Magnesium sulphate for treatment of severe acute asthma

Recruitment & Eligibility

Status: Completed

Sex: All

Target Recruitment: 1200

Inclusion Criteria

Current inclusion criteria as of 30/04/2008:
We will recruit adults (aged greater than 16 years) admitted to the Emergency Department with acute severe asthma as defined by the British Thoracic Society (BTS) and Scottish Intercollegiate Guideline Network (SIGN) guidelines, i.e. acute asthma with either peak expiratory flow rate (PEFR) less than 50% of best or predicted, respiratory rate greater than 25/min, heart rate greater than 110/min, or inability to complete sentences in one breath.

Eligible patients will be identified by medical staff and informed consent sought from the patient. Oral consent can be obtained initially, and written consent will be obtained before departure from the emergency department.

Consented participants will be randomised by telephone or internet using a system developed for the Sheffield Clinical Trials Research Unit (CTRU). A simple randomisation sequence will be used to allocate participants to numbered treatment packs kept in the emergency department. Each treatment pack will contain an intravenous infusion and a nebuliser solution, either of which could be active treatment or placebo. Participants, hospital staff and research staff will all be blind to allocated treatment.

Clinical staff will record baseline data, details of co-interventions and outcome data up to two hours after presentation. Further data will be collected at one month after recruitment by research nurses using routine data sources and by patient self-completion questionnaire.

Previous inclusion criteria:
We will recruit adults (age>16) admitted to the emergency department with acute severe asthma as defined by the British Thoracic Society (BTS) and Scottish Intercollegiate Guideline Network (SIGN) guidelines, i.e. acute asthma with either Peak Expiratory Flow Rate (PEFR) < 50% of best or predicted, respiratory rate > 25/min, heart rate > 110/min, or inability to complete sentences in one breath.

Eligible patients will be identified by medical staff and written, informed consent sought from either the patient, a personal legal representative or a professional legal representative (as outlined in Medicine for Human Use (Clinical Trials) Regulations 2004).

Consented participants will be randomised by telephone to the Sheffield Clinical Trials Support Unit (CTSU). A simple randomisation sequence will be used to allocate participants to numbered treatment packs kept in the emergency department. The CTSU will only reveal the allocated pack number after patient details have been recorded and the patient irreversibly entered into the trial. Each treatment pack will contain an intravenous infusion and a nebuliser solution, either of which could be active treatment or placebo. Participants, hospital staff and research staff will all be blind to allocated treatment.

Clinical staff will record baseline data, details of co-interventions and outcome data up to two hours after presentation. Further data will be collected at one month after recruitment by research nurses using routine data sources and by patient self-completion questionnaire.

Exclusion Criteria

Current exclusion criteria as of 30/04/2008:
1. Patients with life threatening features (oxygen saturation less than 92%, silent chest, cyanosis, poor respiratory effort, bradycardia, arrhythmia, hypotension, exhaustion, coma or confusion)
2. Patients who are unable to provide oral or written informed consent
3. Patients with a contra-indication to either nebulised or intravenous magnesium sulphate: pregnancy, hepatic or renal failure, heart block or known hypermagnesaemia
4. Previous participants in the 3Mg Trial
Added 21/03/2011:
5. Patients who have received IV or nebulised magnesium sulphate in the previous 24 hours prior to admission to the emergency department.

Previous exclusion criteria:
1. Patients with life threatening features (oxygen saturation < 92%, silent chest, cyanosis, poor respiratory effort, bradycardia, arrhythmia, hypotension, exhaustion, coma or confusion)
2. Patients who are unable to provide written consent and for whom no personal or professional legal representative can be identified to act on their behalf
3. Patients with a contraindication to either nebulised or intravenous magnesium sulphate: pregnancy, hepatic or renal failure, heart block or known hypermagnesaemia
4. Previous participants in the 3Mg Trial

Study & Design

Study Type: Interventional

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
1. The health service primary outcome will be the proportion of patients who are admitted to hospital, either after emergency department treatment or at any time over the subsequent week.<br>2. The patient-centred primary outcome will be the patient?s visual analogue scale (VAS) for breathlessness over two hours after initiation of treatment.

Secondary Outcome Measures

Name	Time	Method
1. Mortality<br>2. Adverse events<br>3. Use of ventilation or respiratory support<br>4. Length of hospital stay<br>5. Use of high dependency or intensive care<br>6. Change in PEFR and physiological variables (oxygen saturation, heart rate, respiratory rate) over two hours<br>7. Quality of life at baseline and one month (measured by EQ-5D)<br>8. Number of unscheduled health care contacts (emergency department, walk-in centre or general practitioner attendances) over the subsequent month<br>9. Satisfaction with care (measured by a modified Group Health Association of America survey)