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Effect of intravenous, perioperative-administrated lidocaine on serum levels of endocannabinoids and related N-acylethanolamines in children.

BACKGROUND
Endocannabinoids and N-acylethanolamines (NAEs) are compounds that play a significant role in nociception. The promising therapeutic opportunities in postoperative pain management are connected with intra-venous (i.v.) lidocaine administration as a part of multimodal analgesia. Therefore, we analyzed the influence of intra-operative, i.v. lidocaine infusion in children on postoperative serum concentrations of endocannabinoids and NAEs.


METHODS
Forty-four children undergoing extensive spinal surgery were divided into two groups: the lidocaine group (LG; n=23), anaesthetized generally with lidocaine as a co-analgesic, and the non-lidocaine group (NLG; n=22), anaesthetized generally without lidocaine. We also recruited 23 healthy age- and gender-matched children to the control group. Blood samples were collected before surgery, immediately after surgery, at 6 h, and following morning after surgery, while in healthy children we collected blood samples only once. The serum concentrations of endocannabinoids (anandanamide [AEA] and 2-arachidonyl glycerol [2-AG]) and NAEs (palmitoylethanolamide [PEA] and oleoylethanolamide [OEA]) were quantified by ultra-high- performance liquid chromatography-mass spectrometry.


RESULTS
The concentrations of measured compounds were comparable in controls and in patients before surgery (all P > 0.05). During the postoperative period, we found significantly higher AEA and lower 2-AG concentrations in the LG when compared to the NLG. The highest concentration of PEA was observed in LG patients 6 h after the operation and, at that time it was significantly elevated when compared to the NLG (P = 0.0003).


CONCLUSIONS
Perioperative, i.v. lidocaine administration influences postoperative serum concentrations of endocannabinoids and NAEs in children.