-
Journal of Equine Veterinary Science Apr 2024Equine asthma (EA) is a respiratory syndrome associated with the increase of different leukocyte populations in the bronchoalveolar lavage fluid (BALF). Its pathogenetic...
Equine asthma (EA) is a respiratory syndrome associated with the increase of different leukocyte populations in the bronchoalveolar lavage fluid (BALF). Its pathogenetic mechanisms remain unclear. This study aimed to evaluate the associations between the mRNA expression of different cytokines in the BALF, different EA subtypes and lung function. Fifteen horses underwent physical examination, airway endoscopy, BALF cytology and lung function testing (8/15). One horse did not have evidence of EA and was used as healthy reference, while the others were classified as affected by neutrophilic or mixed granulocytic EA. Cells isolated from the residual BALF were used for IL-1β, IL-2, IFN-γ, IL-4, IL-17A genes expression by quantitative RT-PCR., Cytokine expression was compared between groups, and their correlations with BALF leukocyte and lung function were evaluated. IL-1β expression was positively correlated with BALF neutrophils count (p=0.038, r=0.56) and with increased expiratory resistance (p=0.047, r=0.76). IFN-γ was correlated with BALF mast cells (p=0.029, r=0.58). IL-4 was higher in horses with mixed granulocytic EA than neutrophilic (p=0.008), positively correlated with BALF mast cells (p=0.028, r=0.59) and inversely with whole-breath (p=0.046, r=-0.76) and expiratory reactance (p=0.003, r=-0.93). Finally, IL-17A was inversely correlated with expiratory reactance (p=0.009, r=-0.92). These results support that multiple immune responses are involved in EA pathogenesis; innate, Th2, and Th17 responses. Innate immunity appeared associated with neutrophilic inflammation, and Th2 response with increased mast cells. The role of Th1 response in EA remains questionable.
Topics: Horses; Animals; Cytokines; Interleukin-17; Interleukin-4; Bronchoalveolar Lavage; Asthma; RNA, Messenger; Horse Diseases
PubMed: 38423374
DOI: 10.1016/j.jevs.2024.105033 -
Tuberculosis and Respiratory Diseases Apr 2024The prevalence of small airway dysfunction (SAD) in patients with chronic obstructive pulmonary disease (COPD) across different ethnicities is poorly understood. This...
BACKGROUND
The prevalence of small airway dysfunction (SAD) in patients with chronic obstructive pulmonary disease (COPD) across different ethnicities is poorly understood. This study aimed to estimate the prevalence of SAD in stable COPD patients.
METHODS
We conducted a cross-sectional study of 196 consecutive stable COPD patients. We measured pre- and post-bronchodilator (BD) lung function and respiratory impedance. The severity of COPD and lung function abnormalities was graded in accordance with the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines. SAD was defined as either difference in whole-breath resistance at 5 and 19 Hz > upper limit of normal or respiratory system reactance at 5 Hz < lower limit of normal.
RESULTS
The cohort consisted of 95.9% men, with an average age of 66.3 years. The mean forced expiratory volume 1 second (FEV1) % predicted was 56.4%. The median COPD assessment test (CAT) scores were 14. The prevalence of post-BD SAD across the GOLD grades 1 to 4 was 14.3%, 51.1%, 91%, and 100%, respectively. The post-BD SAD and expiratory flow limitation at tidal breath (EFLT) were present in 62.8% (95% confidence interval [CI], 56.1 to 69.9) and 28.1% (95% CI, 21.9 to 34.2), respectively. COPD patients with SAD had higher CAT scores (15.5 vs. 12.8, p<0.01); poor lung function (FEV1% predicted 46.6% vs. 72.8%, p<0.01); lower diffusion capacity for CO (4.8 mmol/min/kPa vs. 5.6 mmol/min/kPa, p<0.01); hyperinflation (ratio of residual volume to total lung capacity % predicted: 159.7% vs. 129%, p<0.01), and shorter 6-minute walk distance (367.5 m vs. 390 m, p=0.02).
CONCLUSION
SAD is present across all severities of COPD. The prevalence of SAD increases with disease severity. SAD is associated with poor lung function and higher symptom burden. Severe SAD is indicated by the presence of EFLT.
PubMed: 38225686
DOI: 10.4046/trd.2023.0139 -
Respiratory Research Jan 2024Lung recruitment and continuous distending pressure (CDP) titration are critical for assuring the efficacy of high-frequency ventilation (HFOV) in preterm infants. The... (Observational Study)
Observational Study
RATIONALE
Lung recruitment and continuous distending pressure (CDP) titration are critical for assuring the efficacy of high-frequency ventilation (HFOV) in preterm infants. The limitation of oxygenation (peripheral oxygen saturation, SpO) in optimizing CDP calls for evaluating other non-invasive bedside measurements. Respiratory reactance (Xrs) at 10 Hz measured by oscillometry reflects lung volume recruitment and tissue strain. In particular, lung volume recruitment and decreased tissue strain result in increased Xrs values.
OBJECTIVES
In extremely preterm infants treated with HFOV as first intention, we aimed to measure the relationship between CDP and Xrs during SpO-driven CDP optimization.
METHODS
In this prospective observational study, extremely preterm infants born before 28 weeks of gestation undergoing SpO-guided lung recruitment maneuvers were included in the study. SpO and Xrs were recorded at each CDP step. The optimal CDP identified by oxygenation (CDP) was compared to the CDP providing maximal Xrs on the deflation limb of the recruitment maneuver (CDP).
RESULTS
We studied 40 infants (gestational age at birth = 22-27 wk; postnatal age = 1-23 days). Measurements were well tolerated and provided reliable results in 96% of cases. On average, Xrs decreased during the inflation limb and increased during the deflation limb. Xrs changes were heterogeneous among the infants for the amount of decrease with increasing CDP, the decrease at the lowest CDP of the deflation limb, and the hysteresis of the Xrs vs. CDP curve. In all but five infants, the hysteresis of the Xrs vs. CDP curve suggested effective lung recruitment. CDP and CDP were highly correlated (ρ = 0.71, p < 0.001) and not statistically different (median difference [range] = -1 [-3; 9] cmHO). However, CDP were equal to CDP in only 6 infants, greater than CDP in 10, and lower in 24 infants.
CONCLUSIONS
The Xrs changes described provide complementary information to oxygenation. Further investigation is warranted to refine recruitment maneuvers and CPD settings in preterm infants.
Topics: Humans; Infant, Newborn; Infant, Extremely Premature; Oscillometry; Lung; Lung Volume Measurements; High-Frequency Ventilation
PubMed: 38178216
DOI: 10.1186/s12931-023-02639-4