A Rapid, Handheld Device to Assess Respiratory Resistance: Clinical and Normative Evidence

Introduction: Following reports of respiratory symptoms among service members returning from deployment to South West Asia (SWA), an expert panel recommended pre-deployment spirometry be used to assess disease burden. Unfortunately, testing with spirometry is high cost and time-consuming. The airflow perturbation device (APD) is a handheld monitor that rapidly measures respiratory resistance (APD-Rr) and has promising but limited clinical data. Its speed and portability make it ideally suited for large volume pre-deployment screening. We conducted a pilot study to assess APD performance characteristics and develop normative values. Materials and Methods: We prospectively enrolled subjects and derived reference equations for the APD from those without respiratory symptoms, pulmonary disease, or tobacco exposure. APD testing was conducted by medical technicians who received a 10-min in-service on its use. A subset of subjects performed spirometry and impulse oscillometry (iOS), administered by trained respiratory therapists. APD measures were compared with spirometry and iOS. Results: The total study population included 199 subjects (55.8% males, body mass index 27.7 ± 6.0 kg/m2, age 49.9 ± 18.7 yr). Across the three APD trials, mean inspiratory (APD-Ri), expiratory (APD-Re), and average (APD-Ravg) resistances were 3.30 ± 1.0, 3.69 ± 1.2, and 3.50 ± 1.1 cm H2O/L/s. Reference equations were derived from 142 clinically normal volunteers. Height, weight, and body mass index were independently associated with APD-Ri, APD-Re, and APD-Ravg and were combined with age and gender in linear regression models. APD-Ri, APD-Re, and APD-Ravg were significantly inversely correlated with FEV1 (r = −0.39 to −0.42), FVC (r = −0.37 to −0.40), and FEF25–75 (r = −0.31 to −0.35) and positively correlated with R5 (r = 0.61–0.62), R20 (r = 0.50–0.52), X5 (r = −0.57 to −0.59), and FRES (r = 0.42–0.43). Bland–Altman plots showed that the APD-Rr closely approximates iOS when resistance is normal. Conclusion: Rapid testing was achieved with minimal training required, and reference equations were constructed. APD-Rr correlated moderately with iOS and weakly with spirometry. More testing is required to determine whether the APD has value for pre- and post-deployment respiratory assessment

Atypical Q Fever in US Soldiers

Q fever is an emerging infectious disease among US soldiers serving in Iraq. Three patients have had atypical manifestations, including 2 patients with acute cholecystitis and 1 patient with acute respiratory distress syndrome. Providers must be aware of Q fever’s signs and symptoms to avoid delays in treatment

The Impact Of Combat Deployment On Asthma Diagnosis And Severity

Environmental exposures during military deployments to Iraq and Afghanistan may lead to higher rates of respiratory complaints and diagnoses. This study investigates whether there is a relationship between rates of asthma diagnosis and severity associated with military deployment. Methods: Retrospective review of active duty Army personnel underwent fitness for duty evaluation (Medical Evaluation Board) for asthma. The electronic medical record was reviewed for onset of diagnosis (pre-or post-deployment), disease severity, screening spirometry, bronchodilator response and bronchoprovocation testing. We compared patients with and without a history of combat deployment to Operations Iraqi Freedom/Enduring Freedom. Results: Four hundred consecutive Army personnel with a clinical diagnosis of asthma were evaluated. Equal numbers of patients had deployed (48.5%) versus never deployed (51.5%). Of those who deployed, 98 (24.5%) were diagnosed post-deployment. The diagnosis of asthma was objectively confirmed in 74.8% of patients by obstructive screening spirometry, bronchodilator response, and/or methacholine challenge testing. There were no significant differences in spirometry between deployers and non-deployers or based on pre-and post-deployment diagnosis. Similarly, asthma severity classification did not differ between deployed and non-deployed service members, or by pre-and post-deployment diagnosis status. Conclusions: Among active duty military personnel with career limiting asthma, there is no significant relationship between rates of diagnosis or severity based on history of deployment to Southwest Asia

Prevention, diagnosis and treatment of venous thromboembolism in patients with COVID-19: CHEST Guideline and Expert Panel Report.

BACKGROUND Emerging evidence shows that severe COVID-19 can be complicated by a significant coagulopathy, that likely manifests in the form of both microthrombosis and venous thromboembolism (VTE). This recognition has led to the urgent need for practical guidance regarding prevention, diagnosis, and treatment of VTE. METHODS A group of approved panelists developed key clinical questions by using the PICO (population, intervention, comparator, and outcome) format that addressed urgent clinical questions regarding the prevention, diagnosis and treatment of venous thromboembolism in patients with COVID-19. MEDLINE (via PubMed or Ovid), Embase and Cochrane Controlled Register of Trials were systematically searched for relevant literature and references were screened for inclusion. Validated evaluation tools were used to grade the level of evidence to support each recommendation. When evidence did not exist, guidance was developed based on consensus using the modified Delphi process. RESULTS The systematic review and critical analysis of the literature based on13 PICO questions resulted in 22 statements. Very little evidence exists in the COVID-19 population. The panel thus used expert consensus and existing evidence-based guidelines to craft the guidance statements. CONCLUSIONS The evidence on the optimal strategies to prevent, diagnose, and treat venous thromboembolism in patients with COVID-19 is sparse, but rapidly evolving

A Rapid, Handheld Device to Assess Respiratory Resistance: Clinical and Normative Evidence

Introduction: Following reports of respiratory symptoms among service members returning from deployment to South West Asia (SWA), an expert panel recommended pre-deployment spirometry be used to assess disease burden. Unfortunately, testing with spirometry is high cost and time-consuming. The airflow perturbation device (APD) is a handheld monitor that rapidly measures respiratory resistance (APD-Rr) and has promising but limited clinical data. Its speed and portability make it ideally suited for large volume pre-deployment screening. We conducted a pilot study to assess APD performance characteristics and develop normative values. Materials and Methods: We prospectively enrolled subjects and derived reference equations for the APD from those without respiratory symptoms, pulmonary disease, or tobacco exposure. APD testing was conducted by medical technicians who received a 10-min in-service on its use. A subset of subjects performed spirometry and impulse oscillometry (iOS), administered by trained respiratory therapists. APD measures were compared with spirometry and iOS. Results: The total study population included 199 subjects (55.8% males, body mass index 27.7 ± 6.0 kg/m2, age 49.9 ± 18.7 yr). Across the three APD trials, mean inspiratory (APD-Ri), expiratory (APD-Re), and average (APD-Ravg) resistances were 3.30 ± 1.0, 3.69 ± 1.2, and 3.50 ± 1.1 cm H2O/L/s. Reference equations were derived from 142 clinically normal volunteers. Height, weight, and body mass index were independently associated with APD-Ri, APD-Re, and APD-Ravg and were combined with age and gender in linear regression models. APD-Ri, APD-Re, and APD-Ravg were significantly inversely correlated with FEV1 (r = −0.39 to −0.42), FVC (r = −0.37 to −0.40), and FEF25–75 (r = −0.31 to −0.35) and positively correlated with R5 (r = 0.61–0.62), R20 (r = 0.50–0.52), X5 (r = −0.57 to −0.59), and FRES (r = 0.42–0.43). Bland–Altman plots showed that the APD-Rr closely approximates iOS when resistance is normal. Conclusion: Rapid testing was achieved with minimal training required, and reference equations were constructed. APD-Rr correlated moderately with iOS and weakly with spirometry. More testing is required to determine whether the APD has value for pre- and post-deployment respiratory assessment

Post-COVID-19 Pulmonary Fibrosis: Novel Sequelae of the Current Pandemic

Since the initial identification of the novel coronavirus SARS-CoV-2 in December 2019, the COVID-19 pandemic has become a leading cause of morbidity and mortality worldwide. As effective vaccines and treatments begin to emerge, it will become increasingly important to identify and proactively manage the long-term respiratory complications of severe disease. The patterns of imaging abnormalities coupled with data from prior coronavirus outbreaks suggest that patients with severe COVID-19 pneumonia are likely at an increased risk of progression to interstitial lung disease (ILD) and chronic pulmonary vascular disease. In this paper, we briefly review the definition, classification, and underlying pathophysiology of interstitial lung disease (ILD). We then review the current literature on the proposed mechanisms of lung injury in severe COVID-19 infection, and outline potential viral- and immune-mediated processes implicated in the development of post-COVID-19 pulmonary fibrosis (PCPF). Finally, we address patient-specific and iatrogenic risk factors that could lead to PCPF and discuss strategies for reducing risk of pulmonary complications/sequelae

Thromboprophylaxis in Patients with COVID-19. A Brief Update to the CHEST Guideline and Expert Panel Report.

BACKGROUND Patients hospitalized with COVID-19 often exhibit markers of a hypercoagulable state and have an increased incidence of venous thromboembolism (VTE). In response, CHEST issued rapid clinical guidance regarding prevention of VTE. Over the past 18 months the quality of the evidence has improved. We thus sought to incorporate this evidence and update our recommendations as necessary. METHODS This update focuses on the optimal approach to thromboprophylaxis in hospitalized patients. The original questions were used to guide the search, using MEDLINE via PubMed. Eight randomized controlled trials and one observational study were included. Meta-analysis, using a random effects model, was performed. The panel created summaries using the GRADE Evidence-to-Decision framework. Updated guidance statements were drafted, and a modified Delphi approach was used to obtain consensus. RESULTS We provide separate guidance statements for VTE prevention for acutely (moderately) ill hospitalized patients and critically ill patients in the ICU. However, we divided each original question and resulting recommendation into two questions: standard prophylaxis vs. therapeutic (or escalated dose) prophylaxis and standard prophylaxis vs. intermediate dose prophylaxis. This led to a change in one recommendation, and an upgrading of three additional recommendations based upon higher quality evidence. CONCLUSIONS Advances in care for patients with COVID-19 have improved overall outcomes. Despite this, rates of VTE in these patients remain elevated. Critically ill patients should receive standard thromboprophylaxis for VTE and moderately ill patients with a low bleeding risk might benefit from therapeutic heparin. We see no role for intermediate dose thromboprophylaxis in either setting