Erector Spinae Plane vs Serratus Anterior Plane Catheter Infusions for Acute Pain Management in Patients With Traumatic Rib Fractures

Rib fractures happen in about 10-20% of patients with blunt trauma and can be serious, with higher death rates in older adults. These injuries often lead to lung problems like pneumonia, collapsed lung areas (atelectasis), fluid buildup, or even respiratory failure. A major reason for this is pain-patients avoid deep breathing and coughing, which worsens lung function. Good pain control helps prevent these complications. Opioids are commonly used for pain but can cause problems such as slowed breathing, delirium, nausea, and longer time on a ventilator. Because of this, regional anesthesia (nerve blocks) is increasingly used to control pain while reducing opioid use. Common options include epidurals, paravertebral blocks, and newer techniques like erector spinae plane (ESP) and serratus anterior plane (SAP) blocks. Continuous catheter techniques are especially useful in trauma patients because they can provide ongoing pain relief and have fewer contraindications than epidurals. The SAP block is done at the side of the chest and works well for rib fractures in the front and side. It may not work as well for fractures in the back, although trauma may sometimes allow the anesthetic to spread further than expected. The ESP block is done near the spine and may cover a broader area, including both front and back of the chest. It is relatively easy to perform at the bedside and is considered safe. Studies suggest it provides pain relief similar to epidurals in some patients. There is still limited evidence directly comparing continuous SAP and ESP catheters. Only one study (using single injections) suggests ESP may provide better pain relief. It is unclear whether that difference holds true with continuous infusions, or whether SAP might be preferable because it is easier and quicker to perform. We propose a randomized trial comparing continuous ESP and SAP catheters in patients with rib fractures to determine which provides better pain control, reduces opioid use, improves breathing outcomes, and is easier to perform in routine practice. Our hypotheses are that ESP will provide better pain relief, SAP will be easier and safer to place, and both techniques will reduce opioid use while maintaining good patient comfort and breathing.

Inclusion Criteria: * Age \>18; * Traumatic rib fractures (unilateral or bilateral); * Minimum of 3 rib fractures per side; * Admitted to hospital for \ 4 at rest or with movement for chest pain at the time of eligibility assessment Exclusion Criteria: * Severe traumatic brain injury (Glasgow Coma Scale \< 9); * Surgery performed/planned within 72 hours of catheter infusion start; * Uncontrolled coagulopathy; * Skin infection or anatomical abnormality (i.e. open fracture) at insertion sites; * Allergy to local anesthetic; * Chronic high dose opioid use preadmission (Morphine Equivalent Dose \> 30mg per day); * Pregnancy; * Acute respiratory failure requiring intubation at enrolment; * Inability to comply with Intravenous Patient-Controlled Analgesia use; * Contraindications to nerve blocks * High likelihood of loss to follow-up