How long should Atrovent be given in acute asthma?

Pharmacologic approaches to life-threatening asthma

Following a peak in asthma mortality in the late 1980s and early 1990s, we have been fortunate to see a substantial decrease in asthma deaths in recent years. Although most asthma deaths occur outside the hospital, near-fatal events are commonplace, with anywhere from 2-20% of patients with acute asthma admitted to intensive care, and 2-4% intubated for respiratory failure. Standard therapies for acute severe and near-fatal asthma include administration of systemic corticosteroids, and frequent or continuous inhaled beta agonists. Controversy remains regarding the optimal therapy of those who fail to respond to these initial treatments, those who remain at risk of acute respiratory failure, and patients requiring mechanical ventilation. There remain significant gaps in our knowledge regarding relative benefits of intravenous versus oral corticosteroids, intermittent versus continuous beta agonists, and the role of various adjunctive treatments including intravenous magnesium, systemic beta agonists, aminophylline, and helium-oxygen mixtures. Using models and radiolabeled aerosols, there is a greater understanding regarding effective administration of inhaled beta-agonists in ventilated patients. There is limited available evidence for treatment of near-fatal asthma, a fact reflected by the significant variability in asthma critical care practice. Much of the data guiding treatment in this setting has been generalized from studies of acute asthma in the ED and from general populations of hospitalized patients with acute asthma. This review will focus on pharmacologic approaches to life-threatening asthma by reviewing current guideline recommendations, reviewing the scientific basis of the guidelines, and highlighting gaps in our knowledge in treatment of refractory acute or near-fatal asthma.

Relative and additional bronchodilator response of salbutamol and ipratropium in smoker and nonsmoker asthmatics

PURPOSE

This study was conducted in the Department of Tuberculosis and Respiratory Diseases, J. N. Medical College, Aligarh, India, from January 2006 to December 2007. The fact that smoker asthmatics can behave like chronic obstructive pulmonary disease (COPD) patients encourages the researcher to therapeutically exploit the important cholinergic influence in these patients. To clarify the clinical importance of the issue, the present nonblind and nonrandomized study was aimed at relative bronchodilator response to adrenergic and cholinergic agents.

METHODS

Ninety-six patients of asthma, 48 nonsmokers and 48 smokers, were given sequential doses of inhaled salbutamol and after achieving maximum bronchodilation, ipratropium was administered to observe the additional bronchodilation. On the next day, the sequence of drugs was reversed. Ipratropium was given first and after achieving maximal response, salbutamol was given.

RESULTS

On giving salbutamol first, maximal improvement in forced expiratory volume in one second (FEV(1)) was 67.04% +/- 12.98% in nonsmokers and 60.64% +/- 13.6% in smokers. The additional improvement with ipratropium was 9.22% +/- 2.08% in smokers and was significantly higher (p <.001) than in nonsmokers (0.13% +/- 2.14%). When ipratropium was given first, maximum improvement in FEV(1) was 41.95% +/- 4.57% in smokers, which was significantly higher (p <.001) than in nonsmokers (20.06% +/- 7.06%). The additional improvement with salbutamol was 23.16% +/- 5.07% and 19.09% +/- 4.9%, respectively, in nonsmokers and smokers.

CONCLUSIONS

With the above results, the authors concluded that in smoker asthmatics, cholinergic tone was more prominent and there was down-regulation of adrenergic receptors, as both drugs caused significant additional dilatation. So in smoker asthmatics, addition of a cholinergic agent will result in better control of asthma. In nonsmoker asthmatics, addition of cholinergic agent is of little or no value.

Asthma exacerbations. 5: assessment and management of severe asthma in adults in hospital

It is difficult to understand why there is such a huge discrepancy between the management of severe asthma recommended by evidence-based guidelines and that observed in clinical practice. The recommendations are relatively straightforward and have been widely promoted both in guidelines and reviews. Specialist physicians need to be more proactive in their implementation of such guidelines through the use of locally derived protocols and assessment sheets, reinforced by audit. The common occurrence of severe asthma and its considerable burden to the community would support such an approach.

A randomized, clinical trial comparing the efficacy of continuous nebulized albuterol (15 mg) versus continuous nebulized albuterol (15 mg) plus ipratropium bromide (2 mg) for the treatment of acute asthma

Multiple studies have examined adding nebulized ipratropium bromide to intermittent albuterol for the treatment of acute asthma. Although continuous nebulized treatments in themselves offer benefits; few data exist regarding the efficacy of adding ipratropium bromide to a continuous nebulized system. To compare continuous nebulized albuterol alone (A) vs. albuterol and ipratropium bromide (AI) in adult Emergency Department (ED) patients with acute asthma, a prospective, randomized, double-blind, controlled clinical trial was conducted on a convenience sample of patients (IRB approved). The setting was an urban ED. Consenting patients > 18 years of age with peak expiratory flow rates (PEFR) < 70% predicted, between October 15 and December 28, 1999, were randomized to albuterol (7.5 mg/h) + ipratropium bromide (1.0 mg/h), or albuterol alone via continuous nebulization using the Hope Nebulizer (B&B Technologies Inc., Orangevale, CA) for 2 h. Main outcome measures were changed in mean improvement at 60 and 120 min PEFR compared to baseline (time 0). Secondary measures were admission rates. Data were analyzed using appropriate parametric and non-parametric tests (p < 0.05 statistically significant). Sixty-two patients (30 women) completed enrollment: 32 in (AI) and (30) in (A). Four (A) and 2 (AI) patients are without 120 min data: 3 (A) and 1 (AI) were discharged after 60 min, whereas one each (A) and (AI) worsened and were admitted before 120 min. There were no statistically significant differences between treatment groups in age, sex, predicted or initial PEFR. Thirteen (19.4%) patients were admitted. There was no statistically significant difference in improvement of mean PEFR at 60 min or 120 min compared to baseline, between groups, using repeated measures analysis of variance. Mean improvement in PEFR at 60 min compared to baseline (time 0): (A) = 93.2 L/min (95% confidence interval [CI] 64.5-121.8), (AI) = 86.6 L/min (95% CI 58.9-114.3); mean improvement in PEFR at 120 min compared to baseline (time 0) (A) = 116.5 L/min (95% CI 84.5-148.5), (AI) = 126.4 L/min (95% CI 95.4-157.4). There was no statistically significant difference in admission rates between groups: 5/30 (A) and 8/32 (AI) (p = 0.62). There were no significant differences in mean improvement of PEFR at either 60 or 120 min between ED patients with acute asthma receiving continuous albuterol alone vs. those receiving albuterol in combination with ipratropium bromide.

Atropine pretreatment enhances airway hyperreactivity in antigen-challenged guinea pigs through an eosinophil-dependent mechanism

Airway hyperreactivity in antigen-challenged animals is mediated by eosinophil major basic protein (MBP) that blocks inhibitory M(2) muscarinic receptors on parasympathetic nerves, increasing acetylcholine release onto M(3) muscarinic receptors on airway smooth muscle. Acutely, anticholinergics block hyperreactivity in antigen-challenged animals and reverse asthma exacerbations in the human, but are less effective in chronic asthma. We tested whether atropine, given before antigen challenge, affected hyperreactivity, M(2) receptor function, eosinophil accumulation, and activation. Sensitized guinea pigs received atropine (1 mg/kg ip) 1 h before challenge and 6 h later. Twenty-four hours after challenge, animals were anesthetized, vagotomized, paralyzed, and ventilated. Airway reactivity to electrical stimulation of the vagi and to intravenous acetylcholine was not altered by atropine pretreatment in nonsensitized animals, indicating that atropine was no longer blocking postjunctional muscarinic receptors. Antigen challenge induced airway hyperreactivity to vagal stimulation that was significantly potentiated by atropine pretreatment. Bronchoconstriction induced by acetylcholine was not changed by antigen challenge or by atropine pretreatment. M(2) receptor function was lost in challenged animals but protected by atropine pretreatment. Eosinophils in bronchoalveolar lavage and within airway tissues were significantly increased by challenge but significantly reduced by atropine pretreatment. However, extracellular MBP in challenged airways was significantly increased by atropine pretreatment, which may account for reduced eosinophils. Depleting eosinophils with antibody to IL-5 before challenge prevented hyperreactivity and significantly reduced MBP in airways of atropine-pretreated animals. Thus atropine pretreatment potentiated airway hyperreactivity by increasing eosinophil activation and degranulation. These data suggest that anticholinergics enhance eosinophil interactions with airway nerves.

Effects of muscarinic receptor antagonists with or without M2 antagonist activity on cholinergic reflex bronchoconstriction in ovalbumin-sensitized and -challenged mice

To investigate whether the inhibition of muscarinic M(2) receptors results in the enhancement of reflex bronchoconstriction under airway hyperresponsiveness, we evaluated the effects of muscarinic antagonists with or without M(2) antagonist activity on methacholine (MCh)- and SO(2)-induced airway responses in ovalbumin (OVA)-sensitized and -challenged mice. In this model, similar airway hyperresponsiveness to MCh (12 mg/ml) was observed on Days 31 and 37 (2.2-fold and 2.7-fold, respectively). However, airway hyperresponsiveness to SO(2) (0.05 l/min) on Day 37 was less than that on Day 31 (4.0- and 2.7-fold on Days 31 and 37), indicating reflex bronchoconstriction was enhanced on Day 31 in comparison to Day 37. Ipratropium (0.03 - 0.3 mg/ml, inhalation) and Compound A (0.1 - 3 mg/kg, p.o.) inhibited MCh-induced responses on Days 31 and 37. Although ipratropium (0.03 - 1 mg/ml) dose-dependently inhibited SO(2)-induced responses on Day 31, ipratropium at a dose of 0.1 mg/ml significantly increased SO(2)-induced responses on Day 37 (162.2% of the corresponding control). On the other hand, Compound A (0.03 - 0.3 mg/kg, p.o.) inhibited SO(2)-induced responses without any increases on Days 31 and 37. These results suggest that two different conditions of reflex bronchoconstriction are presented in this model: 1) SO(2)-induced responses are enhanced by dysfunctional M(2) receptors on Day 31; 2) the dysfunctional M(2) receptors are partially restored on Day 37. In addition, the inhibition of the restored M(2) receptors further enhance reflex bronchoconstriction.

Anticholinergic therapy for chronic asthma in children over two years of age

BACKGROUND

In the intrinsic system of controlling airway calibre, the cholinergic (muscarinic) sympathetic nervous system has an important role. Anticholinergic, anti muscarinic bronchodilators such as ipratropium bromide are frequently used in the management of childhood airway disease. In asthma, ipratropium is a less potent bronchodilator than beta-2 adrenergic agents but it is known to be a useful adjunct to other therapies, particularly in status asthmaticus. What remains unclear is the role of anticholinergic drugs in the maintenance treatment of chronic asthma.

OBJECTIVES

To determine the effectiveness of anticholinergic drugs in chronic asthma in children over the age of 2 years.

SEARCH STRATEGY

The Cochrane Airways Group trials register and reference lists of articles were searched in January 2002.

SELECTION CRITERIA

Randomised controlled trials in which anticholinergic drugs were given for chronic asthma in children over 2 years of age were included. Studies including comparison of: anticholinergics with placebo, and anticholinergics with any other drug were included.

DATA COLLECTION AND ANALYSIS

Eligibility for inclusion and quality of trials were assessed independently by two reviewers.

MAIN RESULTS

Eight studies met the inclusion criteria.Three papers compared the effects of anticholinergic drugs with placebo, and a meta-analysis of these results demonstrated no statistically significant benefit of the use of anticholinergic drugs over placebo in any of the outcome measures used. The results of one of these trials could not be included in the meta-analysis but the authors did report significantly lower symptom scores with inhaled anticholinergics compared with placebo. However, there was no significant difference between ipratropium bromide and placebo in the percentage of symptom-free nights or days. Two trials studied the effects of anticholinergics on bronchial hyper responsiveness to histamine, by measuring the provocation dose of histamine needed to cause a fall of 20 % in FEV1 (PD 20). One study (comparing anticholinergics with placebo) reported a statistically significant increase in PD 20 but this was not found in another study (comparing anticholinergics with a beta-2 agonist). Both trials also examined the effect of anticholinergic drugs on diurnal variation in peak expiratory flow rate (PEFR) and reported no significant effect. Two studies compared the addition of an anticholinergic drug to a beta-2 agonist with the beta-2 agonist alone. Both trials failed to show any significant benefit from the long term use of combined anticholinergics with beta-2 agonists compared with beta-2 agonists alone. One trial compared the effects of oral and inhaled anticholinergic drugs with placebo. No statistically significant differences were found in any of the outcome measures except for a higher FEV1 / VC ratio and RV / TLC ratio with oral anticholinergic therapy when compared with placebo.

REVIEWER'S CONCLUSIONS

The present review summarises the best evidence available to date. Although there were some small beneficial findings in favour of anticholinergic therapy, there is insufficient data to support the use of anticholinergic drugs in the maintenance treatment of chronic asthma in children.

Management of acute pediatric asthma

Pediatric asthma prevalence, morbidity, and severity are increasing. Direct costs associated with providing emergency department and inpatient care account for more than 40% of overall dollars spent for this disease in the United States. Physicians in many health care settings may be required to treat a child in severe respiratory distress caused by acute asthma. This article reviews the pathophysiology, evaluation, and treatment of severe asthma exacerbations, or status asthmaticus.

Intravenous versus oral corticosteroids for treatment of acute asthma exacerbations

OBJECTIVE

To compare the duration of hospitalization of patients treated with either oral or intravenous corticosteroids for an acute asthma exacerbation.

METHODS

A retrospective chart review was performed on a random sample of inpatients. Patients were included with the following: a discharge diagnosis of an acute asthma exacerbation, a past medical history significant for asthma, age between 16 and 60 years, and treatment with either oral or intravenous corticosteroids at the time of admission. Exclusion criteria included: patients receiving chronic prednisone therapy, a past medical history significant for chronic obstructive pulmonary disease, an admission to the intensive care unit, or a consistent smoking habit of at least 1 pack daily. Length of hospitalization was the primary outcome measured. Secondary outcomes included 24-hour peak expiratory flow rate, 24-hour pulse oximetry (pO(2)), and amount of beta-agonist and ipratropium used.

RESULTS

Fifty-three patients were included in the final data analysis. Patients were grouped by route of corticosteroid administration (intravenous or oral). No significant differences were noted between the 2 groups for race, gender, age, height, weight, admission peak expiratory flow rate, admission pO(2), or types of asthma medications used prior to admission. No significant differences were demonstrated in any of the outcome measures.

CONCLUSIONS

Both the intravenous and oral corticosteroid groups demonstrated similar clinical outcomes and lengths of hospitalization in the treatment of acute asthma exacerbations. These results support the initial use of oral corticosteroids for the treatment of acute asthma exacerbations in adult patients admitted to a general medical service.

Discharge of the asthmatic patient

Asthma continues to be a challenging disease to treat in both the inpatient and outpatient settings. The growing database on therapeutic interventions at the time of transition from the acute to chronic phase of this disease is encouraging. Glucocorticoids and inhaled beta-agonists clearly reduce readmission and relapse. Other medications and educational interventions also appear effective. Still, no true discharge guidelines have been established. Multiple statements by consensus panels have recommended using FEV1 or PEFR as indicators of readiness for discharge, but this has not been prospectively validated from either the emergency department or inpatient setting. In contrast, some studies argue that pulmonary functions do not accurately predict relapse and readmission, so the usefulness of these discharge recommendations is debatable. Large studies, especially in the adult asthmatic population, are needed to validate these recommendation.

Acute asthma in the pediatric emergency department

The management of children with acute asthma remains a difficult and challenging process. Although newer asthma medications are being developed, they are unlikely to have a large impact on the management of children with acute asthma. The leukotriene inhibitors are new anti-inflammatory agents for asthma and are beneficial for the treatment of patients with chronic asthma but have no therapeutic effect during the acute phase of an exacerbation. Older treatments, including the use of magnesium and heliox, have been revisited. Although some children with severe asthma may respond, these do not provide relief for most children with acute exacerbation. The new challenge for asthma care is finding ways to link children with their primary care providers so that regular asthma care can be established. The NHLBI recommends that children with asthma have regular visits with their primary care providers (e.g., four times a year). Regular care results in better adherence to medical and preventive management plans and improves the relationship between patients and physicians. Instituting an asthma action plan, which instructs families on when and how to begin therapy for an acute exacerbation, may prevent progression to a more severe condition.

A meta-analysis of the effects of ipratropium bromide in adults with acute asthma

PURPOSE

To review the literature to determine whether inhaled ipratropium bromide provides additive benefits to adults with acute asthma who are being treated with beta-agonists in an emergency department.

SUBJECTS AND METHODS

English-language studies, both published (1978 to 1999) and unpublished, were retrieved using Medline, Science Citation Index, Current Contents, bibliographic reviews of primary research, review articles, consultation with experts, and the register of Medical Editors' Trial Amnesty. Only randomized, double-blind, controlled trials that enrolled patients having an exacerbation of asthma were included. The main outcome measure was pulmonary function; hospital admission rate was also evaluated.

RESULTS

Ten studies including 1,483 adults with acute asthma were selected (mean age 32 +/- 13 years, 36% men). The overall effect size in SD units of pulmonary function showed a significant benefit from ipratropium (effect size 0.14, 95% confidence interval [CI]: 0.04 to 0.24, P = 0.008). Study-specific effect sizes ranged from 0.03 to 0.63. This pooled effect size was equivalent to a 10% (95% CI: 2% to 18%) increase in forced expiratory volume in 1 second (FEV1) or peak expiratory flow in the ipratropium group compared with the control group. Analysis of the four studies that included patients with extreme obstruction (FEV1 or peak flow <35% of predicted at presentation) showed substantial improvement with ipratropium therapy (effect size 0.38, 95% CI: 0.09 to 0.67). In the five trials (1,186 patients) that studied the effect of ipratropium administration on hospital admissions, pooled results revealed that ipratropium reduced admission rates significantly (odds ratio 0.62, 95% CI: 0.44 to 0.88, P = 0.007).

CONCLUSIONS

The addition of ipratropium to beta-agonist therapy offers a statistically significant, albeit modest, improvement in pulmonary function, as well as a reduction in the rate of hospital admissions.