Asher 1990.

Methods	Design: randomised controlled trial Total duration of study: six months Country: New Zealand Study setting: inpatient Method of randomisation: participants were assigned using a table of random numbers to either a placebo treatment group or a chest physiotherapy (PT) group Method of allocation concealment: not described Outcome assessor blinding: assessor was blinded to the treatment received Withdrawals/drop‐outs: four withdrawals
Participants	Severity of condition: acute severe asthma Diagnostic criteria: acute asthma was defined as "acute asthma poorly responsive to inhaled bronchodilator on admission to hospital" Total sample: 38 children (19 in each group). Results available for 34 children (16 in chest PT group and 18 in placebo group) Mean age: 9.5 ± 2.7 years in chest PT group and 10.0 ± 2.6 years in placebo group Gender: 11 boys and eight girls in chest PT group and nine boys and 10 girls in placebo group Age range: 6‐13 years Exclusion criteria: participants who were critically ill or who had complications identified on a chest radiograph such as lobar atelectasis or pneumonia
Interventions	Treatments were started in the study between six and 24 hours after admission to hospital. Each child then received four treatments over a two‐day period (two each day). First treatment began in the morning and the subsequent treatments were separated by approximately 4 hours. Each treatment period lasted about 1 hour. Before every treatment, participants received inhaled salbutamol via a nebuliser over 10 minutes, followed by a rest period of 20 minutes. This was then followed by either a placebo treatment or chest PT lasting 20‐30 minutes Intervention: during PT sessions appropriate techniques were used according to the participant's presentation. The breathing exercise techniques used were lateral costal breathing and diaphragmatic breathing. The study also performed vibrations, percussions and the forced expiration technique. Education and psychological support were also provided as appropriate Control: a 20‐minute visit by a volunteer who provided emotional support to children in hospital. They were instructed to provide no form of chest PT and to ignore coughing
Outcomes	Lung function
Notes	Financial support from the Auckland Medical Research Foundation
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants were assigned using a table of random numbers to either a placebo treatment group or a chest PT group
Allocation concealment (selection bias)	Unclear risk	Insufficient information to permit judgement of 'low risk' or 'high risk'
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Insufficient information to permit judgement of 'low risk' or 'high risk'
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Blinding of outcome assessment ensured
Incomplete outcome data (attrition bias) All outcomes	Low risk	Reasons for missing outcome data unlikely to be related to true outcome
Selective reporting (reporting bias)	Low risk	Study protocol was not available, but the published reports included all expected outcomes, including those that were pre‐specified
Other bias	Unclear risk	Insufficient information to permit judgement of 'low risk' or 'high risk'