OBJECTIVE: To describe the use of intraoperative transsplenic injection of agitated saline (TIAS) and confirm temporarily full attenuation of extrahepatic portosystemic shunt (EHPSS) in dogs. STUDY DESIGN: Retrospective case series. ANIMALS: A total of 40 dogs. METHODS: Medical records of dogs that underwent surgical attenuation of EHPSS between January 2014 and May 2021 were reviewed. A ventral midline celiotomy was performed, the EHPSS identified and dissected, and temporal occlusion performed using Rummel tourniquets or silicone vascular loops. A wide range microconvex transducer was used to visualize the right atrium via a subxiphoid acoustic window. Agitated saline was injected into the splenic parenchyma while the right atrium was ultrasonographically monitored before and after temporary occlusion of the EHPSS. Case details, intra- and postoperative findings, and long-term outcome were recorded. RESULTS: The agitated saline was immediately identified within the right atrium after injection into the splenic parenchyma before temporary occlusion of the EHPSS in all cases. After temporary occlusion, the agitated saline was not observed within the right heart, except in two dogs in which a second vessel bypassing the liver circulation was identified. No intra- or postoperative complications were recorded. Long-term clinical outcome was considered good to excellent in all cases. CONCLUSION: Intraoperative TIAS confirmed temporary full attenuation of EHPSS. CLINICAL SIGNIFICANCE: Intraoperative TIAS is an easy, safe and reproducible technique to assess intraoperative full occlusion of EHPSS.