The perfusion index (PI) derived from a pulse oximeter has been used for assessing peripheral perfusion dynamics due to changes in peripheral vascular tone. Change in baseline peripheral vascular tone due to pregnancy may affect the degree of hypotension resulting from SAB. The aim of this study was to examine whether baseline PI could predict the incidence of spinal anaesthesia-induced hypotension during Caesarean delivery.

120 Parturients undergoing elective Caesarean delivery under spinal anaesthesia with hyperbaric bupivacaine 10 mg were enrolled in this prospective observational study. The correlation between baseline PI and the incidence, degree of hypotension during spinal anaesthesia and predictability of spinal anaesthesia-induced hypotension during Caesarean delivery by PI were investigated. Enrolled parturients were divided into two groups based on baseline PI with PI ≤3.5 allotted to Group I, and PI >3.5 allotted to Group II.

The systolic, diastolic and mean arterial pressure were lower in group II in comparison to group I. The incidence of hypotension in Group I was 12.5% (5/40) compared to 67.34% (33/ 49) (p - <0.001, odds ratio – 0.07) in Group II. Spearman rank correlation revealed highly significant correlation between baseline PI >3.5 and number of episodes of hypotension (rs- 0.567,p-<0.001), total dose of ephedrine used (rs- 0.567,p-<0.001) and total intravenous fluids used (rs- 0.249,p-0.019). The Receiver Operating Curve for baseline PI and the probability of hypotension was highly significant (AUC-0.833, p<0.001).

Baseline PI > 3.5 is a good predictor of intra operative spinal induced hypotension in LSCS