Validated risk scores in premedication: RCRI, Duke Activity Status Index, Apfel score

What does the Revised Cardiac Risk Index (RCRI) measure?

The RCRI was developed in 1999 by Lee et al. to estimate cardiac risk in non-cardiac surgery and takes six criteria into account:

• History of ischaemic heart disease
• History of heart failure
• History of cerebrovascular event (stroke or TIA)
• Insulin-dependent diabetes mellitus
• Preoperative serum creatinine > 2.0 mg/dl
• High-risk surgery (suprainguinal vascular, intraperitoneal or intrathoracic)

As the number of criteria met increases, so does the risk of major cardiac complications. In the validation cohort of Lee et al., it was 0.4% with no criteria, 0.9% with one, 7% with two and 11% with three or more.

Source: Lee TH, Marcantonio ER, Mangione CM et al. “Derivation and prospective validation of a simple index for prediction of cardiac risk of major noncardiac surgery.” Circulation 1999; 100(10): 1043–1049.

What does the Duke Activity Status Index (DASI) measure?

The DASI assesses functional capacity using twelve questions on activities of daily living – from self-care to sporting activity. The resulting score correlates with maximal oxygen uptake (VO2max) and metabolic equivalents (METs), which could otherwise only be determined by cardiopulmonary exercise testing. In preoperative risk evaluation, a DASI score of around 34 points or more is considered an indication of lower perioperative risk, while lower scores are associated with increased risk. The DASI does not replace an overall clinical assessment, but supplements it with a structured estimate of functional capacity where this is not already clinically obvious.

What does the Apfel score for PONV measure?

The Apfel score estimates the risk of postoperative nausea and vomiting (PONV) on the basis of four factors, each scoring one point:

• Female sex
• Non-smoking status
• History of PONV or motion sickness
• Planned postoperative opioid administration

The estimated probability of PONV rises with the number of points from around 10% with no risk factors to around 80% with all four factors. These values serve as clinical orientation and are often used to escalate antiemetic prophylaxis from a score of two points or more.

How does the reliability of these scores depend on the medical history?

All three scores are based predominantly on medical history information that can be captured in structured form – only the RCRI also needs a laboratory value (serum creatinine). This is precisely what makes them vulnerable to incomplete input data: if information on insulin-dependent diabetes or a history of PONV is missing, the score in question cannot be calculated correctly, no matter how sophisticated the underlying calculation logic is. A structured digital medical history that captures exactly this information in a targeted and complete way is therefore the prerequisite for reliable score calculation – it is not the calculation itself that replaces the physician’s evaluation; rather, the data on which it is based must be complete.

medudoc can calculate standardised scores from the medical history data captured and display risk factors in the Healthcare Professional Dashboard (HCP Dashboard). The final interpretation of the scores and the clinical decision derived from it – for example on the choice of anaesthetic technique or on antiemetic prophylaxis – remain entirely with the physician.

Conclusion

The RCRI, DASI and Apfel score are established, validated instruments of preoperative risk evaluation – but their validity depends directly on the completeness of the medical history from which they are calculated. A structured digital medical history provides exactly the level of detail these scores require, and thus creates the basis for reliable preoperative risk classification.