San Francisco Syncope Rule Calculator
San Francisco Syncope Rule (SFSR)
Assess risk of serious outcomes in patients with syncope
What is the San Francisco Syncope Rule?
The San Francisco Syncope Rule (SFSR) is a clinical decision tool used to identify patients at risk for serious outcomes after an episode of syncope (fainting). It helps clinicians determine which patients can be safely discharged and which require further evaluation or admission.
The CHESS Criteria
The San Francisco Syncope Rule uses the mnemonic CHESS to remember the five risk factors:
- C: Congestive heart failure history
- H: Hematocrit < 30% (severe anemia)
- E: ECG abnormal (new changes or non-sinus rhythm)
- S: Shortness of breath
- S: Systolic blood pressure < 90 mmHg at triage
Clinical Significance
If any of the CHESS criteria are present, the patient is considered at high risk for a serious outcome within 30 days of the syncope event. Serious outcomes include:
- Death
- Myocardial infarction
- Arrhythmia
- Pulmonary embolism
- Stroke
- Subarachnoid hemorrhage
- Significant hemorrhage
- Any condition causing a return ED visit and hospitalization
Interpretation
| Result | Interpretation |
|---|---|
| Negative (No CHESS criteria present) | Low risk for serious outcome (0.7% risk) |
| Positive (Any CHESS criteria present) | High risk for serious outcome (consider admission or further evaluation) |
Limitations
The San Francisco Syncope Rule has several limitations:
- It does not apply to patients with obvious serious conditions requiring admission
- It should not be used in patients with near-syncope or altered mental status
- External validation studies have shown variable sensitivity (52-98%)
- Clinical judgment should always be used alongside this rule
References
- Quinn J, McDermott D, Stiell I, et al. Prospective validation of the San Francisco Syncope Rule to predict patients with serious outcomes. Ann Emerg Med. 2006;47(5):448-454.
- Birnbaum A, Esses D, Bijur P, et al. Failure to validate the San Francisco Syncope Rule in an independent emergency department population. Ann Emerg Med. 2008;52(2):151-159.
- Thiruganasambandamoorthy V, Hess EP, Alreesi A, et al. External validation of the San Francisco Syncope Rule in the Canadian setting. Ann Emerg Med. 2010;55(5):464-472.