Comparison of Pleth Variability Index vs. Diastolic Shock Index for Predicting Hypotension During Anesthesia Induction

Peripheral perfusion index (PI) is an easy-to-implement and low-cost monitoring procedure obtained by interpreting non-invasive data obtained from pulse oximetry via plethysmography. It is a tool that allows interpretation of fluid status through changes in pulse oximetry waves caused by respiration. High perfusion indices are interpreted as low arterial tone. Changes in perfusion index are interpreted as indicators of vascular tone or fluid deficit problems in patients. The ratio of the highest and lowest PI values gives the Pleth Variability Index (PVI) (3,4). Hypotension can be predicted during anesthesia induction with PVI

The Diastolic Shock Index (DSI) is a hemodynamic parameter calculated by dividing the heart rate (HR) by the diastolic blood pressure (DBP). It reflects the balance between cardiac output and systemic vascular resistance, particularly in critically ill patients. A higher DSI can indicate impaired vascular resistance and may be useful for predicting the need for vasopressor support, especially in conditions like septic shock. However, its application in predicting hypotension during anesthesia induction is still under investigation.