• K Uutela, S Verscheure, and G Hans.
• University Department of Anaesthesia and ICM, CHR Citadelle, Liege, Belgium.
• Acta Anaesthesiol Scand. 2012 Jul 1;56(6):787-96.

BackgroundThe Surgical Pleth Index (SPI), derived from pulse amplitude and heartbeat interval, is proposed to monitor anti-nociception during anaesthesia. Its response to noxious stimulation can be affected by the intravascular volume status. This study investigated the effect of a fluid challenge (FC) on SPI during steady-state conditions.MethodsAfter Institutional Review Board approval, 33 consenting patients undergoing neurosurgery received a 4 ml/kg starch FC over less than 5 min under stable surgical stimulation conditions and stable propofol (Ce(PPF) ) and remifentanil (Ce(REMI) ) effect-site concentrations as estimated by target-controlled infusion systems. Intravascular volume status was assessed using the Delta Down (DD). We looked at the SPI response to FC according to DD, Ce(PPF) , and Ce(REMI) .ResultsFollowing FC, SPI did not change in 16, increased in 12, and decreased in 3 patients. Ce(REMI) poorly affected the SPI response to FC. In normovolaemic patients, the probability of an SPI change after FC was low under common Ce(PPF) (0.9 to 3.9 μg/ml). A decrease in SPI was more probable with worsening hypovolaemia and lowering Ce(PPF) , while an increase in SPI was more probable with increasing Ce(PPF) . SPI changes were only attributable to modifications in pulse wave amplitude and not in heart rate.ConclusionsDuring stable anaesthesia and surgery, SPI may change in response to FC. The effect of FC on SPI is influenced by volaemia and Ce(PPF) through pulse wave amplitude modifications. These situations may confound the interpretation of SPI as a surrogate measure of the nociception-anti-nociception balance.© 2012 The Authors. Acta Anaesthesiologica Scandinavica © 2012 The Acta Anaesthesiologica Scandinavica Foundation.

39 keywords...

hide…