The San Francisco Syncope Rule is designed to assess the likelihood of a serious outcome following a syncope event, based on the presence of certain clinical factors. This rule utilizes a decision-making process based on five specific inputs related to the patient's condition.

The inputs include:

1. History of congestive heart failure
2. Hematocrit < 30%
3. New changes on ECG or any non-sinus rhythm
4. Shortness of breath
5. Systolic blood pressure < 90 mmHg at triage

For each input, a binary condition is checked: if any one of these conditions is true (i.e., the patient meets any one of these criteria), then the result will indicate a likelihood of a serious outcome. Conversely, if none of these conditions are met, the result would indicate that a serious outcome is unlikely.

The computation process is as follows:

1. Check if the patient has a history of congestive heart failure.
2. Determine if the patient's hematocrit level is less than 30%.
3. Identify any new changes on the ECG or non-sinus rhythm.
4. Check for the presence of shortness of breath.
5. Verify if the patient's systolic blood pressure is less than 90 mmHg at triage.

If any of these conditions is true, the result returned is "Serious outcome is likely". If none of these conditions are true, the result is "Serious outcome is unlikely". 

The San Francisco Syncope Rule (SFSR) is a clinical prediction rule used to evaluate patients who present with syncope, or sudden temporary loss of consciousness. This rule is specifically designed for patients in the emergency department setting. The SFSR helps clinicians identify patients who are at risk of serious outcomes within 7 days of a syncope episode, such as death, myocardial infarction, arrhythmia, pulmonary embolism, stroke, subarachnoid hemorrhage, significant hemorrhage, or any condition causing a return to the emergency department and hospitalization for related events. 

The rule uses five criteria, represented by the acronym CHESS: Congestive heart failure, Hematocrit less than 30%, abnormal Electrocardiogram (ECG), Shortness of breath, and systolic blood Pressure less than 90 mmHg. If any of these criteria are present, the patient is considered at high risk.

The SFSR should not be used in patients with obvious trauma, seizure, or a clear non-cardiac cause of syncope, as well as in patients with persistent altered mental status or who are not back to their neurological baseline.