Table 1.
Method of risk assessment | Definition | Advantages | Limitations |
---|---|---|---|
Clinical prediction rules |
The use of a scoring system based on patient- or procedure-related risk factors to quantify risk |
Often cost-neutral |
Estimates population risk for patient rather than providing an individualized risk assessment |
|
|
Requires no specialist knowledge
[34] |
|
ASA-PS |
Six-point scale used to grade patient according to comorbidities
[35] |
Validated in a number of settings
[36-38] |
Inter-observer variability
[39] |
|
|
|
Poor sensitivity and specificity for prediction of morbidity and mortality on an individual patient basis
[33,40] |
Lee Revised Cardiac Risk Index (RCRI) |
Scores patients according to six variables, including whether the surgery is high risk |
Discriminates moderately well between patients at low versus high risk for cardiac events after mixed noncardiac surgery
[42] |
Designed to identify patients at risk of cardiac complications so may miss patients at risk of other complications who may benefit from PACU care |
|
Assesses cardiac risk
[41] |
Well validated |
|
POSSUM |
A more detailed scoring system with 18 components, 6 operative variables and 12 physiological variables
[46] |
A revision of POSSUM, the Portsmouth POSSUM
[43] has been shown to be a better predictor of outcome in certain surgical settings
[33,44,45] |
Some variables cannot be ascertained until after surgery, making it of limited use for preoperative identification of patients who may benefit from PACU care |
|
|
Variations in the model have been devised for specific patient groups, such as the Cr-POSSUM (colorectal), which has been shown to be a better predictor of outcome in this type of surgery
[47] |
|
Cardiopulmonary exercise testing | CPET is an integrative and quantitative measure of a patient’s cardiopulmonary reserve |
Good evidence that CPET is useful to help predict perioperative morbidity and mortality and may aid triage to an appropriate level of postoperative care
[48-50] |
In 2008, 17% of Hospital Trusts in England had a CPET service, and a further 7% were in the process of setting one up [52] |
The assessment requires the patient to exercise (usually on a cycle ergometer) while oxygen consumption, carbon dioxide production, and other cardiorespiratory variables are measured | RCT in progress to further evaluate its use to stratify to appropriate level of postoperative care [51] |
ASA-PS, American Society of Anesthesiology Physical Status Score; CPET, cardiopulmonary exercise testing; PACU, postanaesthetic care unit; POSSUM, physiological and operative severity score for the enumeration of mortality and morbidity; RCRI, Lee Revised Cardiac Risk Index; RCT, randomized controlled trial.