Role of perfusion index in early detection of hypotension following spinal anesthesia for cesarean section

ABSTRACT Background The most common drawback of spinal anesthesia (SA) is hypotension, which has adverse effects on both mother and fetus; consequently, early detection and management of spinal hypotension have been considered a very important topic in obstetric anesthesia. Additionally, the capability to ultimately diagnose hypotension could permit initiation of adequate treatment. The standard method to estimate blood pressure during cesarean section is noninvasive blood pressure measurement. However, periods of hypotension could be missed within a reasonable time frame. Methods Perfusion index (PI) and blood pressure were measured in 100 pregnant women during elective cesarean section under SA. Results PI had a significant negative correlation with the change occurred in systolic blood pressure (SBP) (r = −.432, p < .0001); by using univariate linear regression analysis, the PI explains 20.2% of variability in SBP as PI significantly predicts the change occurred in SBP (F = 24.8, p < .0001), as each one unit increase in PI, accompanied by a significant decrease in SBP by 2.089 (mm/hg), as (b, t, p) (−2.089, −4.987, .0001), respectively. There was a significant difference in SBP and PI before and after giving oxytocin bolus [(z = −1.9, P = .05) and (z = −4.3, P < .0001), respectively]. By comparing PI before vs. after taking ephedrine bolus, there was a significant decrease in median of PI [median of PI before 10 (5.5–15) vs. median of PI after 7.5 (6–15.5) (z = −6.6, P < .0001)]. Discussion After SA with sympathetic blockade, peripheral vascular tone declined and therefore PI increased. Conclusion PI could anticipate the incidence of hypotension during cesarean delivery with SA. Ephedrine effect could be evaluated rapidly by the alteration in the PI so that further need can be judged. Oxytocin has a significant impact on vascular tone with 5 international unit bolus, although it does not have a significant effect on blood pressure.