Cardiac Autonomic Neuropathy Bedside Test (CAN Testing)

Valsalva maneuver usually causes an increase in HR followed by a decrease after stopping the maneuver.  The Valsalva ratio is the maximal HR by Valsalva divided by the lowest after Valsalva.  Normal > 1.21,  abnormal < 1.2.  Deep breathing causes an increase in HR by 15 BPM,  borderline 11-14, abnormal < 10 BPM. Standing causes an increase in HR by more than 10% from the 15-30th beat on standing.  Less than 10% abnormal.  Sustained handgrip raises the BP > 16 mmHg, borderline 11-15, and < 10 mmHg abnormal.  Standing up reduces the BP < 10 mmHg, borderline 11-29, and abnormal > 30 mmHg. 

(Clark 2007)

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