Several studies reported fewer unwanted events, reduced opioid consumption and shorter emergence from anaesthesia, when opioid administration was based upon monitoring of the nociceptive-anti-nociceptive balance.¹

The Surgical Pleth Index (SPI)* is a parameter that reacts to haemodynamic responses caused by surgical stimuli and analgesic medications. SPI is an algorithm that uses two components of the GE photoplethysmographic signal when measured on GE SpO₂ finger sensors only.

By observing the SPI value and trend, clinicians can monitor real time adult patient's responses to surgical stimuli and analgesic medications therefore saving valuable time for optimization analgesia delivery.

The optimal SPI target has not been recommended yet as more studies need to prove the clinically relevant range of SPI measurements. However, in several studies, a range of [20; 50] has been considered for guiding opioids titration.^2,3

Published literature suggests that SPI-guided anaesthesia may result in lower remifentanil consumption, more stable haemodynamics and lower incidence of unwanted events.^2,4

Know more about how SPI works and its clinical benefits:

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_{1.Gruenewald and Ilies C. Monitoring the nociception-anti-nociception balance. Best Pract Res Clin Anaesthesiol. 2013 Jun;27(2):235-47. doi:10.1016/j.bpa.2013.06.007.}
_{2.Chen et al.: Comparison of Surgical Stress Index-guided analgesia with standard clinical practice during routine general anaesthesia Anaesthesiology, V 112, No.5 2010.}
_{3.Wennervirta et al. Surgical stress index as a measure of nociception/antinociception balance during general anaesthesia. Acta Anaesthesiol Scand 2008; 52: 1038-45

_{4.Bergmann I. and al. Surgical pleth index-guided remifentanil administration reduces remifentanil and propofol consumption and shortens recovery times in outpatient anaesthesia. BJA 110 (4): 622-8 (2013)}}