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In the European Society of Cardiology–European Society of Hypertension guidelines of the year 2007, the consequences of arterial stiffness and wave reflection on cardiovascular mortality have a major role. But the investigators claimed the poor availability of devices/methods providing easy and widely suitable measuring of arterial wall stiffness or their surrogates like augmentation index (AIx) or aortic systolic blood pressure (aSBP). The aim of this study was the validation of a novel method determining AIx and aSBP based on an oscillometric method using a common cuff (ARCSolver) against a validated tonometric system (SphygmoCor). aSBP and AIx measured with the SphygmoCor and ARCSolver method were compared for 302 subjects. The mean age was 56 years with an s.d. of 20 years. At least two iterations were performed in each session. This resulted in 749 measurements. For aSBP the mean difference was −0.1 mm Hg with an s.d. of 3.1 mm Hg. The mean difference for AIx was 1.2% with an s.d. of 7.9%. There was no significant difference in reproducibility of AIx for both methods. The variation estimate of inter- and intraobserver measurements was 6.3% for ARCSolver and 7.5% for SphygmoCor. The ARCSolver method is a novel method determining AIx and aSBP based on an oscillometric system with a cuff. The results agree with common accepted tonometric measurements. Its application is easy and for widespread use.

Converging electrophysiological evidence suggests that the alpha rhythm plays an important and active role in cognitive processing. Here, we systematically studied variability in posterior alpha peak frequency both between and within subjects. We recorded brain activity using MEG in 51 healthy human subjects under three experimental conditions — rest, passive visual stimulation and an N-back working memory paradigm, using source reconstruction methods to separate alpha activity from parietal and occipital sources. We asked how alpha peak frequency differed within subjects across cognitive conditions and regions of interest, and looked at the distribution of alpha peak frequency between subjects. In both regions we observed an increase of alpha peak frequency from resting state and passive visual stimulation conditions to the N-back paradigm, with a significantly higher alpha peak frequency in the 2-back compared to the 0-back condition. There was a trend for a greater increase in alpha peak frequency during the N-back task in the occipital vs. parietal cortex. The average alpha peak frequency across all subjects, conditions, and regions of interest was 10.3Hz with a within-subject SD of 0.9Hz and a between-subject SD of 2.8Hz. We also measured beta peak frequencies, and except in the parietal cortex during rest, found no indication of a strictly harmonic relationship with alpha peak frequencies. We conclude that alpha peak frequency in posterior regions increases with increasing cognitive demands, and that the alpha rhythm operates across a wider frequency range than the 8–12Hz band many studies tend to include in their analysis. Thus, using a fixed and limited alpha frequency band might bias results against certain subjects and conditions. •Alpha peak frequency increases with cognitive demand.•No strict harmonic relationship between alpha and beta.•Using a limited and fixed band for alpha biases against certain subjects/conditions.

Oscillometric cuff devices are believed to use fixed ratio algorithms to compute blood pressure (BP) from the oscillogram (cuff pressure oscillation height versus applied cuff pressure function). However, variations in the cuff transducer that occur each time the cuff is wrapped on a given arm and variations in pulse pressure can alter the oscillogram shape and the ratios for computing BP. A popular validated home BP monitor was studied to determine whether and how it considers these effects. The monitor, with its Universal cuff placed on four different mandrels, was analyzed using a non-invasive BP simulator at various settings and an external pressure sensor to construct the oscillograms. Several algorithms were tested to estimate the home monitor BP values. A fixed ratio algorithm estimated the home monitor systolic and diastolic BP with errors of 5.8 and 1.5 mmHg. A variable ratio algorithm in which the ratios go inversely with the maximum oscillogram amplitude estimated the home monitor values with errors of just 1.5 and 0.8 mmHg. Using the maximum oscillogram amplitude may be particularly helpful for mitigating the variable pulse pressure effect. This study shows how oscillometric cuff devices likely work, which is important for understanding and improving their accuracy.

The contribution of forced oscillation technique (FOT), also called oscillometry, in diagnosis and follow-up of progressive pulmonary fibrosis (PPF) is not yet established. The aims of this monocentric retrospective study were to compare the FOT profile between patients suffering from PPF and stable non-idiopathic pulmonary fibrosis (IPF) interstitial lung diseases (ILDs), to look for a correlation between oscillometry and conventional function tests currently used for PPF follow-up and functional definition (forced vital capacity (FVC) and diffusing lung capacity (DLCO)) and correlation with ILD severity according to FVC. Compared to non-IPF stable ILDs (n = 94), PPF patients (n = 45) showed lower median reactance at 5Hz (X rs5 ) values (during inspiratory phase: 0.31 versus -0.39 expressed as Z-scores, p = 0.019595). X rs5 also showed moderate correlation with FVC and DLCO. Finally, among all ILDs (n = 160), X rs5 showed correlation with disease severity according to FVC. These results suggest that, in conjunction with conventional pulmonary function tests, FOT could be an interesting tool to predict progressive course of fibrosing non-IPF ILDs. Its exact contribution to PPF diagnosis and follow-up needs to be determined by a prospective approach.

The aim of this study was to evaluate the accuracy of the single upper‐arm cuff oscillometric blood pressure (BP) monitor RBP‐9000 c developed for office and home blood pressure measurement in the general population according to the Association for the Advancement of Medical Instrumentation/European Society of Hypertension/International Organization for Standardization (AAMI/ESH/ISO) Universal Standard (ISO 81060–2:2018). Subjects were recruited to fulfill the age, gender, BP, and cuff distribution criteria of the AAMI/ESH/ISO Universal Standard in the general population using the same‐arm sequential BP measurement method. The test device incorporates a single built‐in cuff suitable for 17–42 cm arm circumference. For validation criterion 1, the mean ± SD of the differences between the test device and reference BP readings was 2.4 ± 6.7/3.3 ± 6.3 mmHg (systolic/ diastolic). For criterion 2, the SD of the mean BP differences between the test device and reference BP per subject was 5.28/5.32 mmHg (systolic/diastolic). The RBP‐9000c oscillometric device for office and home BP measurement fulfilled all the requirements of the AAMI/ESH/ISO Universal Standard (ISO 81060–2:2018) in the general population and can be recommended for clinical and self‐use at home. Trial Registration: ChiCTR2300075747

Non-pharmacological treatment with high-flow nasal cannula (HFNC) may play a vital role in treatment of patients with chronic obstructive pulmonary disease (COPD). To evaluate the efficacy of HFNC, impulse oscillation system (IOS) is a new noninvasive technique in measuring the impedance of different portions of lungs. It shows higher sensitivity in contrast to conventional pulmonary function tests (PFT). However, whether IOS is an appropriate technique to evaluate the efficacy of HFNC in improving the impedance of small airways or peripheral lung in patients with COPD is still unclear. We enrolled 26 stable COPD participants randomised into two groups receiving HFNC or nasal cannula (NC) for 10 min followed by a 4-week washout period and crossover alternatively. IOS was used to detect the difference of respiratory impedance after HFNC or NC interventions. IOS parameters, PFT results, transcutaneous partial pressure of carbon dioxide, peripheral oxygen saturation, body temperature, respiratory rate, pulse rate, and blood pressure at the time of pre-HFNC, post-HFNC, pre-NC, and post-NC, were collected and analysed using SPSS (version 25.0, IBM, Armonk, NY, USA). The IOS measurement indicated that HFNC significantly improved R5, R5% predicted, R5–R20, X5-predicted, and Fres compared with NC, whereas no significant difference was observed through the PFT measurement. The beneficial effect of HFNC in improving small airway resistance and peripheral lung reactance compared with that of NC in patients with stable COPD was confirmed through IOS measurement. Trial registration: ClinicalTrials.gov NCT05130112 22/11/2021.

Background Subjects with chronic respiratory symptoms and preserved pulmonary function (PPF) may have small airway dysfunction (SAD). As the most common means to detect SAD, spirometry needs good cooperation and its reliability is controversial. Impulse oscillometry (IOS) may complete the deficiency of spirometry and have higher sensitivity. We aimed to explore the diagnostic value of IOS to detect SAD in symptomatic subjects with PPF. Methods The evaluation of symptoms, spirometry and IOS results in 209 subjects with chronic respiratory symptoms and PPF were assessed. ROC curves of IOS to detect SAD were analyzed. Results 209 subjects with chronic respiratory symptoms and PPF were included. Subjects who reported sputum had higher R5–R20 and Fres than those who didn’t. Subjects with dyspnea had higher R5, R5–R20 and AX than those without. CAT and mMRC scores correlated better with IOS parameters than with spirometry. R5, R5–R20, AX and Fres in subjects with SAD (n = 42) significantly increased compared to those without. Cutoff values for IOS parameters to detect SAD were 0.30 kPa/L s for R5, 0.015 kPa/L s for R5–R20, 0.30 kPa/L for AX and 11.23 Hz for Fres. Fres has the largest AUC (0.665, P = 0.001) among these parameters. Compared with spirometry, prevalence of SAD was higher when measured with IOS. R5 could detect the most SAD subjects with a prevalence of 60.77% and a sensitivity of 81% (AUC = 0.659, P = 0.002). Conclusion IOS is more sensitive to detect SAD than spirometry in subjects with chronic respiratory symptoms and PPF, and it correlates better with symptoms. IOS could be an additional method for SAD detection in the early stage of diseases.

We present a robust method for testing and calibrating the performance of oscillometric non-invasive blood pressure (NIBP) monitors, using an industry standard NIBP simulator to determine the characteristic ratios used, and to explore differences between different devices. Assuming that classical auscultatory sphygmomanometry provides the best approximation to intra-arterial pressure, the results obtained from oscillometric measurements for a range of characteristic ratios are compared against a modified auscultatory method to determine an optimum characteristic ratio, Rs for systolic blood pressure (SBP), which was found to be 0.565. We demonstrate that whilst three Chinese manufactured NIBP monitors we tested used the conventional maximum amplitude algorithm (MAA) with characteristic ratios Rs = 0.4624±0.0303 (Mean±SD) and Rd = 0.6275±0.0222, another three devices manufactured in Germany and Japan either do not implement this standard protocol or used different characteristic ratios. Using a reference database of 304 records from 102 patients, containing both the Korotkoff sounds and the oscillometric waveforms, we showed that none of the devices tested used the optimal value of 0.565 for the characteristic ratio Rs, and as a result, three of the devices tested would underestimate systolic pressure by an average of 4.8mmHg, and three would overestimate the systolic pressure by an average of 6.2 mmHg.

Oscillometry devices (also termed forced oscillation technique) devices such as MasterScreen-IOS® (Jaeger, Hochberg, Germany) and MostGraph-01® (Chest, Tokyo, Japan) are useful for obtaining physiological assessments in patients with obstructive lung diseases, including asthma. However, as oscillometry measurements have not been fully compared between MasterScreen-IOS® and MostGraph-01® in patients with asthma, it is unknown whether there are differences in the measurements between the devices. This study aimed to determine whether there is any difference in oscillometry measurements obtained using the two devices in patients with asthma. Oscillometry measurements obtained using MasterScreen-IOS® and MostGraph-01® were retrospectively evaluated in 95 patients with asthma at Juntendo University Hospital between October 2009 and November 2009. There was a strong positive correlation in the measurements between the two devices. However, the values of R5, R20, ALX and Fres were lower when measured with MostGraph-01® than with MasterScreen-IOS®, and vice versa for the values of X5. The results were used in correction equations to convert oscillometry parameters measured using MasterScreen-IOS® to those measured using MostGraph-01®. To our knowledge, this is the first report to compare MostGraph-01® and MasterScreen-IOS® devices using practical clinical data obtained in patients with asthma. The values obtained by both devices can be interpreted in a similar way, although there is slight variation. The conversion equations produced in this study may assist to compare the oscillometry measurements obtained by each of the two devices.

Background The forced oscillation technique (FOT) measures respiratory impedance during normal tidal breathing and requires minimal patient cooperation. Objective To compare IOS and AOS devices in patients with asthma and COPD. Methods We compared two different FOT devices, namely impulse oscillometry using a loudspeaker (IOS: Jaeger Masterscreen) and airwave oscillometry using a vibrating mesh (AOS: Thorasys Tremoflo) for pre- and post-bronchodilator measurements in 84 patients with asthma and COPD. Results The overall pattern of measurement bias was for higher resistance with IOS and higher reactance with AOS, this being the case in asthma and COPD separately. There were small but significantly higher values using IOS for resistance at 5 Hz (R5) and 20(19) Hz (R20(19)). In converse, values for reactance at 5 Hz (X5), reactance area (AX) and resonant frequency (Fres) were significantly higher using AOS but to a much larger extent. The difference in AX between devices was more pronounced in COPD than in asthma. Salbutamol reversibility as % change was greater in asthma than COPD patients with AX but not FEV1. Conclusion Our study showed evidence of better agreement for resistance than reactance when comparing IOS and AOS, perhaps inferring that AOS may be more sensitive at measuring reactance in patients with airflow obstruction.