Use Of Oscillometry Research Articles

Oscillometry helps assess treatment responsiveness in adults with asthma exacerbations

BackgroundIt is necessary to evaluate the severity of asthma exacerbations for subjective symptoms and objective indicators. When patients cannot perform spirometry, oscillometry is a surrogate test. ObjectiveWe assessed the usefulness of oscillometry for the evaluation of treatment responsiveness in patients with asthma exacerbations. MethodsThe subjects included 21 consecutive patients with asthma exacerbations. Symptomatic responses, oscillometry, and spirometry (if possible) were assessed before and after treatment with corticosteroids and aminophylline. ResultsAfter treatment, all of the patients were allowed to return home and had no hospital visits. Oscillometry was feasible in all patients; however, spirometry could not be performed in 9 patients. Overall, there was a significant improvement in wheezing scores and oscillometric parameters, but not in FEV1 after treatment. The thresholds for a positive bronchodilator response in oscillometry were observed in 4 or more patients, while the minimal clinically important differences in FEV1 were observed in one patient. ConclusionOscillometry can detect improvements that cannot

Lung disease burden assessment by oscillometry in a systematically disadvantaged urban population experiencing homelessness or at-risk for homelessness in Ottawa, Canada from a prospective observational study

RationaleOscillometry is an emerging technique that offers some advantages over spirometry as it does not require forced exhalation and may detect early changes in respiratory pathology. Obstructive lung disease disproportionately impacts people experiencing homelessness with a high symptoms burden, yet oscillometry is not studied in this population.ObjectivesTo assess lung disease and symptom burden using oscillometry in people experiencing homelessness or at-risk of homelessness using a community-based participatory action research approach (The Bridge Model™).MethodsOf 80 recruited, 55 completed baseline oscillometry, 64 completed spirometry, and all completed patient-reported outcomes with demographics, health, and respiratory symptom related questionnaires in the Participatory Research in Ottawa: Management and Point-of-Care for Tobacco Dependence project. Using a two-tail t-test, we compared mean oscillometry values for airway resistance (R5–20), reactance area under the curve (Ax) and reactance at 5 Hz (X5) amongst individuals with fixed-ratio method (FEV1/FVC ratio < 0.70) and LLN (FEV1/FVC ratio ≤ LLN) spirometry diagnosed chronic obstructive pulmonary disease (COPD). We compared mean oscillometry parameters based on participants’ COPD assessment test (CAT) scores using ANOVA test.ResultsThere was no significant difference between the pre- and post- bronchodilator values of R5–20 and Ax for the fixed ratio method (p = 0.63 and 0.43) and the LLN method (p = 0.45 and 0.36). There was a significant difference in all three of the oscillometry parameters, R5–20, Ax and X5, based on CAT score (p = 0.009, 0.007 and 0.05, respectively). There was a significant difference in R5–20 and Ax based on the presence of phlegm (p = 0.03 and 0.02, respectively) and the presence of wheeze (p = 0.05 and 0.01, respectively). Oscillometry data did not correlate with spirometry data, but it was associated with CAT scores and correlated with the presence of self-reported symptoms of phlegm and wheeze in this population.ConclusionsOscillometry is associated with respiratory symptom burden and highlights the need for future studies to generate more robust data regarding the use of oscillometry in systematically disadvantaged populations where disease burden is disproportionately higher than the general population.TrialRegistration: ClinicalTrails.gov—NCT03626064, Retrospective registered: August 2018, https://clinicaltrials.gov/ct2/show/NCT03626064

Clinical application of oscillometry in respiratory diseases: an impulse oscillometry registry.

BackgroundRespiratory oscillometry is a promising complement to the traditional pulmonary function tests for its simplicity. The usefulness of oscillometry in adult clinical practice has not been clarified. This study aimed to analyse the characteristics and diagnostic performance of oscillometry in respiratory diseases, and explore the cut-offs of oscillometric parameters for severity grading.MethodsIn this multicentre registry of impulse oscillometry (IOS), IOS and spirometric data of healthy individuals and patients with respiratory diseases were collected and analysed. Linear mixed model analysis was performed to explore the effects of disease and forced expiratory volume in 1 s (FEV1) on oscillometric parameters.ResultsThe study included 567 healthy subjects, 781 asthmatic patients, 688 patients with chronic obstructive pulmonary disease (COPD), 109 patients with bronchiectasis, 40 patients with upper airway obstruction (UAO) and 274 patients with interstitial lung disease (ILD) in the analysis. Compared at the same FEV1 level, asthma, COPD, bronchiectasis, UAO and ILD displayed different oscillometric characteristics. The z-score of resistance at 5 Hz (R5) was the best variable to identify respiratory diseases with a sensitivity of 62.4–66.7% and a specificity of 81.5–90.3%. With reference to the severity grading cut-offs of FEV1, R5 z-scores of 2.5 and 4 were defined as the cut-off values of moderately and severely increased R5.ConclusionRespiratory oscillometry is more appropriate to be a tool of evaluating, rather than of diagnosing, respiratory diseases. A severity grading system of oscillometric parameters was developed to help the interpretation of oscillometry in clinical practice.

Intrabreath oscillometry is a sensitive test for assessing disease control in adults with severe asthma

BackgroundAsthma control is not well reflected by spirometry, yet this is the most frequently used measure of lung function in asthma clinics. Oscillometry is an alternative technique suitable for those with severe asthma. ObjectiveTo investigate usefulness of oscillometry in subjects with severe asthma to determine which outcome variables best reflected asthma control. MethodsAdults with severe asthma were recruited from a severe asthma clinic in Brazil. Oscillometry (conventional multifrequency measurements between 6 and 32 Hz; intrabreath tracking at 8 Hz) and spirometry were performed. Asthma control was determined by the asthma control test. ResultsA total of 60 adults were evaluated; mean age was 56.7 years. There was predominance of women (82%), and most patients (63%) reported onset of asthma symptoms in childhood or adolescence. There were no differences between controlled and uncontrolled asthma in spirometry. Uncontrolled asthma was associated with higher resistance (at 8 and 10 Hz) and more negative reactance (for 6, 8, and 10 Hz) (P < .05) on conventional oscillometry. Intrabreath oscillometry revealed significant differences between controlled and uncontrolled patients with asthma (P < .01 for changes in resistance and reactance between end expiration and end inspiration). The accuracy of the lung function tests in discriminating between controlled and uncontrolled asthma was higher for intrabreath variables (area under the curve = 0.65-0.72). ConclusionOscillometry, particularly the intrabreath technique, better reflected asthma control than spirometry measures. Our findings suggest that oscillometry may be a useful technique to aid management of severe asthma, with a potential to reflect loss of disease control.

Comparison of oscillometry devices using active mechanical test loads.

Noninvasiveness, low cooperation demand and the potential for detailed physiological characterisation have promoted the use of oscillometry in the assessment of lung function. However, concerns have been raised about the comparability of measurement outcomes delivered by the different oscillometry devices. The present study compares the performances of oscillometers in the measurement of mechanical test loads with and without simulated breathing.Six devices (five were commercially available and one was custom made) were tested with mechanical test loads combining resistors (R), gas compliances (C) and a tube inertance (L), to mimic respiratory resistance (Rrs) and reactance (Xrs) spectra encountered in clinical practice. A ventilator was used to simulate breathing at tidal volumes of 300 and 700 mL at frequencies of 30 and 15 min−1, respectively. Measurements were evaluated in terms of R, C, L, resonance frequency (fres), reactance area (AX) and resistance change between 5 and 20 or 19 Hz (R5–20(19)).Increasing test loads caused progressive deviations in Rrs and Xrs from calculated values at various degrees in the different oscillometers. While mean values of Rrs were recovered acceptably, some devices exhibited serious distortions in the frequency dependences of Rrs and Xrs, leading to large errors in C, L, fres, AX and R5–20(19). The results were largely independent of the simulated breathing.Simplistic calibration procedures and mouthpiece corrections, in addition to unknown instrumental and signal processing factors, may be responsible for the large differences in oscillometry measures. Rigorous testing and ongoing harmonisation efforts are necessary to better exploit the diagnostic and scientific potential of oscillometry.

Impact of Atrial Fibrillation on the Accuracy of Oscillometric Blood Pressure Monitoring

The introduction of automated oscillometric blood pressure monitors was the basis for today's widespread use of blood pressure self-measurement. However, in atrial fibrillation, there is a controversial debate on the use of oscillometry because there is a high variability of heart rate and stroke volume. To date, the accuracy of oscillometric blood pressure monitoring in atrial fibrillation has only been investigated using auscultatory sphygmomanometry as reference method, which may be biased by arrhythmia as well. We performed a cross-sectional study in 102 patients (52 sinus rhythm, 50 atrial fibrillation) assessing the accuracy of an automated and validated oscillometric upper arm (M5 Professional, Omron) and wrist device (R5 Professional, Omron) to invasively assessed arterial pressure. Blood pressure values were calculated as the mean of 3 consecutive measurements. Systolic and diastolic blood pressure did not significantly differ in patients with sinus rhythm and atrial fibrillation, independent of the method of measurement (P>0.05 each). The within-subject variability of the oscillometric measurements was higher in patients with atrial fibrillation compared with sinus rhythm (P<0.01 each). The biases of systolic and diastolic blood pressure, however, did not significantly differ in presence or absence of atrial fibrillation in Bland-Altmann analysis (P>0.05 each). In conclusion, atrial fibrillation did not significantly affect the accuracy of oscillometric measurements, if 3 repeated measurements were performed.

The Use of Oscillometry as a Measure of Airway Responsiveness in Asthmatic Children After Histamine and Methacholine Bronchoprovocation with Dosimeter-MedicAid and DeVilbiss Nebulizers

To explore the use of oscillometry as a measure of airway responsiveness, 69 asthmatic children underwent histamine and methacholine bronchoprovocation using dosimeter-MedicAid (Jaeger Co.; Germany) and DeVilbiss nebulizers (DeVilbiss, Bornemouth; England). The mean increase in R5 resistance in challenge testing measured after methacholine with the dosimeter-MedicAid nebulizer was 77.14% compared with 65.05% using histamine. Using the dosimeter-DeVilbiss nebulizer, the mean increases in R5 resistance following methacholine and histamine testing were 57.50% and 59.36%, respectively. The resistance R5 over R20 significantly correlated with forced expiratory volume in 1 second (FEV1). The MedicAid produced a more aggressive challenge than the DeVilbliss nebulizer. Oscillometry can be used to monitor the level of airway hyperresponsiveness following bronchoprovocation tests.

Effects of tension of the girth strap on respiratory system mechanics in horses at rest and during hyperpnea induced by administration of lobeline hydrochloride

To determine whether tension of the girth strap of a saddle would sufficiently affect rib motion and reduce lung volume to alter pulmonary resistance in horses. 10 healthy adult horses. We used classical techniques to measure the effects of tightening a girth strap (15 kg of tension) on pulmonary dynamics during eupnea and hyperpnea in horses. Respiratory impedance was evaluated by use of oscillometry, and resistance and reactance data were partitioned into lung and chest wall components. Rib cage and abdominal contributions to tidal volume and minute ventilation were measured by use of respiratory inductance plethysmography. Effects of strap tension on functional residual capacity (FRC) were measured during eupnea by use of a helium-dilution technique. In a subgroup of 6 horses, we also measured transdiaphragmatic pressures during eupnea and hyperpnea induced by administration of lobeline hydrochloride (0.2 mg/kg, i.v.). Pulmonary resistance measured by use of oscillometry but not by use of classical methods was significantly increased by the tension of the girth strap. However, the increase in pulmonary resistance could not be explained by a decrease in FRC. Motion of the rib cage was significantly reduced during eupnea and hyperpnea. However, ventilatory variables (tidal volume, minute ventilation, and peak flows), FRC, and transdiaphragmatic pressures were unaltered by strap tension. Although tension of the girth strap caused measurable changes in respiratory mechanics (loss of rib motion and increased pulmonary resistance), there was no evidence that ventilation was limited.