Course of plasma substance P concentrations during umbilical surgery in calves

Abstract

The objective of this orientating study was to describe plasma concentrations of substance P in calves undergoing umbilical surgery with two different analgesic protocols. The study was conducted as a randomized controlled double blinded trial. Ten calves (aged 39 10 days) were treated with meloxicam (CON) for analgesia, and 11 calves (aged 37 8 days) with meloxicam and metamizole (MET). Umbilical surgery under general anaesthesia was performed according to a strictly standardized protocol. Blood samples were taken at the day of surgery (one hour before and 5, 15, 30, 45, 60, 90, 150 and 510 minutes after skin incision). Plasma concentrations and AUC of substance P were determined. Plasma substance P increased during umbilical surgery in both groups. In CON, there was a significant difference to plasma substance P baseline concentration 5, 30 and 90 minutes after skin incision. Plasma substance P concentrations were lower in MET compared with CON at all times, and did not differ significantly from baseline concentration. Even though there was no significant difference in the plasma substance P concentrations in-between the groups, the results show that after the administration of metamizole additionally to meloxicam, plasma substance P concentrations in MET were lower than in CON at all times. This fact could indicate that substance P might be a suitable biomarker for nociception and pain. Further studies are needed to confirm this hypothesis.