Pneumothorax following serratus anterior plane block

Serratus anterior plane blocks may provide analgesia for rib fractures, thoracic surgery and breast surgery. There remains uncertainty regarding the location of injection, be it superficial or deep to the serratus anterior muscle. We describe the case of a 63-year-old ASA physical status 3 woman undergoing a wire-guided wide local excision of a right breast lump. A modified right serratus anterior plane block was performed under ultrasound guidance, injecting 20 ml of bupivacaine 0.25% deep to the serratus anterior muscle. No immediate complications were noted. Intra-operatively the patient developed arterial desaturation associated with high airway pressures. A subsequent chest radiograph in the post-anaesthetic care unit demonstrated a large right-sided pneumothorax which was treated with immediate needle decompression and chest drain insertion. This is the first case of pneumothorax reported from this approach to serratus anterior plane blockade and serves as a reminder of a potential serious complication.