| 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 |
[1] Salbutamol MDI (adults): Rodrigo C, Rodrigo G. Salbutamol treatment of acute severe asthma in the ED: MDI versus hand-held nebulizer. Am J Emerg Med. 1998 Nov16(7):637-42. https://www.ncbi.nlm.nih.gov/pubmed/9827736
Salbutamol MDI (adults): National Department of Health, Essential Drugs Programme: Adult Hospital Level STGs and EML, 2015. http://www.health.gov.za/