Details of the review

• First author name

• Year of publication

• Number of included primary studies

• Countries and years pf the original studies

• Eligibility criteria of included studies

• Numbers of included participants

• Sample size of included RCTs

• Details of included RCTs

Participant characteristics

• Age

• Severity of asthma

• Definition of exacerbation of asthma for each RCT

• Treatment before enrolment

Setting

• Emergency department

• Hospital ward

• Intensive care unit

Types of interventions

• Name of medication/intervention

• Dose of medication/intervention

• Duration of treatment

• Frequency of intervention administration

Description of the comparative treatment (placebo, regular doses of bronchodilators)

Description of outcome measures used

For each outcome measure

• Number of participants in the intervention group

• Number of participants in the control group

• Intervention event rate

• Control event rate

• Effect estimates for pooled results (risk ratio, odds ratio, hazard ratio, standardised mean difference, or absolute risk reduction and corresponding 95% confidence intervals)

• Details of statistical tests for heterogeneity

  • Chi² test

  • I² test

Predefined primary outcome measures

• Length of stay

  • Emergency department length of stay

  • Hospital length of stay

• Emergency department disposition

  • Hospital admission

  • ICU admission

  • ED discharge

• Adverse events

  • Vomiting

  • Nausea

  • Tremor

  • Tachycardia

  • Arrhythmia

  • Convulsion

  • Other (specify)

Predefined secondary outcome measures

• Symptom scores/clinical asthma scores

  • Name of score

  • Definition/reference

  • Time of recording of outcome measure

  • Interpretation of score result (cutoff)

• Lung function tests

  • Examples: peak expiratory flow rate, forced expiratory volume in one second, and other measures

  • Name of test

  • Definition/reference

  • Time of recording of outcome measure

  • Interpretation of test result (cutoff)

• Vital signs

  • Examples: pulse, blood pressure, respiratory rate, pulse oximetry

  • Name of vital sign

  • Definition/reference

  • Time of recording of vital signs

  • Interpretation of vital signs results (cutoff)

• Requirement for additional bronchodilator treatment

  • Name of outcome measure

  • Definition/reference

  • Time of recording of outcome

  • Interpretation

• Requirement for respiratory support

  • Intubation

  • Time of recording of outcome

• Non‐invasive ventilation

  • Name of outcome measure (CPAP, BiPap, etc.)

  • Definition/reference

  • Time of recording of outcome

  • Interpretation

• Economic outcomes/healthcare costs

  • Definition/reference

  • Time of recording of outcome

  • Interpretation

• Additional outcome measures

  • Name of outcome measure

  • Definition/reference

  • Time of recording of outcome

  • Interpretation

Risk of bias assessments of RCTs included in the reviews.

Quality assessment tools used (e.g. GRADE) along with the mean or median and range of any reported quality scores.

Conclusions of each review.

Review recommendations for further research.

If the included systematic review includes all studies relevant to a particular outcome, we will extract summary data alone. If data are required to be extracted from a subgroup of studies (i.e. only children), then we will extract study‐level data from all RCTs included in the review. These data will include numerical primary study results and risk of bias data.

Phase 1. Assessing relevance (optional)

For intervention reviews, assessment of patients/populations; interventions; comparators; and outcomes.

Phase 2. Identifying concerns with the review process

Domain 1. Study eligibility criteria.

• Did the review adhere to predefined objectives and eligibility criteria?

• Were the eligibility criteria appropriate for the review question?

• Were eligibility criteria unambiguous?

• Were all restrictions in eligibility criteria based on study characteristics appropriate?

• Were any restrictions in eligibility criteria based on sources of information appropriate?

Domain 2. Identification and selection of studies

• Did the search include an appropriate range of databases/electronic sources for published and unpublished reports?

• Were methods additional to database searching used to identify relevant reports?

• Were the terms and structure of the search strategy likely to retrieve as many eligible studies as possible?

• Were restrictions based on date, publication format, or language appropriate?

• Were efforts made to minimise error in selection of studies?

Domain 3. Data collection and study appraisal

• Were efforts made to minimise errors in data collection?

• Were sufficient study characteristics available for both review authors and readers to be able to interpret the results?

• Were all relevant study results collected for use in the synthesis?

• Was risk of bias (or methodological quality) formally assessed by appropriate criteria?

• Were efforts made to minimise error in risk of bias assessment?

Domain 4. Synthesis and findings

• Did the synthesis include all studies that it should?

• Were all predefined analyses reported or departures explained?

• Was the synthesis appropriate given the nature and similarity of research questions, study designs, and outcomes across included studies?

• Was between‐study variation (heterogeneity) minimal or addressed in the synthesis?

• Were the findings robust (e.g. as demonstrated through funnel plot or sensitivity analyses)?

• Were biases in primary studies minimal or addressed in the synthesis?

We will rate each criterion as Y = Yes, PY = Probably yes, PN = Probably no, N = No, NI = No information.

We will then interpret each domain as having 'Low', 'High', or 'Unclear' concerns for bias.

Phase 3. Judging the risk of bias

Concerns from each domain are summarised.

We will then determine whether the conclusions are supported by the evidence presented.

• Did interpretation of the findings address all concerns identified in domains one through four?

• Was the relevance of identified studies to the review's research question appropriately considered?

• Did the review authors avoid emphasising results on the basis of their statistical significance?

• Risk of bias in the review? LOW/HIGH/UNCLEAR.