Increase of plasmatic beta-endorphin immunoreactive material in children in the perioperative period: the influence of the site of surgery

BACKGROUND: The primary aim of the study was to confirm the increase of plasmatic IR beta-endorphin material during the perioperative period in children. The second was to search for the factors responsible for this increment. METHODS: Seventy-two consecutive children undergoing a surgical procedure were recruited. Pre-anaesthesia and anaesthesia were standardised. Plasmatic IR beta-endorphin material was measured at three timepoints: at baseline (t (0)), before induction (t (1)), and at the end of anaesthesia (t (2)). Two general linear models were set up to analyse the influence of demographics and clinics on the IR beta-endorphin variation between t (0) and t (1). A third model was established to process the possible surgical factors contributing to the IR beta-endorphin variation between t (1) and t (2). RESULTS: ANOVA showed that IR beta-endorphin concentrations increased significantly across the three timepoints (p < 0.0001). Wilcoxon test proved that the difference was significant both for t (0) vs. t (1) and for t (1) vs. t (2). None of the factors taken into account in the pre-operative period influenced the increase in IR beta-endorphin between t (0) and t (1). Of the factors taken into account in the surgical period, only the type of procedure was significant (p = 0.005). The t-test showed that IR beta-endorphin significantly increased during spermatic and epigastric anastomosis (p = 0.000), orchidopexy (p = 0.02), Van der Meulen urethroplasty (p = 0.004), and Duckett urethroplasty (p = 0.003). CONCLUSION: Plasmatic beta-endorphin increases during the perioperative period in children. The site of surgery is responsible for this increment during intervention.