| 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 |
[31] Labetalol, Scott DB. The use of labetalol in anaesthesia. Br J Clin Pharmacol. 1982 Jun;13(1 Suppl):133S-135S. http://www.ncbi.nlm.nih.gov/pubmed/7093097
Labetalol, IV: Varon J, Marik PE. Perioperative hypertension management. Vascular Health and Risk Management. 2008;4(3):615-627. http://www.ncbi.nlm.nih.gov/pubmed/18827911