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박봉석,이원용,임정현,나용준,김용한,김형수 대한흉부외과학회 2017 Journal of Chest Surgery (J Chest Surg) Vol.50 No.3
Outcomes of ventricular septal rupture (VSR) as a complication of acute myocardial infarction are extremely poor, with an in-hospital mortality rate of 45% in surgically treated patients and 90% in patients managed with medication. Delaying surgery for VSR is a strategy for reducing mortality. However, hemodynamic instability is the main problem with this strategy. In the present case, venoarterial extracorporeal membrane oxygenation (ECMO) was used to provide stable hemodynamic support before the delayed surgery. Awake ECMO was also used to avoiding the complications of sedatives and mechanical ventilation. Here, we describe a successful operation using awake ECMO as a bridge to surgery.
Surgical Outcomes for Native Valve Endocarditis
박봉석,이원용,나용준,이홍규,구병모,양준태 대한흉부외과학회 2020 Journal of Chest Surgery (J Chest Surg) Vol.53 No.1
Background: The aim of this study was to evaluate the short-term and long-term results of surgical treatment for native valve endocarditis (NVE) and to investigate the risk factors associated with mortality. Methods: Data including patients’ characteristics, operative findings, postoperative results, and survival indices were retrospectively obtained from Hallym University Sacred Heart Hospital. Results: A total of 29 patients underwent surgery for NVE (affecting the mitral valve in 20 patients and the aortic valve in 9) between 2003 and 2017. During the follow-up period (median, 46.9 months; interquartile range, 19.1.107.0 months), the 5-year survival rate was 77.2%. In logistic regression analysis, body mass index (p=0.031; odds ratio [OR], 0.574; 95% confidence interval [CI], 0.346.0.951), end-stage renal disease (ESRD) (p=0.026; OR, 24.0; 95% CI, 1.459.394.8), and urgent surgery (p=0.010; OR, 34.5; 95% CI, 2.353.505.7) were significantly associated with in-hospital mortality. Based on Cox proportional hazard regression analysis, the statistically significant predictors of long-term outcomes were hypertension, ESRD, and urgent surgery. Conclusion: Surgical treatment for NVE is associated with considerable mortality. The in-hospital mortality and 5-year survival rates of this study were 13.8% and 77.2%, respectively. Underlying conditions, including hypertension and ESRD, and urgent surgery were independent risk factors for unfavorable outcomes.
Adaptive Observer-based Trajectory Tracking Control of Nonholonomic Mobile Robots
박봉석,박진배,최윤호 제어·로봇·시스템학회 2011 International Journal of Control, Automation, and Vol.9 No.3
In this paper, an adaptive observer-based trajectory tracking problem is solved for nonholonomic mobile robots with uncertainties. An adaptive observer is first developed to estimate the unmeasured velocities of a mobile robot with model uncertainties. Using the designed observer and the back-stepping technique, a trajectory tracking controller is designed to generate the torque as an input. Using Lyapunov stability analysis, we prove that the closed-loop system is asymptotically stable with respect to the estimation errors and tracking errors. Finally, the simulation results are presented to validate the performance and robustness of the proposed control system against uncertainties.