Comparison of Intermittent Bolus vs. Continuous Infusion PENG Block for Postoperative Pain in Hip Surgery

Postoperative pain management after hip surgery remains a critical factor in recovery quality, opioid consumption, and overall patient outcomes. Among regional anesthesia techniques, the PENG Block is increasingly utilized for pain control due to its ability to provide effective analgesia while minimizing systemic opioid use. However, the optimal administration method of PENG block remains unclear.

This retrospective cohort study evaluates the effectiveness of two different PENG block administration techniques in patients undergoing hip surgery:

• Intermittent Bolus Group: A researcher manually administered 20 mL of 0.25% bupivacaine every 4 hours via a catheter placed under ultrasound guidance at the end of surgery.
• Continuous Infusion Group: A pump delivered 5 mL/hour of 0.25% bupivacaine continuously via a catheter placed under ultrasound guidance at the end of surgery.

Total local anesthetic volume over 24 hours was equal in both groups.

Study Objectives:

The primary objective is to compare intermittent bolus vs. continuous infusion PENG block administration in terms of:

• Postoperative pain control (Visual Analog Scale) (VAS scores)
• Total opioid consumption (morphine equivalent)
• Time to first rescue analgesia
• Quality of recovery (QoR-15 at 24 hours postoperative)

Secondary outcomes include:

• Postoperative nausea and vomiting (PONV)
• Incidence of complications (hematoma, infection, nerve injury)

This study aims to provide evidence on whether intermittent bolus or continuous infusion leads to better pain relief, reduced opioid consumption, and improved recovery in hip surgery patients.

Inclusion criteria

Participants must meet all of the following criteria to be included in the study:

• Patients who underwent hip surgery between November 15, 2023 - November 15, 2024.
• Patients who received Pericapsular Nerve Group (PENG) Block via a catheter for postoperative analgesia.
• Patients who received Patient-Controlled Analgesia (PCA) with tramadol.
• Patients aged 18 to 65 years.
• ASA I - III classification.
• BMI ≤ 35 kg/m². Exclusion Criteria

Participants who meet any of the following criteria will be excluded from the study:

• Patients who received analgesia with techniques other than PENG block.
• Patients with incomplete or missing medical records.
• Patients with a psychiatric illness diagnosis that may interfere with pain perception or reporting.
• Patients with coagulation disorders (e.g., INR >1.5, thrombocytopenia).
• Patients with hepatic or renal failure (Creatinine clearance <30 mL/min or AST/ALT >3x normal).
• Patients with chronic opioid use before surgery.