GPU libraries speed performance analysis for RCWA simulation matrix operations

Rigorous Coupled Wave Analysis (RCWA) method is highly efficient for the simulation of diffraction efficiency and field distribution patterns in periodic structures and textured optoelectronic devices. GPU has been increasingly used in complex scientific problems such as climate simulation and the latest Covid-19 spread model. In this paper, we break down the RCWA simulation problem to key computational steps (eigensystem solution, matrix inversion/multiplication) and investigate speed performance provided by optimized linear algebra GPU libraries in comparison to multithreaded Intel MKL CPU library running on IRIDIS 5 supercomputer (1 NVIDIA v100 GPU and 40 Intel Xeon Gold 6138 cores CPU). Our work shows that GPU outperforms CPU significantly for all required steps. Eigensystem solution becomes 60% faster, Matrix inversion improves with size achieving 8x faster for large matrixes. Most significantly, matrix multiplication becomes 40x faster for small and 5x faster for large matrix sizes. © 2023 SPIE.

COVID-RELATED DISTRESS AND DISRUPTIONS IN OVARIAN CANCER SURVIVORS

Background: The objective of this study was to determine how levels of distress and disruption during the COVID-19 pandemic compared between ovarian cancer survivors and a community sample;how clinical and demographic characteristics of survivors were related to COVID-related distress and disruption;and if perceived stress, depression, and emotional well-being at cancer diagnosis predicted COVID-related distress during the first year of the pandemic. Methods: Ovarian cancer patients (N=90) who were part of 3 ongoing studies completed COVID surveys through mail and on REDCAP between 6/20 and 12/20. Responses were compared to those of community females (N=1110) who participated in a COVID survey mailed to an Iowa Statewide Voter Registration-based sample between 8/20 and 12/20. Pre-COVID data on perceived stress, depression, and emotional well-being (EWB) from ovarian cancer patients at the time of diagnosis was available for 30 long-term (≥4 yrs) and 60 shorter-term (<4 yrs) survivors. Hierarchical regressions examined whether psychosocial features at diagnosis, controlling for age, stage, total COVID disruption (healthcare, financial, and daily-life), and time since diagnosis, predicted COVID-related distress. Results: Compared to the community sample, ovarian cancer survivors reported lower levels of healthcare disruption (p=.016), financial hardship (p<.001), and distress (p=.009), but no difference in disruption of daily activities (p=.089). Among survivors, there were no differences in distress or total COVID-related disruptions based on stage or time since diagnosis (all p values ≥0.10). Younger survivors (<63 yr median) showed significantly greater distress (p=.009) and disruption (p=.001) than older survivors. Adjusting for covariates, perceived stress (β=.237, p=.006) and EWB (β= -.338, p<.001) at diagnosis were significant predictors of total COVID-related distress, whereas depression was not. Conclusions: Surprisingly, cancer survivors reported fewer COVID-related disruptions and distress compared to a community sample. Older patients reported less distress and disruptions during COVID, but stage and time since diagnosis were not associated with these factors. The relationship between distress and well-being at diagnosis and COVID-related distress suggests the possibility of identifying patients particularly at-risk during environmental challenges.

Using Medical Claims Data to Explore Missed Opportunities for HPV Vaccination Among Adolescents, Ages 11-13, in Iowa

Purpose: Despite decades of safety and effectiveness data, human papillomavirus (HPV) vaccination rates remain low, and one-third of adolescents fail to initiate the series by age 13, the age at which it should be completed. While there is extensive research on factors related to uptake, there is less known about the times that eligible adolescents do not get vaccinated (missed opportunities [MOs]). This study sought to quantify the extent of MOs among adolescents ages 11 to 13 during both preventive and acute care visits. Methods: Medical claims data from years 2010 to 2017 from a large midwestern insurance provider were used to calculate total numbers of MOs between ages 11 and 13. Adolescents included had continuous health insurance enrollment born between 2001 and 2004 in Iowa for the three-year period between ages 11 and 13 (n=14,505). The creation of the MO definition was informed by input from primary care and pediatric providers to ensure that all visits that could be potential vaccination opportunities were included. MOs were divided into several categories: total, among non-initiators, occurring prior to initiation, occurring after the first dose, and occurring between the first and last dose. Two subgroup comparisons for all categories (urban vs. rural;male vs. female) were explored using t-tests. Results: Overall, less than one-third of adolescents in the sample initiated the series by age 13. Females experienced significantly fewer MOs;5.98 (SD=5.49) for females compared to 6.18 (SD=6.04) for males. For initiators, the majority of MOs occurred prior to initiation of the series, which on average, occurred at age 12;again females experienced significantly fewer MOs compared to males;means for males and females were 3.62 and 4.07, respectively. In sub-group comparisons, rural adolescents tended to have fewer MOs than their urban counterparts and females tended to have fewer MOs than males. For example, urban females had significantly more MOs overall (M=6.08) compared to rural females (M=5.85). Conclusions: Results from this study highlight not only the extent of MOs, but also the utility of medical claims data in understanding patterns of adolescent health care utilization. Claims data provides a comprehensive view and level of granularity not available in other immunization data source. Future research could focus on better understanding the issue of MOs in other geographic areas or among populations with public insurance. Overall, in this sample of privately insured adolescents, it is clear that a lack of opportunity was not a barrier to HPV vaccination, as there were many opportunities in this critical age range, particularly among males and urban adolescents. Additionally, low rates of HPV vaccination have been compounded by the COVID-19 pandemic with many adolescents missing preventive care visits during the pandemic. Moving forward, it will be critical for providers to take advantage of any opportunities to vaccinate, both acute and preventive care visits, to ensure adolescents receive the vaccines they need and reduce these MOs going forward. Sources of Support: Cooperative Agreement 3 U48 DP005021-01S4 from the Centers for Disease Control and Prevention and the National Cancer Institute.

Patient experiences with telehealth in sleep medicine: A qualitative evaluation

Rationale: The field of sleep medicine has been an avid adopter of telehealth, particularly during the COVID-19 pandemic. While numerous randomized trials support the efficacy of telehealth to treat conditions such as obstructive sleep apnea (OSA) and insomnia, relatively little is known about patients' experiences and perceptions of telehealth in typical practice. Methods: We recruited a purposive sample of patients who had sleep provider encounters via one of three telehealth modalities: in-clinic video, home-based video, and telephone. We conducted semi-structured interviews to assess general telehealth experiences, elicit perceptions around most and least helpful aspects, and contrast their experiences with in-person care. Two analysts coded transcripts using content analysis. After review of coding and categorization, the analysts identified emergent themes that cut across participants and categories. Results: We conducted interviews with 35 patients (in-clinic video n=12, home-based video n=11, telephone n=12) at two VA medical centers from June 2019 to May 2020. Five themes emerged including access to care, security and privacy, personalization of care, patient empowerment, and unmet needs. 1) Access to care: Patients perceived that telehealth provided access to sleep care in a timely and convenient manner, especially during the COVID-19 pandemic. Patients also saw telehealth as a way to improve continuity of care with their preferred providers. 2) Security and Privacy: Patients described how home-based telehealth afforded them greater feelings of safety and security within appointments due to avoidance of anxiety provoking triggers (e.g. crowds). However, patients also noted a potential loss of privacy when telehealth was delivered at home. 3) Personalization of care: Patients outlined ways in which telehealth both improved and hindered their ability to communicate their individual needs to providers. In turn, this communication translated into the delivery of personalized care and positive health impacts. 4) Patient Empowerment: Patients described how telehealth empowered them to engage in self-management for their sleep disorders. 5) Unmet Needs: Patients recognized that there were specific areas where telehealth was not meeting their needs, including lack of follow-through with PAP therapy. Patients also expressed concerns around the lack of a physical examination. Conclusion: Patients described both positive and negative experiences with telehealth, highlighting areas where care can be further adapted to better suit their needs. As we continue to refine telehealth practices, we encourage providers and hospital systems to consider these aspects of the patient experience.

Reducing patient harm following inadvertent endobronchial placecement of nasogastric tubes in patients with SARS-COV-2

Introduction: Nasogastric tube (NGT) insertion is essential for enteral feeding but can potentially cause significant injury to the lungs (1). Following a critical incident, we audited our practice of NGT insertion and the consequences of injury in patients with Severe Acute Respiratory Syndrome COVID-19 caused by the (SARS-CoV-2) virus. Methods: NGT insertion followed a local standard safety protocol and were inserted by consultants or senior registrars in anaesthesia and critical care medicine, or advanced critical care practitioners. Individual practitioners were able to choose their technique of insertion. All patients had their post-NGT insertion chest x-ray reviewed and those with misplaced NGTs had their case notes reviewed. Early in the outbreak, blind insertion was recommended in our institution to reduce aerosolisation, this was rapidly changed to direct visualisation with laryngoscopy as our experience managing SARS-CoV-2 patients increased. Results: During the SARS-CoV-2 pandemic, a total of 135 NGTs were inserted into ventilated and/or extracorporeal membrane oxygenation (ECMO) patients. All of NGTs positioned were confirmed by a chest radiograph. Eleven (8.1%) were inadvertently endobronchial, of which four developed pneumothoraces (figure 1). Three patients (including both who had received ECMO) died and a fourth is currently undergoing a prolonged respiratory wean. No patients were fed or received drugs via a misplaced NGT. Chest radiograph of patient with inadvertent NGT placement in right lower lobe. Note the path of the tube suggests breech of the bronchial tree and direct injury to the lung parenchyma (arrowhead). A CT the following day showed a large pneumothorax (arrowhead), some haemothorax (black arrow) and severe ground glass changes consistent with SARS-CoV-2 (white arrow). Discussion: Our inadvertent endobronchial NGT rate is relatively high, compared to our previous clinical experience, which we believe may be related to the challenges of working with cumbersome personal protective equipment and/or changed practice to attempt to reduce transmission of SARS-CoV-2 (2). We suspect the lung parenchyma is particularly fragile in acute respiratory distress syndrome caused by SARS-CoV-2, which contributes to the high rate of pleural breech and subsequent poor outcome (3). We recommend experienced operators place NGTs and do so using direct or videolaryngoscopy to minimise the risk of incorrect placement. We would like to thank the families of our patients for their permission to share the images in this work.