Intravenous theophylline after beta 2-agonist treatment in severe acute asthma. Effect on patients who are not pre-treated with theophylline

Addition of intravenous beta(2)-agonists to inhaled beta(2)-agonists for acute asthma

BACKGROUND

Inhaled beta-agonist therapy is central to the management of acute asthma. This review evaluates the benefit of an additional use of intravenous beta(2)-agonist agents.

OBJECTIVES

To determine the benefit of adding intravenous (IV) beta(2)-agonists to inhaled beta(2)-agonist therapy for acute asthma treated in the emergency department.

SEARCH METHODS

Randomised controlled trials (RCTs) were identified using the Cochrane Airways Group Register which is a compilation of systematic searches of MEDLINE, EMBASE, CINAHL, and CENTRAL as well as handsearching of 20 respiratory journals. Bibliographies from included studies and known reviews were also searched. Primary authors and content experts were contacted to identify eligible studies. The search was performed in September 2012.

SELECTION CRITERIA

Only RCTs were considered for inclusion. Studies were included if patients presented to the emergency department with acute asthma and were treated with IV beta(2)-agonists with inhaled beta(2)-agonist therapy and existing standard treatments versus inhaled beta(2)-agonists and existing standard treatments.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and confirmed their findings with corresponding authors of trials. We obtained missing data from authors or calculated from data present in the papers. We used fixed-effect model for odds ratios (OR) and for mean differences (MD) we used both fixed-effect and random-effects models and reported 95% confidence intervals (CI).

MAIN RESULTS

From 109 potentially relevant studies only three (104 patients) met our inclusion criteria: Bogie 2007 (46 children), Browne 1997 (29 children) and Nowak 2010 (29 adults). Bogie 2007 investigated the addition of intravenous terbutaline to high dose nebulised albuterol in children with acute severe asthma, requiring intensive care unit (ICU) admission. Browne 1997 investigated the benefit of adding intravenous salbutamol to inhaled salbutamol in children with acute severe asthma in the emergency department. Nowak 2010 investigated addition of IV bedoradrine to standard care (nebulised albuterol, ipratropium and oral corticosteroids) among adults, and was reported as a conference abstract only.There was no significant advantage (OR 0.29; 95%CI 0.06 to 1.38, one trial, 29 adults) for adding IV bedoradrine to standard care (nebulised albuterol, ipratropium and oral corticosteroids) with regard to hospitalisation rates.Various outcome indicators for the length of stay were reported among the trials. Browne 1997 reported a significantly shorter recovery time (in terms of cessation of 30 minute salbutamol) for children in the IV salbutamol with inhaled salbutamol group (four hours) versus the 11.1 hours for the inhaled salbutamol group (P = 0.03). Time to cessation of hourly nebuliser was also significantly shorter (P = 0.02) for the IV plus inhaled salbutamol group (11.5 hours versus 21.2 hours), and they were ready for emergency patient discharge on average 9.7 hours earlier than the inhaled salbutamol group (P < 0.05). In a paediatric ICU study Bogie 2007 reported no significant advantage in length of paediatric ICU admission (hours) for adding IV terbutaline to nebulised albuterol (MD -12.95, 95% CI: -38.74, 12.84).Browne 1997 reported there were only six out of 14 children with a pulmonary index score above six in the IV plus inhaled salbutamol group at two hours compared with 14 of the 15 in the inhaled salbutamol group (P = 0.02)In Browne 1997 there was a higher proportion of tremor in the IV plus inhaled salbutamol group than in the inhaled salbutamol group (P < 0.02). Nowak 2010 did not report any statistically significant adverse effects associated with adding IV bedoradrine to standard care (nebulised albuterol, ipratropium and oral corticosteroids). Troponin levels were elevated in three children in the IV terbutaline + nebulised albuterol group at 12 and 24 hours in Bogie 2007

AUTHORS' CONCLUSIONS

There is very limited evidence from one study (Browne 1997) to support the use of IV beta(2)-agonists in children with severe acute asthma with respect to shorter recovery time, and similarly there is limited evidence (again from one study Browne 1997) suggesting benefit with regard to pulmonary index scores; however this advantage needs to be considered carefully in relation to the increased side effects associated with IV beta(2)-agonists. We identified no significant benefits for adults with severe acute asthma. Until more, adequately powered, high quality clinical trials in this area are conducted it is not possible to form a robust evaluation of the addition of IV beta(2)-agonists in children or adults with severe acute asthma.

Intravenous beta(2)-agonists versus intravenous aminophylline for acute asthma

BACKGROUND

Inhaled beta(2)-agonist therapy is central to the management of acute asthma. For rapid bronchodilation in severe cases, penetration of inhaled drug to the affected small conducting airway may be impeded, and the intravenous (IV) rather than inhaled administration of bronchodilators may provide an earlier response. IV beta(2)-agonist agents and IV aminophylline may also be considered as additional interventions in this setting and this review compares IV beta-agonist agents and IV aminophylline in the treatment of people with acute asthma.

OBJECTIVES

To compare the benefit of IV beta(2)-agonists versus IV aminophylline for acute asthma treated in the emergency department and in patients admitted to hospital with acute severe asthma.

SEARCH METHODS

Randomised controlled trials (RCTs) were identified using the Cochrane Airways Group Register, which is compiled from systematic searches of bibliographic databases as well as handsearching of respiratory journals and conference abstracts. The latest search was run in September 2012. We searched bibliographies from included studies and known reviews were also searched. Primary authors and content experts were contacted to identify eligible studies.

SELECTION CRITERIA

We included RCTs of patients who presented to the emergency department with acute asthma, and patients admitted to hospital with acute severe asthma, and were treated with IV beta(2)-agonists versus IV aminophylline. Two review authors independently selected potentially relevant articles and selected articles for inclusion. Methodological quality was independently assessed using two scoring systems and two review authors.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two review authors. Missing data were obtained from authors or calculated from data present in the papers. Trials were combined using a random-effects model for odds ratios (OR) or mean differences (MD) and reported with 95% confidence intervals (95% CI).

MAIN RESULTS

Eleven studies met our inclusion criteria and in total they included 350 patients. However, opportunities to combine these studies in meta-analyses were limited by the variations in the range of outcomes reported in the trials.Length of stayTwo studies reported length of stay. They were both paediatric trials (with one in paediatric intensive care unit), and there was no significant difference between the two groups (MD 23.19 hours; 95% CI -2.40 to 48.77 hours; 2 studies; N = 73). Individual separate MD analyses for the two studies also indicated no significant difference between the aminophylline and beta(2)-agonist on this outcome. However, this finding should be interpreted with caution owing to the small number of trials and participants the analysis.Pulmonary functionThere were no significant differences in the sequential or summative pulmonary function demonstrated across the studies.Heart rateData for serial heart rates were reported in three studies at various points from 15 to 60 minutes and in each case there were no significant differences between people in the IV aminophylline or beta(2)-agonist groups. The difference between the two groups with respect to final heart rate was statistically significant (MD 10.00; 95% CI 0.99 to 19.01), although these data are from a single, small study and should be interpreted with caution.Adverse effectsThe analyses for giddiness (OR 59.22; 95% CI 2.80 to 1253.05; 1 study; N = 30), nausea/vomiting (where reported as a combined outcome) (OR 14.18; 95% CI 1.62 to 124.52; 2 studies; N = 96) and nausea (OR 6.53; 95% CI 1.60 to 26.72; 2 studies; N = 49) all significantly favoured beta(2)-agonists. In view of the very small number of studies and number of patients contributing to these analyses these results should be interpreted with caution. A closely related review considering the possible benefits of adding IV aminophylline to beta-agonists in adults with acute asthma also indicates a higher incidence of adverse effects associated with IV aminophylline.

AUTHORS' CONCLUSIONS

In the included RCTs there was no consistent evidence favouring either IV beta(2)-agonists or IV aminophylline for patients with acute asthma. The opportunity to draw clear conclusions is limited by the heterogeneity of outcomes evaluated and the small sample sizes in the included studies. It is recommended that these data should be viewed carefully alongside the conclusions from separate Cochrane reviews comparing IV beta(2)-agonists plus inhaled beta(2)-agonists versus inhaled beta(2)-agonists alone and IV aminophylline plus inhaled beta(2)-agonists versus inhaled beta(2)-agonists alone.

Intravenous beta2-agonists for acute asthma in the emergency department

BACKGROUND

Inhaled beta-agonist therapy is central to the management of acute asthma. The use of intravenous beta-agonist agents may also be beneficial in this setting.

OBJECTIVES

To determine the benefit of intravenous (IV) beta2-agonists for severe acute asthma treated in the emergency department.

SEARCH STRATEGY

Randomised controlled trials (RCT) were identified using the Cochrane Airways Group Register which is a compilation of systematic searches of MEDLINE, EMBASE, CINAHL, and CENTRAL as well as hand searching of 20 respiratory journals. Bibliographies from included studies and known reviews were also searched. Primary authors and content experts were contacted to identify eligible studies.

SELECTION CRITERIA

Only RCTs were considered for inclusion. Studies were included if patients presented to the emergency department with acute asthma and were treated with IV selective or nonselective beta2-agonists versus placebo, inhaled beta2-agonists, or other standard of care. Pulmonary function, vital signs, arterial gasses, adverse effects, and/or clinical success could be reported as outcome measures. Two reviewers independently selected potentially relevant articles and selected articles for inclusion. Methodological quality was independently assessed using two scoring systems and two reviewers.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two reviewers, and confirmed with corresponding authors. Missing data were obtained from authors or calculated from data present in the papers. Trials were combined using a random effects model for odds ratios (OR) or weighted mean differences (WMD) and reported with 95% confidence intervals (95% CI).

MAIN RESULTS

From 746 identified references, 55 potentially relevant articles were identified and 15 were included. The trials included 584 patients. Overall, selective IV beta2-agonist use conferred no advantage over the comparator regimes. For example, it was associated with a lower PEFR after 60 mins compared to inhaled beta2-agonist, although the difference was not statistically significant (-24.7 l/min; 95%CI 2.9, -52.3). There was no difference in heart rate (4.5 bpm; 95% CI -4.9, 14.0). In the well performed blinded studies there was no difference in autonomic side effects between treatments (Odds Ratio 2.2 (95%CI 0.9, 5.7).

REVIEWER'S CONCLUSIONS

There is no evidence to support the use of IV beta2-agonists in patients with severe acute asthma. These drugs should be given by inhalation. No subgroups were identified in which the IV route should be considered.