Evaluation of perfusion index as an indicator of postoperative pain in parturients undergoing caesarean section: an observational study

ABSTRACT

Objective. Perfusion index (PI) is a non-invasive measure of peripheral perfusion. Previous studies have evaluated PI as an objective tool of pain assessment peri-operatively. Against this background, the present study aimed to evaluate PI as an objective indicator of pain assessment in parturients undergoing lower segment caesarean section and also to observe any correlation of PI with Visual analogue scale (VAS), heart rate (HR) and mean arterial pressure (MAP).

Materials and Methods. This prospective observational study was conducted in 40 parturients scheduled to undergo caesarean section under spinal anaesthesia. After surgery, patients were shifted to post anaesthesia care unit. Pulse co-oximeter probe was attached to the middle fingertip of the hand along with standard routine monitors. HR, MAP, VAS and PI were recorded at first request of analgesia (T1) by the patient and at 30 minutes after administration of analgesia (T2) in the form of 1 g paracetamol iv.

Results. There was a statistically significant increase in PI from T1 to T2 (3.62 ± 2.36 to 8.51± 9.36; p < 0.05). This increase was associated with statistically significant decrease in HR (93.08 ± 12.71 vs 85.65 ± 10.63 beats/min), MAP (96.60 ± 11.606 vs 91.55 ± 10.86 mmHg) and VAS (6.23 ± 1.23 vs 2.53 ± 1.06) at T2 as compared to T1. A statistically significant negative correlation was observed between PI and HR/MAP/VAS from T1 to T2 (rs = -0.433, p < 0.001; rs = 0.896, p < 0.001; rs = -0.231, p = 0.016 respectively).

Conclusions. PI can be used as an additional and objective indicator of pain assessment in post anaesthesia care unit.

Key words

Assessment; pain; heart rate; perfusion index; pulse oximetry; visual analogue scale.