Table 5.

Summary of risk scores.

Risk score	Outcome	Advantages	Disadvantages
ASA	Population-based mortality	Simple to use Correlates with outcome in number of settings	Subjective Does not consider surgery planned
Lee's RCRI	Postoperative cardiac complications (non-cardiac surgery)	Simple to use Non-invasive Identifies those at increased risk before operation	Developed 20 yrs ago in a single centre from elective patients Uncertain generalisability
ARISCAT	Postoperative pulmonary complications	Identifies those at increased risk, contains modifiable features	No widespread agreement in how PPCs are defined