Breathing Airflow Research Articles

Interactive Augmentation of Voice Quality and Reduction of Breath Airflow in the Soprano Voice

In 1985, at a conference sponsored by the National Institutes of Health, Martin Rothenberg first described a form of nonlinear source-tract acoustic interaction mechanism by which some sopranos, singing in their high range, can use to reduce the total airflow, to allow holding the note longer, and simultaneously enrich the quality of the voice, without straining the voice. (M. Rothenberg, "Source-Tract Acoustic Interaction in the Soprano Voice and Implications for Vocal Efficiency," Fourth International Conference on Vocal Fold Physiology, New Haven, Connecticut, June 3-6, 1985.) In this paper, we describe additional evidence for this type of nonlinear source-tract interaction in some soprano singing and describe an analogous interaction phenomenon in communication engineering. We also present some implications for voice research and pedagogy.

An ultrasonic contactless sensor for breathing monitoring.

The monitoring of human breathing activity during a long period has multiple fundamental applications in medicine. In breathing sleep disorders such as apnea, the diagnosis is based on events during which the person stops breathing for several periods during sleep. In polysomnography, the standard for sleep disordered breathing analysis, chest movement and airflow are used to monitor the respiratory activity. However, this method has serious drawbacks. Indeed, as the subject should sleep overnight in a laboratory and because of sensors being in direct contact with him, artifacts modifying sleep quality are often observed. This work investigates an analysis of the viability of an ultrasonic device to quantify the breathing activity, without contact and without any perception by the subject. Based on a low power ultrasonic active source and transducer, the device measures the frequency shift produced by the velocity difference between the exhaled air flow and the ambient environment, i.e., the Doppler effect. After acquisition and digitization, a specific signal processing is applied to separate the effects of breath from those due to subject movements from the Doppler signal. The distance between the source and the sensor, about 50 cm, and the use of ultrasound frequency well above audible frequencies, 40 kHz, allow monitoring the breathing activity without any perception by the subject, and therefore without any modification of the sleep quality which is very important for sleep disorders diagnostic applications. This work is patented (patent pending 2013-7-31 number FR.13/57569).

Respiratory Monitoring by a Field Ionization Sensor Based on Trichel Pulses

In this paper, a novel method for respiratory monitoring is presented. The method is based on Trichel pulses (TPs) using a simple field ionization sensor which consists of a needle electrode and a plate electrode. Experiments have been conducted to demonstrate that different respiratory patterns, including normal, ultra-fast, deep breaths, and apnea could be easily monitored in real time by detecting the changes in the TP frequency. The vital capacity could also be assessed by calculating the variation of TP frequency. It is found that the operation principle of the proposed sensor is based on the effects of breath airflow and the atomized water in exhaled air on the TP frequency by changing the ionization process and the dynamics of charged particles in the short gap. The influences of applied voltage and ambient parameters have also been investigated.

MRI-based finite element simulation on radiofrequency ablation of thyroid cancer

In order to provide a quantitative disclosure on the RFA (radiofrequency ablation)-induced thermal ablation effects within thyroid tissues, this paper has developed a three-dimensional finite element simulation strategy based on a MRI (magnetic resonance imaging)-reconstructed model. The thermal lesion's growth was predicted and interpreted under two treatment conditions, i.e. single-cooled-electrode modality and two-cooled-electrode system. The results show that the thermal lesion's growth is significantly affected by two factors including the position of RF electrode and thermal–physiological behavior of the breathing airflow. Additional parametric studies revealed several valuable phenomena, e.g. with the electrode's movement, thermal injury with varying severity would happen to the trachea wall. Besides, the changes in airflow mass produced evident effects on the total heat flux of thyroid surface, while the changes in breathing frequency only generated minor effects that can be ignored. The present study provided a better understanding on the thermal lesions of RFA within thyroid domain, which will help guide future treatment of the thyroid cancer.

Preliminary results of a miniaturized respiratory sensor system used under hypergravity conditions up to 9 gz

Respiratory gas analyses are used to explore the influence of increased gravity on the physiology of breathing. Due to the mass, size and intricacy of standard measurement systems, previous studies were limited to a maximum acceleration of + 5 gz (head-to-foot direction). Furthermore, no in situ mainstream measurements of oxygen and carbon dioxide concentration were possible under hypergravity conditions so far. This paper shows a first study which demonstrates a respiratory sensor system developed at the Institute for Aerospace Engineering at TU Dresden. This system is suitable for an in situ measurement of respiratory changes up to + 9 gz (maximum acceleration of jet pilots) and therefore provides a possibility for detailed physiological analyses in future. Three jet pilots were equipped with this system and accelerated under a defined profile up to 7, 8 and + 9 gz. The breathing air flow, oxygen and carbon dioxide concentration were recorded with our miniaturized solid state electrolyte gas sensors, which are also described in this paper. The analysed data show significant changes of the measured respiratory parameters depending on the G-level, the acceleration rate (G-rate of onset [g s−1]) and the examination time.

MRI-based three-dimensional thermal physiological characterization of thyroid gland of human body

This article is dedicated to present a MRI (magnetic resonance imaging) based three-dimensional finite element modeling on the thermal manifestations relating to the pathophysiology of thyroid gland. An efficient approach for identifying the metabolic dysfunctions of thyroid has also been demonstrated through tracking the localized non-uniform thermal distribution or enhanced dynamic imaging. The temperature features over the skin surface and thyroid domain have been characterized using the numerical simulation and experimental measurement which will help better interpret the thermal physiological mechanisms of the thyroid under steady-state or water-cooling condition. Further, parametric simulations on the hypermetabolism symptoms of hyperthyroidism and thermal effects within thyroid domain caused by varying breathing airflow in the trachea and blood-flow in artery and vein were performed. It was disclosed that among all the parameters, the airflow volume has the largest effect on the total heat flux of thyroid surface. However, thermal contributions caused by varying the breathing frequency and blood-flow velocity are negligibly small. The present study suggests a generalized way for simulating the close to reality physiological behavior or process of human thyroid, which is of significance for disease diagnosis and treatment planning.

Main mediated molecules of airway shear stress-stimulated MUC5AC extracellular secretion

To explore the main mediated molecules of mucin (MUC) 5AC extracellular secretion stimulated by airway shear stress (SS). The 16 human bronchial epithelial (HBE) cells were cultured and randomized divided by Stata software into 5 groups: A. control group; B. SS stimulated group; C. SS stimulated & NSC23766 (a specific inhibitor of Rac-1) incubated group; D. SS stimulated & Cytochalasin D incubated group; E. Cortactin-siRNA (a small interfering RNA of Cortactin) transfected & SS stimulated group. Each group consisted of 6 parallel wells. Triplicate experiments were performed for statistical analysis. Rhythmic rotating device was used to simulate the breathing air flow mediated shear stress. The function of Cortactin was inhibited by Cortactin-siRNA. The relative content of MUC5AC in supernatant was measured by enzyme linked immunosorbent assay (ELISA). The p-Cortactin (phosphorylation Cortactin) relative level, Cortactin relative level and the effect of transfection were measured with Western blotting. And laser confocal microscope was used to observe the polymerization of F-actin. The transfection of Cortactin-siRNA successfully inhibited the function of Cortactin. The relative content of MUC5AC was (0.210 ± 0.013), (0.631 ± 0.025), (0.473 ± 0.112), (0.330 ± 0.067), (0.272 ± 0.019) in groups A, B, C, D and E, the group B was significantly higher than any other group (P = 0.000, 0.043, 0.000, 0.000). The Cortactin relative level in group B (0.670 ± 0.048) was significantly higher than that in group E (0.132 ± 0.014) (P < 0.01). But as compared with groups A, C, D (0.641 ± 0.016, 0.622 ± 0.012, 0.653 ± 0.027), there was no significance (all P > 0.05). The p-Cortactin relative level in group B (0.582 ± 0.067) was significantly higher than that in groups A, C, E (0.131 ± 0.011, 0.393 ± 0.045, 0.170 ± 0.016) (P = 0.000, 0.021, 0.000). But as compared with group D (0.511 ± 0.029), there was no significance (P = 0.246). Rac-1, Cortactin and F-actin are the main mediated molecules of airway shear stress-stimulated MUC5AC extracellular secretion.

A system for portable sleep apnea diagnosis using an embedded data capturing module

Sleep apnea (SA) is a very common disease with serious health consequences, yet is very under-diagnosed, partially because of the high cost and limited accessibility of in-laboratory polysomnography (PSG). The purpose of this work is to introduce a newly developed portable system for the diagnosis of SA at home that is both reliable and easy to use. The system includes personal devices for recording breath sounds and airflow during sleep and diagnostic algorithms to process the recorded data. The data capturing device consists of a wearable face frame with an embedded electronic module featuring a unidirectional microphone, a differential microphone preamplifier, a microcontroller with an onboard differential analogue to digital converter, and a microSD memory card. The device provides continuous data capturing for 8 h. Upon completion of the recording session, the memory card is returned to a location for acoustic analysis. We recruited 49 subjects who used the device independently at home, after which each subject answered a usability questionnaire. Random data samples were selected to measure the signal-to-noise ratio (SNR) as a gauge of hardware functionality. A subset of 11 subjects used the device on 2 different nights and their results were compared to examine diagnostic reproducibility. Independent of those, system's performance was evaluated against PSG in the lab environment in 32 subject. The overall success rate of applying the device in un-attended settings was 94 % and the overall rating for ease-of-use was 'excellent'. Signal examination showed excellent capturing of breath sounds with an average SNR of 31.7 dB. Nine of the 11 (82 %) subjects had equivalent results on both nights, which is consistent with reported inter-night variability. The system showed 96 % correlation with simultaneously performed in-lab PSG. Our results suggest excellent usability and performance of this system and provide a strong rationale to further improve it and test its robustness in a larger study.

Copd and Periodontitis ... Past Facts and the Present Status!!!

Periodontitis is a chronic bacterial infection characterized by persistent inflammation, connective tissue breakdown and alveolar bone destruction. Accumulating evidence suggests periodontitis and its possible link in the development of respiratory infections like bacterial pneumonia and chronic obstructive pulmonary disease (COPD). COPD is characterized by blockage in the airflow and difficulty in breathing .The etiological factors of COPD are smoking and tobacoo , however, periodontopathic bacteria and genetic factors also play an important role in the pathogenesis. Routes of infection occur by aspiration of oral pathogens in to the lungs, colonization of dental plaque by respiratory pathogens followed by aspiration. The periodontopathic bacteria is also known to facilitate the subsequent colonization of respiratory tract by pulmonary pathogens. This review throws light on the pathogenesis and available evidences on the relationship between periodontitis and COPD .

Computational Fluid Dynamics Simulation of Airflow Patterns and Particle Deposition Characteristics in Children Upper Respiratory Tracts

As findings from studies of airflow patterns and particle deposition in the upper respiratory tracts (URTs) of adults may not be readily extrapolated to studies of the URTs of children, due to the differences in airway anatomy and breathing conditions, the effects of pediatric, physiological features on airflow patterns and particle deposition have been investigated utilizing an idealized model of the URTs of children. Particle deposition characteristics in a 0.01–10 mm spectrum were assessed employing a well-verified, Lagrangian tracking method for different inhalation flow rates, consistent with sedentary (3.5 L/min), light (7.0 L/min) and high (10.5 L/min) activity levels. The main results are: (1) airflow patterns during inhalation and exhalation modes are very different, while airflow patterns are similar during each inhalation or exhalation mode, while subject to three different airflow rates; (2) higher Stokes and impaction numbers are observed in the model for a 3 year old child, when compared to adults under comparably scaled activity levels; and (3) breathing airflow rates, particle diameters and particle densities are three key factors influencing particle deposition rates, with higher deposition rates for children observed when compared to adults under comparable activity levels. For identical impaction parameters, all deposition rates for children are also higher. The localized particle deposition rates in the mouth cavity are similar for children and adults, while those in the larynx, pharynx, trachea and bronchi are higher for children than for adults. Results of this study demonstrate that differences do exist between children and adults in both airflow distribution and aerosol deposition characteristics. These differences should be taken into account in the determination of children’s risk exposure levels for airborne toxicants.

CPAP and measures of cardiovascular risk in males with OSAS

Obstructive sleep apnoea syndrome (OSAS) has been associated with hypertension, stroke and myocardial ischaemia in epidemiological and observational studies. Continuous positive airway pressure (CPAP) is the treatment of choice for OSAS, but the impact of this intervention on established risk factors for cardiovascular disease remains incompletely understood. A total of 102 males with moderate-to-severe OSAS were randomised to therapeutic (n = 51) or subtherapeutic (n = 51) CPAP treatment for 4 weeks to investigate the effects of active treatment on 24-h urinary catecholamine excretion, baroreflex sensitivity (BRS), arterial stiffness (augmentation index) and 24-h ambulatory blood pressure (ABP). After 4 weeks of therapeutic CPAP, significant reductions were seen in urine normetanephrine excretion (from mean+/-sd 179.7+/-80.1 to 132.7+/-46.5 micromol x mol(-1) creatinine) and augmentation index (from 14.5+/-11.3 to 9.1+/-13.8%) compared with the subtherapeutic control group. Furthermore, therapeutic CPAP significantly improved BRS (from 7.1+/-3.3 to 8.8+/-4.2 ms x mmHg(-1)) and reduced mean arterial ABP by 2.6+/-5.4 mmHg. In conclusion, treatment of obstructive sleep apnoea with continuous positive airway pressure may lower cardiovascular risk by reducing sympathetic nerve activity, ambulatory blood pressure and arterial stiffness and by increasing sensitivity of the arterial baroreflex.

Use of the pulse transit time trend to relate tidal breathing and central respiratory events

Central sleep apnoea (CSA) is a respiratory event where cessation of breathing effort and airflow occurs. Numerous lumped models have related the physical phenomena in the arterial tree to properties of the arterial wall. However, a limited model is available that describes pulse transit time (PTT) oscillations during CSA and tidal breathing. Data from 28 children (22 males; aged 6.2 +/- 3.6 years) were obtained during overnight polysomnography. Using a lumped-element model, PTT fluctuations during both respiratory events were described and compared with actual experimental data. 222 valid CSA and 222 tidal breathing events were acquired and analysed. For the tidal breathing, undamped PTT oscillations of 3.89 s were predicted while actual data showed a mean value of 3.68 +/- 0.83 s. Conversely, a damped PTT trend was observed during CSA as predicted by the model. The results attained showed that clustered CSA occurrences led to an increase of 7.23 +/- 3.34 per cent in PTT baseline value while the model predicted 7.86 +/- 2.63 per cent. The marginal increase in PTT baseline was expected since the blood pressure and heart rate decreased during such occurrences. The findings herein suggest that the described model has the potential to describe respiratory event characteristics of a sleeping child.

Mechanistic Mathematical Model for In Vivo Aroma Release during Eating of Semiliquid Foods

The paper describes a mechanistic mathematical model for aroma release in the oropharynx to the nasal cavity during food consumption. The model is based on the physiology of the swallowing process and is validated with atmospheric pressure chemical ionization coupled with mass spectrometry measurements of aroma concentration in the nasal cavity of subjects eating flavored yogurt. The study is conducted on 3 aroma compounds representative for strawberry flavor (ethyl acetate, ethyl butanoate, and ethyl hexanoate) and 3 panelists. The model provides reasonably accurate time predictions of the relative aroma concentration in the nasal cavity and is able to simulate successive swallowing events as well as imperfect velopharyngeal closure. The most influent parameters are found to be the amount of the residual product in the pharynx and its contact area with the air flux, the volume of the nasal cavity, the equilibrium air/product partition coefficient of the volatile compound, the breath airflow rate, as well as the mass transfer coefficient of the aroma compound in the product, and the amount of product in the mouth. This work constitutes a first step toward computer-aided product formulation by allowing calculation of retronasal aroma intensity as a function of transfer and volatility properties of aroma compounds in food matrices and anatomophysiological characteristics of consumers.

DESIGN OF A NEWLY DEVELOPED NON-ATTACHED APNEA MONITOR FOR PATIENTS IN PERSISTENT VEGETATIVE STATE

The conventional apnea monitor adopts disposable electrodes as sensors for apnea detection and thus inducing the problems of skin irritation and other side effects. To tackle these shortcomings, we develop a non-attached type of apnea monitor. The device monitors the temperature of the breathing airflow by means of thermo sensors. These airflow frequencies linked with respiratory rates are indicated on the monitor. There is absolutely no contact with the patients' skin, avoiding the possibilities of any skin irritation. The system detects temperature changes induced by breathing and analyzes the breathing frequency changes displayed by both LED array and computer monitor. The data are collected and analyzed simultaneously by a personal computer, which can link to the central nursery room. The device provides a convenient way for family or nurses to detect abnormal respiratory rate in real time so they can handle any emergency and give the necessary treatment immediately for those patients in persistent vegetative state. Clinic application is presented and function validation of the device, on the other hand, is performed as well.

Nanostructured optical fibre sensors for breathing airflow monitoring

A nanostructured optical fibre-based thin film sensor was designed for non-invasive, fast and reliable monitoring of respiratory airflow. Molecular-level self-assembly processing method was used to form multi-layered inorganic nanocluster and polymer thin films on the distal ends of optical fibres to form such sensors. In order to optimize the sensing performance, an analytical model based on the condensation of exhaled water vapour on the coating surface was established for the breathing analysis. By varying thin film chemistry the physically small sensors offer high sensitivity to breathing air in terms of variations in the reflected optical power. Moreover, the sensor performances in comparison with a medical nasal thermistor suggest such a thin film sensor is an excellent device for advanced breathing airflow monitoring.

341 声門直上呼気流速変動測定による声帯振動解析

Human voices are originated by vibration of vocal folds in the larynx. Vocal folds are mainly composed of internal (muscle) bands and mucous tissue. It is considered that this tissue vibrates responding to breath airflow from the lungs and the resulting oscillation makes the origin of vocal sound, i.e., phonation. The vocal fold tissue is relatively flexible and an easily deformable substance. However its movement cannot be controlled at will, but the vocal fold may be either tensed or relaxed by controlling the internal laryngeal muscles. Such control may change the vibrating part and its frequency so that the radiated voice tone can be changed. The oscillation of the human vocal fold during phonation can be directly observed in a stroboscopic way or by direct picturing with the help of a high-speed video-scope. Further, the oscillation frequency can be determined by analyzing a sequence of pictures so obtained. However it has been unsuccessful to show clearly the general belief that human phonation originates in consequence of the wave-like motion of the vocal fold tissue induced by the interaction of the tissue and the expiratory airflow (simply, airflow, hereafter). In other words, the complex feature of this phenomenon may not be sufficiently captured by planar observation. Detailed study of this airflow is believed to be important to elucidate mechanism of human phonation with the help of simultaneous observation of vocal fold movement, more specifically, glottal opening by means of ultra-high-speed digital camera. Thus in the present study experimental analysis of this airflow just above glottis was made to clarify phonation mechanism and seek better modeling of vocal folds, focusing on direct measurement of airflow velocity by means of a tiny hot wire probe. Voice was also recorded simultaneously with a microphone located near the mouth of the subject.

DESIGN AND CLINIC MONITORING OF A NEWLY DEVELOPED NON-ATTACHED INFANT APNEA MONITOR

Tragically more babies fall victim to sudden infant death syndrome than the combined numbers of respiratory ailment, heart disease and cancer deaths. The cases take place for those babies who were under one year of age and especially often for those babies who were in the age around two to four month old. Despite extensive research, the exact cause of sudden infant death syndrome is still not known. Shockingly, it can even happen to apparently healthy babies left alone for just a little while. The conventional infant apnea monitor adopts disposable electrodes as sensors for apnea detection and thus inducing the problems of skin irritated or other hazards. To tackle these shortcomings, we develop a non-attached type apnea monitor. The device monitors the temperature of the breathing airflow by means of thermo sensors. These airflow frequencies linking with respiratory rates are indicated on the monitor. There is absolutely no contact with the babies' skin, avoiding the possibilities of any skin irritations. The system detects temperature changes induced by breathing and analyzes the breathing frequency changes displayed with both LED array and computer monitor. The data are collected and analyzed simultaneously by a personal computer, which can link to the central nursery room. The device provides a convenient way for pediatricians or nurses to detect abnormal respiratory frequency in real time so they can handle any emergency and gives the necessary treatment immediately. Ten clinic cases have been analyzed and presented. Function validation of the device, on the other hand, is performed as well.

Fusion of respiration-correlated PET and CT scans: correlated lung tumour motion in anatomical and functional scans

Lower lobe lung tumours in particular can move up to 2 cm in the cranio–caudal direction during the respiration cycle. This breathing motion causes image artefacts in conventional free-breathing computed tomography (CT) and positron emission tomography (PET) scanning, rendering delineation of structures for radiotherapy inaccurate. The purpose of this study was to develop a method for four-dimensional (4D) respiration-correlated (RC) acquisition of both CT and PET scans and to develop a framework to fuse these modalities. The breathing signal was acquired using a thermometer in the breathing airflow of the patient. Using this breathing signal, the acquired CT and PET data were grouped to the corresponding respiratory phases, thereby obtaining 4D CT and PET scans. Tumour motion curves were assessed in both image modalities. From these tumour motion curves, the deviation with respect to the mean tumour position was calculated for each phase. The absolute position of the centre of the tumour, relative to the bony anatomy, in the RCCT and gated PET scans was determined. This 4D acquisition and 4D fusion methodology was performed for five patients with lower lobe tumours. The peak-to-peak amplitude range in this sample group was 1–2 cm. The 3D tumour motion curve differed less than 1 mm between PET and CT for all phases. The mean difference in amplitude was less than 1 mm. The position of the centre of the tumour (relative to the bony anatomy) in the RCCT and gated PET scan was similar (difference <1 mm) when no atelectasis was present. Based on these results, we conclude that the method described in this study allows for accurate quantification of tumour motion in CT and PET scans and yields accurate respiration-correlated 4D anatomical and functional information on the tumour region.

Fiberoptic assessment of laryngeal mask airway placement: Blind insertion versus direct visual epiglottoscopy

Purpose The study aims to compare the frequency of ideal anatomic placement of the laryngeal mask airway (LMA) using the traditional blind insertion approach with one where placement was facilitated by the use of a laryngoscope (epiglottoscopy). Patients and Methods A prospective comparison of 132 patients divided into 2 groups (38 with the blind technique and 94 with the direct technique) were evaluated with 2 airway assessment methods, Wilson and Mallampati. We also considered whether there was a relationship between these criteria and the successful placement into an ideal position. Other variables were considered, including breathing airflow dynamics, body size, and skill level of the anesthesia care provider. Five placement visual ordinals were used to grade the LMA position. Results All of the patients studied except one had good to excellent breathing patterns after LMA placement. Statistically more patients who had ideal to nearly ideal placement position of the LMA were placed under direct epiglottoscopy than when placed by the classic blind technique. The position of the LMA was assessed by fiberoptic examination through an attachment between the LMA and the anesthetic circuit. Eighty-six of 94 patients (91.5%) in the direct visual placement group had ideal position compared with 16 of 38 (42%) in the blind placement group. Both groups had more successful placement than any other studies by comparison. Even several obese patients were successfully treated by either technique, and even the inexperienced anesthesia care provider could place the LMA with considerable accuracy. Conclusion One hundred thirty-one of 132 patients had no airway difficulties after LMA placement with either blind (classic) or direct visual epiglottoscopy (laryngoscopy). A fiberoptic scope proved to be a valuable tool to assess the results. When ideal placement is either highly desirable or necessary, the direct visual technique is considered to be a better choice for placement than the blind, classic method.

Developing a Respiratory Protection Program

1. Respirators can be the last defense for the estimated 5 million employees who use them for protection from dusts and fibers, fumes, mists, gases, vapors, and biological hazards. Because of these potentially lethal respiratory hazards, occupational and environmental health nurses need to be able to determine the need for, understand, develop, update, and implement an actionable respiratory protection program (RPP). 2. Regulated per 29 CFR 1910.134, a written RPP becomes the map or guideline process specific to the workplace that needs to be followed to ensure employee protection. 3. The nine required written elements of a RPP include respirator selection; fit testing; respirator use in routine and emergency situations; respirator maintenance and change schedules; ensuring adequate breathing air supply, quantity, and flow for atmosphere supplying respirators; regular evaluation of program effectiveness; medical evaluation; training employees in the respiratory hazards in routine and emergent situations; and training employees in proper use of the respirator. 4. Occupational and environmental health nurses are in a unique position to be a RPP program administrator, its designated licensed health care professional, or an active member of a team implementing the RPP process.