The Experts below are selected from a list of 1287 Experts worldwide ranked by ideXlab platform
G U Kulkarni - One of the best experts on this subject based on the ideXlab platform.
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fabrication of oxidation resistant metal wire network based transparent electrodes by a spray roll coating process
ACS Applied Materials & Interfaces, 2015Co-Authors: Shanmugam Kiruthika, Ama Anand, Ankush Kuma, Ritu Gupta, G U KulkarniAbstract:Roll and spray coating methods have been employed for the fabrication of highly oxidation resistant transparent and conducting electrodes (TCEs) by a simple solution process using Crackle lithography technique. We have spray-coated a Crackle paint-based precursor to produce highly interconnected Crackle network on PET roll mounted on a roll coater with web speed of 0.6 m/min. Ag TCE with a transmittance of 78% and sheet resistance of ∼20 Ω/□ was derived by spraying Ag precursor ink over the Crackle template followed by lift-off and annealing under ambient conditions. The Ag wire mesh was stable toward bending and sonication tests but prone to oxidation in air. When electrolessly coated with Pd, its robustness toward harsh oxidation conditions was enhanced. A low-cost transparent electrode has also been realized by using only small amounts of Ag as seed layer and growing Cu wire mesh by electroless method. Thus, made Ag/Cu meshes are found to be highly stable for more than a year even under ambient atmosphere.
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Fabrication of Oxidation-Resistant Metal Wire Network-Based Transparent Electrodes by a Spray-Roll Coating Process
2015Co-Authors: Shanmugam Kiruthika, Ritu Gupta, Aman Anand, Ankush Kumar, G U KulkarniAbstract:Roll and spray coating methods have been employed for the fabrication of highly oxidation resistant transparent and conducting electrodes (TCEs) by a simple solution process using Crackle lithography technique. We have spray-coated a Crackle paint-based precursor to produce highly interconnected Crackle network on PET roll mounted on a roll coater with web speed of 0.6 m/min. Ag TCE with a transmittance of 78% and sheet resistance of ∼20 Ω/□ was derived by spraying Ag precursor ink over the Crackle template followed by lift-off and annealing under ambient conditions. The Ag wire mesh was stable toward bending and sonication tests but prone to oxidation in air. When electrolessly coated with Pd, its robustness toward harsh oxidation conditions was enhanced. A low-cost transparent electrode has also been realized by using only small amounts of Ag as seed layer and growing Cu wire mesh by electroless method. Thus, made Ag/Cu meshes are found to be highly stable for more than a year even under ambient atmosphere
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large area solution processed transparent conducting electrode based on highly interconnected cu wire network
Journal of Materials Chemistry C, 2014Co-Authors: Shanmugam Kiruthika, Ritu Gupta, K D M Rao, Swati Chakraborty, Nagarajan Padmavathy, G U KulkarniAbstract:Virtually unlimited and highly interconnected Cu wire networks have been fabricated on polyethylene terephthalate (PET) substrates with sheet resistance of <5 Ω □−1 and transmittance of ∼75%, as alternatives to the commonly used tin doped indium oxide (ITO) based electrodes. This is a four step process involving deposition of commercially available colloidal dispersions onto PET, drying to induce Crackle network formation, nucleating Au or Pd seed nanoparticles inside the Crackle regions, washing away the sacrificial layer and finally, depositing Cu electrolessly or by electroplating. The formed Cu wire network is continuous and seamless, and devoid of crossbar junctions, a property which brings high stability to the electrode towards oxidation in air even at 130 °C. The flexible property of the PET substrate is easily carried over to the TCE. The sheet resistance remained unaltered even after a thousand bending cycles. The as-prepared Cu wire network TCE is hydrophobic (contact angle, 80°) which, upon UV–ozone treatment, turned to hydrophilic (∼40°).
Shanmugam Kiruthika - One of the best experts on this subject based on the ideXlab platform.
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fabrication of oxidation resistant metal wire network based transparent electrodes by a spray roll coating process
ACS Applied Materials & Interfaces, 2015Co-Authors: Shanmugam Kiruthika, Ama Anand, Ankush Kuma, Ritu Gupta, G U KulkarniAbstract:Roll and spray coating methods have been employed for the fabrication of highly oxidation resistant transparent and conducting electrodes (TCEs) by a simple solution process using Crackle lithography technique. We have spray-coated a Crackle paint-based precursor to produce highly interconnected Crackle network on PET roll mounted on a roll coater with web speed of 0.6 m/min. Ag TCE with a transmittance of 78% and sheet resistance of ∼20 Ω/□ was derived by spraying Ag precursor ink over the Crackle template followed by lift-off and annealing under ambient conditions. The Ag wire mesh was stable toward bending and sonication tests but prone to oxidation in air. When electrolessly coated with Pd, its robustness toward harsh oxidation conditions was enhanced. A low-cost transparent electrode has also been realized by using only small amounts of Ag as seed layer and growing Cu wire mesh by electroless method. Thus, made Ag/Cu meshes are found to be highly stable for more than a year even under ambient atmosphere.
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Fabrication of Oxidation-Resistant Metal Wire Network-Based Transparent Electrodes by a Spray-Roll Coating Process
2015Co-Authors: Shanmugam Kiruthika, Ritu Gupta, Aman Anand, Ankush Kumar, G U KulkarniAbstract:Roll and spray coating methods have been employed for the fabrication of highly oxidation resistant transparent and conducting electrodes (TCEs) by a simple solution process using Crackle lithography technique. We have spray-coated a Crackle paint-based precursor to produce highly interconnected Crackle network on PET roll mounted on a roll coater with web speed of 0.6 m/min. Ag TCE with a transmittance of 78% and sheet resistance of ∼20 Ω/□ was derived by spraying Ag precursor ink over the Crackle template followed by lift-off and annealing under ambient conditions. The Ag wire mesh was stable toward bending and sonication tests but prone to oxidation in air. When electrolessly coated with Pd, its robustness toward harsh oxidation conditions was enhanced. A low-cost transparent electrode has also been realized by using only small amounts of Ag as seed layer and growing Cu wire mesh by electroless method. Thus, made Ag/Cu meshes are found to be highly stable for more than a year even under ambient atmosphere
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large area solution processed transparent conducting electrode based on highly interconnected cu wire network
Journal of Materials Chemistry C, 2014Co-Authors: Shanmugam Kiruthika, Ritu Gupta, K D M Rao, Swati Chakraborty, Nagarajan Padmavathy, G U KulkarniAbstract:Virtually unlimited and highly interconnected Cu wire networks have been fabricated on polyethylene terephthalate (PET) substrates with sheet resistance of <5 Ω □−1 and transmittance of ∼75%, as alternatives to the commonly used tin doped indium oxide (ITO) based electrodes. This is a four step process involving deposition of commercially available colloidal dispersions onto PET, drying to induce Crackle network formation, nucleating Au or Pd seed nanoparticles inside the Crackle regions, washing away the sacrificial layer and finally, depositing Cu electrolessly or by electroplating. The formed Cu wire network is continuous and seamless, and devoid of crossbar junctions, a property which brings high stability to the electrode towards oxidation in air even at 130 °C. The flexible property of the PET substrate is easily carried over to the TCE. The sheet resistance remained unaltered even after a thousand bending cycles. The as-prepared Cu wire network TCE is hydrophobic (contact angle, 80°) which, upon UV–ozone treatment, turned to hydrophilic (∼40°).
Yasemin P. Kahya - One of the best experts on this subject based on the ideXlab platform.
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an automated lung sound preprocessing and classification system based onspectral analysis methods
Biomedical and Health Informatics, 2018Co-Authors: Gorkem Serbes, Sezer Ulukaya, Yasemin P. KahyaAbstract:In this work, respiratory sounds are classified into four classes in the presence of various noises (talking, coughing, motion artefacts, heart and intestinal sounds) using support vector machine classifier with radial basis function kernel. The four classes can be listed as normal, wheeze, Crackle and Crackle plus wheeze. Crackle and wheeze adventitious sounds have opposite behavior in the time-frequency domain. In order to better represent and resolve the discriminative characteristics of adventitious sounds, non-linear novel spectral feature extraction algorithms are proposed to be employed in four class classification problem. The proposed algorithm, which has achieved 49.86% accuracy on a very challenging and rich dataset, is a promising tool to be used as preprocessor in lung disease decision support systems.
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overcomplete discrete wavelet transform based respiratory sound discrimination with feature and decision level fusion
Biomedical Signal Processing and Control, 2017Co-Authors: Sezer Ulukaya, Gorkem Serbes, Yasemin P. KahyaAbstract:Abstract Background and objective Crackle, wheeze and normal lung sound discrimination is vital in diagnosing pulmonary diseases. Previous works suffer from limited frequency resolution and lack of the ability to deal with oscillatory signals (wheezes). The main objective of this study is to propose a novel wavelet based lung sound classification system that is capable of adaptively representing Crackle, wheeze and normal lung sound signal time-frequency properties. Methods A method which is based on rational dilation wavelet transform is proposed to classify lung sounds into three main categories, namely, normal, wheeze and Crackle. Six different feature extraction methods were used with five different classifiers all of which were compared with the proposed method on 600 lung sound episodes in a cross validation scheme. Six statistical subset features were extracted from raw features and fed into classifiers. After comparative evaluation of the proposed method, an ensemble learning scheme was built to increase the performance of the proposed method. Results It has been shown that performance of the proposed method was superior to previous methods in terms of accuracy. Moreover, its computational time was far less than its nearest competitor (S transform). It has also been shown that the proposed method was able to cope with oscillatory type signals as well as transient sounds performing 95.17% average accuracy for energy subset and 97.38% ensemble average accuracy showing a promising time-frequency tool for biological signals. Conclusions The proposed method has shown better performance even using only one subset of extracted features. It provides better time-frequency resolution for all types of signals of interest and is less redundant than continuous wavelet transform and significantly faster than its nearest competitor.
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resonance based respiratory sound decomposition aiming at localization of Crackles in noisy measurements
International Conference of the IEEE Engineering in Medicine and Biology Society, 2016Co-Authors: Sezer Ulukaya, Gorkem Serbes, Yasemin P. KahyaAbstract:In this work, resonance based decomposition of lung sounds that aims to separate wheeze, Crackle and vesicular sounds into three individual channels while automatically localizing Crackles for both synthetic and real data is presented. Previous works focus on stationary-non stationary discrimination to separate Crackles and vesicular sounds disregarding wheezes which are stationary as compared to Crackles. However, wheeze sounds include important cues about the underlying pathology. Using two different threshold methods and synthetic sound generation scenarios in the presence of wheezes, resonance based decomposition performs 89.5 % Crackle localization recall rate for white Gaussian noise and 98.6 % Crackle localization recall rate for healthy vesicular sound treated as noise at low signal-to-noise ratios. Besides, an adaptive threshold determination which is independent from the channel at which it will be applied is used and is found to be robust to noise.
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Pulmonary Crackle detection using time-frequency and time-scale analysis
Digital Signal Processing, 2013Co-Authors: Gorkem Serbes, Yasemin P. Kahya, C. Okan Sakar, Nizamettin AydinAbstract:Pulmonary Crackles are used as indicators for the diagnosis of different pulmonary disorders in auscultation. Crackles are very common adventitious transient sounds. From the characteristics of Crackles such as timing and number of occurrences, the type and the severity of the pulmonary diseases may be assessed. In this study, a method is proposed for Crackle detection. In this method, various feature sets are extracted using time-frequency and time-scale analysis from pulmonary signals. In order to understand the effect of using different window and wavelet types in time-frequency and time-scale analysis in detecting Crackles, different windows and wavelets are tested such as Gaussian, Blackman, Hanning, Hamming, Bartlett, Triangular and Rectangular windows for time-frequency analysis and Morlet, Mexican Hat and Paul wavelets for time-scale analysis. The extracted feature sets, both individually and as an ensemble of networks, are fed into three different machine learning algorithms: Support Vector Machines, k-Nearest Neighbor and Multilayer Perceptron. Moreover, in order to improve the success of the model, prior to the time-frequency/scale analysis, frequency bands containing no-Crackle information are removed using dual-tree complex wavelet transform, which is a shift invariant transform with limited redundancy compared to the conventional discrete wavelet transform. The comparative results of individual feature sets and ensemble of sets, which are extracted using different window and wavelet types, for both pre-processed and non-pre-processed data with different machine learning algorithms, are extensively evaluated and compared.
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feature extraction using time frequency scale analysis and ensemble of feature sets for Crackle detection
International Conference of the IEEE Engineering in Medicine and Biology Society, 2011Co-Authors: Gorkem Serbes, Yasemin P. Kahya, Okan C Sakar, Nizamettin AydinAbstract:Pulmonary Crackles are used as indicators for the diagnosis of different pulmonary disorders. Crackles are very common adventitious sounds which have transient characteristic. From the characteristics of Crackles such as timing and number of occurrences, the type and the severity of the pulmonary diseases can be obtained. In this study, a novel method is proposed for Crackle detection. In this method, various feature sets are extracted using time-frequency and time-scale analysis. The extracted feature sets are fed into support vector machines both individually and as an ensemble of networks. Besides, as a preprocessing stage in order to improve the success of the model, frequency bands containing no-information are removed using dual tree complex wavelet transform, which is a shift invariant transform with limited redundancy and an improved version of discrete wavelet transform. The comparative results of individual feature sets and ensemble of sets with pre-processed and non pre-processed data are proposed.
Sergey V Buldyrev - One of the best experts on this subject based on the ideXlab platform.
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crackling sound generation during the formation of liquid bridges a lattice gas model
Physica A-statistical Mechanics and Its Applications, 2013Co-Authors: Alexandre B Almeida, Sergey V Buldyrev, Adriano M AlencarAbstract:Abstract Due to abnormal mechanical instabilities, liquid bridges may form in the small airways blocking airflow. Liquid bridge ruptures during inhalation are the major cause of the crackling adventitious lung sound, which can be heard using a simple stethoscope. Recently, Vyshedskiy and colleagues (2009) [1] described and characterized a Crackle sound originated during expiration. However, the mechanism and origin of the expiratory Crackle are still controversial. Thus, in this paper, we propose a mechanism for expiratory Crackles. We hypothesize that the expiratory Crackle sound is a result of the energy released in the form of acoustic waves during the formation of the liquid bridge. The magnitude of the energy released is proportional to the difference in free energy prior and after the bridge formation. We use a lattice gas model to describe the liquid bridge formation between two parallel planes. Specifically, we determine the surface free energy and the conditions of the liquid bridge formation between two parallel planes separated by a distance 2 h by a liquid droplet of volume Ω and contact angle Θ , using both Monte Carlo simulation of a lattice gas model and variational calculus based on minimization of the surface area with the volume and the contact angle constrained. We numerically and analytically determine the phase diagram of the system as a function of the dimensionless parameter h Ω − 1 / 3 and Θ . We can distinguish two different phases: one droplet and one liquid bridge. We observe a hysteresis curve for the energy changes between these two states, and a finite size effect in the bridge formation. We compute the release of free energy during the formation of the liquid bridge and discuss the results in terms of system size. We also calculate the force exerted from liquid bridge on the planes by studying the dependence of the free energy on the separation between the planes 2 h . The simulation results are in agreement with the analytical solution.
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Crackles and instabilities during lung inflation
Physica A-statistical Mechanics and Its Applications, 2005Co-Authors: Adriano M Alencar, Arnab Majumdar, Zoltan Hantos, Sergey V Buldyrev, Eugene H Stanley, Bela SukiAbstract:In a variety of physico-chemical reactions, the actual process takes place in a reactive zone, called the ‘‘active surface’’. We define the active surface of the lung as the set of airway segments that are closed but connected to the trachea through an open pathway, which is the interface between closed and open regions in a collapsed lung. To study the active surface and the time interval between consecutive openings, we measured the sound pressure of Crackles, associated with the opening of collapsed airway segments in isolated dog lungs, inflating from the collapsed state in 120 s. We analyzed the sequence of Crackle amplitudes, inter-Crackle intervals, and low frequency energy from acoustic data. The series of spike amplitudes spans two orders of magnitude and the inter-Crackle intervals spans over five orders of magnitude. The distribution of spike amplitudes follows a power law for nearly two decades, while the distribution of time intervals between consecutive Crackles shows two regimes of power law behavior, where the first region represents Crackles coming from avalanches of openings whereas the second region is due to the time intervals between separate avalanches. Using the time interval between measured Crackles, we estimated the time evolution of the active surface during lung inflation. In addition, we show that recruitment and instabilities along the pressure–volume curve are associated with airway opening and recruitment. We find a good agreement between the theory of the dynamics of lung inflation and the experimental data
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avalanche dynamics of Crackle sound in the lung
Physical Review Letters, 2001Co-Authors: Adriano M Alencar, Arnab Majumdar, Sergey V Buldyrev, Eugene H Stanley, Bela SukiAbstract:We analyze a sequence of short transient sound waves, called iCrackles,i which are associated with explosive openings of airways during lung ination. The distribution of time intervals between consecutive Crackles shows two regimes of power law behavior. We develop an avalanche model which ts the data over ve decades of . We nd that the regime for large is related to the dynamics of distinct avalanches in a Cayley tree, and the regime for small is determined by the dynamics of Crackle propagation within a single avalanche. We also obtain a mean-eld solution of the model which provides information about lung ination. The temporal patterns of natural events have been studied extensively to identify hidden dynamics in various processes, including such diverse phenomena as mass extinction in fossil records [1] and popping bubbles in aqueous foams [2]. Here we study a distinct form of popping sound called Crackles, which are among the many lung sounds generated in the airways in a diseased lung during breathing. Crackles are characterized by a rapid initial pressure de ection, called a spike, followed by a short duration ringing. Crackles are associated with the sudden opening of closed airways during lung ination and have long been used as a qualitative diagnostic tool [3]. Studies of airway closure and opening indicate that, during ination, airways open in avalanches triggered by overcoming a hierarchy of critical opening threshold pressures along the airway tree [4,5]. The distribution of interavalanche time intervals has been reported to be a power law for intervals ranging from 1 to 20 s [4]. Avalanches may be composed of discrete Crackles which are natural probes containing information about the dynamics of avalanches. Here we analyze the interCrackle intervals from acoustic data spanning over 5 orders of magnitude, from to 20 s. These data allow us to extend the scaling region found in [4] to cover the range of 0.01 to 20 s. However, we also nd a plateau between and s and discover a new scaling region for time intervals below s. We interpret the scaling behavior using a numerical model of avalanche dynamics of airway opening for which we also present a mean-eld solution. We analyze sound recordings from dog lung lobes during lung ination [6]. The lung lobe was rst degased in a vacuum chamber collapsing almost all the airways, followed by a controlled ination during which the pressure at the root of the airway tree was increased at a uniform rate from 0 to max kPa to ll the lung in max s. A microphone recorded the sound pressure at the root of the airway tree, the main bronchus of the lobe, as a function of time (Fig. 1a). We detect the negative spikes in using a thresholding algorithm that can nd an abrupt change in the derivative of . We use several thresholds between 1% and 8% of the maximum amplitude of to generate a time series of interspike intervals .T w o examples are shown in Figs. 1b and 1c. The magnitude of uctuates signicantly with a decreasing envelope (Fig. 2a). The histogram of has two power law regions extending through over 5 orders of magnitude interrupted by a plateau of one decade (Fig. 2b). The exponents of the two regions are for max between
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scaling behavior in Crackle sound during lung inflation
Physical Review E, 1999Co-Authors: Adriano M Alencar, Zoltan Hantos, Ferenc Petak, Jozsef Tolnai, Tibor Asztalos, Stefano Zapperi, J S Andrade, Sergey V BuldyrevAbstract:During slow inflation of lung lobes, we measure a sequence of short explosive transient sound waves called ``Crackles,'' each consisting of an initial spike followed by ringing. The Crackle time series is irregular and intermittent, with the number of spikes of size s following a power law, $n(s)\ensuremath{\propto}{s}^{\ensuremath{-}\ensuremath{\alpha}},$ with $\ensuremath{\alpha}=2.77\ifmmode\pm\else\textpm\fi{}0.05.$ We develop a model of Crackle wave generation and propagation in a tree structure that combines the avalanchelike opening of airway segments with the wave propagation of Crackles in a tree structure. The agreement between experiments and simulations suggests that (i) the irregularities are a consequence of structural heterogeneity in the lung, (ii) the intermittent behavior is due to the avalanchelike opening, and (iii) the scaling is a result of successive attenuations acting on the sound spikes as they propagate through a cascade of bifurcations along the airway tree.
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scaling behavior in Crackle sound during lung inflation
International Conference of the IEEE Engineering in Medicine and Biology Society, 1999Co-Authors: Bela Suki, Adriano M Alencar, Zoltan Hantos, Sergey V Buldyrev, Ferenc Petak, Jozsef Tolnai, Tibor Asztalos, Stefano Zapperi, J S Andrade, H E StanleyAbstract:During slow inflation of lung lobes, we analyzed a sequence of short explosive transient sound waves called "Crackles", each consisting of an initial spike followed by ringing. The Crackle time series is irregular, with the distribution of spike size s following a power law, n(s)/spl sim/s/sup -/spl alpha// (/spl alpha/=2.77/spl plusmn/0.05). We develop a model of Crackle wave generation and propagation in a tree structure. The agreement between experiment and simulations suggests that (i) the irregularities are a consequence of structural heterogeneity in the lung and (ii) the scaling is a result of successive attenuations acting on the sound spikes as they propagate through a cascade of bifurcations along the airway tree.
Raymond L H Murphy - One of the best experts on this subject based on the ideXlab platform.
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Crackle pitch rises progressively during inspiration in pneumonia chf and ipf patients
Pulmonary Medicine, 2012Co-Authors: Andrey Vyshedskiy, Raymond L H MurphyAbstract:Objective. It is generally accepted that Crackles are due to sudden opening of airways and that larger airways produce Crackles of lower pitch than smaller airways do. As larger airways are likely to open earlier in inspiration than smaller airways and the reverse is likely to be true in expiration, we studied Crackle pitch as a function of Crackle timing in inspiration and expiration. Our goal was to see if the measurement of Crackle pitch was consistent with this theory. Methods. Patients with a significant number of Crackles were examined using a multichannel lung sound analyzer. These patients included 34 with pneumonia, 38 with heart failure, and 28 with interstitial fibrosis. Results. Crackle pitch progressively increased during inspirations in 79% of all patients. In these patients Crackle pitch increased by approximately 40 Hz from the early to midinspiration and by another 40 Hz from mid to late-inspiration. In 10% of patients, Crackle pitch did not change and in 11% of patients Crackle pitch decreased. During expiration Crackle pitch progressively decreased in 72% of patients and did not change in 28% of patients. Conclusion. In the majority of patients, we observed progressive Crackle pitch increase during inspiration and decrease during expiration. Increased Crackle pitch at larger lung volumes is likely a result of recruitment of smaller diameter airways. An alternate explanation is that Crackle pitch may be influenced by airway tension that increases at greater lung volume. In any case improved understanding of the mechanism of production of these common lung sounds may help improve our understanding of pathophysiology of these disorders.
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Crackle pitch and rate do not vary significantly during a single automated auscultation session in patients with pneumonia congestive heart failure or interstitial pulmonary fibrosis
Respiratory Care, 2011Co-Authors: Andrey Vyshedskiy, Sadamu Ishikawa, Raymond L H MurphyAbstract:OBJECTIVE: To determine the variability of Crackle pitch and Crackle rate during a single automated-auscultation session with a computerized 16-channel lung-sound analyzer. METHODS: Forty-nine patients with pneumonia, 52 with congestive heart failure (CHF), and 18 with interstitial pulmonary fibrosis (IPF) performed breathing maneuvers in the following sequence: normal breathing, deep breathing, cough several times; deep breathing, vital-capacity maneuver, and deep breathing. From the auscultation recordings we measured the Crackle pitch and Crackle rate. RESULTS: Crackle pitch variability, expressed as a percentage of the average Crackle pitch, was small in all patients and in all maneuvers: pneumonia 11%, CHF 11%, pulmonary fibrosis 7%. Crackle rate variability was also small: pneumonia 31%, CHF 32%, IPF 24%. Compared to the first deepbreathing maneuver (100%), the average Crackle pitch did not significantly change following coughing (pneumonia 100%, CHF 103%, IPF 100%), the vital-capacity maneuver (pneumonia 100%, CHF 92%, IPF 104%), or during quiet breathing (pneumonia 97%, CHF 100%, IPF 104%). Similarly,theaverageCrackleratedidnotchangesignificantlyfollowingcoughing(pneumonia105%, CHF 110%, IPF 90%) or the vital-capacity maneuver (pneumonia 102%, CHF 101%, IPF 99%). However, during normal breathing the Crackle rate was significantly lower in the patients with pneumonia (74%, P < .001) and significantly higher in the patients with IPF (147%, P < .05) than it was during deep breathing. In patients with CHF the average Crackle rate during normal breathingwasnotsignificantlydifferentfromthatduringthefirstdeep-breathingmaneuver(108%). CONCLUSIONS: Crackle pitch and rate were surprisingly stable in all 3 conditions. Neither Crackle pitch nor Crackle rate changed significantly from breath to breath or from one deepbreathing maneuver to another, even when the maneuvers were separated by cough or the vitalcapacity maneuver. The observation that Crackle rate is a reproducible measurement during one automated-auscultation session suggests that Crackle rate can be used to follow the course of cardiopulmonary illnesses such as pneumonia, IPF, and CHF. Key words: auscultation; Crackles; pitch; pneumonia; congestive heart failure; pulmonary; fibrosis. [Respir Care 2011;56(6):806–817. © 2011 Daedalus Enterprises]
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automated analysis of Crackles in patients with interstitial pulmonary fibrosis
Pulmonary Medicine, 2011Co-Authors: B Flietstra, Andrey Vyshedskiy, N Markuzon, Raymond L H MurphyAbstract:Background. The Crackles in patients with interstitial pulmonary fibrosis (IPF) can be difficult to distinguish from those heard in patients with congestive heart failure (CHF) and pneumonia (PN). Misinterpretation of these Crackles can lead to inappropriate therapy. The purpose of this study was to determine whether the Crackles in patients with IPF differ from those in patients with CHF and PN. Methods. We studied 39 patients with IPF, 95 with CHF and 123 with PN using a 16-channel lung sound analyzer. Crackle features were analyzed using machine learning methods including neural networks and support vector machines. Results. The IPF Crackles had distinctive features that allowed them to be separated from those in patients with PN with a sensitivity of 0.82, a specificity of 0.88 and an accuracy of 0.86. They were separated from those of CHF patients with a sensitivity of 0.77, a specificity of 0.85 and an accuracy of 0.82. Conclusion. Distinctive features are present in the Crackles of IPF that help separate them from the Crackles of CHF and PN. Computer analysis of Crackles at the bedside has the potential of aiding clinicians in diagnosing IPF more easily and thus helping to avoid medication errors.