1,720,985 research outputs found
Sistema e metodo per la misura dell'impedenza meccanica del sistema respiratorio.
No full textSistema per misura dell’impedenza meccanica del sistema respiratorio caratterizzato dal fatto di comprendere un sistema per la registrazione delle misure di pressione e di flusso dell’aria e per la generazione di stimoli pressori comprendente: una cavità; un motore che aziona una ventola; detto motore e detta ventola sono posti in detta cavità; detta cavità comprende una estremità iniziale ed un estremità finale, entrambe di accesso all’esterno; detta ventola preleva aria da detta estremità finale; detta estremità iniziale comprende un sensore di pressione dell’aria ed un sensore di flusso dell’aria; detto sistema comprende una memoria per memorizzare i valori dei segnali derivanti da detto sensore di pressione e da detto sensore di flusso dell’aria ed una unita' di elaborazione per il calcolo dell'impedenza meccanica del sistema respiratorio e dei parametri ad essa collegati
METHOD FOR THE AUTOMATIC DETECTION OF RESPIRATORY DISEASES AND FOR THE PREDICTION OF FUTURE ACUTE AIRWAY INSTABILITIES
No full textSistema per la valutazione automatica di patologie respiratorie e per la predizione di acute future instabilita' delle vie aeree.
No full textSistema di rilevamento automatico di patologie respiratorie e loro gravità e di previsione di future instabilità acute delle vie aeree comprendente: un dispositivo per misurare l'impedenza respiratoria di un soggetto umano durante una pluralità di cicli respiratori di detto soggetto umano; detto dispositivo per misurare misura detta impedenza respiratoria almeno una volta al giorno per almeno due giorni, e fornisce una pluralità di misurazioni; una memoria per conservare dette misurazioni; un computer per calcolare variazione di detta pluralità di misurazioni; un computer per indicare il posizionamento di detta variazione paragonata ad un valore di soglia prefissato o paragonato ad una curva statistica
Effect of bronchodilation on expiratory flow limitation and resting lung mechanics in COPD.
No full textABSTRACT: Bronchodilator drugs produce variable improvements in forced expiratory volume in
1 s (FEV1), but larger changes in end-expiratory lung volume (EELV) in chronic obstructive
pulmonary disease (COPD), which were suggested to be related to the presence of expiratory
flow limitation (EFL) at rest.
We tested this concept in 42 COPD patients (FEV1 42.3¡13.8% predicted) during spontaneous
breathing before and after 5 mg nebulised salbutamol. EFL was detected by within-breath
changes in respiratory system reactance measured by a multifrequency forced oscillation
method, while changes in EELV were assessed by inspiratory capacity (IC). Bronchodilation (BD)
increased IC (from 1.8¡0.5 to 2.1¡0.6 L, p,0.001) and reduced inspiration resistance (R
–
insp) at
5 Hz (from 5.1¡1.6 to 4.2¡1.5 cmH2O?s?L-1, p,0.001). R
–
insp identified BD responders with a
discriminative power of 80.1%.
In total, 20 patients were flow-limited before BD. They showed worse spirometry and higher
residual volume, but significant improvements in IC were seen in all patients irrespective of flow
limitation. Changes inR –
insp were confined to flow-limited patients, as were reactance changes. BD
reduced the degree of heterogeneity in the respiratory system, a change best seen with
inspiratory values.
BD has complex effects on lung mechanics in COPD, and EFL affects both this and the
response of some respiratory variables to treatment. However, changes in EELV are consistently
seen, irrespective of the presence of flow limitation at rest
Within-breath oscillometry for identifying exercise-induced bronchoconstriction in pediatric patients reporting symptoms with exercise
Full text linkBackground: Evaluating oscillometry parameters separately for the inspiratory and expiratory breath phases and their within-breath differences can help to identify exercise-induced bronchoconstriction (EIB) in pediatric outpatients disclosing exercise-induced symptoms (EIS). Aims: To assess the response in impedance parameters following an exercise challenge in patients reporting EIS. Methods: Sixty-eight patients reporting EIS (34 asthmatics and 34 suspected of asthma, age mean = 10.8 years, range = 6.0-16.0) underwent an incremental treadmill exercise test. Spirometry was performed at baseline and 1, 5-, 10-, 15-, and 20-min post exercise. Oscillometry was performed at baseline and at 3- and 18-min post exercise. Bronchodilator response to 200 μg albuterol was then assessed. EIB was defined as a forced expiratory volume in 1 s (FEV1) fall ≥10% from baseline. Expiratory and inspiratory resistance (Rrs) and reactance (Xrs), their z-score (Ducharme et al. 2022), and their mean within-breath differences (ΔRrs = Rrsexp-Rrsinsp, ΔXrs = Xrsexp-Xrsinsp) were calculated. Receiver operating characteristic (ROC) curves and their areas (AUCs) were used to evaluate impedance parameters' performances in classifying EIB. Results: Asthmatic patients developed EIB more frequently than those suspected of asthma [18/34 (52.9%) vs. 2/34 (5.9%), p < 0.001]. In the 20 subjects with EIB, Rrsinsp, Rrsexp, Xrsinsp, and Xrsexp peaked early (3'), and remained steady except for Xrsinsp, which recovered faster afterward. ΔXrs widened 18 min following the exercise and reversed sharply after bronchodilation (BD) (-1.81 ± 1.60 vs. -0.52 ± 0.80 cmH2O × s/L, p < 0.001). Cutoffs for EIB leading to the highest AUCs were a rise of 0.41 in z-score Rrsinsp (Se: 90.0%, Sp: 66.7%), and a fall of -0.64 in z-score Xrsinsp (Se: 90.0%, Sp: 75.0%). Accepting as having "positive" postexercise oscillometry changes those subjects who had both z-scores beyond respective cutoffs, sensitivity for EIB was 90.0% (18/20) and specificity, 83.3% (40/48). Conclusion: Oscillometry parameters and their within-breath differences changed markedly in pediatric patients presenting EIB and were restored after the bronchodilator. Strong agreement between z-scores of inspiratory oscillometry parameters and spirometry supports their clinical utility, though larger studies are required to validate these findings in a broader population
Optimizing positive end-expiratory pressure by oscillatory mechanics minimizes tidal recruitment and distension: an experimental study in a lavage model of lung injury
No full textExpiratory flow limitation detected by forced oscillation and negative expiratory pressure.
No full textMeasurement of Local Chest Wall Displacement by a Custom Self-Mixing Laser Interferometer
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