Infectious Diseases Society of America Guidelines on Infection Prevention for Healthcare Personnel Caring for Patients with Suspected or Known COVID-19.

BACKGROUND: Since its emergence in late 2019, SARS-CoV-2 continues to pose a risk to healthcare personnel (HCP) and patients in healthcare settings. Although all clinical interactions likely carry some risk of transmission, human actions like coughing and care activities like aerosol-generating procedures likely have a higher risk of transmission. The rapid emergence and global spread of SARS-CoV-2 continues to create significant challenges in healthcare facilities, particularly with shortages of personal protective equipment (PPE) used by HCP. Evidence-based recommendations for what PPE to use in conventional, contingency, and crisis standards of care continue to be needed. Where evidence is lacking, the development of specific research questions can help direct funders and investigators. OBJECTIVE: Develop evidence-based rapid guidelines intended to support HCP in their decisions about infection prevention when caring for patients with suspected or known COVID-19. METHODS: IDSA formed a multidisciplinary guideline panel including frontline clinicians, infectious disease specialists, experts in infection control, and guideline methodologists with representation from the disciplines of public health, medical microbiology, pediatrics, critical care medicine and gastroenterology. The process followed a rapid recommendation checklist. The panel prioritized questions and outcomes. Then a systematic review of the peer-reviewed and grey literature was conducted. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess the certainty of evidence and make recommendations. RESULTS: The IDSA guideline panel agreed on eight recommendations, including two updated recommendations and one new recommendation added since the first version of the guideline. Narrative summaries of other interventions undergoing evaluations are also included. CONCLUSIONS: Using a combination of direct and indirect evidence, the panel was able to provide recommendations for eight specific questions on the use of PPE for HCP providing care for patients with suspected or known COVID-19. Where evidence was lacking, attempts were made to provide potential avenues for investigation. There remain significant gaps in the understanding of the transmission dynamics of SARS-CoV-2 and PPE recommendations may need to be modified in response to new evidence. These recommendations should serve as a minimum for PPE use in healthcare facilities and do not preclude decisions based on local risk assessments or requirements of local health jurisdictions or other regulatory bodies.

Systematic review and meta-analysis of outcomes in patients with suspected pulmonary embolism.

Prompt evaluation and therapeutic intervention of suspected pulmonary embolism (PE) are of paramount importance for improvement in outcomes. We systematically reviewed outcomes in patients with suspected PE, including mortality, incidence of recurrent PE, major bleeding, intracranial hemorrhage, and postthrombotic sequelae. We searched the Cochrane Central Register of Controlled Trials, MEDLINE, and Embase for eligible studies, reference lists of relevant reviews, registered trials, and relevant conference proceedings. We included 22 studies with 15 865 patients. Among patients who were diagnosed with PE and discharged with anticoagulation, 3-month follow-up revealed that all-cause mortality was 5.69% (91/1599; 95% confidence interval [CI], 4.56-6.83), mortality from PE was 1.19% (19/1597; 95% CI, 0.66-1.72), recurrent venous thromboembolism (VTE) occurred in 1.38% (22/1597; 95% CI: 0.81-1.95), and major bleeding occurred in 0.90% (2/221%; 95% CI, 0-2.15). In patients with a low pretest probability (PTP) and negative D-dimer, 3-month follow-up revealed mortality from PE was 0% (0/808) and incidence of VTE was 0.37% (4/1094; 95% CI: 0.007-0.72). In patients with intermediate PTP and negative D-dimer, 3-month follow-up revealed that mortality from PE was 0% (0/2747) and incidence of VTE was 0.46% (14/3015; 95% CI: 0.22-0.71). In patients with high PTP and negative computed tomography (CT) scan, 3-month follow-up revealed mortality from PE was 0% (0/651) and incidence of VTE was 0.84% (11/1302; 95% CI: 0.35-1.34). We further summarize outcomes evaluated by various diagnostic tests and diagnostic pathways (ie, D-dimer followed by CT scan).

Systematic review and meta-analysis of test accuracy for the diagnosis of suspected pulmonary embolism.

Pulmonary embolism (PE) is a common, potentially life-threatening yet treatable condition. Prompt diagnosis and expeditious therapeutic intervention is of paramount importance for optimal patient management. Our objective was to systematically review the accuracy of D-dimer assay, compression ultrasonography (CUS), computed tomography pulmonary angiography (CTPA), and ventilation-perfusion (V/Q) scanning for the diagnosis of suspected first and recurrent PE. We searched Cochrane Central, MEDLINE, and EMBASE for eligible studies, reference lists of relevant reviews, registered trials, and relevant conference proceedings. 2 investigators screened and abstracted data. Risk of bias was assessed using Quality Assessment of Diagnostic Accuracy Studies-2 and certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation framework. We pooled estimates of sensitivity and specificity. The review included 61 studies. The pooled estimates for D-dimer sensitivity and specificity were 0.97 (95% confidence interval [CI], 0.96-0.98) and 0.41 (95% CI, 0.36-0.46) respectively, whereas CTPA sensitivity and specificity were 0.94 (95% CI, 0.89-0.97) and 0.98 (95% CI, 0.97-0.99), respectively, and CUS sensitivity and specificity were 0.49 (95% CI, 0.31-0.66) and 0.96 (95% CI, 0.95-0.98), respectively. Three variations of pooled estimates for sensitivity and specificity of V/Q scan were carried out, based on interpretation of test results. D-dimer had the highest sensitivity when compared with imaging. CTPA and V/Q scans (high probability scan as a positive and low/non-diagnostic/normal scan as negative) both had the highest specificity. This systematic review was registered on PROSPERO as CRD42018084669.

Diagnosis of deep vein thrombosis of the upper extremity: a systematic review and meta-analysis of test accuracy.

Upper extremity deep vein thrombosis (UEDVT) accounts for ≤10% of DVT and can be associated with morbidity and mortality. Accurate diagnosis and treatment are necessary for safe and effective patient management. We systematically reviewed the accuracy of D-dimer and duplex ultrasonography (US) for the evaluation of suspected first-episode UEDVT. We searched the Cochrane Central Register, OVID MEDLINE, EMBASE, and PubMed for eligible studies, reference lists of relevant reviews, registered trials, and relevant conference proceedings. We included prospective cross-sectional and cohort studies that evaluated test accuracy. Two investigators independently screened and collected data. The risk of bias was assessed using Quality Assessment of Diagnostic Accuracy Studies 2 and certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation framework. We pooled estimates of sensitivity and specificity. The review included 9 studies. The pooled estimates for D-dimer sensitivity and specificity were 0.96 (95% confidence interval [CI], 0.87-0.99) and 0.47 (95% CI, 0.43-0.52), respectively. The pooled estimates for duplex US sensitivity and specificity were 0.87 (95% CI, 0.73-0.94) and 0.85 (95% CI, 0.72-0.93), respectively. Certainty of evidence was moderate. In this review, we summarized the test accuracy (sensitivity and specificity) of D-dimer and duplex US for this indication. The sensitivity and specificity of the tests found in the present review should be considered in the context of whether they are used alone or in combination, which is dependent on the prevalence of disease in the population, the clinical setting in which the patient is being evaluated, cost, potential harms, and patient outcomes. This study was registered at PROSPERO as Systematic Review Registration Number CRD42018098488.

Systematic review and meta-analysis of outcomes in patients with suspected deep vein thrombosis.

After deep vein thrombosis (DVT) is diagnosed, prompt evaluation and therapeutic intervention are of paramount importance for improvement in patient-important outcomes. We systematically reviewed patient-important outcomes in patients with suspected DVT, including mortality, incidence of pulmonary embolism (PE) and DVT, major bleeding, intracranial hemorrhage, and postthrombotic sequelae. We searched the Cochrane Central Register of Controlled Trials, Ovid Medline, Embase for eligible studies, references lists of relevant reviews, registered trials, and relevant conference proceedings. Two investigators screened and abstracted data. Nine studies with 5126 patients were included for lower extremity DVT. Three studies with 500 patients were included for upper extremity DVT. Among patients with lower extremity DVT, 0.85% (95% confidence interval [CI], 0% to 2.10%) and 0% developed recurrent DVT and PE, respectively, at 3 months. Among patients with upper extremity DVT, 0.49% (95% CI, 0% to 1.16%) and 1.98% (95% CI, 0.62% to 3.33%) developed recurrent DVT and PE, respectively, at 3 months. No major bleeding events were reported for those anticoagulated, which is lower than in other systematic reviews. For both upper and lower extremity DVT, low pretest probability patients with a negative D-dimer had a comparable incidence of VTE at 3 months (∼1%) as patients with a negative ultrasound (US). At higher pretest probabilities, negative US testing with or without serial US appears to be the safer option. In this review, we summarized the outcomes of patients evaluated by various diagnostic pathways. In most instances, there was significant limitation due to small population size or lack of direct evidence of effects of using a specific pathway. This systematic review was registered at PROSPERO as CRD42018100502.

Diagnosis of deep vein thrombosis of the lower extremity: a systematic review and meta-analysis of test accuracy.

Deep vein thrombosis (DVT) of the lower extremities can be associated with significant morbidity and may progress to pulmonary embolism and postthrombotic syndrome. Early diagnosis and treatment are important to minimize the risk of these complications. We systematically reviewed the accuracy of diagnostic tests for first-episode and recurrent DVT of the lower extremities, including proximal compression ultrasonography (US), whole leg US, serial US, and high-sensitivity quantitative D-dimer assays. We searched Cochrane Central, MEDLINE, and EMBASE for eligible studies, reference lists of relevant reviews, registered trials, and relevant conference proceedings. Two investigators screened and abstracted data. Risk of bias was assessed using Quality Assessment of Diagnostic Accuracy Studies-2 and certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation framework. We pooled estimates of sensitivity and specificity. The review included 43 studies. For any suspected DVT, the pooled estimates for sensitivity and specificity of proximal compression US were 90.1% (95% confidence interval [CI], 86.5-92.8) and 98.5% (95% CI, 97.6-99.1), respectively. For whole-leg US, pooled estimates were 94.0% (95% CI, 91.3-95.9) and 97.3% (95% CI, 94.8-98.6); for serial US pooled estimates were 97.9% (95% CI, 96.0-98.9) and 99.8% (95% CI, 99.3-99.9). For D-dimer, pooled estimates were 96.1% (95% CI, 92.6-98.0) and 35.7% (95% CI, 29.5-42.4). Recurrent DVT studies were not pooled. Certainty of evidence varied from low to high. This systematic review of current diagnostic tests for DVT of the lower extremities provides accuracy estimates. The tests are evaluated when performed in a stand-alone fashion, and in a diagnostic pathway. The pretest probability of DVT often assessed by a clinical decision rule will influence how, together with sensitivity and specificity estimates, patients will be managed.

Molecular mechanisms of cardiac myofilament activation: modulation by pH and a troponin T mutant R92Q.

Activation of cardiac myofilaments is a complex process involving steric, allosteric, and cooperative mechanisms. The complexity of the protein-protein interactions that result in the rise and fall of tension in the heartbeat provide many points that may be modified by various control mechanisms. These include modulation by the sarcomere length, covalent modulation by protein phosphorylation and non-covalent modulation by the chemical environment surrounding the myofilaments. We focus here on effects of pH change in the context of one of the mutations in cardiac troponin T (R92Q) that causes familial hypertrophic cardiomyopathy (FHC). We tested whether this change in charge would manifest itself functionally by a difference in the pCa-force relations of skinned fiber bundles activated at pH values of 6.5, 7.0 and 7.5. Fiber bundles containing the cTnT-R92Q mutant demonstrated an increase in sensitivity to Ca2+ at all three pH values. However, the relative magnitude of the increase in Ca2+-sensitivity induced by the mutant cTnT increased as the pH was decreased from pH 7.5 to pH 7.0 and to pH 6.5. Maximum force generated by the myofilaments fell as pH was lowered over this range, but the percent fall in maximum force was the same for fiber bundles containing wild-type and mutant cTnT. Our results indicate that ischemia that may be associated with FHC may exacerbate the functional changes induced by the cTnT mutation.