Showing papers on "Pulmonary diffusion published in 2019"

Pulmonary diffusion capacity predicts major complications after esophagectomy for patients with esophageal cancer

Abstract: © The Author(s) 2018 Published by Oxford University Press on behalf of International Society for Diseases of the Esophagus

Respiratory resistance and reactance in adults with sickle cell anemia: Part 2-Fractional-order modeling and a clinical decision support system for the diagnosis of respiratory disorders.

Abstract: Background A better understanding of sickle cell anemia (SCA) and improvements in drug therapy and health policy have contributed to the emergence of a large population of adults living with this disease. The mechanisms by which SCA produces adverse effects on the respiratory system of these patients are largely unknown. Fractional-order (FrOr) models have a high potential to improve pulmonary clinical science and could be useful for diagnostic purposes, offering accurate models with an improved ability to mimic nature. Part 2 of this two-part study examines the changes in respiratory mechanics in patients with SCA using the new perspective of the FrOr models. These results are compared with those obtained in traditional forced oscillation (FOT) parameters, investigated in Part 1 of the present study, complementing this first analysis. Methodology/Principal findings The data consisted of three categories of subjects: controls (n = 23), patients with a normal spirometric exam (n = 21) and those presenting restriction (n = 24). The diagnostic accuracy was evaluated by investigating the area under the receiver operating characteristic curve (AUC). Initially, it was observed that biomechanical changes in SCA included increased values of fractional inertance, as well as damping and hysteresivity (p<0.001). The correlation analysis showed that FrOr parameters are associated with functional exercise capacity (R = -0.57), pulmonary diffusion (R = -0.71), respiratory muscle performance (R = 0.50), pulmonary flows (R = -0.62) and airway obstruction (R = 0.60). Fractional-order modeling showed high diagnostic accuracy in the detection of early respiratory abnormalities (AUC = 0.93), outperforming spirometry (p<0.03) and standard FOT analysis (p<0.01) used in Part 1 of this study. A combination of machine learning methods with fractional-order modeling further improved diagnostic accuracy (AUC = 0.97). Conclusions FrOr modeling improved our knowledge about the biomechanical abnormalities in adults with SCA. Changes in FrOr parameters are associated with functional exercise capacity decline, abnormal pulmonary mechanics and diffusion. FrOr modeling outperformed spirometric and traditional forced oscillation analyses, showing a high diagnostic accuracy in the diagnosis of early respiratory abnormalities that was further improved by an automatic clinical decision support system. This finding suggested the potential utility of this combination to help identify early respiratory changes in patients with SCA.

Lung diffusion capacity in advanced heart failure: relation to central haemodynamics and outcome.

Abstract: AIMS Patients with heart failure (HF) are known to have a reduced pulmonary diffusion capacity for carbon monoxide (DLCO ), but little is known about how lung function relates to central haemodynamics. The aim of this study was to investigate the association between haemodynamic variables and pulmonary diffusion capacity adjusted for alveolar volume in congestive HF patients and to analyse how predicted DLCO /VA affects mortality in relation to the haemodynamic status. METHODS AND RESULTS We retrospectively studied right heart catheterization (RHC) and lung function data on 262 HF patients (mean age 51 ± 13 years) with a left ventricular ejection fraction < 45% referred non-urgently for evaluation for heart transplantation (HTX) or left ventricular assist device (LVAD). Univariate and multivariate linear regression models were constructed to examine the associations between predicted values of DLCO /VA , forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1 ), and haemodynamic parameters [pulmonary capillary wedge pressure (PCWP), central venous pressure, cardiac index, mean pulmonary artery pressure, and mean arterial pressure] as well as other factors known to affect lung function in HF. FEV1 was reduced to <80% of predicted value in 55% of the population, and DLCO/ VA was reduced in 63% of the population. DLCO /VA correlated positively with pulmonary capillary wedge pressure in both univariate and multivariate analyses for all included patients (P < 0.001 and P = 0.045, respectively) and a restricted population of patients with the shortest time between RHC and lung function testing (P = 0.005, P = 0.015). DLCO /VA predicted mortality in multivariate models [hazard ratio 1.5 (1.1-2.1)] but not the combined endpoint of death, LVAD implantation, or HTX. There was no significant correlation between haemodynamics and predicted FVC or FEV1 . CONCLUSIONS Pulmonary diffusion capacity correlates positively with left ventricular fillings pressures, and reduced values predict increased mortality in patients with HF. This might be driven by increased lung capillary volume in patients with pulmonary congestion.

Using SpO 2 Recovery Index after a 6-Minute Walk Test to Predict Respiratory-Related Events in Hospitalized Patients with Interstitial Pneumonia

Abstract: Although the prognostic factors of interstitial pneumonia (IP) patients have been reported, IP has poor prognosis. Hospitalized patients with IP have severely impaired pulmonary diffusion capacity and prominent desaturation. We hypothesized that determining oxygen saturation recovery (SpO2 recovery index) after the 6-minute walk test (6MWT) can provide additional prognostic information regarding rehospitalization for respiratory-related events. We evaluated 73 IP patients at our hospital for demographic characteristics, pulmonary function tests and 6MWT. The Kaplan–Meier method was used to estimate rehospitalisation for respiratory-related events using SpO2 recovery index. Cox regression analysis revealed a relationship between SpO2 recovery index and rehospitalisation. The optimum cutoff value of SpO2 recovery index was 4% (sensitivity, 71.4%; specificity, 79.2%). SpO2 recovery index was most closely related to pulmonary diffusion capacity (r = 0.684, P < 0.001). In a multivariable model, it was the strongest independent predictor of rehospitalisation for respiratory-related events (hazard ratio, 0.3; 95% confidence interval, 0.10–0.90; P = 0.032). In this study, we estimated pulmonary diffusion capacity using SpO2 recovery index values obtained from 6MWT. A SpO2 recovery index of <4% can be useful in predicting rehospitalisation for respiratory-related events.

Prospective Long-Term Follow-Up of Pulmonary Diffusion Capacity Reduction Caused by Dose-Dense Chemotherapy in Patients with Breast Cancer.

Abstract: Background. Our previous study of pulmonary function in 34 patients with early breast cancer without preexisting lung disease showed that anthracycline- and taxane-based adjuvant dose-dense chemotherapy (DDC) caused a significant 16.4% mean reduction in carbon monoxide diffusing capacity (DLCO). The present study reports the pulmonary and oncological outcomes of these patients on long-term follow-up. Patients and methods. The primary endpoint was DLCO measured by the pulmonary function test (PFT) performed at a median of 27 months after DDC (range, 8–97) in 25 patients without disease recurrence. DLCO values were recorded as a percentage of predicted values according to age, height, and hemoglobin level and analyzed relative to baseline pre-DDC DLCO values. The secondary endpoints were symptoms, additional therapies, and cancer outcomes during a median of 11 years’ follow-up (range, 4.4–11.4). Results. A longitudinal general linear model showed significant effects of time on DLCO and its trend (F(1, 87) = 14.68, and F(1, 87) = 10.26, , respectively). Complementary descriptive analysis showed a significant recovery on the follow-up PFT (75.6% vs. 81.9%, ), but it was still significantly lower than the baseline DLCO (81.9% vs. 92.0%, ). Five patients (20%) still showed a >20% relative DLCO reduction from baseline. Patients with dyspnea or fatigue at later clinical follow-up had a significantly lower DLCO value on the follow-up PFT than nonsymptomatic patients (80.5% vs. 92.1%, ). DLCO recovery was inversely correlated with age (R = −0.39, ), but no significant correlation was found with the length of time until the follow-up PFT or additional therapies. There was no association of DDC-related DLCO reduction with cancer outcomes. Conclusions. The significant reduction in DLCO seen after DDC in patients with potentially curable breast cancer is evident years afterwards, especially in older patients. While most patients partly recover, some will have a lasting symptomatic DLCO impairment.