title: How can we identify the high-risk patient?
abstract: OBJECTIVE
  Accurate and early identification of high-risk surgical patients allows for targeted use of perioperative monitoring and interventions that may improve their outcomes. This review summarizes current evidence on how information from the preoperative, operative, and immediate postoperative periods can help identify such individuals.
  
  
  RESULTS
  Simple risk indices, such as the Revised Cardiac Risk Index or American Society of Anesthesiologists Physical Status scale, and online calculators allow risk to be estimated with moderate accuracy using readily available preoperative clinical information. Both specific specialized tests (i.e., cardiopulmonary exercise testing and cardiac stress testing) and promising novel biomarkers (i.e., troponins and natriuretic peptides) can help refine these risk estimates before surgery. Estimates of perioperative risk can be further informed by information acquired during the operative and immediate postoperative periods, such as risk indices (i.e., surgical Apgar score), individual risk factors (i.e., intraoperative hypotension), or postoperative biomarkers (i.e., troponins and natriuretic peptides).
  
  
  CONCLUSIONS
  Preoperative clinical risk indices and risk calculators estimate surgical risk with moderate accuracy. Although novel biomarkers, specialized preoperative testing, and immediate postoperative risk indices show promise as methods to refine these risk estimates, more research is needed on how best to integrate risk information from these different sources.
authors.affiliation: aDepartment of Anesthesia, University of Toronto bDepartment of Anesthesia, Toronto General Hospital cLi Ka Shing Knowledge Institute of St. Michael's Hospital dInstitute of Health Policy Management and Evaluation, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Ashwin
authors.initials: A
authors.lastname: Sankar
authors.forename: W Scott
authors.initials: WS
authors.lastname: Beattie
authors.forename: Duminda N
authors.initials: DN
authors.lastname: Wijeysundera
mesh_terms: D015415:Biomarkers / Q000097:blood*; D003422:Critical Care; D005080:Exercise Test; D006801:Humans; D045265:Natriuretic Peptides / Q000097:blood; D011183:Postoperative Complications / Q000401:mortality / Q000517:prevention & control; D011300:Preoperative Care; D018570:Risk Assessment; D012307:Risk Factors; D013514:Surgical Procedures, Operative / Q000401:mortality*; D014336:Troponin / Q000097:blood
chemical_list: D015415:Biomarkers; D045265:Natriuretic Peptides; D014336:Troponin