Elevated blood lactate in COPD exacerbations associates with adverse clinical outcomes and signals excessive treatment with β2 -agonists

BACKGROUND AND OBJECTIVE

Raised blood lactate secondary to high dose β2 -agonist treatment has been reported in asthma exacerbations but has not been investigated during acute exacerbations of COPD (AECOPD). We explored associations of blood lactate measurements with disease outcomes and β2 -agonist treatments during AECOPD.

METHODS

Retrospective (n = 199) and prospective studies (n = 142) of patients hospitalized with AECOPD were conducted. The retrospective cohort was identified via medical records and the prospective cohort was recruited during hospitalization for AECOPD. Baseline demographics, comorbidities, β2 -agonist treatment, biochemical measurements and clinical outcomes were compared between patients with normal (≤2.0 mmol/L) versus elevated lactate (>2.0 mmol/L). Regression analyses examined associations of lactate measurements with β2 -agonist dosages.

RESULTS

Demographic data and comorbidities were similar between high versus normal lactate groups in both cohorts. The populations were elderly (mean >70 years), predominantly male (>60%) with reduced FEV1 (%) 48.2 ± 19 (prospective cohort). Lactate was elevated in approximately 50% of patients during AECOPD and not related to evidence of sepsis. In the prospective cohort, patients with high lactate had more tachypnoea, tachycardia, acidosis and hyperglycaemia (p < 0.05) and received more non-invasive ventilation (37% vs. 9.7%, p < 0.001, prospective cohort). There was a trend to longer hospitalization (6 vs. 5 days, p = 0.06, prospective cohort). Higher cumulative β2 -agonist dosages were linked to elevated lactate levels (OR 1.04, p = 0.01).

CONCLUSION

Elevated lactate during AECOPD was common, unrelated to sepsis and correlated with high cumulative doses of β2 -agonists. Raised lactate may indicate excessive β2 -agonist treatment and should now be investigated as a possible biomarker.

Computed Tomography Imaging of the Larynx for Diagnosis of Vocal Cord Dysfunction

Larynx CT for Vocal Cord Dysfunction DiagnosisThis study compared VCD diagnosis using CT imaging of the larynx with laryngoscopy (diagnostic standard). In one, CT imaging and laryngoscopy were performed on the same day; in the other, diagnostic studies were 4 to 6 weeks apart. A negative CT imaging result had a negative predictive value for VCD greater than 80% when positive population prevalence was 30%.

OUP accepted manuscript

Background

Healthcare workers (HCWs) are at risk from aerosol transmission of severe acute respiratory syndrome coronavirus 2. The aims of this study were to (1) quantify the protection provided by masks (surgical, fit-test_FAILED N95, fit-test_PASSED N95) and personal protective equipment (PPE), and (2) determine if a portable high-efficiency particulate air (HEPA) filter can enhance the benefit of PPE.

Methods

Virus aerosol exposure experiments using bacteriophage PhiX174 were performed. An HCW wearing PPE (mask, gloves, gown, face shield) was exposed to nebulized viruses (10⁸ copies/mL) for 40 minutes in a sealed clinical room. Virus exposure was quantified via skin swabs applied to the face, nostrils, forearms, neck, and forehead. Experiments were repeated with a HEPA filter (13.4 volume-filtrations/hour).

Results

Significant virus counts were detected on the face while the participants were wearing either surgical or N95 masks. Only the fit-test_PASSED N95 resulted in lower virus counts compared to control (P = .007). Nasal swabs demonstrated high virus exposure, which was not mitigated by the surgical/fit-test_FAILED N95 masks, although there was a trend for the fit-test_PASSED N95 mask to reduce virus counts (P = .058). HEPA filtration reduced virus to near-zero levels when combined with fit-test_PASSED N95 mask, gloves, gown, and face shield.

Conclusions

N95 masks that have passed a quantitative fit-test combined with HEPA filtration protects against high virus aerosol loads at close range and for prolonged periods of time.

Right ventricular end-diastolic volume and outcomes in exacerbations of COPD

BACKGROUND AND OBJECTIVE

Right ventricular (RV) volumes are crucial outcome determinants in pulmonary diseases. Little is known about the associations of RV volumes during hospitalized acute exacerbations of chronic obstructive pulmonary disease (AECOPD). We aimed to ascertain associations of RV end-diastolic volume indexed to body surface area (RVEDVI) during hospitalized AECOPD and its relationship with mortality in long-term follow-up.

METHODS

This is a prospective observational cohort study (December 2013-November 2019, ACTRN12617001562369) using dynamic retrospective ECG-gated computed tomography during hospitalized AECOPD. RVEDVI was defined as normal or high using Framingham Offspring Cohort values. Cox regression determined the prognostic relevance of RVEDVI for death.

RESULTS

A total of 148 participants (70 ± 10 years [mean ± SD], 88 [59%] men) were included, of whom 75 (51%) had high RVEDVI. This was associated with more frequent hospital admissions in the 12 months before admission (52/75 [69%] vs. 38/73 [52%], p = 0.04) and higher breathlessness (modified Medical Research Council score, 2.9 ± 1.3 vs. 2.4 ± 1.2, p = 0.007). During follow-up, high RVEDVI was associated with greater mortality (log-rank p = 0.001). In univariable Cox regression, increasing RVEDVI was associated with higher mortality (hazard ratio [HR]: 1.02 per ml/m² ; 95% CI: 1.01, 1.03; p = 0.001). In multivariable Cox regression, RVEDVI was independently associated with mortality (HR: 1.01 per ml/m² ; 95% CI: 1.00, 1.03; p = 0.050) at a borderline significance level. Adding RVEDVI to three COPD mortality prediction systems improved model fit (pooled chi-square test [BODE: p = 0.05, ADO: p = 0.04, DOSE: p = 0.02]).

CONCLUSION

In patients with hospitalized AECOPD, higher RV end-diastolic volume was associated with worse acute clinical parameters and greater mortality.

MULTI-PHACET: multidimensional clinical phenotyping of hospitalised acute COPD exacerbations

Background

The generic term “exacerbation” does not reflect the heterogeneity of acute exacerbations of COPD (AECOPD). We utilised a novel algorithmic strategy to profile exacerbation phenotypes based on underlying aetiologies.

Methods

Patients hospitalised for AECOPD (n=146) were investigated for aetiological contributors summarised in a mnemonic acronym ABCDEFGX (A: airway virus; B: bacterial; C: co-infection; D: depression/anxiety; E: eosinophils; F: failure (cardiac); G: general environment; X: unknown). Results from clinical investigations were combined to construct AECOPD phenotypes. Relationships to clinical outcomes were examined for both composite phenotypes and their specific aetiological components. Aetiologies identified at exacerbation were reassessed at outpatient follow-up.

Results

Hospitalised AECOPDs were remarkably diverse, with 26 distinct phenotypes identified. Multiple aetiologies were common (70%) and unidentifiable aetiology rare (4.1%). If viruses were detected (29.5%), patients had longer hospitalisation (7.7±5.6 versus 6.0±3.9 days, p=0.03) despite fewer “frequent exacerbators” (9.3% versus 37%, p=0.001) and lower mortality at 1 year (p=0.03). If bacterial infection was found (40.4%), patients were commonly “frequent exacerbators” (44% versus 18.4%, p=0.001). Eosinophilic exacerbations (28%) were associated with lower pH (7.32±0.06 versus 7.36±0.09, p=0.04), higher venous carbon dioxide tension (P_vCO2) (53.7±10.5 versus 48.8±12.8, p=0.04), greater noninvasive ventilation (NIV) usage (34.1% versus 18.1%) but shorter hospitalisation (4 (3–5) versus 6 (4–9) days, p<0.001) and lower infection rates (41.4% versus 80.9%, p<0.0001). Cardiac dysfunction and severe anxiety/depression were common in both infective and non-infective exacerbations. Characteristics identified at exacerbation often persisted after recovery.

Conclusions

Hospitalised AECOPDs have numerous causes, often in combination, that converge in complex, multi-faceted phenotypes. Clinically important differences in outcomes suggest that a phenotyping strategy based on aetiologies can enhance AECOPD management.

Hospitalised #AECOPD present as complex multidimensional clinical phenotypes, often comprising multiple distinct aetiologies. Profiling AECOPDs according to their multifactorial aetiological components has important prognostic and therapeutic implications.https://bit.ly/3nIHEnO

Viable virus aerosol propagation by positive airway pressure circuit leak and mitigation with a ventilated patient hood

INTRODUCTION

Nosocomial transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been a major feature of the COVID-19 pandemic. Evidence suggests patients can auto-emit aerosols containing viable viruses; these aerosols could be further propagated when patients undergo certain treatments, including continuous positive airway pressure (PAP) therapy. Our aim was to assess 1) the degree of viable virus propagated from PAP circuit mask leak and 2) the efficacy of a ventilated plastic canopy to mitigate virus propagation.

METHODS

Bacteriophage phiX174 (10⁸ copies·mL^-1) was nebulised into a custom PAP circuit. Mask leak was systematically varied at the mask interface. Plates containing Escherichia coli host quantified viable virus (via plaque forming unit) settling on surfaces around the room. The efficacy of a low-cost ventilated headboard created from a tarpaulin hood and a high-efficiency particulate air (HEPA) filter was tested.

RESULTS

Mask leak was associated with virus contamination in a dose-dependent manner (χ²=58.24, df=4, p<0.001). Moderate mask leak (≥21 L·min^-1) was associated with virus counts equivalent to using PAP with a vented mask. The highest frequency of viruses was detected on surfaces <1 m away; however, viable viruses were recorded up to 3.86 m from the source. A plastic hood with HEPA filtration significantly reduced viable viruses on all plates. HEPA exchange rates ≥170 m³·h^-1 eradicated all evidence of virus contamination.

CONCLUSIONS

Mask leak from PAP may be a major source of environmental contamination and nosocomial spread of infectious respiratory diseases. Subclinical mask leak levels should be treated as an infectious risk. Low-cost patient hoods with HEPA filtration are an effective countermeasure.

Treatable cardiac disease in hospitalised COPD exacerbations

Introduction

Acute exacerbations of COPD (AECOPD) are accompanied by escalations in cardiac risk superimposed upon elevated baseline risk. Appropriate treatment for coronary artery disease (CAD) and heart failure with reduced ejection fraction (HFrEF) could improve outcomes. However, securing these diagnoses during AECOPD is difficult, so their true prevalence remains unknown, as does the magnitude of this treatment opportunity. We aimed to determine the prevalence of severe CAD and severe HFrEF during hospitalised AECOPD using dynamic computed tomography (CT).

Methods

A cross-sectional study of 148 patients with hospitalised AECOPD was conducted. Dynamic CT was used to identify severe CAD (Agatston score ≥400) and HFrEF (left ventricular ejection fraction ≤40% and/or right ventricular ejection fraction ≤35%).

Results

Severe CAD was detected in 51 of 148 patients (35%), left ventricular systolic dysfunction was identified in 12 cases (8%) and right ventricular systolic dysfunction was present in 18 (12%). Clinical history and examination did not identify severe CAD in approximately one-third of cases and missed HFrEF in two-thirds of cases. Elevated troponin and brain natriuretic peptide did not differentiate subjects with severe CAD from nonsevere CAD, nor distinguish HFrEF from normal ejection fraction. Undertreatment was common. Of those with severe CAD, only 39% were prescribed an antiplatelet agent, and 53% received a statin. Of individuals with HFrEF, 50% or less received angiotensin blockers, beta blockers or antimineralocorticoids.

Conclusion

Dynamic CT detects clinically covert CAD and HFrEF during AECOPD, identifying opportunities to improve outcomes via well-established cardiac treatments.

Severe, treatable cardiac disease is present during hospitalised #AECOPD exacerbations, and is often clinically unsuspected. This cardiac disease can be detected with dynamic CT. Appropriate treatment could change outcomes.https://bit.ly/2Is45wO

Expiratory central airway collapse in stable COPD and during exacerbations

Background

Tracheal obstruction resulting from expiratory tracheal deformation has been associated with respiratory symptoms and severe airway exacerbations. In chronic obstructive pulmonary disease (COPD), acute exacerbations (AECOPD) create large intrathoracic pressure swings which may increase tracheal deformation. Excessive central airway collapse (ECAC) may be diagnosed when the tracheal area on expiration is less than 50% of that on inspiration. The prevalence of ECAC in AECOPD and its temporal course have not been systematically studied.

Methods

We prospectively recruited healthy volunteers (n = 53), stable outpatients with COPD (n = 40) and patients with hospitalised acute exacerbations of COPD (AECOPD, n = 64). 17 of the AECOPD group returned for repeat evaluation when clinically well at 6–12 weeks. All subjects underwent dynamic 320-slice computed tomography of the larynx and trachea during tidal breathing, enabling quantitation of tracheal area and dimensions (mean ± SD).

Results

No healthy individuals had ECAC. The prevalence of ECAC in stable COPD and AECOPD was 35% and 39% respectively. Mean tracheal collapse did not differ between stable COPD (57.5 ± 19.8%), AECOPD (53.8 ± 19.3%) and in the subset who returned when convalescent (54.9 ± 17.2%). AECOPD patients with and without ECAC had similar clinical characteristics.

Conclusions

Tracheal collapse in both stable and AECOPD is considerably more prevalent than in healthy individuals. ECAC warrants assessment as part of comprehensive COPD evaluation and management. Further studies should evaluate the aetiology of ECAC and whether it predisposes to exacerbations.

Electronic supplementary material

The online version of this article (10.1186/s12931-017-0646-2) contains supplementary material, which is available to authorized users.

Human Metapneumovirus Infection in Chronic Obstructive Pulmonary Disease: Impact of Glucocorticosteroids and Interferon

Background

Human metapneumovirus (hMPV) infection is implicated in exacerbations of asthma and chronic obstructive pulmonary disease (COPD). Research into the pathogenesis of infection is restricted to animal models, and information about hMPV replication and inflammatory and immune responses in human disease is limited.

Methods

Human primary bronchial epithelial cells (PBECs) from healthy and asthmatic subjects and those with COPD were infected with hMPV, with or without glucocorticosteroid (GCS) exposure. Viral replication, inflammatory and immune responses, and apoptosis were analyzed. We also determined whether adjuvant interferon (IFN) can blunt hMPV infection in vitro and in a murine model.

Results

hMPV infected human PBECs and viral replication was enhanced in cells from patients with COPD. The virus induced gene expression of IFN-stimulated gene 56 (ISG56) and IFN-β, as well as IFN-γ-inducible protein 10 (IP-10) and regulated on activation, normal T cell expressed and secreted (RANTES), and more so in cells from patients with COPD. GCS exposure enhanced hMPV replication despite increased IFN expression. Augmented virus replication associated with GCS was mediated by reduced apoptosis via induction of antiapoptotic genes. Adjuvant IFN treatment suppressed hMPV replication in PBECs and reduced hMPV viral titers and inflammation in vivo.

Conclusions

hMPV infects human PBECs, eliciting innate and inflammatory responses. Replication is enhanced by GCS and adjuvant IFN is an effective treatment, restricting virus replication and proinflammatory consequences of hMPV infections.