What are the anesthetic considerations for abdominoperineal (abdomino perineal) resection?

Anesthetic Considerations for Abdominoperineal Resection

For abdominoperineal resection (APR), thoracic epidural anesthesia is strongly recommended as the primary anesthetic technique for open procedures due to superior pain relief and reduced respiratory complications compared to systemic opioids. 1

Preoperative Assessment and Preparation

• Evaluate for comorbidities that may affect anesthetic management, including history of neoadjuvant radiotherapy which may cause neuropathic pain requiring multimodal approaches 1
• Assess airway and risk factors for difficult intubation, especially in patients with obesity 1
• Consider preoperative optimization including smoking cessation to reduce wound complications 2
• Evaluate baseline respiratory function as APR is associated with significant tissue dissection and potential for respiratory complications 1

Intraoperative Anesthetic Management

Anesthetic Technique

• Use short-acting induction agents such as propofol combined with short-acting opioids (fentanyl, alfentanil, or remifentanil) 1
• Maintain anesthesia with short-acting inhalational agents (sevoflurane or desflurane) or total intravenous anesthesia (TIVA) 1
• Consider using bispectral index (BIS) monitoring to guide anesthetic depth, particularly in elderly patients to avoid excessive depth 1
• Ensure complete reversal of neuromuscular blockade before extubation using quantitative monitoring (train-of-four ratio ≥0.90) 1

Regional Anesthesia

• For open APR, thoracic epidural anesthesia (TEA) inserted at T7-10 level is recommended 1
• For APR with perineal component, standard thoracic epidural may not provide adequate coverage of perineal and sacral incisions 1
• Consider these options for perineal pain management:
  • Addition of morphine to bupivacaine in the thoracic epidural to increase spread 1
  • Combination of thoracic epidural (with local anesthetic only) plus systemic opioids for perineal pain 1
  • In selected cases, a separate lumbar epidural (L3-4) may be considered, though this carries risk of motor block and urinary retention 1

Alternative Analgesic Techniques

• For laparoscopic APR, consider:
  • Intravenous lidocaine infusion (1.5 mg/kg at induction followed by 2 mg/kg/h during surgery) 1
  • Transversus abdominis plane (TAP) blocks, though evidence is limited 1
  • Spinal anesthesia with long-acting opioids, though respiratory monitoring is required 1

Fluid Management

• Use goal-directed fluid therapy guided by cardiac output monitoring to maintain adequate gut perfusion 1
• Maintain mean arterial pressure with vasopressors once normovolemia is established to avoid fluid overload 1
• This is particularly important when using epidural anesthesia to maintain gut blood flow 1

Temperature Management

• Maintain normothermia with active warming devices and warmed intravenous fluids 1

Postoperative Pain Management

• For open APR, continue thoracic epidural analgesia for 48-72 hours 1
• Implement multimodal analgesia with paracetamol (acetaminophen) and NSAIDs/COX-2 inhibitors to reduce opioid requirements by up to 30% 1
• Be cautious with NSAIDs as some studies suggest a possible association between certain NSAIDs (ibuprofen, diclofenac, celecoxib) and anastomotic dehiscence 1
• For patients without epidural, consider:
  • Patient-controlled analgesia (PCA) with opioids 1
  • Continued intravenous lidocaine infusion 1
  • Local anesthetic wound catheters placed between fascia and peritoneum 1

Special Considerations

• APR involves extensive tissue dissection and creates a large dead space in the pelvis, predisposing to wound complications, especially after neoadjuvant chemoradiotherapy 3
• Perineal wound complications are common (reported in up to 50% of cases) and may require prolonged healing time 2, 3, 4
• Patients may have preoperative pain from neoadjuvant radiotherapy that is neuropathic in nature, requiring multimodal approaches 1
• Monitor for urinary retention and bladder dysfunction, which are common complications (reported in 25% of patients) 4
• Daily monitoring by an Acute Pain Team is recommended to optimize analgesia and facilitate mobilization while limiting side effects 1

Common Pitfalls and Caveats

• Up to one-third of epidurals may not function satisfactorily; test sensory block before induction and monitor daily 1
• For upper transverse incisions, epidural catheters should be inserted between T5-T8 root levels 1
• Epidural hypotension should be treated with vasopressors after confirming euvolemia to avoid fluid overload 1
• Perineal pain may not be adequately covered by standard thoracic epidural placement, requiring additional analgesic strategies 1
• Avoid deep anesthetic levels in elderly patients as this may increase risk of postoperative confusion 1
• Monitor blood glucose levels during surgery and maintain <10 mmol/l to reduce postoperative complications 1