Target-controlled dosing of remifentanil during cardiac surgery reduces postoperative hyperalgesia.

OBJECTIVE

One of the strategies to attenuate opioid-induced hyperalgesia (OIH) may be to decrease intraoperative doses of opioids by using target-controlled infusion (TCI).

DESIGN

Double-blind and randomized study.

SETTING

A single university hospital.

PARTICIPANTS

Forty American Society of Anesthesiologists II to III patients scheduled for elective cardiac surgery.

INTERVENTIONS: patients were randomized to 1 of the 2 groups: 1 group received an infusion of intraoperative remifentanil using TCI (target: 7 ng/mL), and the 2nd one was given an intraoperative continuous infusion (CI) (0.3 μg/kg/min). The anesthestic protocol and postoperative pain management were the same in both groups. The extent of mechanical dynamic hyperalgesia on the middle line perpendicular to the wound was considered the primary endpoint. The secondary endpoints were other results of dynamic and punctuate hyperalgesia until postoperative day 7, visual analog scale (VAS) and verbal rating scale (VRS) scores, and total morphine consumption until postoperative day 2.

MEASUREMENTS AND MAIN

RESULTS

Morphometric and demographic characteristics and duration of surgery were comparable in both groups. Intraoperative remifentanil consumption was greater in CI than in TCI group (5,329 [1,833] v 3,662 [1,160] μg, p = 0.003). During the first 44 hours, there were no differences in morphine consumption, VAS, and VRS. The extent of hyperalgesia was significantly lower on postoperative days 1, 2, and 4 in the TCI group than in the CI group on the 3 evaluated lines (p < 0.05). Punctuate hyperalgesia evaluating 3 different points was lower in the TCI than in the CI group from postoperative day 1 until postoperative day 7 (p < 0.05).

CONCLUSIONS

The intraoperative decrease of opioid consumption when comparing the CI versus TCI mode of administration of remifentanil led to less OIH after cardiac surgery.