What is the recommended protocol for performing continuous local anesthetic wound infiltration?

Continuous Local Anesthetic Wound Infiltration Protocol

Continuous local wound infusion catheters should be placed in the pre-peritoneal or subcutaneous space above the fascia at the end of surgery, with 0.2% ropivacaine infused at 6 ml/hour for 48 hours to provide effective postoperative analgesia. 1, 2

Catheter Placement Technique

Positioning and Insertion

• Insert a multi-hole, 20-gauge catheter percutaneously above the fascia in the pre-peritoneal or subcutaneous space at the end of the surgical procedure 2
• The catheter should be positioned to cover the entire length of the surgical wound 2
• Aspirate the catheter prior to injection to avoid intravascular administration 1

Initial Bolus Dose

• Administer an initial bolus of 10 ml of 0.2% ropivacaine through the catheter immediately after placement 2
• This provides immediate local anesthetic effect before starting the continuous infusion 2

Continuous Infusion Protocol

Anesthetic Agent and Concentration

• Use 0.2% ropivacaine as the primary agent for continuous wound infiltration 2
• Ropivacaine is preferred over bupivacaine due to lower systemic toxicity, allowing higher doses 3
• The FDA label supports ropivacaine for local infiltration at concentrations up to 5 mg/mL (0.5%), though 0.2% is most commonly used for continuous infusion 4

Infusion Rate and Duration

• Initiate continuous infusion at 6 ml/hour of 0.2% ropivacaine 2
• Continue infusion for 48 hours postoperatively 2
• This provides total delivery of approximately 288 ml over 48 hours (12 mg/hour or 576 mg total) 2

Maximum Dosing Guidelines

Adults

• For wound infiltration: maximum 1 ml/kg of 0.25% bupivacaine (2.5 mg/kg) or 1.5 ml/kg of 0.2% ropivacaine (3 mg/kg) as single-shot infiltration 1
• For continuous infusion with ropivacaine: the 6 ml/hour rate at 0.2% concentration (12 mg/hour) remains well below toxic thresholds when distributed over 48 hours 2

Pediatric Patients

• Maximum 1 ml/kg of 0.25% bupivacaine (2.5 mg/kg) for single-shot wound infiltration 1
• Maximum 1.5 ml/kg of 0.2% ropivacaine (3 mg/kg) for single-shot wound infiltration 1

Safety Monitoring and Precautions

Toxicity Prevention

• Use the lowest effective dose to minimize risk of local anesthetic systemic toxicity (LAST) 1
• Aspirate before each injection or bolus to prevent intravascular administration 1
• Continuously monitor patients for early signs of toxicity: perioral numbness, metallic taste, tinnitus, confusion, or seizures 1

Infection Risk

• Pre-peritoneal catheters are not associated with increased surgical site infection risk 1
• However, catheters retained in situ do carry theoretical infection risk with prolonged use beyond 48-72 hours 5

Catheter Removal Planning

• Establish a planned removal process with institution of appropriate alternative analgesia before discontinuing the catheter 1
• Transition to oral or parenteral analgesics should begin before catheter removal to prevent pain breakthrough 1

Clinical Efficacy Outcomes

Pain Reduction

• Continuous wound infusion significantly decreases visual analog pain scores at rest and with activity at 6,12,24, and 48 hours postoperatively 1
• Pain scores at 12 hours are significantly lower compared to patient-controlled analgesia (PCA) alone 1

Opioid-Sparing Effect

• Consistently reduces total opioid consumption and rescue analgesic requirements 1, 2
• This technique should be incorporated as part of multimodal analgesia rather than sole analgesic strategy 1

Functional Recovery

• Patients experience improved ambulation time and earlier return of intestinal function 1, 2
• Respiratory function shows trends toward improvement, though not always statistically significant 2

Common Pitfalls to Avoid

• Do not place catheters in patients with active surgical site infection or systemic sepsis 1
• Avoid in patients on therapeutic anticoagulation without appropriate risk assessment 1
• Do not exceed maximum dosing limits when combining continuous infusion with other local anesthetic techniques (e.g., TAP blocks, epidurals) 1
• Ensure catheter is secured properly to prevent dislodgement during patient movement 2
• Do not abruptly discontinue infusion without transitioning to alternative analgesia 1