Correlation of surgical pleth index with stress hormones during propofol-remifentanil anaesthesia

Abstract

Eighty patients undergoing elective ear-nose-throat surgery were enrolled in the present study to investigate the relationship between surgical pleth index (SPI) and stress hormones (ACTH, cortisol, epinephrine, norepinephrine) during general anaesthesia which was induced and maintained with propofol and remifentanil using a target-controlled infusion. The study concluded that the SPI had moderate correlation to the stress hormones during general anaesthesia, but no correlation during consciousness. Furthermore, SPI values were able to predict ACTH values with high sensitivity and specificity.

Figure 1

Values are mean ± SD. Base: baseline before anaesthesia; Intu: after tracheal intubation; Max: at maximum operative trauma which was defined intraoperatively by the surgeon; After-Max: 15 min after the maximum operative trauma; Mean: mean blood pressure; HR: heart rate; SPI: the group in which remifentanil administration was guided by SPI; Control: the group in which remifentanil administration was guided by standard traditional inadequate anaesthesia criteria. *P < 0.05, **P < 0.01 compared with respective values at Base in the same group with one-way ANOVA followed by LSD test. ^# P < 0.05, ^## P < 0.01 compared with respective values at Intu in the same group with one-way ANOVA followed by LSD test. ^& P < 0.05, ^&& P < 0.01 compared with respective values at Maxi in the same group with one-way ANOVA followed by LSD test. No differences were found between the SPI group and the Control group at all four event-related time points (P > 0.05).

Figure 2

Linear regression analysis and correlation analysis between the SSI values and and stress hormones (ACTH, cortisol, epinephrine and norepinephrine). Bold line is regression line. Slopes of the above lines between time points are significantly different, P < 0.01. ACTH: adrenocorticotropic hormone; SPI: surgical pleth index; Base: baseline before anaesthesia; Intu: after tracheal intubation; Max: at maximum operative trauma, defined intraoperatively by the surgeon; After-Max: 15 min after the maximum operative trauma.