Reference 1

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] Medication used for sedation: American Society of Anesthesiologists Task Force on Sedation and Analgesia by Non-Anesthesiologists. Practice guidelines for sedation and analgesia by non-anesthesiologists. Anesthesiology. 2002 Apr;96(4):1004-17. http://www.ncbi.nlm.nih.gov/pubmed/11964611

Medication used for sedation: The South African Society of Anaesthesiologists. South African Society of Anaesthesiologists Sedation Guidelines, 2015. South Afr J AnaesthAnalg 2015;21(2)S1-S36.http://www.sasaweb.com/content/images/SAJAA_V21N2_1665_Sedation_Guideline.pdf