Use of the rectus sheath block for perioperative analgesia in three foals undergoing omphalectomy and cystoplasty.

This study demonstrates the potential for a local anesthesia technique known as the rectus sheath block (RSB), to reduce pain in foals undergoing abdominal surgery. The research notes that this technique could be effective in providing analgesia during as well as after surgery, and that it may help reduce the need for general anesthesia.

Study Methodology

• The study focused on three foals that were undergoing omphalectomy and cystoplasty, which are surgical procedures involving the belly button area and bladder respectively. These surgeries were performed under general anesthesia.
• Before the surgeries, all the foals were premedicated intravenously with drugs known as xylazine and butorphanol.
• Anaesthesia was induced with ketamine and propofol and was maintained with isoflurane in 100% oxygen.
• The researchers then proceeded to use a technique known as a rectus sheath block (RSB), applying bupivacaine in doses of 0.25-0.3 mL per kg of weight per half of the abdomen. Bupivacaine was placed between the rectus abdominis muscle and its internal sheath. This method aims at desensitizing the midsection of the abdomen, thereby reducing pain.

Monitoring and Pain Management

• During the surgery, the research team closely monitored the foals’ responses to the surgical stimulus and their vital signs. If heart rate or mean arterial pressure increased by more than 20% from their baseline due to surgical stimuli, additional analgesia (butorphanol or ketamine) was given as a rescue measure.
• After the surgery, the team evaluated pain every 2 hours using a facial pain scale designed specifically for foals. This was done for 12 hours following the procedure.

Findings

• The study found that the technique appeared to successfully contribute to pain management before, during, and after surgery. In fact, the postoperative pain scores showed minimal discomfort for the foals, and no opioids were necessary after surgery.
• This suggests that using a rectus sheath block (RSB) can be an efficacious method of managing pain in foals undergoing serious abdominal surgeries and could potentially reduce their need for general anaesthesia.