American journal of respiratory and critical care medicine
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Am. J. Respir. Crit. Care Med. · Oct 2020
Tissue Doppler Imaging of the Diaphragm in Healthy Subjects and Critically Ill Patients.
Rationale: Tissue Doppler imaging (TDI) is an echocardiographic method that measures the velocity of moving tissue. Objectives: We applied this technique to the diaphragm to assess the velocity of diaphragmatic muscle motion during contraction and relaxation. Methods: In 20 healthy volunteers, diaphragmatic TDI was performed to assess the pattern of diaphragmatic motion velocity, measure its normal values, and determine the intra- and interobserver variability of measurements. ⋯ Peak contraction velocity was strongly correlated with peak transdiaphragmatic pressure and pressure-time product, whereas Pdi-maximal relaxation rate was significantly correlated with TDI-maximal relaxation rate. Conclusions: Diaphragmatic tissue Doppler allows real-time assessment of the diaphragmatic tissue motion velocity. Diaphragmatic TDI-derived parameters differentiate patients who fail a weaning trial from those who succeed and correlate well with Pdi-derived parameters.
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Am. J. Respir. Crit. Care Med. · Oct 2020
Evidence for Exacerbation-Prone Asthma and Predictive Biomarkers of Exacerbation Frequency.
Rationale: Cross-sectional studies suggest an exacerbation-prone asthma (EPA) phenotype and the utility of blood eosinophils and plasma IL-6 as predictive biomarkers. Objectives: To prospectively test for EPA phenotype and utility of baseline blood measures of eosinophils and IL-6 as predictive biomarkers. Methods: Three-year asthma exacerbation data were analyzed in 406 adults in the Severe Asthma Research Program-3. ⋯ Although high blood eosinophils did not occur in EPA, the incident rate ratio for exacerbations increased 9% for each 100-cell/μl increase in baseline eosinophil number. Conclusions: Longitudinal analysis confirms an EPA phenotype characterized by features of metabolic dysfunction. Blood measures of IL-6, but not eosinophils, were significantly associated with EPA, and IL-6 and eosinophils predicted exacerbations in the sample as a whole.
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Am. J. Respir. Crit. Care Med. · Oct 2020
Age Associated B Cells Appear in Patients with Granulomatous Lung Diseases.
Rationale: A subpopulation of B cells (age-associated B cells [ABCs]) is increased in mice and humans with infections or autoimmune diseases. Because depletion of these cells might be valuable in patients with certain lung diseases, the goal was to find out if ABC-like cells were at elevated levels in such patients. Objectives: To measure ABC-like cell percentages in patients with lung granulomatous diseases. ⋯ Treatment of patients with sarcoidosis led to reduced percentages of ABC-like cells in blood. Conclusions: Increased levels of ABC-like cells in patients with sarcoidosis may be useful in diagnosis. The increase in percentage of ABC-like cells in patients with lung granulomatous diseases and decrease in treated patients suggests that depletion of these cells may be valuable.