We demonstrate a large chest wall hematoma involving the serratus anterior muscle with an extension between the pectoralis major and minor muscles. The images (fig. 1, A–D) are noncontrast chest computed tomography scans in the axial and coronal planes, showing the hematoma, noted 1 day after an uneventful and smooth removal of bilateral deep serratus anterior plane block catheters in a 61-yr-old man who had a bilateral orthotopic lung transplant 8 days before and needed continuous infusion of heparin due to a history of deep vein thrombosis. The catheters were placed on postoperative day 1 under direct ultrasound guidance and removed on postoperative day 8 in adherence with institutional and American Society of Regional Anesthesia and Pain Medicine anticoagulation guidelines for placement and removal of peripheral nerve catheters.  The heparin infusion was stopped 4 h before removal and restarted 6 h after. Chest wall hematoma was first managed conservatively; however, he had persistent chest wall swelling, pain with respiration and movement, intermittent usage of vasopressors, and transfusion of red blood cells. The repeated chest computed tomography in 7 days showed a slight increase in the size of the hematoma. It was then evacuated, and the patient had an extended hospital stay.

Fig. 1.
Computed tomography of serratus anterior muscle hematoma (14.4 × 6.2 × 16.1 cm) in axial (A and C) and coronal (B and D) planes. Red arrows demark hematoma, green line outlines serratus anterior muscle.

Computed tomography of serratus anterior muscle hematoma (14.4 × 6.2 × 16.1 cm) in axial (A and C) and coronal (B and D) planes. Red arrows demark hematoma, green line outlines serratus anterior muscle.

The serratus anterior plane block is considered for postthoracotomy patients, especially in patients with altered hemostasis.  The authors believe that the absence of previous bleeding reports from this block may lead experts to rate the serratus anterior plane block as a peripheral nerve block with an intermediate bleeding risk. Despite adherence to the recommended guidelines and atraumatic placement of the serratus anterior plane block, the possibility of a chest wall hematoma should be considered after this block with persistent severe pain and swelling, especially with anticoagulation therapy continuing. Chest computed tomography scan and angiography can effectively diagnose this complication.  Stable chest wall hematoma after this block may be managed conservatively. However, an expanding chest wall hematoma after this block, especially with hemoglobin drop, vasopressors requirement, and worsening clinical picture, may prompt intervention. Treatment is similar to traumatic chest wall hematoma and includes minimally invasive angiography with embolization or surgical evacuation of the hematoma.