Magnesium-Enhanced ESPB for Respiratory Recovery and Analgesia in Unilateral Rib Fractures

Chest wall trauma is a major cause of morbidity among trauma patients. Rib fractures are associated with severe pain, impaired ventilation, reduced cough efficiency, secretion retention, prolonged hospital stay, and increased mortality. Rib fractures are also associated with concomitant thoracic injuries, head, extremity, abdominal, and blunt cardiac injuries. These patients have poor overall clinical outcomes and are at increased risk for multiple complications. Thoracic complications of rib fractures are common, including pneumonia, pulmonary effusion, aspiration, acute respiratory distress syndrome (ARDS), pulmonary emboli, and atelectasis or lobar collapse. these complications are important as targeted interventions may enable risk reductions. Effective analgesia is therefore a cornerstone in the management of chest trauma. Systemic opioids have traditionally been used for pain management; however, their use is associated with respiratory depression, sedation, nausea, vomiting, and impaired pulmonary rehabilitation. Regional anesthesia techniques have emerged as valuable alternatives that provide effective analgesia while minimizing opioid-related adverse effects. The ultrasound-guided erector spinae plane block (ESPB), first described by Forero, is a fascial plane block in which local anesthetic is deposited deep to the erector spinae muscle adjacent to the transverse process. ESPB has demonstrated efficacy in thoracic surgery, breast surgery, and rib fracture analgesia, improving pain scores and respiratory mechanics. Magnesium sulfate (MgSO₄) possesses antinociceptive properties through antagonism of N-methyl-D-aspartate (NMDA) receptors and modulation of calcium influx. As an adjuvant to local anesthetics, magnesium sulfate has been shown to prolong analgesia and reduce opioid requirements in various regional anesthesia techniques. Recent ESPB studies and systematic reviews have suggested improved analgesic efficacy when magnesium sulfate is added to local anesthetics. However, there is currently limited evidence regarding the role of magnesium sulfate as an adjuvant to ESPB specifically in patients with unilateral rib fractures. Therefore, this study aims to investigate whether adding magnesium sulfate to bupivacaine in ESPB improves analgesic outcomes and respiratory recovery in this patient population.

Inclusion Criteria: Age 18-65 years. ASA physical status I-II. Patients with 2-5 unilateral rib fractures confirmed radiologically. Stable hemodynamics Exclusion Criteria: Patient refusal. Bilateral rib fractures or flail chest. Severe head, abdominal, or spinal injury Contraindications to regional anesthesia (coagulopathy, local infection). Known allergies to amide local anesthetics or magnesium sulfate. Severe traumatic brain injury. Heart block or severe hepatic or renal impairment.