Biomechanics are gaining ground in gastroenterology in the creation of educational models and to describe the necessary forces to perforate hallow organs during endoscopy. We thus investigated the breaking forces of porcine intestinal segments and whether they could be predicted based on body weight or crown–rump length. Based on a priori power-analyses, 10 pigs were included. The breaking forces were determined with a motorized test stand. We found that the breaking forces of intestinal segments were different (H(6) = 33.7, p < 0.0001): Ileal breaking force ($\overline{\mathrm{x}}$ = 24.14 N) was higher than jejunal ($\overline{\mathrm{x}}$ = 14.24 N, p = 0.0082) and colonic ($\overline{\mathrm{x}}$ = 11.33 N, p < 0.0001) breaking force. The latter was also smaller than cecal breaking force ($\overline{\mathrm{x}}$ = 24.6 N, p = 0.0044). Likewise, rectal ($\overline{\mathrm{x}}$ = 23.57 N) breaking force was higher than jejunal (p = 0.0455) and colonic (p = 0.0006) breaking force. Breaking forces were not correlated to body weight or crown–rump length (R < 0.49, p > 0.148). Intestinal segments differ in their breaking forces. The colon had the least resistance to traction forces. It remains to be determined if similar relationships exist in humans in order to validate porcine models for endoscopy and surgery.

Background: Palliative surgery for the treatment of functionally univentricular heart malformations consists of a staged approach to separation of the pulmonary and systemic circulation, including the creation of a superior cavopulmonary connection. Literature on the superior cavopulmonary connection in porcine models lacks information on details of the procedure as well as data on its acute hemodynamic effects. In preliminary experiments, we were unable to reproduce an already published porcine model. Therefore, we used a conduit extension and cardiopulmonary bypass in order to achieve hemodynamic stability and still employ the commonly used straight downward pathway for the superior caval vein onto the right pulmonary artery, as in the human clinical setting. This model of a univentricular circulation utilising the superior cavopulmonary anastomosis is intended to be applied in the setting of unilateral diaphragmatic palsy. Hence, we aim to investigate the effect of unilateral diaphragmatic pacing in a reproducible model of univentricular physiology. Methods: Therefore, we constructed an anastomosis between the superior caval vein and the right pulmonary artery (RPA) in 14 pigs on cardiopulmonary bypass using a 12 mm expanded polytetrafluorethylene interposition graft. Six pigs received a bidirectional cavopulmonary connection with unrestricted atrial septal communication (BDCPC), while eight pigs received a unidirectional cavopulmonary connection (UDCPC) to the excluded RPA. Results: The BDCPC resulted in an impaired cardiopulmonary state (cardiac output dropped from 3.15 ± 0.21 to 2.17 ± 0.19 L/min; p < 0.01), mean arterial pressure plummeted (from 80.8 ± 3.7 to 49.3 ± 7.3 mmHg; p = 0.02), arterial lactate concentration rose (from 0.82 ± 0.09 to 4.36 ± 0.96 mmol/L; p = 0.01), arterial oxygen saturation dropped (from 95.8 ± 1.1 to 60.9 ± 10.4%; p < 0.01), and right ventricular function deteriorated (tricuspid annular plane systolic excursion decreased from 12 ± 0.7 to 5 ± 0.7 mm; p < 0.01). In contrast, in the UDCPC group, the cardiopulmonary parameters indicated a stable condition. Conclusions: Consequently, a UDCPC is a more suitable acute model in pigs for a univentricular circulation. The model’s reproducibility may aid in future research on partial cavopulmonary connection.