Einfluss der Kompression auf dei Berstdrücke nach bipolarer Gefäßversiegelung - Untersuchung an einem ex vivo Modell der Pulmonalarterie

Background: With the bipolar sealing system arteries and veins can be sealed and divided in one step. By closing the instrument’s jaws a defined compression force is generated, so the collagen and fibrin fibres in the vascular wall are pressed together. The subsequent coagulation process causes the fibres to coalesce. In this paper an ex vivo pulmonary artery model is used to investigate, which impact the compression force and compression duration has on the bursting pressure achieved. Material and methods: The experiments were performed on pulmonary arteries of pigs. Firstly the whole pulmonary artery was exposed from the pulmonary valve up to the periphery of the left lung of heart-lung preparations, which were removed at a slaughterhouse. In order to measure the bursting pressure (in mbar) a digital pressure sensor was implanted. Vessels of different diameter were examinated: 1-6 mm, 7-12 mm and >12 mm. After bipolar sealing, bursting pressures were determined by pneumatic testing. We used the bipolar sealing device MARSEAL® (Gebrüder Martin GmbH & CoKG, Tuttlingen, Germany), SealSafe® G3 electric current and three different jaw compression forces (35N, 45N and 55N). With 35N compression bursting pressures were also measured after different compression durations (0s, 5s, 10s and 20s). After completing the experiments the mean bursting pressure was measured for each group (n=15) and the groups were compared to each other using a non-parametric test (Mann-Whitney U test). The significance level was p<0,05. Results: Mean bursting pressures in the 1-6 mm blood vessels were 290.5 ± 77.1 mbar (35N), 323.0 ± 76.0 mbar (45N) and 301.6 ± 69.9 mbar (55N). The groups did not differ significantly. Mean bursting pressures in the 7-12 mm vessels were 108.1 ± 19.1 mbar (35N), 154.3 ± 28.5 mbar (45N) and 212.4 ± 45.3 mbar (55N). In blood vessels > 12 mm in diameter we found mean bursting pressures of 77.7 ± 11.7 mbar (35N), 117.6 ± 27.1 mbar (45N) und 166.3 ± 56.6 mbar (55N). The results for the groups with 55N compression were significantly higher than for the other groups. A compression duration of 5s led to significantly higher mean bursting pressures than a duration of 0 s but a duration of > 5s did not bring a further significant increase in mean bursting pressure. Histological staining (HE) of the seal zone and microscopic examination did not reveal any differences relating to compression force. Conclusion: By increasing the compression force, higher burst pressures can be measured in particular for blood vessels of larger diameter. A compression of 5s before starting coagulation has also a positive effect on the stability of the sealing. A longer compression however causes no further advantage.