No abstract

Background. Myocardial ischemia-reperfusion injury (MIRI) is a very common adverse reaction after cardiac valve replacement (CVR) under cardiopulmonary bypass, which seriously affects the rehabilitation and prognosis of patients. Objective. The prevention and treatment of MIRI are a hotspot of modern medical research, and this study is aimed at providing reliable reference and guidance for future clinical prevention and treatment of MIRI by analyzing the effects of ulinastatin (UL) on cardiac function and MIRI of patients after CVR. Methods. A total of 104 patients undergoing CVR under cardiopulmonary bypass in our hospital were selected as research participants. Among them, 52 patients treated with UL were assigned to the observation group, and the rest 52 patients given the same amount of normal saline were assigned to the control group. The cardiopulmonary bypass status, postoperative status, cardiac function, inflammatory response, oxidative stress response, and hemodynamics were observed and compared between the two groups. In addition, clinical efficacy and safety and patient prognosis were compared. Results. Through experimental analysis, we found that UL had no significant effect on the clinical efficacy, safety, and prognosis of patients after surgery ( P > 0.05 ) but had obvious protective effects on cardiopulmonary bypass status, cardiac function, inflammation, oxidative stress, and hemodynamics ( P < 0.05 ). Conclusion. UL can effectively prevent the occurrence of MIRI after CVR under cardiopulmonary bypass, which is worthy of clinical application.

Background During total aortic arch replacement surgery (TARS) for patients with acute type A aortic dissection, the organs in the lower body, such as the viscera and spinal cord, are at risk of ischemia even when antegrade cerebral perfusion (ACP) is performed. Combining ACP with retrograde inferior vena caval perfusion (RIVP) during TARS may improve outcomes by providing the lower body with oxygenated blood. Methods This study is designed as a multicenter, computer-generated, randomized controlled, assessor-blind, parallel-group study with a superiority framework in patients scheduled for TARS. A total of 636 patients will be randomized on a 1:1 basis to a moderate hypothermia circulatory arrest (MHCA) group, which will receive selective ACP with moderate hypothermia during TARS; or to an RIVP group, which will receive the combination of RIVP and selective ACP under moderate hypothermia during TARS. The primary outcome will be a composite of early mortality and major complications, including paraplegia, postoperative renal failure, severe liver dysfunction, and gastrointestinal complications. All patients will be analyzed according to the intention-to-treat protocol. Discussion This study aims to assess whether RIVP combined with ACP leads to superior outcomes than ACP alone for patients undergoing TARS under moderate hypothermia. This study seeks to provide high-quality evidence for RIVP to be used in patients with acute type A aortic dissection undergoing TARS. Trial registration Clinicaltrials.gov, ID: NCT03607786 . Registered on 30 July 2018. Electronic supplementary material The online version of this article (10.1186/s13063-019-3319-2) contains supplementary material, which is available to authorized users.

In this paper, a disturbance-observer-based composite anti-disturbance control method is proposed for landing control of the carrier-based UAV subject to both external and internal disturbances. By the virtue of the composite control scheme, two nested loops are simultaneously designed. In the inner loop, disturbance observers are employed to estimate the effect of disturbances. On the other hand, in the outer loop, the sliding mode control (SMC) is designed to attenuate both the disturbance estimation error and guarantee the control performance. Then, with the disturbance estimation provided by the disturbance observer, the composite anti-disturbance controller is designed to achieve disturbance compensation and attenuation using both the feed-forward and feed-back channels. Besides, the stability of overall closed-loop is analyzed via Lyapunov theory. Finally, simulation results are presented to demonstrate the effectiveness of the proposed method.