What Is Perfusion Index?

The "perfusion index" or "PI" reflects the amount of blood flow being measured by an instrument called a "pulse oximeter." A health care professional tests blood flow to establish norms and aid in identifying changes in a patient's condition.

Benefits

• As a noninvasive assessment tool, the perfusion index provides information without subjecting the patient to potentially dangerous tests. The pulse oximeter clips on to a patient's finger, toe, ear or nose and gives objective numeric data on the blood flow to the site.

Function

• Past and proposed clinical trials look at the applications of PI for evaluating patient conditions and changes in many scenarios. In the surgical suite, changes in the PI have been tied to the moment when anesthesia takes effect. For an infant, child or unresponsive patient, changes can alert caregivers to deterioration of the patient's condition by identifying decreased oxygenation at the reporting site.

Considerations

• The perfusion index varies from patient to patient and and from one reading location to another. Rather than a generic "normal" PI, the number reflects what is normal for that particular patient.