Surgical Stress Index and epidural analgesia

Surgical pleth index in children younger than 24 months of age: a randomized double-blinded trial

“…The power analysis was based on the results of a previous study comparing the surgical stress index in a group of adult female patients, with or without epidural analgesia at skin incision. 12 The primary outcome measure of our study was the change in SPI value at the time of the surgical incision. Assuming similar responses [20 units difference (Δ) in SPI and standard deviation () of 14.4], nine patients per group would be needed to reach a power of 0.80 (P<0.05).…”

Measurement of surgical stress in anaesthetized children

“…The power analysis was based on the results of Yli-Hankala and colleagues 19 who compared patients with and without epidural anaesthesia and used increase of SSI after incision of the skin as the primary outcome variable. Assuming similar responses (the groups differed by 20 in DSSI and standard deviations were 14.4 and 14.1, respectively) and a power of 0.80, statistical significance at P,0.05 would be reached with nine patients in each group.…”