Atracurium Besylate

A 33-kg adult Labrador Retriever dog presented for investigation of pneumothorax. A computed tomography scan confirmed the diagnosis, and right lateral thoracotomy and lung lobectomy were performed under general anaesthesia. During surgery, anaesthesia was maintained with a propofol constant-rate intravenous (IV) infusion (premedication with methadone and dexmedetomidine) and IV atracurium was given to facilitate surgery. A lumbosacral epidural injection of preservative-free morphine (0.3 mg kg^-1 diluted to 6.6 mL with sterile saline) was performed. Using a spinal needle, the 'hanging drop' method of detecting the epidural space was attempted but the saline drop was not aspirated, and cerebrospinal fluid entered the needle hub, indicating inadvertent dural puncture. The needle was partially withdrawn and a lack of resistance to injection confirmed before injection of morphine. Following injection, myoclonus of the tail was observed throughout surgery, continuing after atracurium administration. Following surgery, the propofol infusion was reduced from 0.3 to 0.1 mg kg^-1 minute^-1 to encourage spontaneous ventilation after confirmation of neuromuscular function. Spontaneous ventilation, swallow and palpebral reflexes did not return. The following treatments were unsuccessful in eliciting spontaneous ventilation: allowing end-tidal CO₂ to increase [up to 60 mmHg (8 kPa)], reducing inspired oxygen fraction to 0.4, injection of neostigmine and glycopyrrolate, and stopping propofol delivery. Three doses of butorphanol (each 0.5 mg kg^-1 IV) were given 30 minutes apart to antagonize the effects of morphine as it was suspected that inadvertent intrathecal injection had been performed. Butorphanol administration was associated with return of spontaneous ventilation, palpebral and swallow reflexes, and full recovery from anaesthesia. Continuous rate infusions of butorphanol and dexmedetomidine were used for 12 hours to treat any residual respiratory depression and provide sedation to manage continued myoclonus. Myoclonus resolved within 24 hours. The dog was discharged 3 days later and suffered no ongoing adverse effects.

Cardiohepatic syndrome (CHS) presents a significant challenge in perioperative management due to the complex interaction between liver and heart dysfunction. CHS, analogous to cardiorenal syndrome, encompasses various conditions where hepatic and cardiovascular pathologies exacerbate one another. Patients with chronic liver disease, cirrhosis, or heart failure often exhibit increased perioperative morbidity and mortality, necessitating tailored anesthetic strategies. A comprehensive understanding of CHS pathophysiology is crucial, as it informs risk assessment and guides perioperative management. Risk stratification tools such as the Child-Pugh and MELD scores are commonly used, but they have limitations in fully capturing perioperative risks. The updated STS 2024 model includes liver-specific parameters, improving risk prediction in cardiac surgeries. Additionally, the VOCAL-Penn score addresses gaps in traditional risk models, providing a more accurate assessment for patients with advanced liver disease. Perioperative management focuses on minimizing hemodynamic stress and avoiding drugs metabolized by the liver. Agents like Remifentanil, Atracurium, and Esmolol are preferred for their minimal hepatic metabolism. Vasopressors such as terlipressin and vasopressin, which target the splanchnic circulation, improve hemodynamics in these patients. Within the Enhanced Recovery After Surgery (ERAS) framework, optimizing nutrition and fluid management is essential for reducing perioperative complications. Effective management of patients with CHS requires a multidisciplinary approach that integrates comprehensive risk assessment and individualized anesthetic strategies. This approach improves outcomes by reducing perioperative complications and mortality in this high-risk population.