| Level I | Good quality evidence |
Systematic review of RCTs with consistent findings High quality individual RCT |
| Level II |
Limited quality patient orientated evidence |
Systematic review of lower quality studies or studies with inconsistent findings Low quality clinical trial Cohort studies Case-control studies |
| Level III | Other |
Consensus guidelines, extrapolations from bench research, usual practice, opinion, disease-oriented evidence (intermediate or physiologic outcomes only), or case series |
[15] Ipratropium bromide 0.5 mg nebulisation (paediatrics): Kling S, Zar HJ, Levin ME, Green RJ, Jeena PM, Risenga SM, Thula SA ,Goussard P, Gie RP, for the South African Childhood Asthma Working Group (SACAWG)S Afr Med J 2013;103(3):199-207. http://www.samj.org.za/index.php/samj/article/view/6658