Akihiko Oshita, MD, PhD, Masahide Shinzawa, MD, PhD, Masaru Sasaki, MD, PhD, Satoshi Inoue, MD, Yuta Kuroo, MD, Takuro Yamaguchi, MD, Hiroyuki Nakamura, MD, PhD, Yoichi Sugiyama, MD, PhD, Tatsuya Tazaki, MD, PhD, Mohei Kouyama, MD, PhD, Yuji Imamura, MD, PhD, Masakazu Nakao, MD, PhD, Astushi Nakamitsu, MD, PhD. JA Hiroshima General Hospital.
Objectives: Owing to the development of new surgical devices, laparoscopic liver resection (LLR) has become an alternative to the conventional open liver resection despite the difficult surgical technique required. In liver parenchymal transection, not only techniques and instruments, including portal triad occlusion, precoagulation, and endostaplers, but also high-pressure pneumoperitoneum has been used to control bleeding. However, high-pressure pneumoperitoneum has been reported to be associated with the risk of carbon dioxide (CO2) gas embolism, although this remains to be elucidated. This study is aimed to investigate that the right atrium monitoring using transesophageal echocardiography (TEE) could prevent life-threatening carbon dioxide gas embolism in LLR.
Methods: From January to September 2013, a total of 25 cases underwent LLR in our hospital. Among them, right atrium monitoring using TEE was performed in 19 cases without esophago-gastric varices. During hepatic parenchymal transection, bipolar coagulation, cavitron ultrasonic surgical aspirator, laparoscopic coagulating shears, and VIO soft-coagulation system containing a bipolar clamp (BiClamp) were used without portal triad clamping. The pneumoperitoneal pressure ranged from 8 to 12 mmHg during liver transection. CO2 gas was assessed as bubbles in the bicaval view on TEE. The severity of bubbles were classified into three groups: Grade 0, 5 or less in a still frame; Grade 1, more than 5 in a still frame; Grade 2, the frame is completely filled with bubbles.
Results: TEE revealed Grade 0 bubbles in 12 cases, Grade 1 in 5 cases, and Grade 2 in 2 cases. In 5 cases with Grade 1 bubbles, intra-operative course was uneventful. 4 cases had Grade 1 bubbles in pure LLR while only 1 case had even during open parenchymal transection in hybrid LLR. When one case had Grade 2 bubbles continuously observed due to the injury of a tributary of the middle hepatic vein, the oxygen saturation (SpO2) level abruptly decreased to 87%. Based on the report of the anesthesiologist that the TEE result indicated CO2 gas embolism, pure oxgen ventilation (6L/min) and compression hemostasis was performed immediately. Consequently, the bubbles completely disappeared on TEE, resulting in the improvement of the SpO2 level. Whereas, the other case with Grade 2 bubbles, temporally observed due to the injury of the subphrenic vein, was treated with prompt compression hemostasis, resulting in the stable vital signs. Moreover, in 1 case, TEE revealed a patent foramen ovale, that is a high risk of cerebral infarction in case of Grade 2 bubbles.
Conclusion: Right atrium monitoring using TEE could be useful for preventing the development of critical CO2 gas embolism in LLR. The immediate treatment would be an essential recommendation for cases with Grade 2 bubbles.