Bronchodilator response assessment through impulse oscillometry system and spirometry in children and adolescents with cystic fibrosis.

OBJECTIVE: To investigate the effect of bronchodilator on the respiratory mechanics and pulmonary function of children and adolescents with cystic fibrosis. METHODS: Cross-sectional study on clinically stable children and adolescents with cystic fibrosis aged from six to 15 years. Participants underwent impulse oscillometry and spirometry evaluations before and 15 minutes after bronchodilator inhalation. The Kolmogorov-Smirnov test was applied to verify the sample distribution, and the Student's t-test and Wilcoxon test were used to compare the data before and after bronchodilator inhalation. RESULTS: The study included 54 individuals with a mean age of 9.7±2.8 years. The analysis showed a statistically significant improvement in impulse oscillometry and spirometry parameters after bronchodilator inhalation. However, according to the American Thoracic Society (ATS) and European Respiratory Society (ERS) recommendations (2020 and 2021), this improvement was not sufficient to classify it as a bronchodilator response. CONCLUSIONS: The use of bronchodilator medication improved respiratory mechanics and pulmonary function parameters of children and adolescents with cystic fibrosis; however, most patients did not show bronchodilator response according to ATS/ERS recommendations.

Comparison of Doppler ultrasonic sphygmomanometry, oscillometry and high-definition oscillometry for non-invasive blood pressure measurement in conscious cats.

OBJECTIVES: Systemic arterial hypertension is a common occurrence and can have serious adverse consequences in cats. Therefore, measuring blood pressure is very important. There are many indirect blood pressure measurement devices available. This study compared Doppler, oscillometric (petMAP Graphic II, SunTech Vet20, the Cardell Insight-X0000) and high-definition oscillometry devices for the non-invasive measurement of blood pressure in conscious cats. METHODS: In this prospective study, blood pressure was measured in 32 cats using the different devices according to the recommendations of the American College of Veterinary Internal Medicine Consensus Statement. Blood pressures (systolic blood pressure [SBP], diastolic blood pressure [DBP], mean arterial pressure [MAP]), time to complete measurements, number of attempts needed, coefficient of variation (CV) between the blood pressure measurements of the different devices, ease of completing measurements and apparent stress level of the cat were assessed. RESULTS: There was a significant difference between devices in the time taken to obtain blood pressure readings and the number of attempts necessary to obtain six reliable measurements. The CV of the Doppler device was significantly smaller than that of the rest of the devices, but there were no other differences between the devices. The mean SBP, DBP and MAP measured by the petMAP device were significantly higher than the measurements from the other devices. The perceived ease of measurement was not significantly different between the various machines. The perceived level of stress of measurement with the Doppler device was significantly higher compared with the other devices but did not lead to an increased SBP. CONCLUSIONS AND RELEVANCE: Using a Doppler device to measure blood pressure in conscious cats is fast, relatively easy and gives reliable results. A disadvantage is that the Doppler device can only measure SBP, while oscillometric devices also provide DBP and MAP. However, in veterinary medicine, systolic hypertension is considered the most relevant.

Impulse Oscillometry as an Alternative Lung Function Test for Hospitalized Adults.

BACKGROUND: Impulse oscillometry (IOS) is a noninvasive technique that measures lung physiology independently of patient effort. In the present study, we aimed to investigate the utility of IOS parameters in comparison with pulmonary function testing (PFT) among hospitalized subjects, with emphasis on obstructive and small airway diseases. METHODS: Sixty-one subjects hospitalized either with unexplained dyspnea or for pre-surgery evaluation were included in the study. All subjects underwent PFTs and IOS test. The correlation between IOS results and PFTs was examined in different subgroups. The ability of IOS parameters to predict abnormal PFTs was evaluated using the area under the receiver operating characteristic (ROC) curve, and optimal cutoff values were calculated. RESULTS: IOS results were found to correlate with PFT values. Subgroup analysis revealed that these correlations were higher in younger (age < 70) and non-obese (body mass index < 25kg/m2) subjects. The resonant frequency was an independent predictor and had the best predictive ability for abnormal FEV1/FVC (area under the ROC curve 0.732 [95% CI 0.57-0.90], optimal cutoff 17 Hz, 87% sensitivity, 62% specificity) and abnormal forced expiratory flow during the middle half of the FVC maneuver (area under the ROC curve 0.667 [95% CI 0.53-0.81], optimal cutoff 15 Hz, 77% sensitivity, 54% specificity). Area of reactance and the difference in respiratory resistance at 5 Hz and 20 Hz also showed a good predictive ability for abnormal FEV1/FVC (area under the ROC curve 0.716 and 0.730, respectively). CONCLUSIONS: We found that the IOS performed well in diagnosing small airway and obstructive diseases among hospitalized subjects. IOS might serve as an alternative to standard PFTs in non-cooperative or dyspneic hospitalized patients.

The impact of respiratory reactance in oscillometry on survival in patients with idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a progressive disease with a poor prognosis. Pulmonary function tests (PFTs) aid in evaluating the disease status of IPF. The clinical significance of oscillometry measurements in interstitial lung diseases has recently been reported. Our previous study showed that respiratory reactance (Xrs) measured by oscillometry reflected disease severity and predicted subsequent lung capacity decline in patients with IPF. However, the direct impact of Xrs on survival needs to be determined, and there are currently no reference values in oscillometry to predict prognosis. Therefore, this study aimed to investigate the association between oscillometry measurements, particularly Xrs, and survival in patients with IPF and to determine the cutoff values of Xrs that predict 3-year survival. METHODS: We analyzed the relationship between the measured values of PFT and oscillometry derived from 178 patients with IPF. Univariate and multivariate Cox proportional hazards analyses were performed to investigate the relationships between clinical indices at the time of the first oscillometry and survival. We performed the time-dependent receiver operating characteristic (ROC) curve analysis to set the optimized cutoff values of Xrs for 3-year survival prediction. We examined the discriminating power of cutoff values of Xrs on survival using the Kaplan-Meier method and the log-rank test. RESULTS: Xrs components, especially in the inspiratory phase (In), significantly correlated with the PFT values. In the multivariate analyses, Xrs (all of reactance at 5 Hz [X5], resonant frequency [Fres], and low-frequency reactance area [ALX] in the inspiratory phase) had a significant impact on survival (X5, p = 0.003; Fres, p = 0.016; ALX, p = 0.003) independent of age, sex, and other prognostic factors derived from the univariate analysis. The area under the ROC curve was 0.765, 0.759, and 0.766 for X5 In, Fres In, and ALX In, with cutoff values determined at - 0.98, 10.67, and 5.32, respectively. We found significant differences in survival after dividing patients using each of the cutoff values of Xrs. CONCLUSIONS: In patients with IPF, Xrs measured by oscillometry significantly impacted survival. We also determined the cutoff values of Xrs to discriminate patients with poor prognoses.

Use of impulse oscillometry to assess lung function in prematurely born children and young people: Comparisons with spirometry.

Premature birth is a risk factor for bronchopulmonary dysplasia (BPD); both of which are associated with obstructive airway disease throughout childhood. Impulse oscillometry (IOS) is an effort-independent, passive measure of tidal breathing, which could have benefits in assessing lung function amongst younger patients unable to perform valid spirometry. A literature search was conducted to investigate the use of IOS in prematurely born children and young people. IOS results correlate with those of spirometry. Reversibility of airway obstruction in children with BPD is variable. IOS could have benefits in assessing individual patient response and suitability for bronchodilator therapy. More work, however, is required to establish multi-ethnic reference ranges and standardise commercially available devices prior to its routine incorporation into clinical practice.

The impact of adenoid hypertrophy on pulmonary functions measured using impulse oscillometry in preschool-age children.

PURPOSE: To assess pulmonary impedance [resistance (zR5, zR20, R5-20, Fres, and AX) and reactance (zX5 and zX20)] using impulse oscillometry (IOS) in children with adenoid hypertrophy (AH) and its association with the degree of AH, and to evaluate subsequent changes in pulmonary function 3 months after adenoidectomy. METHODS: This prospective cross-sectional study was conducted with 170 preschool-age children [110 with AH and 60 sex- and age-matched healthy controls (HCs)]. Pulmonary function was analyzed using IOS at baseline (1st visit) in all participants and 3 months after adenoidectomy (2nd visit) in patients who underwent the operation. RESULTS: The IOS parameters of zR5, zR20, R5-20, Fres, and AX were higher, but zX20 was lower, in children with AH compared to the HCs (p < 0.05 for all). The parameters of zR5, Fres, and AX were higher in children with grade IV AH than in those with grade I (p < 0.001). zR5, zR20, R5-20, Fres, and AX decreased, but zX20 increased, after adenoidectomy (2nd visit) compared to baseline (1st visit) (p < 0.05). Post-adenoidectomy (2nd visit) zR5, AX, Fres values were higher in children with AH compared to baseline values in the HCs (1st visit) (p < 0.05). The area under the ROC curve (AUC) value for estimating adenoidectomy was 0.741 for zX20 (CI 0.648-0.834, p < 0.001) with a cut-off value of  ≤ -3.21, sensitivity of 68.8%, and specificity of 70%. CONCLUSION: This study shows that IOS is a useful method for demonstrating subclinical bronchial obstruction in preschool-age children with AH with greater pulmonary impedance (resistance and reactance). Pulmonary impedance decreased 3 months after adenoidectomy, but remained higher than in the HCs. The IOS parameter of X20 may be predictive of adenoidectomy. This study evaluated the pulmonary functions of children with adenoid hypertrophy (AH) using impulse oscillometry (IOS) and the association with the scale of AH. Pulmonary functions were analyzed using IOS. The main IOS parameters include resistances (zR5 and zR20), reactance (zX5 and zX20), R5-20 (resistance at 5 Hz minus resistance at 20 Hz), resonant frequency (Fres), and AX. Fres is the point at which reactance is zero and is measured in Hz (1/s). The Reactance Area (AX - "Goldman Triangle") represents the integrated low-frequency respiratory reactance magnitude between 5 Hz and Fres. Faster frequencies of R (~ 20 Hz) reflect larger airways, regarded as resistance around the central airways. Lower frequencies of R (~ 5 Hz) providing information around the entire (small and large) airways. Peripheral (small) airway resistance is defined by R5-20. IOS parameters of zR5, zX20, Fres, and AX differed among AH grades I-IV and compared to the HCs (p < 0.001 for all).

Three Weeks of Pulmonary Rehabilitation Do Not Influence Oscillometry Parameters in Postoperative Lung Cancer Patients.

Background: Thoracic surgery is a recommended treatment option for non-small cell lung cancer patients. An important part of a patient's therapy, which helps to prevent postoperative complications and improve quality of life, is pulmonary rehabilitation (PR). The aim of this study was to assess whether the implementation of physical activity has an influence on forced oscillation technique (FOT) values in patients after thoracic surgery due to lung cancer. Methods: In this observational study, we enrolled 54 patients after thoracic surgery due to lung cancer, 49 patients with idiopathic interstitial fibrosis (IPF), and 54 patients with chronic obstructive pulmonary disease/asthma−COPD overlap (COPD/ACO). All patients were subjected to three weeks of in-hospital PR and assessed at the baseline as well as after completing PR by FOT, spirometry, grip strength measurement, and the 6-min walk test (6MWT). Results: We observed differences between FOT values under the influence of physical activity in studied groups, mostly between patients after thoracic surgery and COPD/ACO patients; however, no significant improvement after completing PR among FOT parameters was noticed in any group of patients. Improvements in the 6MWT distance, left hand strength, and right hand strength after PR were noticed (p < 0.001, 0.002, and 0.012, respectively). Conclusions: Three weeks of pulmonary rehabilitation had no impact on FOT values in patients after thoracic surgery due to lung cancer. Instead, we observed improvements in the 6MWT distance and the strength of both hands. Similarly, no FOT changes were observed in IPF and COPD/ACO patients after completing PR.

Correlation among clinical, functional and morphological indexes of the respiratory system in non-cystic fibrosis bronchiectasis patients.

BACKGROUND: Non-cystic fibrosis bronchiectasis (NCFB) is a heterogeneous disease, which assessment and severity can't be defined by one particular instrument but using a multidimensional score. Thus, in additional to traditional methods, alternative tools have been developed to assist these patients' evaluation. OBJECTIVE: To correlate functional and morphological indexes with severity and dyspnea in NCFB patients, focusing on the correlation between the impulse oscillometry system (IOS) and the quantitative analysis of computed tomography (CT). METHODS: Clinically stable NCFB patients, between 18 and 80 years old were submitted to clinical, functional and morphological evaluations assessed by Bronchiectasis Severity Index (BSI) and Medical Research Council (MRC) scale; spirometry and IOS; and subjective and quantitative Chest CT scans analysis, respectively. RESULTS: This study included 38 patients. The best correlations obtained between functional and morphological airway indexes were: resistance at 5 Hz-R5 and the normalized thickness of bronchial walls-Pi10 (r = 0.57), and the mean forced expiratory flow (FEF25-75%) and CT score (r = -0.39). BSI as well as MRC showed higher correlations with the quantitative automated analysis of CT (BSI and Pi10: r = 0.41; MRC and Pi10: r = 0.35) than with subjective CT score (BSI and CT score: r = 0.41; MRC and CT score: r = 0.15); and moderate and weak correlations were obtained on both functional airway indexes (BSI and peripheral airways resistance - R5-R20: r = 0.53; BSI and forced expiratory volume at the first second-FEV1: R = -0,64; MRC and R5-R20: r = 0.42; and MRC and VEF1: r = -0.45). CONCLUSION: In NCFB patients, compartmentalized methods for assessing the respiratory system (IOS and the automated quantitative CT analysis) have a good correlation with severity and dyspnea.

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.

RATIONALE: Oscillometry 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. OBJECTIVES: To 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™). METHODS: Of 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. RESULTS: There 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. CONCLUSIONS: Oscillometry 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. TRIAL REGISTRATION: ClinicalTrails.gov-NCT03626064, Retrospective registered: August 2018, https://clinicaltrials.gov/ct2/show/NCT03626064.

Reference values for respiratory sinusoidal oscillometry in children aged 3 to 17 years.

BACKGROUND: New oscillometry devices allowing quantification of respiratory function using tidal breathing are commercially available, but reference equations are lacking for the multiethnic Canadian pediatric population. METHODS: We conducted a prospective cross-sectional study of healthy children carefully selected for absence of asthma, atopy, tobacco smoke, obesity, prematurity, and recent respiratory infection. Triplicate measures were obtained of respiratory system resistance (Rrs) and reactance (Xrs), area under the reactance curve (AX) and resonant frequency (Fres) on four signals, whose testing order was randomized: two signals on the Resmon Pro Full (8 Hz and 5-11-19 Hz) and two signals on the tremoflo C-100 (5-37 Hz and 7-41 Hz). Feasibility was defined as the ability to obtain valid reproducible results. Prediction equations and 95% confidence intervals were derived for whole- and within-breath Rrs and Xrs and for AX and Fres, using linear regression or Generalized Additive Models for Location, Scale and Shape. RESULTS: Of 306 children randomized, valid and reproducible results on ≥1 signal were obtained in 299 (98%) multiethnic (69% Caucasians: 8% Black: 23% Others) children aged 3-17 years, 91-189 cm tall. Standing height was the strongest predictor with no significant effect of sex, age, body mass index or ethnicity. Significant within-patient differences were observed between Resmon Pro and tremoflo C-100 measurements, justifying the derivation of device-specific reference equations. CONCLUSION: Valid reproducible oscillometry measurements are highly feasible in children aged 3 years and older. Device-specific reference equations, valid for our multiethnic population, are derived.

Association between annual change in FEV1 and comorbidities or impulse oscillometry in chronic obstructive pulmonary disease.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by persistent respiratory symptoms and airflow limitation. The decline in forced expiratory volume in one second (FEV1) is considered to be one of the most important outcome measures for evaluating disease progression. However, the only intervention proven to improve COPD prognosis is smoking cessation. This study therefore investigated the factors associated with annual FEV1 decline in COPD. METHODS: This retrospective study followed up 65 patients treated for COPD for 5 years: 13 current smokers and 52 former smokers, 25 with pneumonia, 24 with asthma, 18 with cancer, and 17 with cardiovascular disease. The patients were divided into groups based on clinical cutoff parameters of the impulse oscillometry system (IOS): 11 high and 54 low R5, 8 high and 57 low R20, 21 high and 44 low R5-R20, 26 high and 39 low X5, 38 high and 27 low Fres, and 36 high and 29 low AX. We investigated whether the decline in FEV1 was associated with comorbidities and IOS parameters. RESULTS: The annual change in FEV1 over 5 years was significantly affected by smoking status (current - 66.2 mL/year vs. former - 5.7 mL/year, p < 0.01), pneumonia (with - 31.5 mL/year vs. without - 8.9 mL/year, p < 0.05), asthma (with - 30.2 mL/year vs. - 10.8 mL/year, p < 0.01), but not by cancer and cardiovascular disease. In the groups defined by IOS results, only the high AX group had significantly more annual decline in FEV1 and %FEV1 than the low AX group (- 22.1 vs. - 12.8, p < 0.05 and - 0.20 vs. 0.40, p < 0.05, respectively). CONCLUSIONS: Continuing smoking as well as complications in pneumonia and asthma would be risk factors for the progression of COPD. AX might be a suitable parameter to predict the prognosis of patients with COPD.

Predictive value of impulse oscillometry and multiple breath washout parameters in pediatric patients with cystic fibrosis pulmonary exacerbation.

BACKGROUND: Pulmonary exacerbations (PE) tend to complicate the course of cystic fibrosis (CF) and worsen the disease prognosis. One of the diagnostic criteria for an exacerbation is the forced expiratory volume in the first second (FEV1 ) decline. Not all children, however, are able to perform spirometry. Therefore, the aim of this study was to evaluate alternative lung function tests in the diagnosis of PE. METHODS: We assessed retrospectively the results of impulse oscillometry (IOS) and lung clearance index in multiple breath washout (MBW) during 259 visits in 47 CF paediatric patients. The differences in the results were compared between patients diagnosed with PE (ΔPE) and those in stable condition (ΔS). RESULTS: Among the whole group of patients, we found significant differences between the changes during exacerbation (ΔPEs) and stable condition (ΔSs) values for lung clearance index (LCI), Sacin , R5Hz, R5-20Hz, X10Hz, AX, and Fres. The predictive values of Fres and X10Hz in IOS (AUCROC 0.71 both parameters) were higher than those of LCI (AUCROC 0.67). There was no difference in the predictive values (AUCROC ) of Δ LCI and IOS parameters in the subgroups of patients stratified based on FEV1 z-score cut-off value of -1.64. In both groups of patients, predictive values of LCI were slightly lower than of IOS parameters (AUC 0.66 for LCI vs. 0.69 for both ΔX10Hz z-score and Δ Fres z-score in patients with FEV1 z-score ≥-1.64 and AUC 0.67 for LCI vs 0.69 for both ΔX10Hz zscore and Δ Fres zscore in patients with FEV1 <1.64. CONCLUSIONS: Both IOS and MBW measurements are useful in the assessment of pediatric CF patients with PE. LCI has a similar predictive value to IOS in children with CF independently of their FEV1 value.

Función pulmonar oscilometría de impulso en pediatría: procedimiento y aplicación clínica / Pulmonary function impulse oscillometry in pediatrics: procedure and clinical application

La Oscilometría de Impulso (IOS) es una técnica no invasiva que evalúa las propiedades mecánicas de todo el sistema respiratorio durante la respiración tranquila. Mide la impedancia total del sistema respiratorio, evaluando la resistencia total de la vía aérea, la resistencia de la vía aérea alta y las propiedades elásticas del pulmón. Detecta el compromiso de la vía aérea periférica en forma muy precoz, antes que la espirometría, y es útil en niños pequeños porque no requiere maniobras de espiración forzada. Permite evaluar la respuesta broncodilatadora y broncoconstrictora a través de pruebas de provocación bronquial para el diagnóstico de hiperreactividad bronquial. La IOS tiene un rol en la evaluación temprana y seguimiento de la función pulmonar en niños con enfermedades respiratorias crónicas, principalmente asma bronquial, displasia broncopulmonar y fibrosis quística. Este artículo revisa los aspectos fisiológicos, técnicos y aplicación clínica de la IOS, considerando las últimas recomendaciones para la estandarización del examen y las limitaciones que dificultan su interpretación .

Impulse Oscillometry (IOS) is a non-invasive technique that assesses the mechanical properties of the entire respiratory system during quiet breathing. It measures the total impedance of the respiratory system by evaluating total airway resistance, upper airway resistance, and elastic properties of the lung. It detects peripheral airway compromise very early, before spirometry, and is useful in young children because it does not require forced expiration maneuvers. It allows evaluating the bronchodilator and bronchoconstrictor response through bronchial provocation tests for the diagnosis of bronchial hyperreactivity. The IOS has a role in the early evaluation and monitoring of lung function in children with chronic respiratory diseases, mainly bronchial asthma, bronchopulmonary dysplasia and cystic fibrosis. This article reviews the physiological, technical, and clinical application aspects, considering the latest recommendations for the standardization of the test and the limitations that hinder its interpretation.

Is Impulse Oscillometry System a Useful Method for the Evaluation and Follow-Up of Patients with Cystic Fibrosis?

Background: Although the impulse oscillometry system (IOS) is a noninvasive, easily accessible, well-tolerated, and alternative test, routine use of IOS in cystic fibrosis (CF) patients is not widespread. In our unit, IOS is routinely used for the evaluation and follow-up of patients with CF. We aimed to show that IOS may be utilized as a complement for measuring pulmonary function in CF patients. Materials and Methods: Retrospective data collection and analysis of pulmonary function tests on CF patients followed at our center between January 1, 2018 and February 1, 2019. IOS and spirometry data were compared as correlated with patients' clinical exacerbation, treatment response, bronchodilator response, and trends during follow-up intervals. Results: There was a significant correlation between spirometry and IOS parameters in 70 patients. In exacerbation, Z5, R5-R10, AX, Fres, and delta R5-R20 were significantly increased and X5-X20 was significantly decreased compared with baseline in 25 patients. After treatment, IOS parameters were observed to return to baseline values. In the evaluation of bronchodilator response in 33 patients, significant changes in IOS (decrease in Z5, R5-R10, AX, Fres, and delta R5-R20, and increase in X5-X10) and in spirometry [increase in forced expiratory volume in 1 s (FEV1) and forced expiratory flow during the middle half of forced vital capacity (FEF25-75)] were found after bronchodilator. While there was no significant difference between spirometry values in follow-up visits in 31 patients, there was a significant increase in Z5% and R5%-R20%. Unlike other studies, there was a significant correlation between clinical scores and IOS. Conclusions: These results show that although IOS is not the gold standard method such as spirometry, it is an alternative method that can be used successfully in the evaluation and follow-up of CF patients. Clinical Trials.gov ID: 99166796-050.06.04.

Comparative evaluation of expiratory airflow limitation between patients with COPD and BE using IOS.

Impulse oscillometry (IOS) allows evaluation of the compartmentalized resistance and reactance of the respiratory system, distinguishing central and peripheral obstruction. The IOS measurements are getting attention in the diagnosis and differentiation of chronic respiratory diseases. However, no data are available in the literature to differentiate between COPD and BE using IOS parameters. We aimed to evaluate the feasibility of IOS in the diagnosis of bronchiectasis non-cystic fibrosis (BE) in comparison to COPD. Whole breath, inspiration, expiration, and inspiratory-expiratory difference (Δ) were evaluated based on the IOS parameters: total resistance (R5), central airway resistance (R20), peripheral airway resistance (R5-R20), reactance (X5), reactance area (AX), and resonance frequency (Fres). Fifty-nine subjects (21 Healthy, 19 BE, and 19 COPD) participated in this study. It was observed a significant difference in the comparison of healthy and pulmonary disease groups (BE and COPD) for total breathing (R5-R20, X5, AX, and Fres), inspiratory phase (R5 and R5-R5), and expiratory phase (R5-R20 and X5). The comparison between BE and COPD groups showed significant difference in the expiratory phase for resistance at 5 and 20 Hz and, ΔR5 and ΔR20. The IOS evidenced an increase of R5, R20 and R5-R20 in patients with BE and COPD when compared to healthy subjects. Expiratory measures of IOS revealed increased airway resistance in COPD compared to BE patients who had similar FEV1 measured by spirometry, however, further studies are needed to confirm these differences.

Intraoperative Blood Pressure Monitoring in Obese Patients.

BACKGROUND: The optimal method for blood pressure monitoring in obese surgical patients remains unknown. Arterial catheters can cause potential complications, and noninvasive oscillometry provides only intermittent values. Finger cuff methods allow continuous noninvasive monitoring. The authors tested the hypothesis that the agreement between finger cuff and intraarterial measurements is better than the agreement between oscillometric and intraarterial measurements. METHODS: This prospective study compared intraarterial (reference method), finger cuff, and oscillometric (upper arm, forearm, and lower leg) blood pressure measurements in 90 obese patients having bariatric surgery using Bland-Altman analysis, four-quadrant plot and concordance analysis (to assess the ability of monitoring methods to follow blood pressure changes), and error grid analysis (to describe the clinical relevance of measurement differences). RESULTS: The difference (mean ± SD) between finger cuff and intraarterial measurements was -1 mmHg (± 11 mmHg) for mean arterial pressure, -7 mmHg (± 14 mmHg) for systolic blood pressure, and 0 mmHg (± 11 mmHg) for diastolic blood pressure. Concordance between changes in finger cuff and intraarterial measurements was 88% (mean arterial pressure), 85% (systolic blood pressure), and 81% (diastolic blood pressure). In error grid analysis comparing finger cuff and intraarterial measurements, the proportions of measurements in risk zones A to E were 77.1%, 21.6%, 0.9%, 0.4%, and 0.0% for mean arterial pressure, respectively, and 89.5%, 9.8%, 0.2%, 0.4%, and 0.2%, respectively, for systolic blood pressure. For mean arterial pressure and diastolic blood pressure, absolute agreement and trending agreement between finger cuff and intraarterial measurements were better than between oscillometric (at each of the three measurement sites) and intraarterial measurements. Forearm performed better than upper arm and lower leg monitoring with regard to absolute agreement and trending agreement with intraarterial monitoring. CONCLUSIONS: The agreement between finger cuff and intraarterial measurements was better than the agreement between oscillometric and intraarterial measurements for mean arterial pressure and diastolic blood pressure in obese patients during surgery. Forearm oscillometry exhibits better measurement performance than upper arm or lower leg oscillometry.

Effects of Controlled Voluntary Increase in the Ventilatory Demand on Respiratory System Resistance in Healthy and Non-Cystic Fibrosis Bronchiectasis Subjects: A Cross-Sectional Study.

INTRODUCTION: Bronchiectasis patients may present a reduced functional capacity due to an increase in the ventilatory demand during exercise. OBJECTIVE: To evaluate the effects of controlled voluntary hyperinflation and increased respiratory rate on the mechanics of the respiratory system, simulating what happens during exercise, in bronchiectasis and healthy subjects. METHODS: Bronchiectasis (n=30) and healthy (n=16) subjects were evaluated by impulse oscillometry (IOS) during a baseline condition, and in controlled conditions with baseline (b) tidal volume (V) and hyperinflation (H), with respiratory rates at 30(R30) and 40(R40) bpm, in a random order. The mixed effects and a significance level at 0.05 were used for comparisons. RESULTS: Resistance at 5Hz (R5), and at minus 20Hz (R5-R20), in kPa/L/s, were higher in subjects with bronchiectasis in all experimental conditions (p<0.05). For the bronchiectasis group, R5 and R5-20 increased with R increase at V (VRb versus VR30 and VR40; VR30 versus VR40; R5, R20 and R5-20 increased with R increase at H (HRb versus HR40; HR30 versus HR40). For the same R, there was a decrease with H compared to V (HRb versus VR30 and VR40; and HR30 versus VR30 and VR40). For the healthy group, only R20 showed differences (HR30 versus HR40; HR40 versus VR40). CONCLUSION: The tachypnea increases the resistance and reactance of the respiratory system in bronchiectasis patients, and the voluntary hyperinflation caused attenuates this increase. These results can guide the development of strategies to reduce the limitation of physical activity in patients with bronchiectasis.

Impulse oscillometry and spirometry measurements relative to personal best values at the time of acute exacerbations of cystic fibrosis in adults.

BACKGROUND: Diagnosis of acute exacerbation (AE) of cystic fibrosis (CF) must be precise because both under- and over-prescription of antibiotics may be detrimental. How lung function tests contribute to diagnose AE is unclear. We aimed to describe variation of spirometry and oscillometry measurements, at Stable state and at AE in adults with CF. METHODS: Patients were included in a retrospective single-centre study when both spirometry (FEV1, FVC) and oscillometry (X5, R5, R5-R20 and AX) data were available for at least one Stable and one AE visit between December 2016 and July 2019. For each visit, we calculated variation (Δ) in spirometry and oscillometry indices in comparison with personal best values. Measurements were expressed as % of predicted values and Z-scores when applicable. Areas under ROC curves (AUC) were computed. RESULTS: Forty-two patients (28 ± 9 years, FEV1 64 ± 21%) were included; 80 AE and 104 Stable visits were analysed. FEV1 (L, %pred and Z-score) and FVC (%pred and Z-score) varied significantly between AE and Stable visits (p < .05), although differences were small (80 ml/2.7%pred for FEV1). Among oscillometry indices, X5 (kPa.s.L-1 ), R5-R20 (kPa.s.L-1 ) and AX (kPa/L) varied significantly. The AUCs for the variation in spirometry indices ranged from 0.601 (ΔFVC L) to 0.635 (ΔFEV1%pred). They were not significantly different from the AUCs for ΔX5 (0.589), ΔR5-R20 (0.649) and ΔAX (0.598). CONCLUSIONS: Performance of both spirometry and oscillometry to discriminate AE from Stable state was poor. Variation of oscillometry indices (X5, R5-R20, AX) may be helpful when spirometry is unreliable or uncomfortable.

Técnica de oscilações forçadas na avaliação e manejo de crianças asmáticas: uma revisão narrativa / Forced oscillation technique in the assessment and management of asthmatic children: a narrative review

Asthma is considered the most prevalent chronic disease in children. The pulmonary function measurements are important in the evaluation of the disease, being able to confirm the diagnosis by demonstrating the reversibility of the obstruction as well as detecting risks of poor prognosis in the control of asthma. However, the most common methods for analyzing pulmonary function in this age group have restrictions on its applicability, especially due to the need for cooperation on the part of patients. The forced oscillation technique (FOT) is considered a modern tool capable of estimating measures of respiratory mechanics related to the lungs. This method is easily applicable due to the low need for patient cooperation, an important element in the assessment of children. The aim of this study is to review the clinical utility of the Forced Oscillation Technique in the pulmonary assessment of asthmatic children. The bibliographic search covered the years between 1950 and 2019, in the databases: Medical Literature Analysis and Retrieval System Online (MEDLINE) and Latin American and Caribbean Literature in Health Sciences (LILACS). It was used as a search strategy the combination of the following Medical Subject Headings (MeSH) terms: "asthma", "oscillometry" and "child" crossed through the AND and OR Boolean connectors. In asthmatic children, FOT showed greater accuracy in the evaluation of smaller caliber peripheral airways, which can be applied as a complementary method to spirometry to strengthen the diagnosis, enabling a better understanding of the disease and its progression.

A asma é considerada a doença crônica de maior incidência em crianças. As medidas de função pulmonar são importantes na avaliação da doença, podendo confirmar o diagnóstico pela demonstração de reversibilidade da obstrução assim como detectar riscos de mau prognóstico no controle da asma. Entretanto, os métodos mais usuais para análise da função pulmonar nesta faixa etária apresentam restrições em sua aplicabilidade, especialmente pela necessidade de cooperação por parte dos pacientes. A técnica de oscilações forçadas (FOT) é considerada uma ferramenta moderna capaz de estimar medidas da mecânica respiratória relativas aos pulmões. Este método apresenta fácil aplicabilidade pela baixa necessidade de cooperação do paciente, elemento importante na avaliação de crianças. O objetivo deste estudo é revisar a utilidade clínica da Técnica de Oscilações Forçadas na avaliação pulmonar de crianças asmáticas. A busca bibliográfica contemplou os anos entre 1950 e 2019, nas bases de dados: Medical Literature Analysis and Retrieval System Online (MEDLINE) e Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS). Foi utilizada como estratégia de busca a combinação dos seguintes Medical Subject Headings(MeSH) terms: "asthma", "oscillometry" e "child" cruzados por meio dos conectores booleanos AND e OR. Em crianças asmáticas, a FOT mostrou maior acurácia na avaliação de vias aéreas periféricas de menor calibre, podendo ser aplicada como método complementar a espirometria para encorpar o diagnóstico, possibilitando compreender melhor a doença e sua progressão.

Noninvasive continuous monitoring versus intermittent oscillometric measurements for the detection of hypotension during digestive endoscopy.

BACKGROUND: Hemodynamic monitoring during digestive endoscopy is usually minimal and involves intermittent brachial pressure measurements. New continuous noninvasive devices to acquire instantaneous arterial blood pressure may be more sensitive to detect procedural hypotension. PURPOSE: To compare the ability of noninvasive continuous monitoring with that of intermittent oscillometric measurements to detect hypotension during digestive endoscopy. METHODS: In this observational prospective study, patients scheduled for gastrointestinal endoscopy and colonoscopy under sedation were monitored using intermittent pressure measurements and a noninvasive continuous technique (ClearSight™, Edwards). Stroke volume was estimated from the arterial pressure waveform. Mean arterial pressure and stroke volume values were recorded at T1 (prior to anesthetic induction), T2 (after anesthetic induction), T3 (gastric insufflation), T4 (end of gastroscopy), T5 (colonic insufflation). Hypotension was defined as mean arterial pressure < 65 mmHg. RESULTS: Twenty patients (53±17 years) were included. Six patients (30%) had a hypotension detected using intermittent pressure measurements versus twelve patients (60%) using noninvasive continuous monitoring (p = 0.06). Mean arterial pressure decreased during the procedure with respect to T1 (p < 0.05), but the continuous method provided an earlier warning than the intermittent method (T3 vs T4). Nine patients (45%) had at least a 25% reduction in stroke volume, with respect to baseline. CONCLUSION: Noninvasive continuous monitoring was more sensitive than intermittent measurements to detect hypotension. Estimation of stroke volume revealed profound reductions in systemic flow. Noninvasive continuous monitoring in high-risk patients undergoing digestive endoscopy under sedation could help in detecting hypoperfusion earlier than the usual intermittent blood pressure measurements.