Magnitude of arsenic pollution in the Mekong and Red River Deltas--Cambodia and Vietnam

Large alluvial deltas of the Mekong River in southern Vietnam and Cambodia and the Red River in northern Vietnam have groundwaters that are exploited for drinking water by private tube-wells, which are of increasing demand since the mid-1990s. This paper presents an overview of groundwater arsenic pollution in the Mekong delta: arsenic concentrations ranged from 1-1610 microg/L in Cambodia (average 217 microg/L) and 1-845 microg/L in southern Vietnam (average 39 microg/L), respectively. It also evaluates the situation in Red River delta where groundwater arsenic concentrations vary from 1-3050 microg/L (average 159 microg/L). In addition to rural areas, the drinking water supply of the city of Hanoi has elevated arsenic concentrations. The sediments of 12-40 m deep cores from the Red River delta contain arsenic levels of 2-33 microg/g (average 7 microg/g, dry weight) and show a remarkable correlation with sediment-bound iron. In all three areas, the groundwater arsenic pollution seem to be of natural origin and caused by reductive dissolution of arsenic-bearing iron phases buried in aquifers. The population at risk of chronic arsenic poisoning is estimated to be 10 million in the Red River delta and 0.5-1 million in the Mekong delta. A subset of hair samples collected in Vietnam and Cambodia from residents drinking groundwater with arsenic levels >50 microg/L have a significantly higher arsenic content than control groups (<50 microg/L). Few cases of arsenic related health problems are recognized in the study areas compared to Bangladesh and West Bengal. This difference probably relates to arsenic contaminated tube-well water only being used substantially over the past 7 to 10 years in Vietnam and Cambodia. Because symptoms of chronic arsenic poisoning usually take more than 10 years to develop, the number of future arsenic related ailments in Cambodia and Vietnam is likely to increase. Early mitigation measures should be a high priority.

Patient care and clinical outcomes for patients with COVID-19 infection admitted to African high-care or intensive care units (ACCCOS): a multicentre, prospective, observational cohort study

BACKGROUND

There have been insufficient data for African patients with COVID-19 who are critically ill. The African COVID-19 Critical Care Outcomes Study (ACCCOS) aimed to determine which resources, comorbidities, and critical care interventions are associated with mortality in this patient population.

METHODS

The ACCCOS study was a multicentre, prospective, observational cohort study in adults (aged 18 years or older) with suspected or confirmed COVID-19 infection who were referred to intensive care or high-care units in 64 hospitals in ten African countries (ie, Egypt, Ethiopia, Ghana, Kenya, Libya, Malawi, Mozambique, Niger, Nigeria, and South Africa). The primary outcome was in-hospital mortality censored at 30 days. We studied the factors (ie, human and facility resources, patient comorbidities, and critical care interventions) that were associated with mortality in these adult patients. This study is registered on ClinicalTrials.gov, NCT04367207.

FINDINGS

From May to December, 2020, 6779 patients were referred to critical care. Of these, 3752 (55·3%) patients were admitted and 3140 (83·7%) patients from 64 hospitals in ten countries participated (mean age 55·6 years; 1890 [60·6%] of 3118 participants were male). The hospitals had a median of two intensivists (IQR 1-4) and pulse oximetry was available to all patients in 49 (86%) of 57 sites. In-hospital mortality within 30 days of admission was 48·2% (95% CI 46·4-50·0; 1483 of 3077 patients). Factors that were independently associated with mortality were increasing age per year (odds ratio 1·03; 1·02-1·04); HIV/AIDS (1·91; 1·31-2·79); diabetes (1·25; 1·01-1·56); chronic liver disease (3·48; 1·48-8·18); chronic kidney disease (1·89; 1·28-2·78); delay in admission due to a shortage of resources (2·14; 1·42-3·22); quick sequential organ failure assessment score at admission (for one factor [1·44; 1·01-2·04], for two factors [2·0; 1·33-2·99], and for three factors [3·66, 2·12-6·33]); respiratory support (high flow oxygenation [2·72; 1·46-5·08]; continuous positive airway pressure [3·93; 2·13-7·26]; invasive mechanical ventilation [15·27; 8·51-27·37]); cardiorespiratory arrest within 24 h of admission (4·43; 2·25-8·73); and vasopressor requirements (3·67; 2·77-4·86). Steroid therapy was associated with survival (0·55; 0·37-0·81). There was no difference in outcome associated with female sex (0·86; 0·69-1·06).

INTERPRETATION

Mortality in critically ill patients with COVID-19 is higher in African countries than reported from studies done in Asia, Europe, North America, and South America. Increased mortality was associated with insufficient critical care resources, as well as the comorbidities of HIV/AIDS, diabetes, chronic liver disease, and kidney disease, and severity of organ dysfunction at admission.

FUNDING

The ACCCOS was partially supported by a grant from the Critical Care Society of Southern Africa.

Adequacy of the emergency point-of-care ultrasound core curriculum for the local burden of disease in South Africa

OBJECTIVE

This prospective cross-sectional study assesses the adequacy of the current South African emergency point-of-care ultrasound (EPCUS) core curriculum against the local burden of disease.

METHOD

Patients presenting to five Emergency Centres during July 2011 were eligible for inclusion. Patients under the age of 12, after-hour presentations, missing folders and folders with incomplete notes were excluded. Emergency physicians with EPCUS exposure were responsible for data collection. They were all blinded to the study's aim. Summary statistics describe the proportion of clinical cases and procedures for which EPCUS was used. One investigator assessed the adequacy of the curriculum by matching the clinical indications of each module with the presenting complaint and final diagnosis of each patient. The ultrasound modules were ranked according to the frequency of their clinical indications. κ-Statistics are reported on 10% randomly selected cases to quantify interobserver agreement.

RESULTS

The study included 2971 patients. Ultrasound assisted with diagnosis in 384 (12.92%) patients and in 34 (1.14%) procedures. A total of 1933 EPCUS procedures were indicated in 1844 (66.07%) patients. The five most frequently indicated modules were pulmonary, musculoskeletal, cardiac, focused assessment with sonography of HIV/tuberculosis co-infection and renal. The interobserver agreement (κ) was 0.602 (95% CI 0.559 to 0.645).

CONCLUSIONS

This study was an attempt to ensure an evidence-based approach to assess the adequacy of the EPCUS core curriculum in South Africa. The results illustrate that our local burden of disease may require a change of the current core curriculum.

A clinically realistic large animal model of intra-articular fracture that progresses to post-traumatic osteoarthritis

OBJECTIVE

Translation of promising treatments for post-traumatic osteoarthritis (PTOA) to patients with intra-articular fracture (IAF) has been limited by the lack of a realistic large animal model. To address this issue we developed a large animal model of IAF in the distal tibia of Yucatan minipigs and documented the natural progression of this injury.

DESIGN

Twenty-two fractures were treated using open reduction and internal fixation with either an anatomic reduction or an intentional 2-mm step-off. Pre-operatively, and 3 days, 1, 2, 4, 8, and 12 weeks post-operatively, animals were sedated for synovial fluid draws and radiographs. Limb loading was monitored at the same time points using a Tekscan Walkway. Animals were sacrificed at 12 weeks and the limbs were harvested for histological evaluation.

RESULTS

All animals achieved bony union by 12 weeks, facilitating nearly complete recovery of the initial 60% decrease in limb loading. TNFα, IL1β, IL6, and IL8 concentrations in the fractured limbs were elevated (P < 0.05) at specific times during the 2 weeks after fracture. Histological cartilage degeneration was more severe in the step-off group (0.0001 < P < 0.27 compared to normal) than in the anatomic reconstruction group (0.27 < P < 0.99 compared to normal).

CONCLUSIONS

This model replicated key features of a human IAF, including surgical stabilization, inflammatory responses, and progression to osteoarthritic cartilage degeneration, thereby providing a potentially useful model for translating promising treatment options to clinical practice.

Investigation of wearable health tracker version updates

Background

Wearable fitness trackers are increasingly used in healthcare applications; however, the frequent updating of these devices is at odds with traditional medical device practices.

Objective

Our objective was to explore the nature and frequency of wearable tracker updates recorded in device changelogs, to reveal the chronology of updates and to estimate the intervals where algorithm updates could impact device validations.

Method

Updates for devices meeting selection criteria (that included their use in clinical trials) were independently labelled by four researchers according to simple function and specificity schema.

Results

Device manufacturers have diverse approaches to update reporting and changelog practice. Visual representations of device changelogs reveal the nature and chronology of device iterations. 13% of update items were unspecified and 32% possibly affected validations with as few as 5 days between updates that may affect validation.

Conclusion

Manufacturers could aid researchers and health professionals by providing more informative device update changelogs.

SARS-CoV-2 Viral Replication Persists in the Human Lung for Several Weeks after Symptom Onset

Rationale: In the upper respiratory tract, replicating (culturable) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is recoverable for ∼4-8 days after symptom onset, but there is a paucity of data about the frequency and duration of replicating virus in the lower respiratory tract (i.e., the human lung).Objectives: We undertook lung tissue sampling (needle biopsy) shortly after death in 42 mechanically ventilated decedents during the Beta and Delta waves. An independent group of 18 ambulatory patients served as a control group.Methods: Lung biopsy cores from decedents underwent viral culture, histopathological analysis, electron microscopy, transcriptomic profiling, and immunohistochemistry.Measurements and Main Results: Thirty-eight percent (16 of 42) of mechanically ventilated decedents had culturable virus in the lung for a median of 15 days (persisting for up to 4 wk) after symptom onset. Lung viral culture positivity was not associated with comorbidities or steroid use. Delta but not Beta variant lung culture positivity was associated with accelerated death and secondary bacterial infection (P < 0.05). Nasopharyngeal culture was negative in 23.1% (6 of 26) of decedents despite lung culture positivity. This hitherto undescribed biophenotype of lung-specific persisting viral replication was associated with an enhanced transcriptomic pulmonary proinflammatory response but with concurrent viral culture positivity.Conclusions: Concurrent rather than sequential active viral replication continues to drive a heightened proinflammatory response in the human lung beyond the second week of illness and was associated with variant-specific increased mortality and morbidity. These findings have potential implications for the design of interventional strategies and clinical management of patients with severe coronavirus disease (COVID-19).

Outcomes of patients with COVID-19 acute respiratory distress syndrome requiring invasive mechanical ventilation admitted to an intensive care unit in South Africa

BACKGROUND

Up to 32% of patients with COVID-19 pneumonia may require intensive care unit (ICU) admission or mechanical ventilation. Data from low- and middle-income countries on COVID-19 acute respiratory distress syndrome (ARDS) are limited. Groote Schuur Hospital in Cape Town, South Africa, expanded its intensive care service to support patients with COVID-19 ARDS requiring invasive mechanical ventilation (IMV).

OBJECTIVES

To report on patients' characteristics and outcomes from the first two pandemic waves.

METHODS

All patients with COVID-19 ARDS admitted to the ICU for IMV were included in this prospective cohort study. Data were collected from 5 April 2020 to 5 April 2021.

RESULTS

Over the 12-month study period, 461 patients were admitted to the designated COVID-19 ICU. Of these, 380 met the study criteria and 377 had confirmed hospital discharge outcomes. The median (range) age of patients was 51 (17 - 71) years, 50.5% were female, and the median (interquartile range (IQR)) body mass index was 32 (28 - 38) kg/m2. The median (IQR) arterial oxygen partial pressure to fractional inspired oxygen (P/F) ratio was 97 (71 - 128) after IMV was initiated. Comorbidities included diabetes (47.6%), hypertension (46.3%) and HIV infection (10.5%). Of the patients admitted, 30.8% survived to hospital discharge with a median (IQR) ICU length of stay of 19.5 (9 - 36) days. Predictors of mortality after adjusting for confounders were male sex (odds ratio (OR) 1.74), increasing age (OR 1.04) and higher Sequential Organ Failure Assessment (SOFA) score (OR 1.29).

CONCLUSIONS

In a resource-limited environment, the provision of IMV support in the ICU achieved 30.8% hospital survival in patients with COVID-19 ARDS. The ability to predict survival remains difficult given this complex disease.

1751. The Impact of Prophylactic Systemic Antibiotics (PSA) on Cytomegalovirus (CMV) Infection: A Post-hoc Analysis of a Randomized Controlled Trial (RCT) in Hematopoietic Cell Transplantation (HCT) Recipients

Background

Prophylactic systemic antibiotics (PSA) during conditioning regimen-induced neutropenia after hematopoietic cell transplantation (HCT) reduce bacteremia but may disrupt the gut microbiota, potentially affecting viral immunity and risk for viral infections. Prior studies suggest a critical role of gut microbiota in the reconstitution of CMV-specific CD8+ T cells and in protection from respiratory viral infections after HCT (J Immunol 2007; 178: 5209; Blood 2018; 131:2978). To identify whether PSA is associated with differences in CMV infection outcomes after HCT, we conducted a post-hoc analysis of CMV infection in the only RCT of PSA exclusively performed in HCT recipients (Infection 1986; 14:115). In that trial, HCT patients received either PSA (ticarcillin/tobramycin/vancomycin or mezlocillin/ceftizoxime) or no systemic antibiotics during neutropenia (absolute neutrophil count <500/mm³).

Methods

A post-hoc analysis was performed of a previously conducted RCT in the pre-antiviral era (1984–1986) at the Fred Hutch. Patients received unscreened blood products and were tested weekly by CMV culture in throat, and disease was evaluated by tissue biopsy or bronchoalveolar lavage. CMV disease was confirmed by chart review. We compared the cumulative incidence of CMV at any site, CMV throat shedding, and CMV disease between randomization groups by day 100 post-transplant, treating death as a competing risk. Overall survival was also compared using Kaplan–Meier method.

Results

119 and 125 allograft recipients were randomized to PSA and no prophylaxis, respectively. Baseline characteristics in both groups were balanced. CMV infection at any site and CMV throat shedding were greater in the PSA group (Figures 1 and 2); CMV disease was numerically reduced in the no PSA group (Figure 3). Overall survival by day 100 was not different between the groups (Figure 4).

Conclusion

CMV infection risk appeared to be increased in recipients of PSA with a significant anaerobic spectrum. While current PSA regimens have narrower spectrum activity, these results provide the rationale to study if changes in gut microbiota play a role in CMV reactivation and adaptive immunity after HCT.

Disclosures

All authors: No reported disclosures.