Comparative analysis of analgesia using different volumes of bupivacaine to block the fascia of the rectus abdominis muscle in bitches undergoing ovariohysterecetomy

• Grant number: 25/01294-5
• Support Opportunities: Scholarships in Brazil - Master
• Start date: June 01, 2025
• End date: July 31, 2026
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Clinics and Surgery
• Principal Investigator: Marcus Antônio Rossi Feliciano
• Grantee: Larissa Rossato Oliveira
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil

Abstract

Ultrasound-guided local anesthesia techniques are becoming increasingly common in veterinary medicine. The objective of this study is to evaluate the analgesic efficacy of the rectus sheath block (RSB) in female dogs undergoing elective ovariohysterectomy, using different volumes of bupivacaine (0.25 mL/kg and 0.5 mL/kg per hemiabdomen). Sixty healthy female dogs will be selected after physical and laboratory evaluations and randomly divided into three groups: RSB with 0.25 mL/kg (G1), RSB with 0.5 mL/kg (G2), and 0.5 mL/kg of saline solution (GC). After pre-anesthetic medication with acepromazine (0.02 mg/kg) and morphine (0.3 mg/kg), the technique will be performed bilaterally under ultrasound guidance following induction with propofol and maintenance with isoflurane in 100% oxygen via a calibrated vaporizer. Postoperative analgesia will be assessed immediately and at predefined intervals using validated scales such as the Modified Glasgow and Colorado scales. Physiological variables will also be monitored during the intraoperative period to evaluate the technique's impact on nociception. The data collected will be statistically analyzed to compare efficacy among groups and the need for rescue analgesia. This study aims to determine the most effective and safest volume of bupivacaine for RSB, contributing to advances in regional anesthesia techniques and animal welfare. (AU)