Design and prototyping of a low-cost portable mechanical ventilator

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. [10]).This paper describes the design and prototyping of a low-cost portable mechanical ventilator for use in mass casualty cases and resource-poor environments. The ventilator delivers breaths by compressing a conventional bag-valve mask (BVM) with a pivoting cam arm, eliminating the need for a human operator for the BVM. An initial prototype was built out of acrylic, measuring 11.25 x 6.7 x 8 inches (285 x 170 x 200 mm) and weighing 9 lbs (4.1 kg). It is driven by a stepper motor powered by a 14.8 VDC battery and features an adjustable tidal volume of up to 900 mL, adjustable breaths per minute (bpm) of 5-30, and inhalation to exhalation time ratio (i:e ratio) options of 1:2, 1:3 and 1:4. Tidal volume, breaths per minute and i:e ratio are set via user-friendly knobs, and the settings are displayed on an LCD screen. The prototype also features an assist-control mode and an alarm to indicate over-pressurization of the system. Future iterations of the device will be fully calibrated to medical standards and include all desired ventilator features. Future iterations will be further optimised for low power-consumption and will be designed for manufacture and assembly. With a prototyping cost of only $420, the bulk-manufacturing price for the ventilator is estimated to be less than$100. Through this prototype, the strategy of cam-actuated BVM compression is proven to be a viable option to achieve low-cost, low-power portable ventilator technology that provides essential ventilator features at a fraction of the cost of existing technology. Keywords: Ventilator, Bag Valve Mask (BVM), Low-Cost, Low-Power, Portable and Automatic.by Stephen K. Powelson.S.B

Pancreas transplantation using compatible but non‐identical ABO blood group donors

Methods A review of all pancreas transplants from a single institution from 01/2003 to 07/2016 (n=606) revealed 41 recipients of a NIC donor pancreas which were matched for age, race, gender, year and type of transplant with 41 ABO identical cases. Groups were compared for allograft survival, incidence of acute cellular rejection (ACR), length of hospital stay, 3‐month readmissions and transfusion requirements. Serum haptoglobin and Lactate dehydrogenase were used to identify hemolysis in patients requiring repeated transfusions without overt blood loss. Results The 1‐year graft survival was 100% and 88% in the study and control groups. In the study group, 6/41(14%) developed hemolysis, all of which were ABO O into A. All responded to donor blood type specific transfusions. Discussion There are limited data on outcomes of solid organ transplant using NIC donors with almost none specifically addressing pancreas transplantation. In this study, graft survival was similar but 14% developed hemolysis, which was transient and treated with transfusion of donor blood type specific blood. Conclusion NIC pancreas transplants have similar graft survival compared to ABO identical. Hemolysis may occur so some caution is required

Excellent outcomes in combined liver-kidney transplantation: Impact of KDPI and delayed kidney transplantation

The positive impact of delayed kidney transplantation (KT) on patient survival for combined liver-KT (CLKT) has already been demonstrated by our group. The purpose of this study is to identify whether the quality of the kidneys (based on KDPI) or the delayed approach KT contributes to improved patient survival. 130 CLKT were performed between 2002-2015; 69 with simultaneous KT (Group S) and 61 with delayed KT (Group D) (performed as a second operation with a mean cold ischemia time [CIT] of 50±15h). All patients were categorized according to the KDPI score; 1-33%, 34-66%, and 67-99%. Recipient and donor characteristics were comparable within Groups S and D. Transplant outcomes were comparable within Groups S and D, including liver and kidney CIT, warm ischemia time, and delayed graft function. Lower KDPI kidneys (<34%) were associated with increased patient survival in both groups. Combination of delayed KT and KDPI 1-33% resulted in 100% patient survival at 3-years. These results support that delayed KT in CLKT improves patient survival. The combination of delayed KT and low KDPI offers excellent patient survival up to 3-years. Improved outcomes in the delayed KT group including high KDPI kidneys supports expansion of the donor pool with the use of more ECD and DCD kidneys

Implementing the CDCs Core Elements of Outpatient Antibiotic Stewardship Program into the Urgent Care

Purpose: The inappropriate use of antibiotics has led to the development of antimicrobial resistance which is a severe threat to the public and an increasing global problem. The Centers for Disease Control and Prevention (CDC) estimates at least two million illnesses and 23,000 deaths are caused by antibiotic-resistant bacteria in the United States (CDC, 2014). The purpose of this quality improvement (QI) project was to evaluate the effectiveness of an antibiotic stewardship program (ASP) on urgent care providers\u27 prescribing on viral respiratory tract infections (RTIs) including the common cold, pharyngitis, and bronchitis. Methods: This QI project implemented the CDCs Core Elements of Outpatient Antibiotic Stewardship Program (CEOASP) into an urgent care setting to determine the impact it had on inappropriate antibiotic prescribing for viral RTIs. The process will included displaying commitment letters and antibiotic stewardship (ABS) educational posters in each exam room, presented education on ABS, pathophysiology, diagnosis and treatment guidelines on viral RTIs, as well as education on patient communication techniques used with patients. Retrospective electronic medical record review was conducted from 600 randomly selected patients who presented for treatment of RTIs during the evaluation period. The statistical analysis used was Exact McNemar test. Results: A total of 600 charts, 300 preintervention, and 300 postintervention were evaluated in this study. The overall rate of inappropriate antibiotic prescribing decreased from 21.7% (n = 65) to 8.7% (n = 26), which is a 60% decrease in inappropriate antibiotic prescribing which results in a p \u3c .001%. Implications for Practice: Implementing the Core Elements of Outpatient ASP is needed to promote ABS and the judicious use of antibiotics in the treatment of RTIs.in the outpatient setting

The Outcomes of Cemented versus Cementless Total Knee Arthroplasty in Modern Day Patients with Osteoarthritis

Osteoarthritis (OA), the degeneration of cartilage and bone, is the most progressive musculoskeletal disease and a leading cause of disability in the United States, affecting over 27 million adults. Although conservative treatments for knee OA are available, total knee arthroplasty (TKA) is the only definitive treatment for end-stage knee OA. For the past several decades, the use of bone cement has been the gold standard for total knee arthroplasty, but the cementless TKA is being revisited as an option as the age of patients seeking TKA decreases and the average BMI increases. This review analyzes and compares the outcomes of cemented versus cementless TKA in today\u27s average patient with end-stage OA

Thorium-based mixed oxide fuel in a pressurized water reactor: A feasibility analysis with MCNP

This dissertation investigates techniques for spent fuel monitoring, and assesses the feasibility of using a thorium-based mixed oxide fuel in a conventional pressurized water reactor for plutonium disposition. Both non-paralyzing and paralyzing dead-time calculations were performed for the Portable Spectroscopic Fast Neutron Probe (N-Probe), which can be used for spent fuel interrogation. Also, a Canberra 3He neutron detector\u27s dead-time was estimated using a combination of subcritical assembly measurements and MCNP simulations. Next, a multitude of fission products were identified as candidates for burnup and spent fuel analysis of irradiated mixed oxide fuel. The best isotopes for these applications were identified by investigating half-life, photon energy, fission yield, branching ratios, production modes, thermal neutron absorption cross section and fuel matrix diffusivity. 132I and 97Nb were identified as good candidates for MOX fuel on-line burnup analysis. In the second, and most important, part of this work, the feasibility of utilizing ThMOX fuel in a pressurized water reactor (PWR) was first examined under steady-state, beginning of life conditions. Using a three-dimensional MCNP model of a Westinghouse-type 17x17 PWR, several fuel compositions and configurations of a one-third ThMOX core were compared to a 100% UO2 core. A blanket-type arrangement of 5.5 wt% PuO2 was determined to be the best candidate for further analysis. Next, the safety of the ThMOX configuration was evaluated through three cycles of burnup at several using the following metrics: axial and radial nuclear hot channel factors, moderator and fuel temperature coefficients, delayed neutron fraction, and shutdown margin. Additionally, the performance of the ThMOX configuration was assessed by tracking cycle length, plutonium destroyed, and fission product poison concentration. --Abstract, page iv

The Image of The American Revolutionary Soldier and The Problem of Historical Memory

Pubic memories of the American Revolution have played a central role in the creation of an American national identity. As a result of the importance of these military memories in creating a sense of social cohesion, images of the men who fought in the Revolution have often been systematically created and propagated, thus leading to myths and stereotypes in popular culture. Master of Arts (MA), August 2012, 111 pp., 2 tables, 4 figures, 76 references, 8 titles. This thesis analyzes the images of the soldiers of the American Revolution in public memory and in professional historiography. There is a perplexing gap between popular memory and the modern day professional historiography of the American Revolutionary soldiers. Although there is a large body of knowledge available that disproves much of the mythical images of the soldiers, the stereotypes have persisted in public memory as a result of the political, psychological and sociological processes involved in the creation and maintenance of memories