Effect of continuously nebulized ipratropium bromide plus albuterol on emergency department length of stay and hospital admission rates in patients with acute bronchospasm. A randomized, controlled trial

Critical Care Management of Severe Asthma Exacerbations

Severe asthma exacerbations, including near-fatal asthma (NFA), have high morbidity and mortality. Mechanical ventilation of patients with severe asthma is difficult due to the complex pathophysiology resulting from severe bronchospasm and dynamic hyperinflation. Life-threatening complications of traditional ventilation strategies in asthma exacerbations include the development of systemic hypotension from hyperinflation, air trapping, and pneumothoraces. Optimizing pharmacologic techniques and ventilation strategies is crucial to treat the underlying bronchospasm. Despite optimal pharmacologic management and mechanical ventilation, the mortality rate of patients with severe asthma in intensive care units is 8%, suggesting a need for advanced non-pharmacologic therapies, including extracorporeal life support (ECLS). This review focuses on the pathophysiology of acute asthma exacerbations, ventilation management including non-invasive ventilation (NIV) and invasive mechanical ventilation (IMV), the pharmacologic management of acute asthma, and ECLS. This review also explores additional advanced non-pharmacologic techniques and monitoring tools for the safe and effective management of critically ill adult asthmatic patients.

Indian Guidelines on Nebulization Therapy

Inhalational therapy, today, happens to be the mainstay of treatment in obstructive airway diseases (OADs), such as asthma, chronic obstructive pulmonary disease (COPD), and is also in the present, used in a variety of other pulmonary and even non-pulmonary disorders. Hand-held inhalation devices may often be difficult to use, particularly for children, elderly, debilitated or distressed patients. Nebulization therapy emerges as a good option in these cases besides being useful in the home care, emergency room and critical care settings. With so many advancements taking place in nebulizer technology; availability of a plethora of drug formulations for its use, and the widening scope of this therapy; medical practitioners, respiratory therapists, and other health care personnel face the challenge of choosing appropriate inhalation devices and drug formulations, besides their rational application and use in different clinical situations. Adequate maintenance of nebulizer equipment including their disinfection and storage are the other relevant issues requiring guidance. Injudicious and improper use of nebulizers and their poor maintenance can sometimes lead to serious health hazards, nosocomial infections, transmission of infection, and other adverse outcomes. Thus, it is imperative to have a proper national guideline on nebulization practices to bridge the knowledge gaps amongst various health care personnel involved in this practice. It will also serve as an educational and scientific resource for healthcare professionals, as well as promote future research by identifying neglected and ignored areas in this field. Such comprehensive guidelines on this subject have not been available in the country and the only available proper international guidelines were released in 1997 which have not been updated for a noticeably long period of over two decades, though many changes and advancements have taken place in this technology in the recent past. Much of nebulization practices in the present may not be evidence-based and even some of these, the way they are currently used, may be ineffective or even harmful. Recognizing the knowledge deficit and paucity of guidelines on the usage of nebulizers in various settings such as inpatient, out-patient, emergency room, critical care, and domiciliary use in India in a wide variety of indications to standardize nebulization practices and to address many other related issues; National College of Chest Physicians (India), commissioned a National task force consisting of eminent experts in the field of Pulmonary Medicine from different backgrounds and different parts of the country to review the available evidence from the medical literature on the scientific principles and clinical practices of nebulization therapy and to formulate evidence-based guidelines on it. The guideline is based on all possible literature that could be explored with the best available evidence and incorporating expert opinions. To support the guideline with high-quality evidence, a systematic search of the electronic databases was performed to identify the relevant studies, position papers, consensus reports, and recommendations published. Rating of the level of the quality of evidence and the strength of recommendation was done using the GRADE system. Six topics were identified, each given to one group of experts comprising of advisors, chairpersons, convenor and members, and such six groups (A-F) were formed and the consensus recommendations of each group was included as a section in the guidelines (Sections I to VI). The topics included were: A. Introduction, basic principles and technical aspects of nebulization, types of equipment, their choice, use, and maintenance B. Nebulization therapy in obstructive airway diseases C. Nebulization therapy in the intensive care unit D. Use of various drugs (other than bronchodilators and inhaled corticosteroids) by nebulized route and miscellaneous uses of nebulization therapy E. Domiciliary/Home/Maintenance nebulization therapy; public & health care workers education, and F. Nebulization therapy in COVID-19 pandemic and in patients of other contagious viral respiratory infections (included later considering the crisis created due to COVID-19 pandemic). Various issues in different sections have been discussed in the form of questions, followed by point-wise evidence statements based on the existing knowledge, and recommendations have been formulated.

Combined inhaled beta-agonist and anticholinergic agents for emergency management in adults with asthma

BACKGROUND

Inhaled short-acting anticholinergics (SAAC) and short-acting beta₂-agonists (SABA) are effective therapies for adult patients with acute asthma who present to the emergency department (ED). It is unclear, however, whether the combination of SAAC and SABA treatment is more effective in reducing hospitalisations compared to treatment with SABA alone.

OBJECTIVES

To conduct an up-to-date systematic search and meta-analysis on the effectiveness of combined inhaled therapy (SAAC + SABA agents) vs. SABA alone to reduce hospitalisations in adult patients presenting to the ED with an exacerbation of asthma.

SEARCH METHODS

We searched MEDLINE, Embase, CINAHL, SCOPUS, LILACS, ProQuest Dissertations & Theses Global and evidence-based medicine (EBM) databases using controlled vocabulary, natural language terms, and a variety of specific and general terms for inhaled SAAC and SABA drugs. The search spanned from 1946 to July 2015. The Cochrane Airways Group provided search results from the Cochrane Airways Group Register of Trials which was most recently conducted in July 2016. An extensive search of the grey literature was completed to identify any other potentially relevant studies.

SELECTION CRITERIA

Included studies were randomised or controlled clinical trials comparing the effectiveness of combined inhaled therapy (SAAC and SABA) to SABA treatment alone to prevent hospitalisations in adults with acute asthma in the emergency department. Two independent review authors assessed studies for inclusion using pre-determined criteria.

DATA COLLECTION AND ANALYSIS

For dichotomous outcomes, we calculated individual and pooled statistics as risk ratios (RR) or odds ratios (OR) with 95% confidence intervals (CI) using a random-effects model and reporting heterogeneity (I²). For continuous outcomes, we reported individual trial results using mean differences (MD) and pooled results as weighted mean differences (WMD) or standardised mean differences (SMD) with 95% CIs using a random-effects model.

MAIN RESULTS

We included 23 studies that involved a total of 2724 enrolled participants. Most studies were rated at unclear or high risk of bias.Overall, participants receiving combination inhaled therapy were less likely to be hospitalised (RR 0.72, 95% CI 0.59 to 0.87; participants = 2120; studies = 16; I² = 12%; moderate quality of evidence). An estimated 65 fewer patients per 1000 would require hospitalisation after receiving combination therapy (95% 30 to 95), compared to 231 per 1000 patients receiving SABA alone. Although combination inhaled therapy was more effective than SABA treatment alone in reducing hospitalisation in participants with severe asthma exacerbations, this was not found for participants with mild or moderate exacerbations (test for difference between subgroups P = 0.02).Participants receiving combination therapy were more likely to experience improved forced expiratory volume in one second (FEV₁) (MD 0.25 L, 95% CI 0.02 to 0.48; participants = 687; studies = 6; I² = 70%; low quality of evidence), peak expiratory flow (PEF) (MD 36.58 L/min, 95% CI 23.07 to 50.09; participants = 1056; studies = 12; I² = 25%; very low quality of evidence), increased percent change in PEF from baseline (MD 24.88, 95% CI 14.83 to 34.93; participants = 551; studies = 7; I² = 23%; moderate quality of evidence), and were less likely to return to the ED for additional care (RR 0.80, 95% CI 0.66 to 0.98; participants = 1180; studies = 5; I² = 0%; moderate quality of evidence) than participants receiving SABA alone.Participants receiving combination inhaled therapy were more likely to experience adverse events than those treated with SABA agents alone (OR 2.03, 95% CI 1.28 to 3.20; participants = 1392; studies = 11; I² = 14%; moderate quality of evidence). Among patients receiving combination therapy, 103 per 1000 were likely to report adverse events (95% 31 to 195 more) compared to 131 per 1000 patients receiving SABA alone.

AUTHORS' CONCLUSIONS

Overall, combination inhaled therapy with SAAC and SABA reduced hospitalisation and improved pulmonary function in adults presenting to the ED with acute asthma. In particular, combination inhaled therapy was more effective in preventing hospitalisation in adults with severe asthma exacerbations who are at increased risk of hospitalisation, compared to those with mild-moderate exacerbations, who were at a lower risk to be hospitalised. A single dose of combination therapy and multiple doses both showed reductions in the risk of hospitalisation among adults with acute asthma. However, adults receiving combination therapy were more likely to experience adverse events, such as tremor, agitation, and palpitations, compared to patients receiving SABA alone.

Inherent antibacterial activity of a peptide-based beta-hairpin hydrogel

Among several important considerations for implantation of a biomaterial, a main concern is the introduction of infection. We have designed a hydrogel scaffold from the self-assembling peptide, MAX1, for tissue regeneration applications whose surface exhibits inherent antibacterial activity. In experiments where MAX1 gels are challenged with bacterial solutions ranging in concentrations from 2 x 10(3) colony forming units (CFUs)/dm2 to 2 x 10(9) CFUs/dm2, gel surfaces exhibit broad-spectrum antibacterial activity. Results show that the hydrogel surface is active against Gram-positive (Staphylococcus epidermidis, Staphylococcus aureus, and Streptococcus pyogenes) and Gram-negative (Klebsiella pneumoniae and Escherichia coli) bacteria, all prevalent in hospital settings. Live-dead assays employing laser scanning confocal microscopy show that bacteria are killed when they engage the surface. In addition, the surface of MAX1 hydrogels was shown to cause inner and outer membrane disruption in experiments that monitor the release of beta-galactosidase from the cytoplasm of lactose permease-deficient E. coli ML-35. These data suggest a mechanism of antibacterial action that involves membrane disruption that leads to cell death upon cellular contact with the gel surface. Although the hydrogel surface exhibits bactericidal activity, co-culture experiments indicate hydrogel surfaces show selective toxicity to bacterial versus mammalian cells. Additionally, gel surfaces are nonhemolytic toward human erythrocytes, which maintain healthy morphologies when in contact with the surface. These material attributes make MAX1 gels attractive candidates for use in tissue regeneration, even in nonsterile environments.

Continuous bronchodilator therapy

Inhaled bronchodilators are first-line treatment for acute exacerbations of asthma. Continuous bronchodilator administration is a novel option for the treatment of bronchospasm, which may be more effective than intermittent therapy for patients with severe airflow obstruction. For 2007, coding and billing changes for this modality become effective. This article reviews clinical aspects and outpatient practice management of continuous bronchodilator therapy.

Acute severe asthma

Acute severe asthma remains a major economic and health burden. The natural history of acute decompensations is one of resolution and only about 0.4% of patients succumb overall. Mortality in medical intensive care units is higher but is less than 3% of hospital admissions. "Near-fatal" episodes may be more frequent, but precise figures are lacking. However, about 30% of medical intensive care unit admissions require intubation and mechanical ventilation with mortality of 8%. Morbidity and mortality increase with socioeconomic deprivation and ethnicity. Seventy to 80% of patients in emergency departments clear within 2 hours with standardized care. The relapse rate varies between 7 and 15%, depending on how aggressively the patient is treated. The airway obstruction in the 20-30% of people resistant to adrenergic agonists in the emergency department slowly reverses over 36-48 hours but requires intense treatment to do so. Current therapeutic options for this group consist of ipratropium and corticosteroids in combination with beta2 selective drugs. Even so, such regimens are not optimal and better approaches are needed. The long-term prognosis after a near-fatal episode is poor and mortality may approach 10%.

Randomised trial of glutamine and selenium supplemented parenteral nutrition for critically ill patients. Protocol Version 9, 19 February 2007 known as SIGNET (Scottish Intensive care Glutamine or seleNium Evaluative Trial)

Background

Mortality rates in the Intensive Care Unit and subsequent hospital mortality rates in the UK remain high. Infections in Intensive Care are associated with a 2–3 times increased risk of death. It is thought that under conditions of severe metabolic stress glutamine becomes "conditionally essential". Selenium is an essential trace element that has antioxidant and anti-inflammatory properties. Approximately 23% of patients in Intensive Care require parenteral nutrition and glutamine and selenium are either absent or present in low amounts. Both glutamine and selenium have the potential to influence the immune system through independent biochemical pathways. Systematic reviews suggest that supplementing parenteral nutrition in critical illness with glutamine or selenium may reduce infections and mortality. Pilot data has shown that more than 50% of participants developed infections, typically resistant organisms. We are powered to show definitively whether supplementation of PN with either glutamine or selenium is effective at reducing new infections in critically ill patients.

Methods/design

2 × 2 factorial, pragmatic, multicentre, double-blind, randomised controlled trial. The trial has an enrolment target of 500 patients. Inclusion criteria include: expected to be in critical care for at least 48 hours, aged 16 years or over, patients who require parenteral nutrition and are expected to have at least half their daily nutritional requirements given by that route.

Allocation is to one of four iso-caloric, iso-nitrogenous groups: glutamine, selenium, both glutamine & selenium or no additional glutamine or selenium. Trial supplementation is given for up to seven days on the Intensive Care Unit and subsequent wards if practicable. The primary outcomes are episodes of infection in the 14 days after starting trial nutrition and mortality. Secondary outcomes include antibiotic usage, length of hospital stay, quality of life and cost-effectiveness.

Discussion

To date more than 285 patients have been recruited to the trial from 10 sites in Scotland. Recruitment is due to finish in August 2008 with a further six months follow up. We expect to report the results of the trial in summer 2009.

Trial registration

This trial is registered with the International Standard Randomised Controlled Trial Number system. ISRCTN87144826

Evidence-based implementation of adult asthma guidelines in the emergency department: a controlled trial

OBJECTIVE

To determine if an evidence-based implementation (EBI) strategy could lead to the successful implementation of guidelines for the management of adult asthma in a large rural ED.

METHODS

This was a pre- and post-intervention trial, comparing data for seven clinical indicators from a study hospital and a control hospital. Retrospective pre-intervention audits were conducted at the study hospital for 3 months (1 April-30 June 2004) and the control hospital for 4 months (1 March-30 June 2004). The effect of an EBI to implement established guidelines for the management of asthma at the study hospital was compared with the effect of a mail-out of guideline booklets and wall charts to the control hospital. Post-intervention audits were then performed at both hospitals. Sustainability of the EBI was gauged by 12 month follow-up data at the study hospital.

RESULTS

There were 55 presentations of adult asthma at the study hospital in the pre-intervention phase and 67 post-intervention. The corresponding numbers for the control hospital were 51 and 42, respectively. Following the EBI there were significant improvements at the study hospital for the documentation of severity (27-99%, P < 0.01), use of spirometry (38-84%, P < 0.01), medication delivery via spacer device (0-26%, P < 0.01), use of systemic steroids (66-84%P < 0.05), use of written short-term asthma plans (14-82%, P < 0.01), reduction of ipratropium use in mild asthma (43-16%, P < 0.05) and reduction in antibiotic use in afebrile asthmatics (37-6%, P < 0.01). For the control hospital there was a significant increase in spirometry use from 2% to 40% (P < 0.01). For seven clinical indicators combined, compliance with the guideline increased from 38% to 79.1% (P < 0.01) at the study hospital, whereas there was no change at the control hospital, 44.3% to 43% (P = 0.75) There were 68 presentations at 12 month follow up at the study hospital and compliance with the seven clinical indicators was 78.2%.

CONCLUSION

An EBI significantly improved compliance at the study hospital with no improvement noted in the control hospital. These improvements were maintained at 12 month follow up. An EBI can lead to significant improvements in the management of asthma at a large rural referral hospital ED and might have implications for hospitals with similar roles and profiles.

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.

Continuous nebulized albuterol attenuates acute lung injury in an ovine model of combined burn and smoke inhalation

OBJECTIVE

Albuterol, due to its bronchodilatory and anti-inflammatory effects, is given via continuous nebulization in children with severe asthma. Combined burn and smoke inhalation injury frequently results in acute lung injury due to a combination of airway obstruction and inflammation. We hypothesized that albuterol administered via continuous nebulization would mitigate acute lung injury after smoke inhalation injury and burn.

DESIGN

Randomized prospective animal model.

SUBJECTS

Twenty adult female sheep (mean weight, 33.1+/-0.9 kg).

INTERVENTIONS

Adult ewes were subjected to a 40% body surface area third-degree flame burn and smoke inhalation injury after tracheostomy. Sheep were allocated to a) sham group, b) saline continuous nebulization group, c) 20 mg of albuterol continuous nebulization group, or d) 40 mg of albuterol continuous nebulization group (n=5 animals per group). All groups received intravenous lactated Ringer's solution at 4 mL.kg-1.%burn(-1).24 hrs-1 for resuscitation and were equally mechanically ventilated throughout the 48-hr study period. Pulmonary and cardiac function, lung lymph flow, bronchial obstruction score, and wet/dry lung weights were recorded.

RESULTS

Compared with saline and control groups, the albuterol groups had lower pause and peak inspiratory pressures, decreased pulmonary transvascular fluid flux, a significantly higher Pao2/Fio2 ratio, and decreased shunt fraction at 48 hrs postinjury. The wet-to-dry lung weight ratio and bronchial obstruction scores were lower for sheep receiving albuterol.

CONCLUSIONS

Continuous nebulization of albuterol improves pulmonary function via improved airway clearance and decreased fluid flux in a combined burn/smoke inhalation injury model.

The efficacy of nebulized albuterol/ipratropium bromide versus albuterol alone in the prehospital treatment of suspected reactive airways disease

OBJECTIVE

Ipratropium bromide has demonstrated efficacy when added to albuterol for the treatment of reactive airways disease (RAD). Its prehospital use has not been explored.

METHODS

A before-and-after design was used. Prehospital and emergency department (ED) medical records were examined retrospectively six months before and six months after institution of a new protocol, which allowed the addition of ipratropium bromide to all nebulized treatments with albuterol. Primary outcome measures included: changes in vital signs (heart rate, respiratory rate, oxygen saturation), clinical improvement as assessed by paramedics, and admission rates.

RESULTS

A total of 371 patients were included (n = 192 albuterol alone, n = 179 ipratropium/albuterol). There was no statistically significant difference between groups with regard to the change in heart rate, respiratory rate, or oxygen saturation. In addition, there was no difference in the proportion of patients with clinical improvement or deterioration as assessed by paramedics. There was no statistically significant difference in the admission rate from the ED except in the subgroup of patients using a metered-dose inhaler at the time of illness. Of note, more than one-third (133/371) of the patients were ultimately determined to have a diagnosis other than RAD, the majority of whom were diagnosed as having cardiac disease.

CONCLUSIONS

The addition of ipratropium bromide to albuterol for the prehospital treatment of RAD does not appear to result in clinical outcome improvements. A substantial number of patients enrolled in the study were diagnosed as having cardiac disease.

Anticholinergics in the treatment of children and adults with acute asthma: a systematic review with meta-analysis

BACKGROUND

Current guidelines recommend the use of a combination of inhaled beta(2) agonists and anticholinergics, particularly for patients with acute severe or life threatening asthma in the emergency setting. However, this statement is based on a relatively small number of randomised controlled trials and related systematic reviews. A review was undertaken to incorporate the more recent evidence available about the effectiveness of treatment with a combination of beta(2) agonists and anticholinergics compared with beta(2) agonists alone in the treatment of acute asthma.

METHODS

A search was conducted of all randomised controlled trials published before April 2005.

RESULTS

Data from 32 randomised controlled trials (n = 3611 subjects) showed significant reductions in hospital admissions in both children (RR = 0.73; 95% CI 0.63 to 0.85, p = 0.0001) and adults (RR = 0.68; 95% CI 0.53 to 0.86, p = 0.002) treated with inhaled anticholinergic agents. Combined treatment also produced a significant increase in spirometric parameters 60-120 minutes after the last treatment in both children (SMD = -0.54; 95% CI -0.28 to -0.81, p = 0.0001) and adults (SMD = -0.36; 95% CI -0.23 to -0.49, p = 0.00001).

CONCLUSIONS

This review strongly suggests that the addition of multiple doses of inhaled ipratropium bromide to beta(2) agonists is indicated as the standard treatment in children, adolescents, and adults with moderate to severe exacerbations of asthma in the emergency setting.

Severe exacerbations of asthma

All asthmatics regardless of their perceived severity, are at risk of exacerbation, particularly if they are suboptimally treated in the outpatient arena. Fortunately most patients recover after administration of bronchodilators and anti-inflammatory medications, but preventable deaths continue to occur and refractory cases result in hospitalization and need for mechanical ventilation. We begin this article by reviewing the pathophysiology of acute exacerbations to build a foundation for the assessment of clinical status and to provide the rationale for a carefully contemplated and evidence-based therapeutic approach. We end this article with an in-depth examination of the particular problems that are encountered during mechanical ventilation and offer a strategy that helps minimize complications. In the final analysis, however, the greatest gains in the field of acute asthma will come not from its treatment but from its prevention by enhanced educational and environmental efforts and by the delivery of optimal medications at home.

Inhaled therapy for acute adult asthma

PURPOSE OF REVIEW

To evaluate recent developments on emergency department inhalotherapy in non-intubated acute adult asthma patients.

RECENT FINDINGS

There is evidence that high-flow oxygen can be associated with hypercarbia, and that full humidification of the inspired gases should be recommended. On the contrary, there is a lack of evidence to support the role of heliox in the initial treatment of acute asthma. Specific short-acting inhaled beta(2)-agonists are the drugs of choice. A more rapid and profound bronchodilatation with fewer side effects and less time of treatment can be achieved when sufficient doses are given using pressurized meter dose inhalers and large-volume valved-spacers, particularly in patients with the most severe obstruction. Findings argue against the routine use of continuous nebulization. High and repetitive doses of ipratropium bromide in combination with beta(2)-agonists are indicated as first line treatment of severe acute asthma. There is insufficient evidence that inhaled corticosteroids alone are as effective as systemic corticosteroids. Finally, the combination of nebulized magnesium and albuterol provides no benefit in addition to that provided by therapy with albuterol in patients with mild-to-moderate asthma exacerbations.

SUMMARY

According to the latest evidence, the goals of treatment may be summarized as follows: maintenance of adequate arterial oxygen saturation with supplemental oxygen, relief of airflow obstruction by administration of inhaled beta-agonists and anticholinergics, and reduction of airway inflammation and prevention of future relapses by using early administration of systemic corticosteroids.

Continuous versus intermittent beta-agonists in the treatment of acute asthma

BACKGROUND

Patients with acute asthma treated in the emergency department are frequently treated with intermittent inhaled beta-agonists delivered by nebulisation. The use of continuous beta-agonist (CBA) via nebulisation in the emergency setting may offer additional benefits in acute asthma.

OBJECTIVES

To determine the efficacy (e.g., reductions in admission, improvement in pulmonary functions) and risks (e.g., adverse events, effects on vital signs) of continuous versus intermittent inhaled beta-agonists for the treatment of patients with acute asthma managed in the emergency department.

SEARCH STRATEGY

Randomised controlled trials were identified from the Cochrane Airways Review Group "Asthma and WHEEZ*" Register which is a compilation of systematic searches of CINAHL, EMBASE, MEDLINE and CENTRAL and hand searching of 20 respiratory journals. In addition, primary authors and content experts were contacted to identify eligible studies. Bibliographies from included studies, known reviews and texts were also searched. The search is considered updated to June 2003.

SELECTION CRITERIA

Only randomised controlled trials (RCTs) were eligible for inclusion. Studies were included if patients presented with acute asthma and were treated with either continuous or intermittent inhaled beta-agonists early in the ED treatment. "Continuous" nebulisation was defined as truly continuous aerosol delivery of beta-agonist medication (e.g., using a commercially available large-volume nebuliser, or a small-volume nebuliser with infusion pump) or sufficiently frequent nebulisations that medication delivery was effectively continuous (i.e., 1 nebulisation every 15 minutes or > 4 nebulisations per hour). Studies also needed to report either pulmonary function or admission results. Two reviewers independently selected potentially relevant articles and two additional reviewers independently selected articles for inclusion. Methodological quality was independently assessed by two reviewers.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two reviewers if the authors were unable to verify the validity of information. Missing data were obtained from authors or calculated from other data presented in the paper. The data were analysed using the Cochrane Review Manager (Version 4.1). Relative risks (RR), weighted mean differences (WMD) and standardized mean differences (SMD) are reported with corresponding 95% confidence intervals (CI); both peak expiratory flow rates (PEFR) and forced expiratory volume in one second (FEV-1) data are reported.

MAIN RESULTS

165 trials were reviewed and eight were included; a total of 461 patients have been studied (229 with CBA; 232 with intermittent beta-agonists). Overall, admission to hospital was reduced with CBA compared to intermittent beta-agonists (RR: 0.68; 95% CI: 0.5 to 0.9); patients with severe airway obstruction at presentation appeared to benefit most from this intervention (RR: 0.64; 95% CI: 0.5 to 0.9). Patients receiving CBA demonstrated small but statistically significant improvements in pulmonary function tests when all studies were pooled. Patients receiving CBA had greater improvements in % predicted FEV-1 (SMD: 0.3; 95% CI: 0.03 to 0.5) and PEFR (SMD: 0.33; 95% CI: 0.1 to 0.5); this effect was observed by 2-3 hours. Continuous treatment was generally well tolerated, with no clinically important differences observed in pulse rate (WMD: -2.87; 95% CI: -6.0 to 0.3) or blood pressure (WMD: -1.75; 95% CI: -5.6 to 2.1) between the treatment groups. Tremor was equally common in both groups (OR: 0.81; 95% CI: 0.5 to 1.3) and potassium concentration was unchanged (WMD: 0.02; 95% CI: -0.2 to 0.2).

REVIEWER'S CONCLUSIONS

Current evidence supports the use of CBA in patients with severe acute asthma who present to the emergency department to increase their pulmonary functions and reduce hospitalisation. Moreover, CBA treatment appears to be safe and well tolerated in patients who receive it.

Linezolid: implications for neurosurgical infections

Nosocomial infections affect a significant number of intensive care unit (ICU) patients including those in the neurosurgical ICU. Gram-positive organisms are responsible for many of these infections and often these pathogens are resistant to some of the older antimicrobial agents. Two new classes of antibiotics have been developed: streptogramins and oxazolidinones. Linezolid is an oxazolidinone, which has been shown to be effective against methicillin- and vancomycin-resistant Gram-positive pathogens. It may be administered orally or parenterally, and displays favorable pharmacokinetic properties, with rapid and complete absorption after oral administration. Linezolid is generally well tolerated with mild gastrointestinal related adverse effects. Linezolid provides a useful alternative in the treatment of Gram-positive infections, particularly those caused by resistant organisms. It has tremendous clinical utility, especially in the ICU where infections and multi-drug resistant rates are high and treatment options become limited.

Antimicrobial resistance in the intensive care unit: understanding the problem

Antimicrobial resistance is a problem that affects healthcare delivery around the globe. Factors associated with antimicrobial resistance include overuse or misuse of antimicrobial agents, immunosuppressed patients, and increased technology. Cellular mechanisms of antimicrobial resistance include the decreased uptake of a drug, efflux of the drug, enzymatic inactivation, and alterations in the antimicrobial target site. New treatment options are currently available for resistant organisms. Therapeutic strategies such as antibiotic control policies and antibiotic "cycling" have been proposed as methods for minimizing the emergence of more resistant organisms. Little evidence is available to indicate that these strategies are effective in limiting the emergence of resistance. Clinicians are urged to be judicious in their use and choice of antimicrobials.

Continuous vs intermittent beta-agonists in the treatment of acute adult asthma: a systematic review with meta-analysis

BACKGROUND

Since the late 1980s, there has been considerable clinical and academic interest in the use of continuous aerosolized bronchodilators for the treatment of patients with acute asthma. These studies have suggested that this therapy is safe, is at least as effective as intermittent nebulization, and may be superior to intermittent nebulization in patients with the most severely impaired pulmonary function.

OBJECTIVES

To determine whether continuous nebulization offered an advantage over intermittent nebulization for the treatment of adults with acute asthma in the emergency department (ED).

DESIGN

Systematic review of randomized controlled trials of adults with acute asthma.

OUTCOMES

Change in pulmonary function tests as primary outcome, and admissions to the hospital and side effects as secondary outcomes.

RESULTS

Six studies including 393 adults with acute asthma were selected. No significant differences were demonstrated between the two delivery methods in terms of pulmonary function measures obtained after 1 h of treatment (standardized mean difference [SMD], -0.15; 95% confidence interval [CI], -0.35 to 0.05) and after 2 to 3 h of treatment (SMD, -0.19; 95% CI, -0.39 to 0.01). No significant heterogeneity was demonstrated (p > 0.5). At the end of treatment, there was a significantly greater decrease in pulse rate when the continuous nebulizer was used (weighted mean difference [WMD], -6.82; 95% CI, -8.67 to -3.90 beats/min; chi(2), 2.55; degrees of freedom [df], 4; p = 0.6). Additionally, the analysis showed a significant decrease of serum potassium concentration with the use of intermittent nebulization (WMD, 0.12; 95% CI, 0.24 to 0.01 mmol/L; chi(2), 0.5; df, 2; p = 0.8). However, this finding was obtained on the analysis of only two trials. Finally, at the end of the study period, no significant differences were identified between patients treated with continuous or intermittent nebulization with respect to hospital admission (relative risk, 0.68; 95% CI, 0.33 to 1.38; chi(2), 2.06; df, 1; p = 0.2).

CONCLUSIONS

Overall, this review supports the equivalence of continuous and intermittent albuterol nebulization in the treatment of acute adult asthma.

The role of anticholinergics in acute asthma treatment: an evidence-based evaluation

The role for anticholinergic medications in acute asthma is not well-defined. Thus, the use of therapy with anticholinergics and beta(2)-agonists, either simultaneously or in sequence, has produced positive as well as negative results in trials. Therefore, the current recommendations for the use of these drugs in the emergency department (ED) and hospital management of asthma exacerbations are not precise. This review answers the following question: what level of evidence is available in the literature to support the use of anticholinergic medications in combination with beta(2)-agonists in acute asthma patients? We limited the search on our therapy question to systematic reviews of randomized trials and/or randomized controlled trials not included in the reviews. After an extensive review of the most relevant evidence, the following conclusions may be emphasized. (1) The use of multiple doses of ipratropium bromide are indicated in the ED treatment of children and adults with severe acute asthma. The studies reported a substantial reduction in hospital admissions (30 to 60%; number needed to treat, 5 to 11) and significant differences in lung function favoring the combined treatment. No apparent increase in the occurrence of side effects was observed. (2) The use of single-dose protocols of ipratropium bromide with beta(2)-agonist treatment produced, particularly in children with more severe acute asthma, a modest improvement in pulmonary function without reduction in hospital admissions; in adults, the data showed a similar increase in pulmonary function with an approximately 35% reduction in the hospital admission rate. In patients with mild-to-moderate acute asthma, there is no apparent benefit from adding a single dose of an anticholinergic medication.

Nosocomial pneumonia: epidemiology, pathogenesis, diagnosis, treatment and prevention

Nosocomial pneumonia is the second most common nosocomial infection and the leading cause of death from hospital-acquired infection. Supine body position in mechanically ventilated patients, and cardiopulmonary resuscitation and continuous sedation are significant risk factors for developing nosocomial pneumonia. During the past 2 years some new therapeutic approaches for nosocomial pneumonia and modifications to established therapies have been described, such as optimal pharmacodynamic evaluations, monotherapy versus combination therapy, computer-assisted management programmes and antibiotic rotations.

First-line therapy for adult patients with acute asthma receiving a multiple-dose protocol of ipratropium bromide plus albuterol in the emergency department

We designed a larger, double-blind, randomized, prospective trial to test our hypothesis that patients with acute asthma given combination high dose therapy with ipratropium bromide (IB) and beta(2)-agonists will have greater improvement in pulmonary function and fewer hospital admissions than those given beta(2)-agonists alone. One hundred eighty patients (mean age +/- SD, 34.3 +/- 10.5 yr) who presented to an emergency department (ED) for treatment of an exacerbation of asthma (baseline FEV(1) < 50% of predicted) were assigned in a randomized, double-blind fashion to receive albuterol and placebo (n = 92) or albuterol and IB (n = 88). Both drugs were administered through a metered-dose inhaler and spacer at 10-min intervals for 3 h (24 puffs or 2,880 microg of albuterol and 504 microg of IB each hour). Primary outcome measures were improvement in pulmonary function (FEV(1) or peak expiratory flow [PEF]), and hospital admission rates. In both groups, pulmonary function improved significantly over baseline values (p < 0.01). Subjects who received IB had an overall 20.5% (95% CI: 2.6 to 38.4%) (p = 0.02) greater improvement in PEF and a 48.1% (95% CI: 19.8 to 76.4%) (p = 0.001) greater improvement in FEV(1) from the control group. At the end of protocol (3 h), 39% (n = 36) of patients in the control group and 20% (n = 18) in the IB group were admitted (p = 0.01). The use of high doses of IB reduced the risk of hospital admission 49% (relative risk = 0.51, 95% CI: 0.31 to 0.83). Five (95% CI: 3 to 17) patients would need to be treated with high doses of IB to prevent a single admission. Kaplan-Meier-estimated curves of the proportion of patients who reached the discharge threshold during the 3 h of treatment, showed a significant difference in favor of the IB group (log-rank test = 0.005). A subgroup analysis showed that patients most likely to benefit from the addition of high doses of IB were those with more severe obstruction (FEV(1) </= 30% of predicted) and long duration of symptoms before the ED presentation (>/= 24 h). On the contrary, previous use of inhaled beta(2)-agonists did not modify the admission rate and the pulmonary function response to IB. In conclusion, our data support a substantial therapeutic benefit from the addition of IB to albuterol administered in high doses through MDI plus spacer, particularly in patients with FEV(1) less than 30%, and with long duration of symptoms before the ED presentation (>/= 24 h).

Treatment of acute asthma. A new look at the old and at the new

beta-Agonists remain the mainstay of therapy for acute asthma and, for most patients, standard doses are acceptable. Although the onset of action of systemic steroids is still not clear, steroids promote recovery and should be given to patients with acute illness. Intravenous magnesium sulfate appears to improve pulmonary function in the most severely ill patients but is not useful in patients with more moderate episodes. Ipratropium bromide is a weak bronchodilator that still needs to be tested as an adjunct to standard treatment regimens before its role in adults with asthma can be determined; given its ease of use and favorable safety profile it could be considered for patients with more severe acute illness. Aminophylline has not been found by most studies to improve outcomes and the narrow therapeutic range and unfavorable safety profile relegate it to a last-line agent or no use at all. Helium-oxygen mixtures currently have no role in moderately ill patients but have a theoretical advantage as a temporizing measure in severely ill patients. Drugs used in the management of chronic asthma, such as inhaled steroids and leukotriene-modifying agents, are making their way into the acute treatment arena, and other newly developed specific mediator inhibitors or blockers deserve attention. The use of isomers of beta-agonists is another area that is attracting attention and study. Systemic steroids are used to prevent relapse after emergency department discharge and the addition of other agents such as leukotriene-modifying agents or inhaled steroids may further prevent the need for urgent visits or hospitalization. The search for optimal treatment strategies for acutely ill patients is challenging and exciting and, with more attention and resources being devoted to this area, newer treatments will be found that will eventually have a greater impact on the high morbidity associated with acute asthma.

Management of respiratory failure in patients with asthma

The goal of management of patients with respiratory failure is to restore them to a state of quiet breathing, without complication. This goal is often achieved by pharmacotherapy alone. Inhaled albuterol sulfate, oxygen, and systemic corticosteroids are mainstays of acute care drug management, whereas other data support the use of inhaled steroids, ipratropium bromide, magnesium sulfate, theophylline, and heliox. Assisted ventilation by face mask or endotracheal tube may be required in refractory patients. In intubated patients, a ventilatory strategy that prolongs exhalation time and accepts hypercapnia minimizes lung hyperinflation and generally results in a good outcome. Acute asthma often represents failure of outpatient management; key aspects of the outpatient program should be addressed in the acute care setting to help prevent recurrent attacks.

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.