Perfusion Index-derived Parameters as Predictors Post-induction Hypotension.

The perfusion index (PI) is a numerical value for the ratio between pulsatile and non-pulsatile blood flow measured by a special pulse oximeter. PI represents the baseline sympathetic tone which is assumed one of the factors contributing for hypotension. Patients with low PI were reported by Mahendale and Rajasekhar to show greater hypotension after induction of anesthesia. This was explained by the high sympathetic tone in these patients which is suddenly masked by propofol administration leading to profound hypotension. This study aims to evaluate the ability of preoperative plethysmographic variability index, perfusion index and the Dicrotic Plethysmography to predict post-induction hypotension.