For these reasons, some authors showed that breathe Heliox (79% helium-21% oxygen) induce reduction of dynamic lung hyperinflation and is associated with consistent improvement in indices of cardio-circulatory function. In hyperinflators, during the exercise, important abnormalities regarding respiratory mechanics and cardiac output occur. There have been several reports demonstrating that, besides COPD patients who dynamically hyperinflate during exercise (hyperinflators), there are also patients who do not hyperinflate during exercise (non-hyperinflators). 6ĬPET and the evaluation of the inspiratory constraints and ventilatory inefficiency have an important role in the evaluation of the exertional dyspnea. 5ĭynamic lung Hyperinflation is the main cause of poor exercise tolerance in COPD patients. The most important of these is the increased airway resistance with prolonged mechanical expiratory time constants and, thus, slow and incomplete lung emptying. In conditions of bronchoconstriction, the hyperinflation is apparently determined mainly by dynamic factors. The mechanisms and pathophysiological consequences of hyperinflation are complex and not fully elucidated. Hyperinflation could be determined by reduced lung elastic recoil combined with expiratory flow limitation and it can be distinguished in static and dynamic. In many cases, airflow obstruction is associated with hyperinflation, which leads to a deterioration in the quality of life and exercise capacity. It is a respiratory disease characterized by progressive airflow obstruction, not fully reversible. In 20, more than 6% of adults aged 40 years or older reported having been diagnosed with COPD. IOS provides supplementary information in the assessment of static hyperinflation.Ĭhronic obstructive pulmonary disease (COPD) represents one of the leading causes of morbidity and mortality in the industrialized and developing countries. No correlation between TLC, RV (L,%) (both helium and Pleth derived) and IOS parameters (R(5– 20), X5, Fres) was found.Ĭonclusion: RV:TLC can represent the most reliable parameter in the assessment of hyperinflation, considering the absence of significant difference in its measurement between the two techniques. Between R5-R20 and RV:TLC, there was a weak correlation (r=0.3 p=0.001). Moreover, we noticed a strong relationship between RV:TLC (%)(He) and X5 (r=− 0.7 p=0.0001) and a mild correlation between RV:TLC (%) (He) and Fres (r=0.4 p=0.003). In particular, we pointed out a weak correlation between RV:TLC (%) (Pleth) and R(5– 20) (r=0.3, p=0.04), Fres (r=0.3 p=0.03), while X5 had a mild correlation with RV:TLC (%) (r=− 0.5 p< 0.0001). The correlation analysis showed that IOS parameters, such as difference in resistance between 5 Hz and 20 Hz (R(5– 20)) and resonant frequency (Fres), were positively correlated with RV:TLC ratio, while reactance at 5 Hz (X(5)) was negatively correlated with it. Results: As expected, we reported a statistically significant difference between these two techniques in terms of mean percentage values of TLC (7.57 ± 3.26 L p= 0.02) and RV (15.24 ± 7.51 L p=0.04), while RV:TLC measured with the two methods was similar (5.21 ± 4.69% p=0.27). Pearson and Spearman correlation determined the relationships between the functional parameters that evaluate static hyperinflation (RV: TLC, TLC, RV) and IOS measurements. IOS measurements (X5, Fres and R5-R20) were performed. TLC, RV and RV:TLC ratio were obtained both with helium and plethysmography techniques. Patients and Methods: Fifty-five COPD patients were enrolled. We investigate which spirometric measurement is more reliable in assessing static lung hyperinflation and which is more related with impulse oscillometry system (IOS) measurements in COPD. Despite the relevance of assessing lung hyperinflation, there is still no single consensus as to what volume should be taken into account. Purpose: Lung hyperinflation is a feature of chronic obstructive pulmonary disease (COPD) and can determine pivotal consequence on symptoms, exercise tolerance and quality of life. Michela D’Ascanio, 1 Fausta Viccaro, 1 Noemi Calabrò, 1 Giulio Guerrieri, 1 Claudia Salvucci, 1 Dario Pizzirusso, 1 Rita Mancini, 1 Claudia De Vitis, 1 Aldo Pezzuto, 2 Alberto Ricci 1ġDepartment of Clinical and Molecular Medicine, Sant’Andrea Hospital, Sapienza University of Rome, Rome, Italy 2Department of Cardiovascular and Respiratory Sciences, Sant’Andrea Hospital, Rome, ItalyĬorrespondence: Michela D’Ascanio Via di Grottarossa 1035/1039, Roma 00189, RM, Italy
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