease in VAS of more than 10%. This correlated with the desire of the patients to continue its use. CONCLUSION: Our preliminary data confirmed the feasibility of nebulized morphine and suggested its possible clinical benefit for dyspneic patients. A randomized controlled study is warranted to exclude a placebo effect and to compare the clinical benefits of nebulized morphine with those of other methods of treatment. (+info)
An essential role of mast cells in the development of airway hyperresponsiveness in a murine asthma model.
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Immunization of BALB/c mice with alum-adsorbed OVA, followed by three bronchoprovocations with aerosolized OVA, resulted in the development of airway hyperresponsiveness (AHR) and allergic inflammation in the lung accompanied by severe infiltration of eosinophils into airways. In this murine asthma model, administration of monoclonal anti-IL-5 Ab before each Ag challenge markedly inhibited airway eosinophilia, but the treatment did not affect the development of AHR. Immunization and aerosol challenges with OVA following the same protocol failed to induce AHR in the mast cell-deficient W/Wv mice, but induced AHR in their congenic littermates, i.e., WBB6F1 (+/+) mice. No significant difference was found between the W/Wv mice and +/+ mice with respect to the IgE and IgG1 anti-OVA Ab responses and to the airway eosinophilia after Ag provocations. It was also found that reconstitution of W/Wv mice with bone marrow-derived mast cells cultured from normal littermates restored the capacity of developing Ag-induced AHR, indicating that lack of mast cells was responsible for the failure of W/Wv mice to develop Ag-induced AHR under the experimental conditions. However, the OVA-immunized W/Wv mice developed AHR by increasing the frequency and Ag dose of bronchoprovocations. The results suggested that AHR could be developed by two distinct cellular mechanisms. One would go through mast cell activation and the other is IgE/mast cell independent but an eosinophil/IL-5-dependent mechanism. (+info)
Nebulised steroid in the treatment of croup: a systematic review of randomised controlled trials.
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BACKGROUND: Croup is one of the commonest respiratory complaints among children. There is growing evidence that steroids may be an effective treatment. AIM: To assess the effectiveness of treatment with nebulised steroid for children with croup. METHOD: Systematic review of randomised controlled trials comparing administration of nebulised steroid with placebo. Trials were identified from searches of three bibliographic databases, the Cochrane Controlled Trials Register, correspondence with the manufacturers of nebulised steroid, and one round of manual citation searching. RESULTS: Eight randomised controlled trials were identified including 574 children with mild to severe croup. Overall, the mean age was 25.2 months and 72% of children were male. All trials were hospital-based and of good methodological quality, with adequate concealment of treatment allocation and blind outcome assessment. Children treated with nebulised steroid were significantly more likely to show an improvement in croup score by five hours (combined relative risk = 1.48, 95% confidence interval [CI] = 1.27 to 1.74) and significantly less likely to need hospital admission after attending the emergency department (combined relative risk = 0.56, 95% CI = 0.42 to 0.75) than the placebo group. The funnel plot indicated the presence of publication bias, with smaller studies showing the larger effects, but this could also be owing to less pronounced effects in studies of older children with milder croup. CONCLUSIONS: Nebulised steroids are effective in the treatment of children attending hospital departments with croup. A meta-analysis based on individual patient data could clarify to what extent the effect depends on age and severity of disease. New trials are needed to define the indications for, and effectiveness of, steroid treatment of croup in the community. (+info)
Equivalence of two steroid-containing inhalers: easyhaler multidose powder inhaler compared with conventional aerosol with large-volume spacer.
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BACKGROUND AND OBJECTIVES: An equivalence study was conducted in which the efficacy and safety of a daily dose of 800 microgram of beclomethasone diproprionate administered via a multidose powder inhaler, Easyhaler, and via a metered-dose inhaler (MDI) with a large-volume spacer were compared in adult, newly diagnosed, steroid-naive asthmatic patients. Acceptability of the medications was also compared. METHODS: One hundred and forty-four patients were recruited into the double-blind, double-dummy, randomised, parallel-group multicentre study. The study treatment period was 8 weeks. It was preceded by a 2-week run-in period. Morning and evening peak expiratory flow (PEF), numbers of inhalations of a sympathomimetic and asthma symptoms were recorded daily. Spirometry and histamine challenge were performed, and health-related quality of life and morning serum cortisol levels measured during control visits. RESULTS: Criteria indicating treatment equivalence were met. The mean of the primary outcome variable, morning PEF, increased significantly, from 426 to 461 litres/min in the Easyhaler group and from 436 to 467 litres/min in the MDI+spacer group. Similar improvements between groups were also seen in relation to all secondary variables. Changes in serum cortisol levels were minor. In 6 out of 10 questions about device acceptability, the majority of patients rated Easyhaler as better than the MDI+spacer combination. CONCLUSION: It was concluded that the devices tested were equivalent in terms of efficacy and safety. (+info)
Baseline airway hyperreactivity in A/J mice is not mediated by cells of the adaptive immune system.
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Human asthma is characterized by increased airway hyperreactivity to a variety of bronchoconstricting agents. Aberrant type 2 immune responses in the lung have been associated with airway hyperreactivity in both human asthma and in murine models of allergic airways disease. Despite their intrinsically elevated basal airway reactivity to smooth muscle constricting agents, A/J mice demonstrated no inherent inflammatory cell infiltration nor elevation of type 2 cytokines in the lung. Crossed bone marrow reconstitution experiments between A/J and MHC congenic B10.A mice revealed enhanced airway reactivity only in A/J recipients, irrespective of whether they had been reconstituted with A/J or B10. A hemopoietic cells. Further, A/J-derived bone marrow cells did not affect the reactivity of B10.A recipients. Although mice on RAG-deficient and IL-4-deficient backgrounds demonstrate substantial abrogation of allergen-induced airway hyperreactivity, these gene deletions had no impact on the elevated baseline reactivity when backcrossed onto A/J mice. Thus, in these mice, basal airway hyperreactivity is maintained independently of type 2 immunity induced by allergens. (+info)