Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Oscillometry”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed2003

Use of the impulse oscillometry system for testing pulmonary function during methacholine bronchoprovocation in horses.

OBJECTIVE: To compare sensitivity of the impulse oscillometry system (IOS) with that of the conventional reference technique (CRT; ie, esophageal balloon method) for pulmonary function testing in horses. ANIMALS: 10 horses (4 healthy; 6 with recurrent airway obstruction [heaves] in remission). PROCEDURE: Healthy horses (group-A horses) and heaves-affected horses (group-B horses) were housed in a controlled environment. At each step of a methacholine bronchoprovocation test, threshold concentration (TC(2SD); results in a 2-fold increase in SD of a value) and sensitivity index (SI) were determined for respiratory tract system resistance (R(rs)) and respiratory tract system reactance (X(rs)) at 5 to 20 Hz by use of IOS and for total pulmonary resistance (RL) and dynamic lung compliance (C(dyn)), by use of CRT. RESULTS: Bronchoconstriction resulted in an increase in R(rs) at 5 Hz (R(5Hz)) and a decrease in X(rs) at all frequencies. Most sensitive parameters were X(rs) at 5 Hz (X(5Hz)), R(5Hz), and R(5Hz):R(10Hz) ratio; RL and the provocation concentration of methacholine resulting in a 35% decrease in dynamic compliance (PC(35)C(dyn)) were significantly less sensitive than these IOS parameters. The TC(2SD) for X(rs) at 5 and 10 Hz was significantly lower in group-B horses, compared with group-A horses. The lowest TC(2SD) was obtained for X(5Hz) in group-B horses and R(5Hz) in group-A horses. CONCLUSIONS AND CLINICAL RELEVANCE: In contrast to CRT parameters, IOS parameters were significantly more sensitive for testing pulmonary function. The IOS provides a practical and noninvasive pulmonary function test that may be useful in assessing subclinical changes in horses.

Airway Obstruction↗
PubMed2004

Measurement of respiratory function by impulse oscillometry in horses.

REASONS FOR PERFORMING STUDY: Due to technical implementations and lack of sensitivity, pulmonary function tests are seldom used in clinical practice. Impulse oscillometry (IOS) could represent an alternative method. OBJECTIVES: To define feasibility, methodology and repeatability of IOS, a forced oscillation technique that measures respiratory resistance (Rrs) and reactance (Xrs) from 5 to 35 Hz during spontaneous breathing, in horses. METHODS: Using 38 healthy horses, Rrs and Xrs reference values were defined and influence of individual biometrical parameters was investigated. In addition, IOS measurements of 6 horses showing clinical signs of heaves were compared to those of 6 healthy horses. RESULTS: Airtightness and minimal dead space in the facemask were prerequisites to IOS testing and standardisation of head position was necessary to avoid variations in Rrs due to modified upper airway geometry. In both healthy and diseased animals, measurements were repeatable. In standard-type breeds, the influence of the horse's size on IOS parameters was negligible. An increase in R5Hz greater than 0.10 kPa/l/sec and R5Hz>R10Hz, combined with negative values of Xrs between 5 and 20 Hz, was indicative of heaves crisis. CONCLUSIONS: IOS is a quick, minimally invasive and informative method for pulmonary function testing in healthy and diseased horses. POTENTIAL RELEVANCE: IOS is a promising method for routine and/or field respiratory clinical testing in the equine species.

Airway Obstruction↗
PubMed2006

Qualitative and quantitative evaluation of equine respiratory mechanics by impulse oscillometry.

REASONS FOR PERFORMING STUDY: The long-established conventional reference technique (CRT) for measuring respiratory mechanics in horses lacks sensitivity and there is a need for further refinement in new technology, such as the impulse oscillometry system (IOS). OBJECTIVES: To evaluate the potential use of the IOS as a clinical respiratory function test and compare it to the current CRT in horses suffering from common upper and lower airway dysfunctions. METHODS: Six healthy horses were tested before and after induction of a unilateral nasal obstruction (UNO) or transient left laryngeal hemiplegia (LLH). Six heaves-affected horses were tested in clinical remission and during a heaves crisis, before and after nebulisation of cumulative doses of a bronchodilator therapy (ipratropium bromide; IPB). RESULTS: As opposed to the CRT, the IOS was able to detect partial upper airway obstruction (UAO) caused by UNO or LLH in resting horses, without differentiating both conditions. Upper airway obstruction caused an upward shift of resistance (R(rs)) from 5 to 35 Hz without altering reactance (X(rs)). As for the CRT, IOS respiratory parameters measured in heaves-affected horses in crisis differed significantly from values measured during remission. The difference in frequency-dependent behaviour of R(rs) and X(rs) allowed discrimination between upper and lower airway obstructions. Bronchodilator treatment induced significant dose-dependent changes in X(rs) at 5 and 10 Hz, from the first dose. Total pulmonary resistance (RL) and R(rs) at 5 Hz were affected from the second dose and displayed similar sensitivity. Although post treatment RL values were comparable to remission, R(rs) and X(rs) remained significantly different, characterising persistent peripheral obstruction. CONCLUSIONS: The IOS was more sensitive than the CRT in detecting partial UAO in resting horses and persistent post treatment peripheral dysfunction in heaves-affected horses. The IOS is a sensitive test that provides graded quantitative and qualitative information on disease-induced respiratory dysfunctions as well as on treatment efficiency in horses. POTENTIAL RELEVANCE: The IOS could represent a practical and sensitive alternative respiratory function test for routine clinical investigations of common airway obstructive diseases and therapy in horses.

Airway Obstruction↗
PubMed1999

The diagnostic value of total respiratory impedance by impulse oscillometry in chronic obstructive lung disease.

OBJECTIVE: To investigate the diagnostic significance of total respiratory impedance for chronic obstructive lung disease. METHODS: The impedance of respiratory system was measured by impulse oscillometry method and compared with parameter values of routine pulmonary function in 57 patients with chronic obstructive pulmonary disease (COPD). RESULTS: It significantly increased in viscous resistance ranging from 5 Hz and 35 Hz and resonant frequency in COPD group than that in healthy group. Reactance from 5 Hz and 35 Hz in COPD group was marked lower than that in healthy group. There were marked frequency dependence of viscous resistance and reactance in COPD patients. Resonant frequency was markedly and negatively correlated with parameters of pulmonary ventilation indices; X5 was positively correlated with parameters of pulmonary ventilation indices. But no statistical correlation was showed between R20 and parameters of pulmonary ventilation indices. Correlation was found between resonance frequency and FEV1, resonance frequency and Vmax. The correlation coefficient values were -0.671 and -0.666 respectively. The sensitivity of resonant frequency, R5 and X5 for diagnosing COPD were 94.74%, 59.65% and 54.38%, respectively. The specificity of them were 86.66%, 96.66% and 90%, respectively. CONCLUSIONS: Resonant frequency was the most sensitive index in the parameters measured by IOS for diagnosing COPD. Since impedance measurement was a non-invasive method and only passive co-operation of the patient was needed. This technique could therefore be applied in COPD patients with acute attack for dynamic examination.

Aged↗
PubMed1999

[Clinical application of impulse oscillometry].

OBJECTIVE: To discuss the clinical significance of impulse oscillometry(IOS) to determine the resistance of large and small airways and the compliance of lung. METHODS: The IOS indices of 40 normal cases, 50 cases of chronic obstructive pulmonary diseases (COPD) and 60 cases of pleural effusion were determined at 5-35 Hz. Their FEV1/FVC and maximal expiratory flow-volume curve (MEFV curve) were measured in conventional method at the same time. RESULTS: Compared with normal cases, the peripheral resistance of the 50 patients with COPD rose obviously and the central airway resistance rose in some of them, the resonance frequency increased, but the peripheral reactance descended at the same time (P < 0.01). Resistance curve show markedly nonlinear decreasing course with increasing frequency. The resistance increased and the reactance descended in end-expiration. FEV1/FVC < 50%, MEFV curve showed severe obstructive shape. 60 patients with pleural effusion were found the resistance increasing and reactance descending to negative values in end-inpiration at low frequencies (inverse values relation at low frequencies). FEV1/FVC were nearly normal, MEFV curve showed restrictive dysfunction shape only in half of them. CONCLUSIONS: IOS can reflect variation of airway resistance and lung compliance. The future development of IOS could be prosperous.

Humans↗
PubMed2005

Comparative analysis of the bronchodilator response measured by impulse oscillometry (IOS), spirometry and body plethysmography in asthmatic children.

BACKGROUND: Asthma is common among young children. The assessment of respiratory resistance by the impulse oscillometry system (IOS), based on the superimposition of respiratory flow by short-time impulses, requires no patient active collaboration. AIM: We evaluated the baseline repeatability and bronchodilator response of IOS indices in preschool children, their correlation with spirometry and whole body plethysmography, and differences between atopic and nonatopic children. PATIENTS AND METHODS: Thirty-three asthmatic children (3-6 yrs.) underwent IOS measurement (R5rs, R20rs and X5rs) by triplicate at the baseline, after placebo and after salbutamol inhalation. Spirometry (FEV1) and whole body plethysmography (sRaw) were made at the baseline and after salbutamol. Baseline within-test (coefficient of variation: CV%) and between-test repeatability (baseline-placebo) were addressed. Bronchodilator response was evaluated by the SD index (change in multiples of the between-test repeatability). RESULTS: Baseline repeatability for R5rs was 4.1%. Its values decreased by 2SD after salbutamol inhalation, and correlated with FEV1 and sRaw at both, baseline (r=-0.51 and r=0.49) and post-salbutamol (r=-0.63 and r=0.54). A trend towards correlation between salbutamol-induced changes in R5rs and in sRaw (r=0.33) was observed. Atopic and non-atopic children showed no differences in lung function. CONCLUSION: IOS was well accepted by young asthmatic children and provided reproducible and sensitive indices of lung function. Resistance values obtained by IOS at low frequency (R5rs) were reproducible and correlated with spirometry and plethysmographic values.

Airway Resistance↗
PubMed1990

[Lung function diagnosis using multi-frequency oscillometry with reference to lung volume].

The ranking of various oscillometry parameters was to be tested in patients with a broad spectrum of disturbances of pulmonary function, objectified by body plethysmographic and technical oesophageal pressure measurement of the respiratory resistance, lung volumes and lung elasticity. For this purpose the oscillatory resistance Rfo and the phase angle phi were measured at 8, 12 and 16Hz and phi was measured as it changed, depending on the lung volume V. It was found that enhanced respiratory resistance values are satisfactorily represented by Rfo for the purposes of preliminary and basic diagnostics. Besides, enhanced Rfo values are markedly dependent on the frequency, phi being shifted to negative values. Difference between Rfo values at 8 and 16 Hz (delta R8-16) less than 0.7 hPa/l/s phi greater than or equal to -10 degrees can be considered as being still normal with the employed measuring principle and are a valuable supplement for assessing the degree of obstruction. The difference between phi in the medium respiratory position and at 90 or 100% total capacity (delta phi) is less than 5 degrees during slow inspiration in 80% of the patients suffering from emphysema. In 80% of the persons with healthy lungs and those suffering from fibrosis there is an inspiratory negativation of phi (delta phi greater than 5 degrees) so that the phi-V relationship appear suitable for distinguishing patients with restricted vital capacity in respect of emphysema and fibrosis. Patients suffering fron fibrosis differ from healthy subjects by slightly more negative phi values. The borderline values for delta R8-16, phi and delta phi were confirmed in two further series of examinations on children and adolescents.

Adult↗
PubMedDate not supplied

Comparison of forced oscillometry and forced expirations for measuring dose-related responses to inhaled methacholine in asthmatic children.

The forced oscillation technique (FOT) is a lung function method which is applicable from the age of 2.5 years onwards, because only passive co-operation is needed. We used the method as described by Làndsér et al. The aim of this study was to compare indices of bronchial responsiveness obtained by FOT (Rrs6, Rrs, dRrs/df, Xrs), with indices derived from maximal and partial expiratory flow-volume curves (MEFV25, PEFV25, FEV1). Bronchial responsiveness was assessed by methacholine inhalation. Threshold dose (TD), i.e. the dose which caused a 2 SD change from baseline lung function, and provocation dose (PD), i.e. the dose which caused a 20% fall in FEV1, a 40% fall in MEFV25 and PEFV25 and a 40% increase in Rrs and Rrs6, were determined. We found that the indices derived from forced oscillometry compared well to those from maximal and partial flow-volume curves. PD20 FEV1 and PD40 Rrs6 were highly correlated (r = 0.84). TD appeared to be as good as PD to measure bronchial responsiveness and is preferred to PD because of the lower dose needed and limited bronchoconstriction obtained.

Adolescent↗
PubMed1997

Comparison of blood pressure measurements obtained in dogs by use of indirect oscillometry in a veterinary clinic versus at home.

OBJECTIVE: To compare blood pressure and heart rate measurements performed in a veterinary clinic to similar measurements performed in a dog's home. DESIGN: Prospective study. ANIMALS: 14 client-owned, clinically normal dogs. PROCEDURE: Sequential blood pressure and heart rate measurements were recorded from the metatarsus and metacarpus of conscious dogs by indirect oscillometry. Measurements were performed in the dogs' homes and were repeated in a veterinary clinic. Blood pressures and heart rate were derived from 7 serial estimates over 8 to 10 minutes. Statistical differences between the home and clinic and between recording sites were calculated. RESULTS: Systolic, diastolic, and mean blood pressure and heart rate measurements obtained from the metatarsus and metacarpus in the dogs' homes were significantly lower than measurements from the metatarsus in the clinic, but were similar to measurements from the metacarpus in the clinic. Significant differences were not found between blood pressure measurements from the metatarsus and metacarpus in the dogs' homes, but systolic and mean blood pressure and heart rate measurements from the metacarpus in the clinic were significantly lower than measurements from the metatarsus. Whereas all dogs had normal blood pressure in their homes, 5 of 14 dogs had transient hypertension (systolic pressure > 165 mm of Hg or diastolic pressure > 95 mm of Hg) in the clinic. CLINICAL IMPLICATIONS: Blood pressure and heart rate measurements obtained in the clinic initially overestimate comparable measurements in a dog's home. The differences are best explained by transient autonomic responses to the stress of the clinic. Blood pressure must be measured by use of standardized techniques on dogs acclimated to the clinic environment.

Acclimatization↗
PubMed1997

[Technical adaptation of impulse oscillometry to special research conditions].

The technical adaptation of the Impulse-Oscillometry (IOS) to different conditions of measurement allows a wide range of applications so that even questions of peripheral user groups using lung function tests can be answered. Thus, the variable connection of the IOS head via fold hose opens the field of bedside measurements and additional applications in pediatrics, intensive care and veterinary medicine. Rhinomanometric examinations are possible with little expenditure and high practicability using nasal tips.

Adult↗
PubMed1997

[Impulse oscillometry and body position].

To assess diurnal profiles of impulse-oscillometry (IOS) changes of IOS-parameters between different body positions have been studied using a special set IOS-Bedside for individual home care. IOS has been applied in lateral lying and in sitting position in 20 healthy female and male probands, aged 10-67, during 24 hours in intervals of 3 hours. In each test during normal breathing for approximately 30 sec about 130 spectral and structural analyses have been performed at an impulse distance of 0.2 sec. The global means of resistance at 5 Hz (R5) in lying position are in men about 0.6 and in women about 0.3 hPa/l/s higher than in sitting position, those of reactance in men and women are only about 0.2 hPa/l/s lower. There is a distinct diurnal periodicity of the differences. The maxima of them may occur at different hours of the day in single probands; but at the average mean the maxima are found at the end of night. The differences of oscillation parameters between lying and sitting position are bigger at end-expiration than at end-inspiration. The resistance-flow-gradients, representing the component of turbulent flow, are enlarged in lying position especially at night.

Adolescent↗
PubMed1997

[Effect of various factors on the results of lung function tests using multifrequent impulse oscillometry in calves and young cattle].

The applicability of impulse oscillometry (IOS) under clinical and field conditions was tested on 31 calves and 27 young bulls over a period from 3 to 5 months, respectively. Based on the obtained 492 test results (the average of four measurements), lung function criteria resistance and reactance, measured at frequencies of 5 to 15 Hz, showed to be diagnostically relevant. In healthy calves aged 4 to 12 weeks, resistance values lay between 0.22 to 0.36 kPa/(l/s) irrespective of frequency. Reactance values were in the range of -0.014 to 0.055 kPa/(l/s) at 5 Hz, but increased with growing frequency. Within the investigated groups no correlation could be established between factors age or body mass of the animals and resistance. Increasing age, however, led to a considerable increase in reactance. Alterations of the upper airway system were coupled with an increase in resistance values while reactance remained constant. Diagnostic evaluation of individual results relating to this category was hampered by the high interindividual test value variance of 25 to 31% between healthy animals. Diseases of the peripheral respiratory system, however, were clearly characterised by a significant decrease in reactance, as well as a negative frequency dependence of resistance. It is concluded that this method at lung function testing provides a sensitive tool for detecting and recording lung function disorders in young cattle.

Aging↗
PubMed1991

Blood pressure changes associated with tilting in normotensive subjects: differences in response pattern as measured by oscillometry and auscultation.

Three non-invasive instruments were used to measure blood pressure in the supine position and on tilting--a conventional and a random-zero sphygmomanometer, and an oscillometric device (Accutorr 1A). Twenty normotensives volunteered for the study. There was no statistically significant difference in systolic blood pressure and diastolic blood pressure measured by the conventional and random-zero sphygmomanometers in the supine position. There was a difference between these recordings and those of the Accutorr, with the Accutorr giving higher readings of systolic blood pressure (p less than 0.001), analysis of variance, 95% confidence interval of the difference between the Accutorr and the random-zero was 5.1-15.7 mmHg) and lower readings of diastolic blood pressure (p less than 0.0001, analysis of variance, 95% confidence interval of the difference between the Accutorr and the random-zero was -12.2- -2.2 mmHg). On tilting, the Accutorr showed an increase in systolic blood pressure while the other two machines did not (p less than 0.01, analysis of variance). By contrast, the Accutorr detected a smaller rise in diastolic blood pressure than with the other two instruments (p less than 0.05, analysis of variance). The difference between blood pressure measurements made in the supine position by the two different techniques, auscultation and oscillometry, might be expected. However, the two different techniques do not detect the same blood pressure responses to a change in posture.

Adult↗
PubMed1986

Skin avulsion during oscillometry.

We observed a case of skin avulsion associated with measurement of blood pressure by oscillometry on an anesthetized patient in the prone position. Epidermal shearing may be avoided in the prone patient by either wrapping the antecubital skin underlying the blood pressure cuff with gauze or preventing weight-bearing by the cuffed portion of the arm.

Blood Pressure Determination↗
PubMed2005

The use of impulse oscillometry for separate analysis of inspiratory and expiratory impedance parameters in horses: effects of sedation with xylazine.

AIM: To improve the outcome of parameters measured by the impulse oscillometry system (IOS) in horses by separate assessment of inspiratory and expiratory impedance spectra in the frequency range between 1 and 10 Hz. As basis for further studies, the influence of sedation with xylazine on respiratory impedance was also investigated. METHODS: (i) The respiratory impedance of 11 horses was measured using IOS before and 6 min after sedation (xylazine; 0.6 mg/kg b.w.). (ii) The time course of impedance parameters in a period of 24 min after administration of xylazine was evaluated in 12 horses at regular intervals of 3 min. Resistance (R(rs)), reactance (X(rs)), and coherence (Co) were calculated as mean spectra (R(rs),X(rs),Co) of the entire measurement as well as separated into inspiration (Ri(rs),Xi(rs),Coi) and expiration (Re(rs),Xe(rs),Coe) at frequencies of 1, 5, and 10 Hz. RESULTS: (i) R(rs), X(rs) as well as Re(rs) and Xe(rs) revealed no significant influence of sedation. However, separate analysis of inspiration and expiration revealed a significant influence of sedation on all inspiratory impedance parameters. (ii) During the 24 min period after sedation, almost all inspiratory parameters were found significantly dependent on the time course of sedation whereas expiratory parameters Re10, Xe1, and Xe5 were not influenced. These results indicate that confounding factors due to sedation act mainly during inspiration. Muscle relaxation in upper airways due to xylazine is suspected to be the main cause of these phenomena.

Animals↗
PubMed2005

A comparison of plethysmography, spirometry and oscillometry for assessing the pulmonary effects of inhaled ipratropium bromide in healthy subjects and patients with asthma.

AIMS: We have compared the ability of plethysmography (sGaw), impulse oscillometry (IOS) and spirometry (FEV(1), MMEF) to detect bronchodilation in response to an anticholinergic. METHODS: IOS (R5, R20, X5, RF), sGaw and spirometry were measured in 12 healthy subjects and 12 asthmatics. Variability was assessed by performing two measurements, 30 min apart and the effect of increasing the number of readings for each sGaw measurement was also studied. Ipratropium bromide (IB) 10, 20, 100 and 200 microg was administered and the sensitivity of the methods compared by determining the lowest dose that caused changes greater than variability. RESULTS: In healthy subjects significant changes (P < or = 0.05) occurred at 10 microg for FEV(1) (mean [95% CI]; 1.3%[0.3-2.3]), R5 (mean [95% CI]; -7.9%, [-13.2-2.6]) and R20 (mean [95% CI], -6.4%, [-11.4-1.4]). No significant change was detected when the mean of 3 sGaw readings was used, but with 10 readings significant change was observed at 20 microg; (mean increase [95% CI] 15.2%[8.3-22.1]). In asthmatics significant changes (P < or = 0.05) occurred with IB 10 microg for sGaw (mean [95% CI] 25.6%[11.1-40.1]), R5 (mean [95% CI]-11.3%, [-15.5-7.2]), RF (mean [95% CI] 11.7%[6.1-16.3]), FEV(1) (mean [95% CI] 5.1%[2.6-7.7]) and MMEF (mean [95% CI] 12.3%[2.3-22.2]). CONCLUSION: IOS and spirometry are more sensitive than sGaw in healthy subjects, but the sensitivity of sGaw improved when the number of readings was increased. The most sensitive method for assessing bronchodilation in asthmatics was sGaw.

Adult↗
PubMed1999

Wrist measurement of blood pressure: some critical remarks to oscillometry.

UNLABELLED: Oscillometric blood pressure measuring devices worn at the wrist are preferred by a growing part of hypertensive patients for self-measurement because of their compactness and ease of use. However, little is known about the accuracy of such instruments. The accuracy of such devices was evaluated by measuring the blood pressure at the end of a coronary angiography procedure in 27 subjects nearly simultaneously in the aortic arch, using a Statham P23 transducer, and at the wrist, using the blood pressure watch (BPW) by NAIS-Matsushita. Four replicate comparative measurements were performed in each subject. On average, the blood pressure measured by the BPW was found to be higher: systolic +1.2+/-(SD)10.2 mm Hg, diastolic +4.1+/-7.2 mm Hg. The correlation coefficient between the two methods was 0.85 for the systolic and 0.84 for the diastolic pressure, but 39% of the systolic and 22% of the diastolic differences were outside the range of +/-1 SD. There was no correlation between systolic differences and blood pressure or patients' variables, but multiple regression analysis revealed that the diastolic blood pressure differences were negatively correlated with the aortic diastolic pressure (r = 0.89, p<0.001), indicating that the BPW is less accurate to detect lower values. CONCLUSIONS: (1) Though the average systolic and diastolic deviations between both methods and the relative correlation coefficients suggest that the BPW is to be used carefully for monitoring blood pressure, the great variability of differences and the inability of the BPW to detect lower diastolic blood pressure calls for a mandatory validation test by an approved protocol before this new device can be recommended for general use. (2) On the basis of our results for wrist oscillometry with the BPW and data reported in the literature for upper-arm oscillometric devices, we recommend to use oscillometric devices only when they were validated properly. In particular, the oscillometric measurement should be employed with caution for epidemiological studies or for investigation of population groups (e.g., children or pregnant women) that are expected to display lower diastolic pressures.

Adult↗