Impulse Oscillometry In Patients Research Articles

Impulse oscillometry in patients with pulmonary arterial hypertension: an exploratory study

IntroductionStudies suggest peripheral airway abnormalities in Pulmonary Arterial Hypertension (PAH). Impulse Oscillometry (IOS) is a noninvasive and sensitive technique for assessing the small airways. It evaluates the impedance of the respiratory system ‒ Resistance (R) and reactance (X) ‒ to a pulse of sound waves sent to the lungs, in a range of frequencies (5‒20 Hz). MethodResistance variables: R5, R20, R5-R20 and reactance variables: AX (reactance area) and Fres (resonance frequency). The aim is to evaluate R and X in patients with idiopathic PAH (IPAH) and to investigate whether there is a correlation between IOS and spirometry. ResultsThirteen IPAH patients and 11 healthy subjects matched for sex and age underwent IOS and spirometry. IPAH patients had lower FVC and FEV1 values (p < 0.001), VEF1/CVF (p = 0.049) and FEF 25-75 (p = 0.006) than healthy patients. At IOS, IPAH patients showed lower tidal volumes and higher AX (p < 0.05) compared to healthy individuals, and 53.8 of patients had R5-R20 values ≥ 0.07 kPa/L/s. Correlation analysis: X5, AX, R5-R20 and Fres showed moderate correlation with FVC (p = 0.036 r = 0.585, p = 0.001 r = -0.687, p = 0.005 r = -0.726 and p = 0.027 r = -0.610); Fres (p = 0.012 r = -0.669) and AX (p = 0.006 r = -0.711) correlated with FEV1; [R5 and R20, (R5-R20)] also correlated with FEV1 (p < 0.001 r = -0.573, p = 0.020 r = -0.634 and p = 0.010 r = -0.683, respectively) in the IPAH group. There were also moderate correlations of FEF 25–75 % with Z5 (p = 0.041), R5 (p = 0.018), Fres (p = 0.043) and AX (p = 0.023). DiscussionPatients showed changes suggestive of increased resistance and reactance in the IOS compared to healthy individuals, and the IOS findings showed a good correlation with spirometry variables.

Bronchodilator Responsiveness Measured by Spirometry and Impulse Oscillometry in Patients with Asthma After Short Acting Antimuscarinic and/or Beta-2-Agonists Inhalation.

Bronchodilator responsiveness (BDR) in asthma involves both the central and peripheral airways but is primarily relieved with beta-2-agonists and evaluated by spirometry. To date, antimuscarinics can be added as a reliever medication in more severe asthma. We hypothesize that combining both short-acting beta-2 agonist (SABA) and short-acting muscarinic antagonist (SAMA) could also improve the responsiveness in mild-moderate asthma. Therefore, we aimed to compare the direct effects of inhaling SABA alone, SAMA alone or combining both SABA and SAMA on the central and peripheral airways in asthma. Twenty-three patients with mild-moderate BDR in asthma performed dynamic spirometry and impulse oscillometry before (baseline) and multiple timepoints within an hour after inhalation of SABA (salbutamol), SAMA (ipratropium bromide), or both SABA and SAMA at three different visits. The use of SAMA alone did not show any improvement compared to the use of SABA alone. Inhalation of SABA+SAMA, however, averaged either similar or better BDR than SABA alone in FEV1, MMEF, FVC, R5, R20 and R5-R20. Inhaling SABA+SAMA reached a stable BDR in more patients within 0-10 minutes and also reached the FEV1 (Δ%)>12% faster (3.5 minutes) than inhaling SABA alone (5.1 minutes). Inhaling SABA+SAMA was significantly better than SAMA alone in FEV1 (p = 0.015), MMEF (p = 0.0059) and R20 (p = 0.0049). Using these three variables highlighted a subgroup (30%, including more males) of patients that were more responsive to inhaling SABA+SAMA than SABA alone. Overall, combining SAMA with SABA was faster and more consistent at increasing the lung function than SABA alone or SAMA alone, and the additive effect was best captured by incorporating peripheral-related variables. Therefore, SAMA should be considered as an add-on reliever for mild-moderate patients with BDR in asthma.

Comparative assessment of small airway dysfunction by impulse oscillometry and spirometry in chronic obstructive pulmonary disease and asthma with and without fixed airflow obstruction.

Small airways play a major role in the pathogenesis and prognosis of chronic obstructive pulmonary disease (COPD) and asthma. More data on small airway dysfunction (SAD) using spirometry and impulse oscillometry (IOS) in these populations are required. The objective of this study was to compare the two methods, spirometry and IOS, for SAD detection and its prevalence defined by spirometry and IOS in subjects with COPD and asthma with and without fixed airflow obstruction (FAO). This is a cross-sectional study. Spirometric and IOS parameters were compared across four groups (COPD, asthma with FAO, asthma without FAO, and healthy subjects). SAD defined by spirometry and IOS criteria were compared. A total of 262 subjects (67 COPD, 55 asthma with FAO, 101 asthma without FAO, and 39 healthy controls) were included. The prevalence of SAD defined by using IOS and spirometry criteria was significantly higher in patients with COPD (62.7 and 95.5%), asthma with FAO (63.6 and 98.2%), and asthma without FAO (38.6 and 19.8%) in comparison with healthy control (7.7 and 2.6%). IOS is more sensitive than spirometry in the detection of SAD in asthma without FAO (38.6% vs. 19.8%, p = 0.003) However, in subjects with FAO (COPD and asthma with FAO), spirometry is more sensitive than IOS to detect SAD (95.5% vs. 62.7%, p < 0.001 and 98.2% vs. 63.6%, p < 0.001, respectively). Small airway dysfunction was significantly detected in COPD and asthma with and without FAO. Although IOS shows more sensitivity than spirometry in the detection of SAD in asthma without FAO, spirometry is more sensitive than IOS in patients with FAO including COPD and asthma with FAO.

Clinical characteristics of airway impairment assessed by impulse oscillometry in patients with chronic obstructive pulmonary disease: findings from the ECOPD study in China

BackgroundThe role of airway impairment assessed by impulse oscillometry (IOS) in patients with chronic obstructive pulmonary disease (COPD) remains unclear. Therefore, this study aimed to analyze the proportion and clinical characteristics of airway impairment assessed by IOS across COPD severities, and explore whether airway impairment is a subtype of COPD.MethodsThis study was based on cross-sectional data from the ECOPD cohort in Guangdong, China. Subjects were consecutively recruited from July 2019 to August 2021. They filled out questionnaires and underwent lung function tests, IOS and computed tomography (CT). COPD was defined as post-bronchodilator forced expiratory volume in one second/forced vital capacity < lower limit of normal (LLN). Meanwhile, airway impairment was defined as IOS parameters > upper limit of normal or < LLN. On the one hand, Poisson regression was employed to analyze the associations between acute exacerbations of COPD (AECOPD) in the previous year and airway impairment. On the other hand, logistic regression was used to assess differences in CT imaging between patients with IOS parameters’ abnormalities and patients with normal IOS parameters.Results768 COPD subjects were finally enrolled in the study. The proportion of airway impairment assessed by R5, R20, R5–R20, X5, AX, and Fres was 59.8%, 29.7%, 62.5%, 52.9%, 60.9% and 67.3%, respectively. Airway impairment assessed by IOS parameters (R5, R5–R20, X5, AX, and Fres) in patients with COPD was present across all severities of COPD, particularly in GOLD 3–4 patients. Compared with patients with normal IOS parameters, patients with IOS parameters’ abnormalities had more respiratory symptoms, more severe airway obstruction and imaging structural abnormalities. Patients with IOS parameters’ abnormalities assessed by R5 [risk ratio (RR): 1.58, 95% confidential interval (CI): 1.13–2.19, P = 0.007], R5–R20 [RR: 1.73, 95%CI: 1.22–2.45, P = 0.002], X5 [RR: 2.11, 95%CI: 1.51–2.95, P < 0.001], AX [RR: 2.20, 95%CI: 1.53–3.16, P < 0.001], and Fres [RR: 2.13, 95%CI: 1.44–3.15, P < 0.001] had a higher risk of AECOPD in the previous year than patients with normal IOS parameters.ConclusionsAirway impairment assessed by IOS may be a subtype of COPD. Future studies are warranted to identify the underlying mechanisms and longitudinal progression of airway impairment.

Research of the diagnostic utility of impulse oscillometry in patients with bronchiectasis

Background: Bronchiectasis is a chronic respiratory condition in which infection, inflammation, and damage of the airways all play a role. Intense airway inflammation is precipitated by pathogenic insults, resulting in chronic airway damage. Impulse oscillometry (IOS) is a noninvasive approach that might offer worldwide information on airway resistance by researching the mechanical waves superimposed upon breathing movements. It has been observed that IOS may differentiate peripheral airways abnormalities in chronic obstructive pulmonary disease (COPD), asthma, interstitial pulmonary disease (ILD) and pulmonary fibrosis (CF) with high degree of precision. Methods: This research was carried out on 40 cases with bronchiectasis diagnosed by HRCT. Such cases were classified into two groups, according to Bronchiectasis Severity Index (BSI)(108): group I: Included 20 cases with mild to moderate bronchiectasis and group II: Included 20 cases with severe bronchiectasis. Cases included in the research were subjected to full history taking and complete physical examination. This includes: Complete blood count (CBC), sputum culture, chest x-ray to exclude cases with other lung diseases, High-Resolution Computerized Tomography (HRCT), that were interpreted for the presence, pattern and distribution of bronchiectasis, arterial blood gases, echocardiography, measuring systolic pulmonary artery pressure, pulmonary function tests (PFT), Impulse Oscillometry and reactance area (AX) were measured. Results: Regarding disease duration, no significant differences was found between both groups while a statistically significant difference was observed between groups regarding the used medications. Regarding laboratory investigations, no significant difference was observed among the groups for any of the measured measurements. Regarding functional assessment data, A statistically evident difference was found between groups in the following: MEF 50%, FEV1% predicted, FEV1/FVC% and FVC% with no significant differences in FEV1. Regarding IOS measurements, A statistically evident difference was found between both groups in R5% predicted while no difference was observed regarding R5 actual, R20, AX, or X5. Positive correlation was very high in between HRCT score and each of FEV1% predicted, FVC (%) AX, R5% predicted, R5 actual, R20 and X5 but negative correlation was very high in between HRCT score and MEF 75%, FEV1/FVC% Conclusions: IOS measurements are markedly increased in cases with bronchiectasis and they are correlated with spirometric measurements and HRCT scores.

Severe asthma with fungal sensitization is associated with worse small airway dysfunction but similar symptom control

Severe asthma with fungal sensitization is associated with worse small airway dysfunction but similar symptom control

Combining low-frequency oscillometry and spirometry measurements in relation to asthma control and exacerbations in moderate-to-severe asthma

Combining low-frequency oscillometry and spirometry measurements in relation to asthma control and exacerbations in moderate-to-severe asthma

Respiratory function in children with nephrotic syndrome: Comparative evaluation of impulse oscillometry and spirometry.

To evaluate the respiratory functions of children with nephrotic syndrome (NS) by impulse oscillometry (IOS) and its correlation with spirometry. Fifty-five NS patients aged 3-18 years were included as the study group and 40 healthy children of the same age formed the control group. Patients were divided into nephrotic phase (first attack and relapse) and remission. Demographic, anthropometric, and laboratory data of the children were recorded. Respiratory functions were evaluated by IOS and spirometry. Children over 6-years old performed both IOS and spirometry while children under 6 years performed only IOS. The R (R5%, R10%, R5-20), AX and Z5% values of IOS in patients with nephrotic phase were higher than remission patients and control group while spirometry indices of PEF% and MEF25-75% were lower. Z scores of MEF25-75 were significantly negatively correlated with z scores of R5, R10, Z5, and Fres while they were significantly positively correlated with z scores of X values (5, 10, 15, and 20 Hz). Z scores of forced expiratory volume in 1 /forced vital capacity significantly negatively correlated with z scores of R values (R5, R10), Z5 and AX and positively correlated with z scores of X values (X5, X10, X15 Hz). Our study demonstrated that respiratory functions measured by IOS and spirometry were affected at the time of nephrotic phase in NS patients. IOS, a novel method easily applicable even in small children, is a potentially valuable tool to detect this condition; given its good correlation with spirometry.

Evaluation of disease severity in bronchiectasis using impulse oscillometry.

Although the diagnostic value of impulse oscillometry (IOS) in bronchiectasis for the differential diagnosis of healthy subjects has been researched, the usefulness of each IOS parameter for predicting disease severity in bronchiectasis has not been thoroughly investigated. In addition, the usefulness of IOS in patients with nontuberculous mycobacteria (NTM) infection has not been reported. This study aimed to determine the predictive significance of respiratory impedance and detect the other most significant IOS parameters for predicting disease severity in bronchiectasis patients and to validate the usefulness of IOS in patients with NTM infection.A total of 206 patients with bronchiectasis who attended clinics at the National Hospital Organization Osaka Toneyama Medical Center were included. Chest high-resolution computed tomography, spirometry and IOS were performed. Hospital admissions, mortality and disease severity indices for bronchiectasis (Bronchiectasis Severity Index (BSI), FACED, and E-FACED scores) were calculated to assess disease severity. The patients were divided into subgroups with and without NTM infection, and subgroup analyses were performed.Respiratory reactance, especially resonant frequency (fres), correlated with both BSI and FACED score better than respiratory resistance. Inspiratory but not expiratory impedance was strongly correlated with BSI, FACED and E-FACED scores. Inspiratory fres was the most useful predictor, increasing as the disease became more severe. The usefulness of IOS was almost equivalent in patients both with and without NTM infection.Inspiratory reactance measured by IOS is useful for estimating disease severity in bronchiectasis. Inspiratory fres best predicts disease severity in bronchiectasis patients both with and without NTM infection.

The use of impulse oscillometry in patients with asthma

The use of impulse oscillometry in patients with asthma

Impulse oscillometry, an aid or a substitute?

IntroductionIn the field of pulmonary medicine, respiratory mechanics and physiology are obviously affected by most pathological lesions and diseases, either primary disease or part of systemic ones. In the era of rheumatoid arthritis (RA), airway abnormality and interstitial lung pneumonia and/or fibrosis are the most common findings that face physicians during the disease course and affect morbidity, survival, and quality of life of patients with RA. Impulse oscillometry (IOS) is a noninvasive technique that needs minimal patient cooperation, which makes it suitable for any age including even children and can be performed by most patients.Aim of the workTo describe the respiratory measures done by IOS in patients with RA and to correlate them with those measured by spirometry.Patients and methodsA total of 60 patients with RA were recruited in this cross-sectional observational study. They were investigated via pulmonary function assessments, including spirometry and IOS, to measure forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and FEV1/FVC, and maximal expiratory flow at 25% (MEF 25%)in addition to R5% of predicted, R20% of predicted, R5–20, X5, and area under the curve.ResultsIOS measures indicated increased airway resistance (R5%, R20%, and R5–20) with decreased lung reactance (X5). Moreover, a positive correlation between disease duration and X5, between X5 and area under the curve and each of FEV1%, FVC%, and MEF 25%, whereas a negative correlation between R5–20 and each of FEV1%, FVC%, and MEF 25%.ConclusionIOS is an easy and rapid maneuver that requires minimal patient cooperation. It can identify lung affection in those who have mild or even normal spirometric changes. It is just a good screening test in patients with RA to detect early pathophysiologic lung changes. However, it needs further investigations to clarify the mechanism of these changes.

Is small airways dysfunction related to asthma control and type 2 inflammation?

Small airways dysfunction (SAD) in adults with persistent asthma and preserved forced expiratory volume in 1 second (FEV1) is related to worse asthma control. [1] Manoharan A Anderson WJ Lipworth J Ibrahim I Lipworth BJ Small airway dysfunction is associated with poorer asthma control. Eur Respir J. 2014; 44: 1353-1355 Crossref PubMed Scopus (46) Google Scholar Impulse oscillometry (IOS) is an effort-independent test used to phenotype SAD, which involves normal quiet tidal breathing. [2] Galant SP Komarow HD Shin HW Siddiqui S Lipworth BJ The case for impulse oscillometry in the management of asthma in children and adults. Ann Allergy Asthma Immunol. 2017; 118: 664-671 Abstract Full Text Full Text PDF PubMed Scopus (78) Google Scholar Peripheral airways resistance can be derived from the difference between resistance at 5 Hz and 20 Hz (R5-R20), whereas the area under the reactance curve (AX) reflects peripheral lung compliance. [3] Lipworth B Manoharan A Anderson W Unlocking the quiet zone: the small airway asthma phenotype. Lancet Respir Med. 2014; 2: 497-506 Abstract Full Text Full Text PDF PubMed Scopus (120) Google Scholar In patients with moderate to severe persistent asthma, R5-R20 and AX, but not spirometry, were closely related to asthma control, as assessed by the Asthma Control Questionnaire (ACQ). [4] Jabbal S Manoharan A Lipworth J Lipworth B Utility of impulse oscillometry in patients with moderate to severe persistent asthma. J Allergy Clin Immunol. 2016; 138: 601-603 Abstract Full Text Full Text PDF PubMed Scopus (25) Google Scholar Type 2 inflammation plays a central role in asthma disease pathophysiology by determining downstream airway hyperresponsiveness and remodeling. Widely used clinical type 2 airway inflammatory biomarkers (T2) include fractional exhaled nitric oxide (FeNO), serum immunoglobulin E (IgE), and blood eosinophils (Eos). [5] Robinson D Humbert M Buhl R et al. Revisiting Type 2-high and Type 2-low airway inflammation in asthma: current knowledge and therapeutic implications. Clin Exp Allergy. 2017; 47: 161-175 Crossref PubMed Scopus (247) Google Scholar

Study the Effect of Spironolactone in Airway Resistance with Impulse Oscillometry in Patients with Congestive Heart Failure

Background: CHF (Congestive Heart Failure) is one of the most important causes of mortality and morbidity in the world. Diuretics such as spironolactone can decrease pulmonary congestion and reduce the amount of fibrosis in CHF patients. The goal was to assess whether spironolactone can decrease air way resistance and can we follow up the effect of diuretic therapy in patients of heart failure quantitatively by means of impulse oscillometry. Methods: It was clinical trial which performed in Ahvaz teaching hospital. 24 patients with congestive heart failure (CHF) which was classified as functional class II-IV and had EF < 40%, were assessed by impulse oscillometry before and after 1 month of taking spironolactone in addition to routine drug therapy for their symptoms. All data were analyzed by SPSS soft ware versed 16. Result: The age of patient was 61 ± 10 and the age of control was 57 ± 7 years old. The data of oscillometry before and after spironolactone were X5 (−0.14 ± 0.05 vs −0.14 ± 0.05, P: 0.93), R5 (0.39 ± 0.21 vs 0.39 ± 0.15, P: 0.35), X20 (−0.04 ± 0.06 vs −0.06 ± 0.06, P: 0.37), R20 (0.04 ± 0.03 vs 0.06 ± 0.06, P: 0.37), Zrs (0.39 ± 0.21 vs 0.39 ± 0.15, P: 0.35). Conclusion: There was a trend toward reduction of peripheral airway resistances in CHF patients than controls with use of 1 month of spironolactone. Although there was not significant change in the number of X5, R5, X20, R20 occurred the trend toward reduction of number triggers the point that oscillometry can be used for quantitative follow up of CHF patients.

Assessment of functional tests on determining resistance of respiratory tract in patients with bronchial asthma, COPD and their combination.

The mechanical properties of the respiratory tract (including airway resistance) is an important indicator of pulmonary function, and definition of resistance is used to diagnose and monitor obstructive lung diseases. This study was performed in order to evaluate and compare functional results of tests to determine the resistance of the airways in patients with asthma, chronic obstructive pulmonary disease and their combination. The study involved 191 patients: with asthma (n=34), with COPD (n=17) and their combination (n=140). Patients underwent bodyplethysmography and impulse oscillometry. A statistically significant correlation of medium strength between parameters of the total resistance, determined with the help of bodyplethysmography and impulse oscillometry, r=0.57, p&lt;0.001. According to ROC-analysis, the best point of distribution of normal and pathological parameters of impulse oscillometry (R5Hz) as a diagnosis of increased respiratory resistance is 130% and higher from the proper values. The area under the ROC curve is 0.807. When interpreting the results of impulse oscillometry in patients with asthma, COPD and their combination, R5Hz level equal to or exceeding 130% of the proper values is proposed to be regarded as a sign of an increased respiratory resistance with sensitivity of technique – 64.0%, specificity – 87.5% and prognostic value of the positive result - 98.2%.

Utility of impulse oscillometry in patients with moderate to severe persistent asthma

Utility of impulse oscillometry in patients with moderate to severe persistent asthma

Assessment of respiratory impedance during deep-slow breathing with impulse oscillometry in patients with chronic obstructive pulmonary disease

Objective: To observe the relationship of deep-slow respiratory pattern and respiratory impedance(RI) in patients with chronic obstructive pulmonary disease (COPD).Methods: RI under normal respiration and during deep-slow respiration was measured one after the other with impulse oscillometry for 8 patients with COPD and for 9 healthy volunteers as control.Results: When respiration was changed from normal pattern to the deep-slow pattern, the tidal volume increased and respiratory frequency significantly decreased in both groups (P < 0. 01), the total respiratory impedance (Z respir) showed a decreasing trend in COPD group, but with no obvious change in the control group. No change in the resonant frequency (fres) was found in both groups, and the respiratory viscous resistance obviously decreased in the COPD group(R5: P=0.0168; R20: P=0.0498; R5-R20: P=0.0388), though in the control group it was unchanged.Conclusion: IOS detection could reflect the response heterogeneity of different compartments of respiratory system during tidal breathing. During deep-slow respiration, the viscous resistance in both central airway and peripheral airway was decreased in patients with COPD. RI measurement by impulse oscillometry may be a convenient pathophysiological method for studying the application of breathing exercise in patients with COPD.