Search

A Blowout Preventer (BOP) serves as a safety valve in the drilling process in the oil and gas industry. It will be closed if an influx of formation fluids occurs and threatens the rig. A Ram BOP is one type of widely used BOP. It is composed of two ram blades, which will move towards each other to shear the drilling pipe and to close the valve. To ensure the shearing process be completed on the rig, lab tests are often run to evaluate the BOP’s capability and the required shearing pressure. The paper presents a new automation CAE (Computer-Aided Engineering) toolkit method recently developed to simulate the Ram BOP pipe shearing process. The toolkit method automates and integrates the process from computer aided design (CAD) to computer aided simulation for the Ram shearing process. It significantly simplifies the modeling effort and facilitates the design optimization process.

Understanding the relationship between patient risk factors, postoperative complications, and morbidity and mortality is important when considering elective endovascular aortic aneurysm repair (E-EVAR) performed to prevent aneurysm rupture mortality. We aimed to stratify complications in E-EVAR and explore their relationship with postoperative death.E-EVAR cases from 2012 NSQIP were identified. 30-day complications were categorized as major (MAJCX) or minor (MINCX) using the Clavien-Dindo classification. Failure to rescue (FTR) was defined as death following a complication. Univariate and multivariate analyses were performed to identify associations between patient risk factors, complications, and mortality. Significance set at P 0.05.3344 E-EVAR's were analyzed, with 155 (4.6%) MINCX, 106 (3.2%) MAJCX, and 39 (1.2%) mortality. Significant univariate risk factors differed between MINCX (preoperative dyspnea 27% vs 19%, COPD 32% vs19%, HTN 87% vs 79%, functional dependence 9% vs 3%) and MAJCX (female sex 33% vs 18%, preoperative diabetes 30% vs 17%, dyspnea 40% vs 19%, COPD 46% vs 20%, anticoagulant use 20% vs 11%, and functional dependence 13% vs 3%). 24 of 39 (62%) of deaths were preceded by a complication. FTR was more frequent following MAJCX than MINCX (16% vs 4.5%, P = 0.002), and occurred most commonly after renal failure with dialysis (33% mortality with complication), cardiac arrest (33%), septic shock (22%), and reintubation (22%). Independent predictors of MAJCX included female sex (OR 2, P = 0.001), COPD (OR 2, P = 0.009), and anticoagulant use (OR 2, P = 0.001). Mortality was independently predicted by MAJCX (OR 29, P 0.001), MINCX (OR 8, P 0.001), and preoperative renal failure (OR 11.6, P 0.001).The majority of deaths within 30 days following E-EVAR are preceded by a complication; both MAJCX and MINCX predict mortality. FTR is more common after MAJCX; prevention efforts should take this into account. Identified risk factors should be taken into consideration when considering E-EVAR.

Percutaneous endovascular aneurysm repair (PEVAR) has become accepted as a suitable alternative to open EVAR (OEVAR) in the treatment of abdominal aortic aneurysms (AAAs). Direct comparisons between the 2 techniques have been infrequently reported and have predominantly focused on immediate procedural outcomes. The objective of this study was to compare contemporary 30-day postoperative outcomes between successfully completed elective PEVAR and OEVAR.The 2012 National Surgical Quality Improvement Program database was queried for all elective primary AAA repairs. Procedures on ruptured AAAs and those involving adjunctive thoracic, abdominal, or extremity procedures were excluded. Cases completed with at least one surgical exposure of the femoral artery for access (OPEN) were compared with those completed without such exposure (PERC). Preoperative, intraoperative, and 30-day postoperative variables were compared using appropriate univariate statistical tests. A P value of ≤0.05 was considered significant for all comparisons.A total of 1,589 (51%) OPEN and 1,533 (49%) PERC cases met inclusion and exclusion criteria. Preoperative characteristics did not differ between groups. OPEN cases took significantly longer (150 ± 69 min) than PERC cases (134 ± 65 min, P 0.001). No significant differences were found between the groups in any postoperative occurrence, but the rate of venous thromboembolism twice as high in OPEN (16, 1.0%) than PERC cases (7, 0.5%, P = 0.07). In addition, wound complications (36, 2.3% OPEN vs. 23, 1.3% PERC, P = 0.11) were more common in OPEN cases but were diagnosed a week sooner on average in PERC cases (19 days OPEN and 12 days PERC). Median postoperative length of stay was 2 days among OPEN cases versus 1 day in PERC cases (P = 0.11). Female gender and obesity predicted wound complications in the OPEN group but not in the PERC group.Successfully completed PEVAR and OEVAR have similar rates of overall complications. Female gender and obesity predict wound complications in OEVAR but not in PEVAR, which appears to be a safe alternative to OEVAR. PEVAR has the advantage of shorter operative time and the potential for a shorter postoperative stay, and may offer the advantage of fewer wound complications in females and obese patients.