The Diagnosis Value and Its Implication of Impulse Oscillometry in Obstructive Sleep Apnea Syndrome Patients

The change of measurements of impulse oscillometry (105) in obstructive sleep apnea syn- drome (OSAS) patients and its mechanism were observed. The respiratory impedance was measured by using IOS technique and polysomnography (PSG) was monitored synchronously in 36 OSAS pa- tients,14 patients with chronic obstructive pulmonary disease (COPD) and 12 normal controls. Re- sults showed that R20 in OSAS group was significantly higher than in COPD group and control group (P<0.01). R5-R20 in OSAS group was lower than that in COPD group, but significantly higher than that in control group(P<0. 01). The levels of R20 and R5-R20 were positively correlated with severity degree of the disease. In addition, apnea-hyponea index (AHI) was positively correlated with R5 and R20 with the correlation index (r)being 0. 66 and 0. 86 respectively. The lowest SO2 was negatively correlated with R5 and R5-R20, with r being-0. 66 and- 0. 79 respectively. The mean SO2 was negatively correlated with R5 and R5-R20 with r being-0. 81 and-0. 69 respectively. IOS technique could be used as a valuable tool for assessing the degree of upper airway obstruction in the patients with OSAS, and could help to explore its pathological mechanism.

Assessment of Respiratory lmpedance During Deep Slow Breathing with lmpulse 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 respira tion was measured one after the other with impulse oscillometry for 8 patients with COPD and for 9 healthy volunteers as control. Results: When r espiration was changed from normal pattern to the deep slow pattern, the tida l volume increased and respiratory frequency significantly decreased in both gro ups , the total respiratory impedance (Z respir) showed a decreasing trend in COPD group, but with no obvious change in the control group. No chang e 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 he terogeneity of different compartments of respiratory system during tidal breathi ng. During deep slow respiration, the viscous resistance in both central airw ay 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.

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 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 (&minus;0.14 ± 0.05 vs &minus;0.14 ± 0.05, P: 0.93), R5 (0.39 ± 0.21 vs 0.39 ± 0.15, P: 0.35), X20 (&minus;0.04 ± 0.06 vs &minus;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.

Association of Superior Vena Cava Syndrome with Sleep Apnea: Investigation Using an Impulse Oscillometry System

Superior vena cava syndrome (SVCS) patients sometimes show signs of obstructive sleep apnea (OSA). However, the mechanism causing hypoxia during sleep in SVCS patients is still uncertain. The aim of this study was to elucidate 1) the changes in central and peripheral respiratory resistance with SVCS, and 2) interpret the mechanism underlying the development of hypoxia during sleep in patients with SVCS related to OSA. Ten SVCS patients related to a neoplasm were recruited for this study. The degree of apnea hypopnea index (AHI) for OSA was evaluated by portable diagnosing device before and after SVCS treatment. We also analyzed the airway resistance and reactance quantitatively in the supine position by Master Screen impulse oscillometry system (MS-IOS?). After SVCS treatment, mean values of AHI were significantly decreased from 30.9 to 16.9 (/hour) (p = 0.001). Central respiratory resistance (R20) also decreased significantly from 0.40 to 0.33 kPa/L/s (p = 0.025) in the supine position. In contrast, peripheral respiratory resistance (R5-R20) and distal capacitive reactance (X5) did not change significantly. It is thought that the exacerbation of OSA due to SVCS is caused by increasing upper airway resistance related to reversible edema of the upper airway mucous or tissue. In contrast, SVCS may not cause peripheral respiratory tract and lung parenchyma edema.

Analysis on relationship of parameters such as R5 and MEFV with severity of chronic cough in 3 to 5 years old children by impulse oscillometry detection

Objective:The article aims to investigate the relationship of parameters such as airway vicosity resistance (R5) and maximal expiratory flow-volume curve (MEFV) with severity of chronic cough in 3 to 5 years old children by impulse oscillometry (IOS) detection when the oscillation frequency is 5Hz.Method: The article chooses eighty children with chronic cough who were diagnosed or treated in our hospital from March 2017 to March 2018 as the research group, and chooses 50 healthy children who had physical examination in our hospital as the control group. Children's asthma control test (C-ACT) is used to assess the disease severity of children. MEFV detection is carried out to the two groups of children to obtain the ratio of forced expiratory volume in one second and forced vital capacity (FEV1/FVC) and the peak expiratory flow (PEF). LsS inductance (X5) is detected by IOS when R5, the resonant frequency (Fres), and the oscillation frequency is 5Hz. The relationship of ACT score with MEFV and IOS indicators is analyzed by Pearson correlation. The receiver operating characteristic (ROC) curve is used to evaluate the diagnostic value of MEFV and IOS indicators to chronic cough. Results: The C-ACT score of the severe group is significantly lower than that of the control group (P<0.05). FEV1/FVC and PEF of the mild and severe groups are both lower than those of the control group, and FEV1/FVC and PEF of the severe group is lower than those of the mild group (P<0.05). Fres, R5 and X5 of the mild and severe groups are significantly higher than those of the control group, and Fres, R5 and X5 of the severe group are higher than the mild group (P<0.05). FEV1/FVC and PEF are positively correlated with C-ACT score (P<0.05), while Fres, R5 and X5 are negatively correlated with C-ACT score (P<0.05). FEV1/FVC and PEF respectively shows significant negative correlations with Fres, R5 and X5 (P<0.05). R5 has a self-high ROC value of 0.938, followed by Fres, which is 0.917. And the value of IOS diagnostic indicators is higher than MEFV indicators.Conclusion: FEV1 / FVC and PEF of children with chronic cough will decrease while Fres, R5 and X5 will increase, of which Fres, R5 and X5 have a higher correlation with the severity of cough symptoms, and ROC analysis results also show that R5 has the highest diagnostic value to 3~5 years old children with chronic cough.

Is there a correlation between the changes in airway inflammation and the changes in respiratory mechanics after vaping in patients with asthma?

BACKGROUND Electronic cigarettes(ECs)have been promoted as alternatives to traditional cigarettes.To investigate ECs’effects on respiratory system,especially in patients with respiratory diseases.METHODS We randomly selected 25 smokers with stable moderate asthma and matched them with 25 healthy smokers.All were subjucted to pulmonary function tests(PFTs),impulse oscillometry(IOS),fraction exhaled Nitric Oxide(FeNO),exhaled breathe condensate(EBC)and biomarker measurements before and after vaping one nicotinecontaining EC.RESULTS The increase in FeNO 30 minutes after EC,reflecting airway inflammation,significantly correlated with increase of residual volume(RV),total lung capacity,respiratory impedance at 5 Hz(Z5Hz)and respiratory resistance at 5 and 20 Hz(R5Hz and R20Hz).No significant correlations were found between EBC biomarkers'changes and respiratory mechanics.CONCLUSION This is the first study demonstrating that the changes in airway inflammation caused by EC have direct effects in respiratory mechanics of asthmatic patients.

A model of Korotkoff sounds method electronic sphygmomanometer equivalent to the mercury one

Mercury sphygmomanometer (MSM) is reliable and widely used in clinics and hospitals. The principle of Korotkoff sounds method (KSM) applied in the MSM is also a gold standard to measure blood pressure. Many efforts have been made attempting to replace MSM, which is criticized for being not healthy and safe. In this research, an electronic blood pressure monitor, named K-sounds electronic sphygmomanometer (KESM), was designed as a substitute to MSM. The three key elements of KSM were proposed for the first time. We used appropriate electronic components to build the KESM which can fulfill the functions related to the three key elements. The KESM, which was easy to operate and free of mercury, followed the same principle as MSM. The same principle guaranteed the comparable accuracy. We took equivalence test and the results showed that the designed KESM was as accurate as the calibrated standard MSM. The designed KESM passed the certifications of SFDA and is qualified in clinics or hospitals for diagnostic purposes.

Noninvasive method for determining blood pressure and contours of arterial and volume pulses

A noninvasive method for monitoring blood pressure, based on the principles established by Riva-Rocci and Korotkoff (K), is described;it furnishes, after a single compression-deflation cycle of the arm-encircling cuff, values of sys-tolic and diastolic blood pressures as well as the contours of the brachial arterial pulse and the corresponding volume pulse. K-sounds are detected by a single microphone situated in the cubital fossa, and the time-varying cuff pressure P(t) is read by a piezoresistive pressure sensor. The behavior of P(t) during deflation is resolved into two parts, P(t)=p(t)+b(t);p is a train of posi-tive going pulses (arising from arterial pulsa-tions), whereas b is a slowly changing baseline. Noise pulses in the microphone output are re-jected by using the observation that the first few K-sounds are emitted when p is close to a maxi-mum, and the last few when dp/dt is close to a maximum. The performance of the instrument is illustrated by showing how it copes with ambi-ent noise and involuntary manual perturbations of P, and by presenting contours of various pulses.

A method for retrieving the waveform of the pressure pulsations from the output of an electronic oscillometer

In the most common version of an oscillometric blood pressure monitor, the output from the pressure transducer, Y(t), is split into two parts, and used for separate determinations of the pressure inside the pneumatic cuff and its fluc-tuating part;the latter is derived by sending Y(t) to a high-pass filter (HPF) and amplifying the fil-tered part to obtain the oscillometric signal O(t). Using a typical HPF-amplifier combination, we show that if p(t), the pulsatile part of the cuff pressure, is defined to be a train of positive-going pulses, O(t) turns out to be rather close but not identical to dp/dt, and to demonstrate that one can easily retrieve p(t) from a record of O(t). This means that, with a small modification, the instrument can provide both p(t) and dp/dt;the practical advantages of this demonstration are pointed out.

The applicable value of respiratory impedance for the stage 0 of chronic obstructive pulmonary disease

Objective ：To evaluate the applicable value of respiratory impedance for the stage 0 of chronic obstructive pulmonary disease （COPD）. Methods：Respiratory impedance was measured by impulse oscillometry （lOS） in 41 cases at stage 0 of COPD （NHLBI/WHO, 2001 Standard） and their conventional pulmonary function values were compared with 42 healthy subjects. Both groups had no significant deviation in age, stature and avoirdupois, etc. Master-Screen pulmonary function test system （Jaeger Co, Germany） were used to determine IOS parameters including viscous resistance of 5Hz, 20 Hz and 35Hz （R5, R20, R35）, reactance of 5Hz, 35 Hz （X3, X35）, resonant frequency （Fres） ,total respiratory impedance （Zrs） and routine pulmonary function values including forced expiratory volume in one second to predicted value （FEV1 % ）, forced expiratory volume in one second to forced vital capacity ratio（ FEV1/ FVC% ）, maximal mid expiratory flow （MMEF%）,V23% and V50%. Results：Both groups had no significant deviation in FEV1%, FEV1/FVC% and X35（P〉0.05）. It was increased significantly in viscous resistance of 5Hz, 20 Hz and 35Hz （R5, R20, R35） in COPD group than that in healthy group （P〈0.01）. So were Fres and Zrs （P〈0.01）. MMEF%,V25%,V50% and reactance of 5Hz （X5） in COPD group were marked lower than that in healthy group （P〈0.01）. The sensitivity of MMEF%, V25%,V50% was higher than others, but its specificity was lower. In parameters of IOS, Fres was the most sensitive index for diagnosis of the small airway function and its specificity was higher than that of MMEF%, V25% ,V50%. Conclusion：In the risk case at the stage 0 of COPD, MMEF%, V25% and V50% could be decreased, but Fres, R5 ,R5-20 could be increased in spite of FEV1% and FEV1/FVC% in normal range.

氣道阻力與常規肺功能測試在慢性阻塞性肺病診斷中的對比研究

目的探討氣道阻力在慢性阻塞性肺病(COPD)診斷中的臨床價值。方法對108例COPD患者及22例正常成人應用脈沖振蕩肺功能測定氣道阻力,並與常規肺功能進行比較,分析它們對COPD的診斷價值。結果COPD各組及對照組間常規肺功能指標FEV1、FEV1/FVC%、FEV1/Pre%、PEF、PEF/Pre%均有統計學意義;COPD組Z5、R5、(R5-R20)、RF、Rp、R5(A/P%)、Z5(A/P%)明顯高於對照組,且隨COPD嚴重程度增加而升高;X5、X20 COPD組顯著低於對照組,且隨COPD嚴重程度增加而降低;Z5、R5、(R5-R20)、RF、Rp、R5(A/P%)、Z5(A/P)%分別與FEV1、FEV1/FVC%、FEV1/Pre%、PEF、PEF/Pre%呈顯著負相關,與X5、X20呈顯著正相關,其中RF的相關性最爲密切;IOS各指標ROC曲線分析顯示,R5(A1/P%)正常值取值爲136時,約登指數最高;Z5(A1/P%)正常值取值爲100時,約登指數最高;RF正常值取值爲18.23時,X5正常值取值爲-0.24時,X20正常值取值爲0.005時,各約登指數最高。結論脈沖振蕩肺功能對COPD具有診斷價值,其指標與病情嚴重程度相關;與常規肺功能指標有顯著相關性。但其預計值方程式及正常值範圍值得進一步研究。

Small airways in asthma:Pathophysiology,identification and management

Background:The aim of this review is to summarize the current evidence regarding small airway disease in asthma,focusing on recent advances in small airway pathophysiology,assessment and therapeutic implications.Methods:A search in Medline was performed,using the keywords“small airways”,“asthma”,“oscillometry”,“nitrogen washout”and“imaging”.Our review was based on studies from adult asthmatic patients,although evidence from pediatric populations is also discussed.Results:In asthma,inflammation in small airways,increased mucus production and airway wall remodelling are the main pathogenetic mechanisms of small airway disease.Small airway dysfunction is a key component of asthma pathophysiology,leading to increased small airway resistance and airway closure,with subsequent ventilation inhomogeneities,hyperresponsiveness and airflow limitation.Classic tests of lung function,such as spirometry and body plethysmography are insensitive to detect small airway disease,providing only indirect measurements.As discussed in our review,both functional and imaging techniques that are more specific for small airways,such as oscillometry and the multiple breath nitrogen washout have delineated the role of small airways in asthma.Small airways disease is prevalent across all asthma disease stages and especially in severe disease,correlating with important clinical outcomes,such as asthma control and exacerbation frequency.Moreover,markers of small airways dysfunction have been used to guide asthma treatment and monitor response to therapy.Conclusions:Assessment of small airway disease provides unique information for asthma diagnosis and monitor-ing,with potential therapeutic implications.

"Reactance inversion" at low frequencies in a child undergoing treatment of a cystic fibrosis exacerbation

Introduction:Impulse oscillometry(IOS)employs high frequency sinusoidal or impulse pressure and flow waveforms to interrogate the mechanical properties of the respiratory system.It has special applications to preschool and younger children who may have difficulty performing the repetitive forced expiratory maneuvers required for spirometry.Case presentation:We present a case illustrating improvements of respiratory system mechanics measured by IOS in a 6-year-old child with cystic fibrosis(CF)who demonstrated clinical and radiological improvement after a course of therapy with hospitalization and intravenous antibiotics,and initiation of a cystic fibrosis transmembrane regulator(CFTR)protein corrector/potentiator agent.We also report a new finding:observed lower than expected reactance at low compared to high frequencies("reactance inversion").Conclusion:Reactance inversion may reflect parallel pathway inhomogeneities in resistance and elastance or intrabreath airway inertance changes in young children with CF.Further study is needed in children with airway obstruction due to asthma,cystic fibrosis,and chronic lung disease of infancy to demonstrate the prevalence of this finding and whether it is specific to a measurement device.