Chun Soo Park

Assembly block storage location assignment at a shipyard: a case of Hyundai Heavy Industries

It is not a trivial issue how to manage assembly blocks at a shipyard. Based on the project experience in Hyundai Heavy Industries, currently the largest shipbuilding company in the world and the leader in the Korean merchant shipbuilding industry, this study points out the difficulties on the block stockyard operations, formalises the assembly block storage location assignment problem, and develops the assembly block storage location assignment algorithm, the purpose of which is to reduce the number of unproductive block moves. Through simulation experiments for various situations, this study demonstrates the usefulness of the assembly block storage location assignment algorithm. In addition, this study examines the impacts of block move sequence rules and of block stockyard layouts on the block stockyard operations.

The significance of pulmonary annulus size in the surgical management of transposition of the great arteries with ventricular septal defect and pulmonary stenosis.

OBJECTIVE Aortic translocation has received growing attention in the management of complete transposition with ventricular septal defect and pulmonary stenosis, but the criteria regarding pulmonary stenosis for selecting this option have yet to be established. The aim of this study is to evaluate the significance of pulmonary annulus size with the outcome after the arterial switch operation. METHODS Between November 1996 and September 2008, 250 patients underwent the arterial switch operation for complete transposition. Among them, 8 patients with a pressure gradient greater than 30 mm Hg, bicuspid pulmonary valve, and an aortic Z-score of the pulmonary annulus less than 0 were included in this retrospective study. The median age was 19.1 months (range, 0.5-80.0 months). The median follow-up was 39.7 months (range 9.1-139.5 months). RESULTS At latest follow-up, the Z-score of the neoaortic annulus increased from -1.50 + or - 1.13 (range, -3.42 to -0.35) to 1.10 + or - 1.15 (range, -0.8 to 2.10) (P < .01). No patient had a significant pressure gradient across the left ventricular outflow tract. There was 1 early death and there were no late deaths. Two reoperations were performed in 1 patient for neoaortic stenosis at 81 months and 110 months after the operation. Latest echocardiogram revealed grade 0 or 1 neoaortic insufficiency. CONCLUSION It was possible to extend the indication for the arterial switch operation with acceptable outcome to the patient with a Z-score of about -3 of the pulmonary annulus despite bicuspid pulmonary valve. Inasmuch as the arterial switch operation has benefits over the other options, a large-scale study is required for more reasonable triage in this group of patients.

Steel stock management on the stockyard operations in shipbuilding: a case of Hyundai Heavy Industries

As the largest shipbuilding company in the world and the leader in the Korean merchant shipbuilding industry, Hyundai Heavy Industries is currently struggling to carry out intensive productivity improvements. These are needed in order to be the global merchant shipbuilding market leader by surpassing the competition from Japan and the threat from China armed with very cheap labour costs. This paper introduces the academy and industry collaborative project, part of the productivity improvement efforts conducted on the steel stockyard operations. As a pilot project it researched a way of improving the stockyard operations and future projects on the stockyard operations. The project defined the stockyard operations, measured current situations, and analysed operational difficulties. In addition, the project developed the steel stockyard operations simulator. Besides the simulator used by the operations manager, who has relied heavily on his work-experienced intuition when making decisions, this paper expects that further projects on the stockyard operations utilise the simulator for their own purposes.

Usefulness of the maximum rate of pressure rise in the central and peripheral arteries after weaning from cardiopulmonary bypass in pediatric congenital heart surgery: A retrospective analysis

Abstract The maximum rate of pressure rise (dP/dtmax) in radial artery has been proposed as a noninvasive surrogate of aortic dp/dtmax, reflecting left ventricular (LV) contractility in children. The aim of this study was to investigate relationship between aortic and radial dp/dtmax at weaning from cardiopulmonary bypass (CPB) and usefulness of these indices for estimating postoperative outcomes in pediatric congenital heart surgery. Aortic and radial arterial pressure waveforms were analyzed simultaneously during weaning from CPB in 29 congenital heart surgery. The maximum first derivatives of aortic and radial arterial waveforms were calculated and averaged from 3 consecutive respiratory cycles. We obtained the maximum vasoactive inotropic score during the first 36 postoperative hours, LV ejection fraction, and fractional shortening on transthoracic echocardiography performed within postoperative day 7. A significant difference between aortic and radial dP/dtmax was observed (mean difference 356 mm Hg/s, 44% of averages), and radial dP/dtmax was weakly correlated with aortic dP/dtmax (r =0.373, P = 0.047). Aortic dP/dtmax was significantly associated with the maximum vasoactive inotropic score (P < 0.001), postoperative LV ejection fraction (P = 0.018), and fractional shortening (P = 0.015); however, radial dP/dtmax was not. On Receiver operating characteristic analysis, aortic dP/dtmax had a greater area under the curve than radial dP/dtmax in predicting higher vasoactive inotropic score (0.827 vs 0.673). Immediately after CPB in pediatric congenital heart surgery, radial dP/dtmax may not replace aortic dP/dtmax because of a discrepancy between central and peripheral arterial waveforms. In this critical period, aortic dP/dtmax can be useful to estimate postoperative ventricular function rather than peripherally derived dP/dtmax.

Cardiac Resynchronization Therapy in Infant with Dilated Cardiomyopathy during Extracorporeal Membrane Oxygenator

Although heart transplantation is a final therapeutic option in pediatric patients with dilated cardiomyopathy (DCMP), the shortage of pediatric heart donors is a major obstacle. In adults with DCMP characterized by cardiac dyssynchrony, cardiac resynchronization therapy (CRT) is known to be an effective treatment option. However, there is a lack of evidence on the effectiveness of CRT in infants with DCMP. Several studies have reported improvement in hemodynamics and cardiac performance following CRT in infants with DCMP. Here, we report CRT in an infant with DCMP during extracorporeal membrane oxygenation with 5 months of follow-up.

Surgical Reconstruction for High-Output Chylothorax Associated with Thrombo-Occlusion of Superior Vena Cava and Left Innominate vein in a Neonate

We report a case of high-output chylothorax associated with thrombo-occlusion of the superior vena cava (SVC) and left innominate vein (LIV) following an arterial switch operation in a neonate. The chylothorax was resolved by 3 weeks after surgical reconstruction of the SVC and LIV using fresh autologous pericardium. We confirmed the patency of the SVC and LIV with a 1-year follow-up computed tomographic scan at our outpatient clinic.

Heart Transplantation in Patients with Superior Vena Cava to Pulmonary Artery Anastomosis: A Single-Institution Experience

Background Heart transplantation (HTx) can be a life-saving procedure for patients in whom single ventricle palliation or one-and-a-half (1½) ventricle repair has failed. However, the presence of a previous bidirectional cavopulmonary shunt (BCS) necessitates extensive pulmonary artery angioplasty, which may lead to worse outcomes. We sought to assess the post-HTx outcomes in patients with a previous BCS, and to assess the technical feasibility of leaving the BCS in place during HTx. Methods From 1992 to 2017, 11 HTx were performed in patients failing from Fontan (n=7), BCS (n=3), or 1½ ventricle (n=1) physiology at Asan Medical Center. The median age at HTx was 12.0 years (range, 3–24 years). Three patients (27.3%) underwent HTx without taking down the previous BCS. Results No early mortality was observed. One patient died of acute rejection 3.5 years after HTx. The overall survival rate was 91% at 2 years. In the 3 patients without BCS take-down, the median anastomosis time was 65 minutes (range, 54–68 minutes), which was shorter than in the patients with BCS take-down (93 minutes; range, 62–128 minutes), while the postoperative central venous pressure (CVP) was comparable to the preoperative CVP. Conclusion Transplantation can be successfully performed in patients with end-stage congenital heart disease after single ventricle palliation or 1½ ventricle repair. Leaving the BCS in place during HTx may simplify the operative procedure without causing significant adverse outcomes.

Pulmonary Atresia with Ventricular Septal Defect and Major Aortopulmonary Collaterals Associated with Left Pulmonary Artery Interruption

A multistage plan and multidisciplinary approach are the keys to successful repair in patients with pulmonary atresia (PA) with ventricular septal defect (VSD) and major aortopulmonary collateral arteries (MAPCAs). In this article, we present a multidisciplinary approach adopted to treat a patient with PA with VSD and MAPCAs associated with left pulmonary artery interruption.