To study the role of perfusion index in assessing efficacy of spinal anaesthesia

Spinal anesthesia, also referred to as central neuraxial blockade is produced when a local anesthetic agent is injected into the subarachnoid space. It induces sympathectomy leading to selective vasodilatation of lower limbs. Perfusion index (PI) is a valuable objective during anesthetic practice to find out noninvasive methods for predicting the effect of anesthesia at our institution we studied the role of PI in assessing the efficacy of spinal anesthesia in 100 patients, scheduled for lower abdominal surgeries. In our study we found that when perfusion index in toe increases continuously from baseline at various intervals, there was simultaneous drop in mean blood pressure. PI in the lower limbs (increase of 602.98% at 20 minutes) has a strong negative correlation with the mean arterial pressure (decrease of 19.67% at 20 minutes) as per our results (p <0.01). We correlated mean sensory block time with PI from baseline to 20 minutes, PI increased even at 1 minute after SAB but no statistically significant correlation could be found (p>0.05) between time of onset of block and PI values.