COMPARATIVE STUDY OF TWO INCISIONAL INFILTRATION TECHNIQUES IN DOGS UNDERGOING OVARIECTOMY: PRELIMINARY RESULTS

Incisional infiltration with local anaesthetic is an important part of multimodal analgesia. Usually, this technique is performed by injection of local anaesthetic directly into the surgical field using a syringe [1]. Comfort-in™ is a needle-free injection system that works by forcing the liquid medication at an elevated speed without piercing the skin; high pressure allows the more rapid administration of drugs by penetrating to the skin in devoid of an injection [2]. The aim of the study is to compare the analgesic effects of midline infiltration of 2% lidocaine using the traditional technique and the Comfort-in™ in dogs undergoing ovariectomy. The study was approved by the Ethical Committee of the Department of Veterinary Sciences of Messina (No. 021/2018). Twenty-two ASA 1 female mixed-breed dogs aged between 2 and 7 years from a private shelter were randomly divided into two groups: 1) lidocaine (2 mg/kg) infiltration with the syringe (group S; n = 11); 2) lidocaine (2 mg/kg) infiltration with the Comfort-in™ Technology (group C; n = 11).
The dogs were premedicated with im medetomidine (5 g/kg) and tramadol (3 mg/kg). General anaesthesia was induced and maintained with iv tiletamine and zolazepam (5 mg/kg). The infiltration of the midline incision was performed 10 minutes before surgery. During anaesthesia, heart and respiratory rates, non-invasive arterial pressure, oxygen haemoglobin saturation and body temperature were measured every 5 minutes and before skin incision, at skin incision, and at skin suture. The data recorded were analysed using a repeated measures analysis of variance and a p-value < 0.05 was considered significant. There were no significant differences in the monitored parameters when compared to the baseline values and between groups. The surgery was completed in all the animals, and there were no anaesthetic or surgical complications. The results of this study confirm that the infiltration using the Comfort-in™ Technology provided effective analgesia in dogs undergoing ovariectomy, in the same way as the traditional infiltration. On the other hand, advantages of the use of incisional lidocaine has been showed by different studies [1,3] and consisted in less use of intraoperative and postoperative analgesics and in a lower postoperative pain score. Comfort-in™ lowers the risk of needle injury that is extremely important when anaesthetic drugs are handed. Further studies are needed in order to demonstrate whether this technique can be a reliable alternative method to perform incisional infiltration, especially in sedated or awake animals.