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Open Access Publications from the University of California

Scholarly Works (14 results)

  • Article
  • Peer Reviewed
UC San Diego Previously Published Works (2024)
BACKGROUND: Mass casualty incident (MCI) triage simulation is an increasingly useful tool for teaching triage systems to medical students, trainees, and hospital staff. MCI simulation in the prehospital setting has not yet been studied in this population. OBJECTIVES/AIMS: We aimed to assess the effectiveness of a prehospital MCI simulation in medical students, residents, and fellows. Our primary outcome was knowledge of the components of the triage algorithms used in MCI response. Our secondary outcome was each participants confidence level if required to assist with or lead a MCI response. METHODS: This was an observational study with pre-post surveys. We recruited 30 medical students, 14 emergency medicine (EM) residents, and four pediatric EM fellows to fill out a survey before and after a 3-h simulation session practicing the START and JumpSTART algorithms on two prehospital MCI scenarios. RESULTS: Overall, all groups demonstrated significant improvement in knowledge of triage colors, information needed to assign a triage color, pediatric airway management during a MCI, and indications for breaths-first CPR. They also demonstrated significant increase in confidence both in assisting with and in leading a MCI response. CONCLUSIONS: Simulated practice triaging patients in prehospital MCI scenarios improves knowledge of triage algorithms and increases confidence in assisting with or leading a MCI response in medical trainees.
    Cover page: Prehospital mass casualty incident triage simulation builds knowledge and confidence in medical trainees.
    • Article
    • Peer Reviewed
    UC San Diego Previously Published Works (2023)
      Cover page: Change in Climbing Performance Measurements after 24 h of Endurance ClimbingCreative Commons 'BY-ND' version 4.0 license
      • Thesis
      • Peer Reviewed
      UC Berkeley Electronic Theses and Dissertations (2017)

      Magnetic particle imaging (MPI) shows extraordinary promise for biomedical applications: it is highly sensitive, linearly quantitative anywhere in the body, has zero signal from biological tissue, and is safe for patients. One of the major challenges in MPI is spatial resolution, which is fundamentally governed by selection field gradient strength and nanoparticle properties. In Chapter 3 of this dissertation, I describe the design and construction of a high gradient field-free line (FFL) scanner for improved spatial resolution. This is the world's first iron return MPI scanner, and the highest resolution FFL imager in the world. Armed with MPI-tailored nanoparticles created by our collaborators at the University of Washington and Lodespin Labs, we were able to achieve 700 micron resolution in vivo. We also successfully demonstrated dynamic projection MPI as well as 3D projection reconstruction MPI with this scanner. In addition to hardware innovations, I have also demonstrated the use of MPI in two very important applications, namely cancer imaging and gastrointestinal (GI) bleed detection. In Chapter 2 of this dissertation, I demonstrated the first use of MPI for in vivo cancer imaging with systemic tracer administration. Due to the enhanced permeability and retention (EPR) effect, the tumor was highlighted with tumor-to-background ratio of up to 50. The nanoparticle dynamics in the tumor was also well appreciated, with initial wash-in on the tumor rim, peak uptake at 6 hours, and eventual clearance beyond 48 hours. In Chapter 4 of this dissertation, I demonstrated the first use of MPI along with long-circulating, PEG-stabilized SPIOs for rapid in vivo detection and quantification of GI bleed. MPI-tailored, long-circulating SPIOs were systemically administered into a disease model of GI bleed. The tracer biodistribution was then tracked over time using our custom-built high resolution FFL MPI scanner which was described in Chapter 3. Dynamic MPI projection images captured tracer accumulation in the lower GI tract with excellent contrast. The robust contrast, sensitivity, safety, ability to image anywhere in the body, along with our MPI-tailored long-circulating SPIOs, demonstrates the outstanding promise of MPI as a clinical diagnostic tool.

        Cover page: Hardware Innovations and Biomedical Applications of Magnetic Particle Imaging
        • Article
        • Peer Reviewed
        UC San Diego Previously Published Works (2023)
          Cover page: Ultrasound-guided superficial fibular nerve block in the emergency department for refractory cancer-related lower extremity painCreative Commons 'BY-ND' version 4.0 license
          • Article
          • Peer Reviewed
          UC San Diego Previously Published Works (2023)
          Background: Non-professional climbers are increasingly attempting long routes in a single day. Many suffer injury or rely on search and rescue teams when they become too fatigued to finish. Predicting fatigue is difficult, and existing studies have only studied climbers over durations less than an hour, while many outdoor multipitch climbs require more than an hour of climbing. Objectives: To determine how strength, endurance, and dexterity reflect fatigue after 24 h of continuous climbing. Methods: Volunteer competitors completed measurements of grip strength, static hang time to failure, and time to tie a figure-eight follow-through knot. Measurements were taken during the registration period before the competition and again within an hour after the competition ended. Measurements were compared using the paired t-test. Subgroup analysis was applied to competitors by division. Linear regression was applied to determine the relationship between vertical feet climbed and the number of routes climbed during the competition on each metric. Results: Thirty-six total climbers (average age 29.4 years old) completed pre- and post-competition measurements. After 24 h of climbing (n = 36), mean grip strength decreased by 14.3–15 lbs or 14.7%–15.1% (p < 0.001) and static hang time decreased by 54.2 s or 71.2% (p < 0.001). There was no significant change in time to tie a figure-eight-follow-through knot. Grip strength and hang time decreases were significant in climbers with outdoor redpoints of 5.10a and above. Hang time decreased by 5.4 s per 1,000 vertical feet climbed (p = 0.044). Conclusion: Climbers can expect to experience a 14.7%–15.1% decrease in grip strength and 71.2% decrease in static hang time after 24 h of continuous climbing. These changes may make it difficult to climb consistently over a long objective, and climbers can use these measures at home to train for longer climbing routes. Future studies on shorter climbing intervals can help determine rates of decline in performance measures.
            Creative Commons 'BY-NC' version 4.0 license
            • Article
            • Peer Reviewed
            UC San Diego Previously Published Works (2024)

            Abstract

            Breath-hold divers, also known as freedivers, are at risk of specific injuries that are unique from those of surface swimmers and compressed air divers. Using peer-reviewed scientific research and expert opinion, we created a guide for medical providers managing breath-hold diving injuries in the field. Hypoxia induced by prolonged apnea and increased oxygen uptake can result in an impaired mental state that can manifest as involuntary movements or full loss of consciousness. Negative pressure barotrauma secondary to airspace collapse can lead to edema and/or hemorrhage. Positive pressure barotrauma secondary to overexpansion of airspaces can result in gas embolism or air entry into tissues and organs. Inert gas loading into tissues from prolonged deep dives or repetitive shallow dives with short surface intervals can lead to decompression sickness. Inert gas narcosis at depth is commonly described as an altered state similar to that experienced by compressed air divers. Asymptomatic cardiac arrhythmias are common during apnea, normally reversing shortly after normal ventilation resumes. The methods of glossopharyngeal breathing (insufflation and exsufflation) can add to the risk of pulmonary overinflation barotrauma or loss of consciousness from decreased cardiac preload. This guide also includes information for medical providers who are tasked with providing medical support at an organized breath-hold diving event with a list of suggested equipment to facilitate diagnosis and treatment outside of the hospital setting.
              Cover page: Breath-Hold Diving Injuries — A Primer for Medical ProvidersCreative Commons 'BY-ND' version 4.0 license
              • Article
              • Peer Reviewed
              UC San Francisco Previously Published Works (2020)
                Cover page: Reply to Corticosteroid‐Induced Osteonecrosis in COVID‐19: A Call for Caution
                • Article
                • Peer Reviewed
                UCLA Previously Published Works (2019)
                AIMS: Studies have suggested relationships between obesity and cardiovascular disease (CVD) morbidity. However, little is known about whether substantial weight reduction affects the risk of CVD-related acute care use in obese patients with CVD. The objective of this study was to determine whether bariatric surgery is associated with decreased risk of CVD-related acute care use. METHODS AND RESULTS: We performed a self-controlled case series study of obese adults with CVD who underwent bariatric surgery, using population-based emergency department (ED), and inpatient samples in California, Florida, and Nebraska from 2005 to 2011. The primary outcome was ED visit or unplanned hospitalization for CVD. We used conditional logistic regression to compare the risk during sequential 12-month periods, using pre-surgery months 13-24 as the reference period. We identified 11 106 obese adults with CVD who underwent bariatric surgery. During the reference period, 20.6% [95% confidence interval (CI), 19.8-21.3%] of patients had an ED visit or unplanned hospitalization for CVD. The risk did not significantly change in the subsequent 12-month pre-surgery period [adjusted odds ratio (aOR) 0.98; 95% CI, 0.93-1.04; P = 0.42]. By contrast, in the first 12-month period after bariatric surgery, the risk significantly decreased (aOR 0.91; 95% CI, 0.86-0.96; P = 0.002). The risk remained reduced in the subsequent 13-24 months post-bariatric surgery (aOR 0.84; 95% CI, 0.79-0.89; P < 0.001). There was no reduction in the risk in separate obese populations that underwent non-bariatric surgery (i.e. cholecystectomy, hysterectomy). By CVD category, the risk of acute care use for coronary artery disease (CAD), heart failure (HF), and hypertension decreased after bariatric surgery, whereas that of dysrhythmia and venous thromboembolism transiently increased (Bonferroni corrected P < 0.05 for all comparisons). CONCLUSION: Bariatric surgery is associated with a lower risk of overall CVD-related ED visit or unplanned hospitalization. The decline was mainly driven by reduced risk of acute care use for CAD, HF, and hypertension after bariatric surgery.
                  Cover page: Bariatric surgery is associated with lower risk of acute care use for cardiovascular disease in obese adults.
                  • Article
                  • Peer Reviewed
                  UC San Francisco Previously Published Works (2020)
                  Osteoporosis is a chronic condition that reflects reduced bone strength and an associated increased risk for fracture. As a chronic condition, osteoporosis generally requires sustained medical intervention(s) to limit the risks for additional bone loss, compromise of skeletal integrity, and fracture occurrence. Further complicating this issue is the fact that the abrupt cessation of some therapies can be associated with an increased risk for harm. It is in this context that the COVID-19 pandemic has brought unprecedented disruption to the provision of health care globally, including near universal requirements for social distancing. In this Perspective, we provide evidence, where available, regarding the general care of patients with osteoporosis in the COVID-19 era and provide clinical recommendations based primarily on expert opinion when data are absent. Particular emphasis is placed on the transition from parenteral osteoporosis therapies. It is hoped that these recommendations can be used to safely guide care for patients with osteoporosis until a return to routine clinical care standards is available. © 2020 American Society for Bone and Mineral Research.
                    Cover page: Osteoporosis Management in the Era of COVID‐19
                    • Article
                    • Peer Reviewed
                    UC San Francisco Previously Published Works (2017)
                    Pulmonary embolism (PE), along with the closely related condition of deep vein thrombosis, affect an estimated 600 000 patients in the US per year. Untreated, PE carries a mortality rate of 30%. Because many patients experience mild or non-specific symptoms, imaging studies are necessary for definitive diagnosis of PE. Iodinated CT pulmonary angiography is recommended for most patients, while nuclear medicine-based ventilation/perfusion (V/Q) scans are reserved for patients in whom the use of iodine is contraindicated. Magnetic particle imaging (MPI) is an emerging tracer imaging modality with high image contrast (no tissue background signal) and sensitivity to superparamagnetic iron oxide (SPIO) tracer. Importantly, unlike CT or nuclear medicine, MPI uses no ionizing radiation. Further, MPI is not derived from magnetic resonance imaging (MRI); MPI directly images SPIO tracers via their strong electronic magnetization, enabling deep imaging of anatomy including within the lungs, which is very challenging with MRI. Here, the first high-contrast in vivo MPI lung perfusion images of rats are shown using a novel lung perfusion agent, MAA-SPIOs.
                      Cover page: First in vivo magnetic particle imaging of lung perfusion in rats
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