Puncture site bleeding complications of peripheral nerve block in patients taking antithrombotic and anticoagulant drugs: An umbrella review

background: While there are multiple guidelines for the management of bleeding complications and hematoma if being treated with antithrombotic and anticoagulant drugs, these risks are not yet stratified for procedures with regional anesthesia. Materials and Methods: This study was an umbrella review of systematic studies and meta-analysis based on PRISMA guidelines in databases of Scopus, PubMed, Medline, Cochrane Library, and Web of Science databases. Due to heterogeneity in evaluated outcomes and methods of studies, only the qualitative evidence synthesis was performed. AMSTAR checklist was used to assess the risk of bias in included systematic reviews. Results: After an extensive search of relevant studies, 971 primary cases were identified. Following a thorough screening process, 5 systematic reviews were selected. The evidence suggests that head and neck punctures generally do not result in bleeding complications, except for rare cases of hematoma associated with Infraclavicular brachial plexus block. A deep cervical plexus block is not recommended. Interscalene blocks have varying findings, with some studies reporting hematoma incidence and spinal injury, while others consider them low risk. Supraclavicular brachial plexus block might be associated with hemothorax and infraclavicular blocks are not favored by reviews. Axillary brachial plexus blocks have a minor incidence of hematoma. Abdomen blocks, TAP blocks, ilioinguinal blocks, and rectus sheath blocks carry a higher risk of hematoma. Pectoral nerve (PECS) blocks have a relatively high risk, while paravertebral and intercostal blocks are considered high risk, but further research is needed regarding paravertebral blocks. Conclusion: The available evidence from systematic reviews and studies suggests varying levels of risk for different blocks and procedures that should be considered before decision-making.