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 perioperative, 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), anesthetized generally with lidocaine as a co-analgesic, and the non-lidocaine group (NLG; N.=21), anesthetized 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 six hours, and following morning after surgery, while in healthy children we collected blood samples only once. The serum concentrations of endocannabinoids (anandamide [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 six hours 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.