Ultrasound Use in Resource-limited Settings: A Systematic Review

Purpose: Over the past decade, ultrasound (US) machines have become smaller, less expensive, more reliable, durable and user-friendly, making ultrasonography an ideal imaging modality in resource-poor settings. We conducted a literature review to examine the use of ultrasound in resource-limited settings, with emphasis on common applications, barriers to implementation, and impact on clinical decision-making and patient disposition. Methods and Materials: Literature review. We conducted a PubMed and Cochrane Central search on the clinical use of ultrasound in the developing world. Search terms included ultrasonography, developing countries, resource limited, remote setting, poverty, and low income. Articles from 2000 to 2015 that included data on the clinical use of ultrasound in resource limited settings were eligible for inclusion. Data on country of origin, medical specialty, US modality, clinical impact, and potential barriers to implementation were recorded. Results: Fifty-eight articles were eligible for inclusion. Most studies were observational, with Africa as the most common site, accounting for 35 articles. Radiology was the most represented specialty. Cardiac and obstetric were the most commonly utilized ultrasound modalities. Most data on cardiac ultrasound pertained to its role in the diagnosis of rheumatic heart disease. Obstetric ultrasound was primarily used for pregnancy dating and diagnosing fetal abnormalities. Twelve studies examined clinical impact of ultrasound in resource-limited settings and showed that its use dramatically altered differential diagnosis and patient disposition. Common barriers to implementation were the high cost of equipment and maintenance, and lack of skilled personnel and formal training programs. A commonly cited consequence of ultrasound use in resource-poor settings was sex-selective abortions. Conclusion: Ultrasound has widespread clinical applications, particularly as a diagnostic tool in the developing world. Significant barriers exist with respect to access and training of US in resource-limited settings. Further research is needed to study its impact on medical decision-making, patient disposition and outcomes

Ultrasound Use in Resource-limited Settings: A Systematic Review

Purpose: Over the past decade, ultrasound (US) machines have become smaller, less expensive, more reliable, durable and user-friendly, making ultrasonography an ideal imaging modality in resource-poor settings. We conducted a literature review to examine the use of ultrasound in resource-limited settings, with emphasis on common applications, barriers to implementation, and impact on clinical decision-making and patient disposition. Methods and Materials: Literature review. We conducted a PubMed and Cochrane Central search on the clinical use of ultrasound in the developing world. Search terms included ultrasonography, developing countries, resource limited, remote setting, poverty, and low income. Articles from 2000 to 2015 that included data on the clinical use of ultrasound in resource limited settings were eligible for inclusion. Data on country of origin, medical specialty, US modality, clinical impact, and potential barriers to implementation were recorded. Results: Fifty-eight articles were eligible for inclusion. Most studies were observational, with Africa as the most common site, accounting for 35 articles. Radiology was the most represented specialty. Cardiac and obstetric were the most commonly utilized ultrasound modalities. Most data on cardiac ultrasound pertained to its role in the diagnosis of rheumatic heart disease. Obstetric ultrasound was primarily used for pregnancy dating and diagnosing fetal abnormalities. Twelve studies examined clinical impact of ultrasound in resource-limited settings and showed that its use dramatically altered differential diagnosis and patient disposition. Common barriers to implementation were the high cost of equipment and maintenance, and lack of skilled personnel and formal training programs. A commonly cited consequence of ultrasound use in resource-poor settings was sex-selective abortions. Conclusion: Ultrasound has widespread clinical applications, particularly as a diagnostic tool in the developing world. Significant barriers exist with respect to access and training of US in resource-limited settings. Further research is needed to study its impact on medical decision-making, patient disposition and outcomes

Practical Diagnostic Accuracy of Nasopharyngeal Swab Testing for Novel Coronavirus Disease 2019 (COVID-19)

Introduction: The novel coronavirus (SARS-CoV-2) is the cause of COVID-19, which has had a devastating international impact. Prior reports of testing have reported low sensitivities of nasopharyngeal polymerase chain reaction (PCR), and reports of viral co-infections have varied from 0-20%. Therefore, we sought to determine the accuracy of nasopharyngeal PCR for COVID-19 and rates of viral co-infection.Methods: We conducted a retrospective chart review of all patients who received viral testing between March 1, 2020–April 28, 2020. Test results of a complete viral pathogen panel and COVID-19 testing were abstracted. We compared patients with more than one COVID-19 test for diagnostic accuracy against the gold standard of chart review.Results: We identified 1950 patients, of whom 1024 were tested for COVID-19. There were 221 repeat tests for COVID-19. Among patients with a repeat test, COVID-19 swabs had a sensitivity of 84.6% (95% confidence interval (CI), 69.5-94.4%) and a specificity of 99.5% (95%CI, 97-100%) compared to a clinical and radiographic criterion reference by chart review. We found viral co-infection rates of 2.3% in patients without COVID-19 and 6.1% in patients with COVID-19. Rates of co-infection appeared to be related to base rates of infection in the community and not a specific property of COVID-19.Conclusion: COVID-19 nasopharyngeal PCR specimens are accurate but have imperfect sensitivity. Repeat testing for high-risk patients should be considered, and presence of an alternative virus should not be used to limit testing for COVID-19 for patients where it would affect treatment or isolation

Practical Diagnostic Accuracy of Nasopharyngeal Swab Testing for Novel Coronavirus Disease 2019 (COVID-19)

Introduction: The novel coronavirus (SARS-CoV-2) is the cause of COVID-19, which has had a devastating international impact. Prior reports of testing have reported low sensitivities of nasopharyngeal polymerase chain reaction (PCR), and reports of viral co-infections have varied from 0-20%. Therefore, we sought to determine the accuracy of nasopharyngeal PCR for COVID-19 and rates of viral co-infection.Methods: We conducted a retrospective chart review of all patients who received viral testing between March 1, 2020–April 28, 2020. Test results of a complete viral pathogen panel and COVID-19 testing were abstracted. We compared patients with more than one COVID-19 test for diagnostic accuracy against the gold standard of chart review.Results: We identified 1950 patients, of whom 1024 were tested for COVID-19. There were 221 repeat tests for COVID-19. Among patients with a repeat test, COVID-19 swabs had a sensitivity of 84.6% (95% confidence interval (CI), 69.5-94.4%) and a specificity of 99.5% (95%CI, 97-100%) compared to a clinical and radiographic criterion reference by chart review. We found viral co-infection rates of 2.3% in patients without COVID-19 and 6.1% in patients with COVID-19. Rates of co-infection appeared to be related to base rates of infection in the community and not a specific property of COVID-19.Conclusion: COVID-19 nasopharyngeal PCR specimens are accurate but have imperfect sensitivity. Repeat testing for high-risk patients should be considered, and presence of an alternative virus should not be used to limit testing for COVID-19 for patients where it would affect treatment or isolation

Returns After Discharge From the Emergency Department Observation Unit: Who, What, When, and Why?

Introduction: The number of emergency department observation units (EDOU) and observation stays has continued to increase. Despite this, there is limited data on the characteristics of patients who return unexpectedly to the ED after EDOU discharge.Methods: We identified the charts of all patients who were admitted to the EDOU of an academic medical center between January 2018–June 2020 and had a return to the ED within 14 days of discharge from the EDOU. Patients were excluded if they were admitted to the hospital from the EDOU, left against medical advice, or died in the EDOU. We manually extracted selected demographic factors, comorbidities, and healthcare utilization data from the charts. Physician reviewers identified return visits thought to be related to the index visit or potentially avoidable.Results: During the study period, there were 176,471 ED visits, 4,179 admissions to the EDOU, and 333 return visits to the ED within 14 days from discharge from the EDOU, representing 9.4% of all patients discharged from the EDOU. We identified a higher rate of return for patients treated for asthma and lower rates of return for patients treated for chest pain or syncope than the overall return rate. Physician reviewers determined that 64.6% of unplanned returns were related to the index visit, and 4.5% were potentially avoidable. Of potentially avoidable visits, 53.3% occurred within 48 hours of discharge, supporting the use of this period as a potential quality metric. While there was no significant difference in the percentage of related return visits between males and females, there was a higher rate of potentially avoidable visits for male patients.Conclusion: This study adds to the limited body of literature on EDOU returns, finding an overall return rate of under 10%, with about two-thirds of returns determined to be related to the index visit and <5% considered to be potentially avoidable

HIV-1 Envelope Protein Binds to and Signals Through Integrin alpha4beta7, the Gut Mucosal Homing Receptor for Peripheral T Cells

Infection with human immunodeficiency virus 1 (HIV-1) results in the dissemination of virus to gut-associated lymphoid tissue. Subsequently, HIV-1 mediates massive depletion of gut CD4+ T cells, which contributes to HIV-1-induced immune dysfunction. The migration of lymphocytes to gut-associated lymphoid tissue is mediated by integrin alpha4beta7. We demonstrate here that the HIV-1 envelope protein gp120 bound to an activated form of alpha4beta7. This interaction was mediated by a tripeptide in the V2 loop of gp120, a peptide motif that mimics structures presented by the natural ligands of alpha4beta7. On CD4+ T cells, engagement of alpha4beta7 by gp120 resulted in rapid activation of LFA-1, the central integrin involved in the establishment of virological synapses, which facilitate efficient cell-to-cell spreading of HIV-1