Background

The Bispectral Index (BIS) is a processed electroencephalographic parameter that correlates with the sedative-hypnotic actions of anaesthetic drugs. Dexmedetomidine and lidocaine have both opioid sparing effects. Their influence in laparoscopic surgery has not been studied yet. We investigated their effect on perioperative opioid consumption, cognitive function and incidence of neuropathic pain.

Keywords: bispectral index, dexmedetomidine, lidocaine

Materials/methods

Randomised controlled trial of the influence of dexmedetomidine and lidocaine on opioid consumption was performed. The anaesthesia type in the control group was continuous propofol infusion (depth of anaesthesia closely monitored with BIS) and fentanyl boluses. Continuous intravenous infusion of dexmedetomidine and lidocaine was added to dexmedetomidine and lidocaine group, respectively. Primary outcome measure was intraoperative fentanyl consumption. Secondary outcome measures were consumption of piritramide on the first and the second postoperative day, cognitive function, and neuropathic pain after the operation.

Results

59 participants were randomised to dexmedetomidine (n=19, average age 66, 47 % males), lidocaine (n=20, average age 61 years, 60 % males) and control treatment (n=20, average age 58 years, 50 % males). There was no reduction in fentanyl consumption neither in lidocaine group nor in dexmedetomidine group compared with control group. We noted significantly lower consumption of piritramide in lidocaine group compared with control group on the first postoperative day (p=0.019). There were no differences in total consumption of piritramide between the groups, changes in cognitive function before and after the surgery and appearance of neuropathic pain two months after the surgery.

Conclusion

Lidocaine reduced piritramide consumption on the first postoperative day. Lidocaine and dexmedetomidine failed to decrease fentanyl demand but reduced intraoperative propofol consumption. Cognitive function did not differ pre- and post-operatively.

Trial Registration: ClinicalTrials.gov NCT02616523

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