W. L. Gore and Associates

Respiratory protective devices (RPDs), commonly called respirators, are one of many types of personal protective equipment devices used to protect workers from a specific hazard. They fall into a category of devices that are being used to protect workers from an existing or recognized and real-time hazard. This chapter has provided an overview of the Occupational Safety and Health Administration and National Institute for Occupational Safety and Health respiratory protection regulations as well as voluntary national consensus standards such as ANSI Z88 and National Fire Protection Association that provide additional guidance on various topics in these regulations. The chapter presents the importance of the RPD program. It describes the following program elements: program administration; written standard operating procedures; hazard assessment; selection; tight-fitting RPD fit testing; use; maintenance and storage; breathing air quality, quantity, and flow; training; audits; program records; problem areas; and glossary.

Polydienes containing a C=C bond in each unit, such as polybutadiene (PBD)- or polyisoprene (PI)-containing polymers, have served as an important backbone of polymer applications in our daily lives. For versatile use of polydienes in various applications, C=C bonds in polydienes can be hydrogenated to achieve a desirable saturation level and/or additionally modified to obtain suitable structure-property sets. Among different hydrogenation procedures, non-catalytic, diimide hydrogenation using p-toluenesulfonyl hydrazide (TSH) can enable easier and precise control of hydrogenation level in C=C bonds at mild conditions. Here, for the first time, we reported a systematic hydrogenation kinetics study of one representative PI-containing polymer, i.e., polystyrene-b-polyisoprene-b-polystyrene (SIS) triblock copolymer with high molecular weight via TSH-based, diimide hydrogenation using NMR, SEC, and thermal analyses. We evaluated hydrogenation level (HL = 0∼99.9%) vs reaction time (0∼24 h) of SIS polymer and compared our kinetics results with other PBD- or PI-containing polymers with different chain architectures, compositions, and hydrogenation conditions to develop a universal efficacy of this diimide hydrogenation method and build a comprehensive understanding among these reports. We achieved HL = 51% in 1 h and HL > 99.9% by 24 h. Our analyses confirm that no side reactions occur up to 48 h without affecting other copolymer blocks. Our kinetics data align well with other similar polydienes but cover a wider range of reaction times (up to 48 h) than those in the literature. Using this information, a target hydrogenation level can be precisely achieved by controlling reaction time under mild conditions. Overall, this TSH-based diimide hydrogenation method is universal and effective over a broad range of PBD- and PI-containing polymers with different chain architectures and compositions.

Objective Recent advancements in endovascular technology have facilitated minimally invasive treatment of thoracoabdominal aortic aneurysms (TAAAs) using fenestrated and/or branched endovascular aortic repair (f/bEVAR). Wider adoption of f/bEVAR has been tempered by concerns regarding higher implant costs compared with open aortic repair (OAR). However, data on the overall economic impact of clinical outcomes of f/bEVAR vs OAR in TAAA are sparse. This study aimed to evaluate the current clinical and cost outcomes of f/bEVAR vs OAR for intact TAAA. Methods We conducted a real-world analysis of hospital-discharge data from patients undergoing intact TAAA repair in the United States from the Premier Healthcare Database (2020-2023). Patients were divided into two cohorts: f/bEVAR and OAR. Patient characteristics, clinical outcomes, complications, rehospitalization/reintervention, and cost of index hospitalization were compared. Results A total of 466 patients who had undergone TAAA repairs were included (160 f/bEVAR and 306 OAR). Patients undergoing f/bEVAR were older (70.5 years vs 62.4 years; P < .0001), less likely to die during hospitalization (7.5% vs 18.3%; P = .0017), and more likely to be discharged home (78.1% vs 56.9%; P < .0001). In addition, hospital stays were 12.7 days shorter (P < .0001) and operating times 228 minutes shorter (P < .0001) among patients undergoing f/bEVAR. Postoperatively, patients undergoing f/bEVAR had fewer complications (32.5% vs 59.8%; P < .0001) and fewer short-term reinterventions (0% vs 2.9%; P = .0311). Disaggregated by hospital department, the higher central supply cost for f/bEVAR ($56,937 vs $17,718; P < .0001) was offset by lower operative and postoperative care costs, resulting in lower overall total hospital costs compared with OAR costs ($82,338 vs $103,155; P = .0028). Conclusions Real-world adoption of f/bEVAR was associated with significantly lower in-hospital mortality and complication rates, as well as a shorter length of stay and fewer short-term reinterventions compared with OAR. Despite higher central supply costs, f/bEVAR was linked to significantly lower total hospital costs. With the increasing availability of dedicated f/bEVAR devices, endovascular TAAA repair presents a promising opportunity for improved patient care with potential cost savings.

BACKGROUND:Endovascular aneurysm repair (EVAR) and open surgical repair (OSR) are both used for elective unruptured infrarenal abdominal aortic aneurysm (AAA), but their relative cost-effectiveness in the UK NHS remains uncertain. RESEARCH DESIGN AND METHODS:A lifetime Markov cohort model compared EVAR and OSR, incorporatingwaiting-list and perioperative mortality, postoperative survival, reinterventions, and imaging surveillance. Time-varying mortality effects were derived from reconstructed individual-patient-data meta-analysis, with equal long-term mortality assumed in the base case. Costs and QALYs were discounted at 3.5%. Uncertainty was explored through deterministic, probabilistic (10,000 iterations), and scenario analyses using alternative survival models. RESULTS:EVAR had higher lifetime costs (£17,710 vs £16,191) but greater QALYs (6.373 vs 6.219), yielding an ICER of £9,865/QALY. Probabilistic analysis produced a mean ICER of £9,793/QALY, with EVAR cost-effective in 56.1% and 62.2% of simulations at £20,000 and £30,000/QALY thresholds, respectively. Results were sensitive to survival modeling assumptions, EVAR device costs, perioperative mortality, and surveillance intensity. CONCLUSIONS:Under contemporary time-varying mortality assumptions, EVAR is likely cost-effective versus OSR at standard UK thresholds, though conclusions depend on long-term survival assumptions and surveillance intensity.