O'Driscoll 1989.

Methods	‐ Prospective, double‐blind trial. ‐ Comparison of ipratropium bromide and salbutamol vs. salbutamol alone. ‐ Patients randomised into groups via year of birth (odd vs. even).
Participants	‐ Patients who presented to the ED with an acute airflow obstruction. ‐ Set in the United Kingdom. ‐ Patients were classified has having either asthma or COPD according to the criteria of the ATS guidelines. ‐ Ages: 17 years and older. ‐ Asthma exacerbation severity of presenting patients was unclear. Not enough information provided to estimate asthma severity based on hospitalisations.
Interventions	‐ Single dose of combination inhaled therapy. Study interventions provided via nebuliser with oxygen. ‐ Group one received a single dose of ipratropium bromide (0.5 mg) and salbutamol (10 mg). ‐ Group two received a single dose of salbutamol alone (10 mg) with additional 2 ml saline solution. ‐ Additional co‐interventions included supplemental oxygen. Intravaneous hydrocortisone and IV aminophylline was provided only if physicians determine further treatment was necessary.
Outcomes	‐ Outcomes included pulmonary function, admission to the ICU, need for mechanical ventilation, and adverse events. ‐ Outcome measurements were performed at baseline and one hour after treatment.
Notes	‐ Contacted authors to clarify results but no response received.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Randomisation generated by odd/even days of birth. Quote (p. 1418): "The solutions were coded and treatment was determined by the patient’s year of birth (odd or even numbers)."
Allocation concealment (selection bias)	High risk	No allocation concealment, patients grouped based on date of birth. Quote (p. 1418): "The solutions were coded and treatment was determined by the patient’s year of birth (odd or even numbers)."
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Reported staff were blinded to treatments but no details provided on whether participants were blinded. Quote (p. 1418): "The staff were blind to the treatment."
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No information provided on whether outcome assessors were blinded.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Excluded patients were equally balanced between groups. No information provided on attrition during the screening process prior to enrolment. Quote (p. 1419): "125 consecutive patients were entered in the study. 2 patients wished to go home within 60 min of starting nebulised treatment and a further 20 patients were transferred to a hospital ward within this period, either because accident and emergency beds were needed for other patients or because the patient was assigned to another hospital. No patient needed urgent admission to the intensive care unit or mechanical ventilation. The 22 patients who did not complete the trial were equally divided between the treatment groups."
Selective reporting (reporting bias)	Unclear risk	No protocol available.
Other bias	Unclear risk	No source of funding provided.