The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
Philip Cole - One of the best experts on this subject based on the ideXlab platform.
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Biophysics of nasal Airflow: a review.
American journal of rhinology, 2000Co-Authors: Philip ColeAbstract:An account is given of the constituents of the flow resistive nasal valve, their aerodynamic function, and the essential role they play in processing inspiratory air. The relatively fixed structural component and the variable mucovascular components of the lateral and medial nasal walls are described, and particular attention is drawn to the septal mucovascular component because its existence is not universally recognized. Common sources of error in subjective and objective assessments of obstruction to nasal Respiratory Airflow are discussed. Comments are presented advocating limitations of surgical interference in the treatment of mucosal and structural nasal airway obstruction.
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Comparison of direct and indirect measurements of Respiratory Airflow: implications for hypopneas.
Sleep, 1997Co-Authors: Søren Berg, James S. J. Haight, Victor Yap, Victor Hoffstein, Philip ColeAbstract:The purpose of this study was to compare indirect methods for measuring Respiratory Airflow, such as temperature difference between inspired and expired air, thoracoabdominal movements, and nasal Respiratory-Airflow pressures-with a more direct measurement of minute ventilation using a head-out body plethysmograph. Measurements were obtained in healthy, awake, seated subjects during sequences of different levels of voluntary hypoventilations at 20 breaths/minute and analyzed to determine how well different methods could identify hypopneas (defined as reduction in minute ventilation by 50% or more). The results varied widely between different methods. Sensitivities ranged from 0 to 1, specificity ranged from 0.33 to 1, positive predictive values (PPV) ranged from 0 to 0.73, negative predictive values (NPV) ranged from 0.68 to 0.93. Cohen's kappa varied between 0 and 0.65 The poorest agreement was for the thermistor method, and the best agreement was obtained when a combination of thoraco-abdominal movements and nasal Respiratory-Airflow pressure was employed (sensitivity = 0.86, specificity = 0.83, PPV = 0.71, NPV = 0.92, Cohen's kappa = 0.65). We conclude that none of the indirect methods investigated, individually or in combination, proved adequate for identification of voluntary hypopneas in awake individuals.
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Postural Changes in Respiratory Airflow Pressure and Resistance in Nasal, Hypopharyngeal, and Pharyngeal Airway in Normal Subjects:
The Annals of otology rhinology and laryngology, 1996Co-Authors: Magne Tvinnereim, Philip Cole, James S. J. Haight, Susan Mateika, Victor HoffsteinAbstract:We investigated the effect of posture on nasal and pharyngeal resistance in 12 healthy subjects studied during wakefulness. Airway pressure and Airflow were measured with subjects seated and in dorsal and left lateral recumbency, during inspiration and expiration. We found that pharyngeal resistance was approximately four to six times lower than the nasal resistance. Only pharyngeal resistance was significantly increased upon assumption of a supine posture, from 0.02 +/- 0.01 Pa/mL per second when seated to 0.06 +/- 0.05 Pa/mL per second in dorsal recumbency and to 0.05 +/- 0.04 Pa/mL per second in left lateral recumbency. Mean nasal and pharyngeal resistances doubled upon assumption of a supine posture, but this difference was not statistically significant. There was no significant difference in pharyngeal resistance between inspiration and expiration. Finally, there was a strong linear relationship between pharyngeal pressure and pharyngeal resistance (r = .98, p
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Resistance to Respiratory Airflow of the extrapulmonary airways.
The Laryngoscope, 1993Co-Authors: Philip Cole, Patrick Savard, Harald Miljeteig, James S. J. HaightAbstract:Resistances to Respiratory Airflow of nasal, pharyngeal, laryngeal, and tracheobronchial airway segments were determined by computer processing of digitized differential pressure and flow signals in four healthy, awake, male adults seated and breathing spontaneously at rest, exclusively through decongested noses. Resistances of the nasal and pharyngeal segments in Pa/cm3 per second averaged 0.139 (SD +/- 0.044) and 0.081 (SD +/- 0.051), respectively, with no resistive evidence of compliance with Airflow pressures. The laryngeal segment exhibited the reciprocal of compliance, expiratory resistances exceeded those of inspiration, averaging 0.125 (SD +/- 0.037) and 0.035 (SD +/- 0.013), respectively (.005 < P < .01). Tracheobronchial resistances during spontaneous resting breathing were too small to record reliably at the calibration used, and values augmented by voluntary hyperventilation averaged only 0.012 (SD +/- 0.004). Laryngeal expiratory resistance approximated one fifth of the sum total of Respiratory Airflow resistances (including the pulmonary airways) and the authors suggest that, in addition to contributing to expiratory Airflow braking, partial laryngeal closure induces orifice flow. This nonlaminar flow regime promotes the mucosal contact and mixing that enables greater than 30% of heat and water to be recovered from expiratory air by the human pharynx and nose.
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Laryngeal resistance to Respiratory Airflow in humans
The Laryngoscope, 1993Co-Authors: Patrick Savard, Philip Cole, Harald Miljeteig, James S. J. HaightAbstract:Although vocal cord adduction has been observed during expiration, measurements of absolute values of resistance changes in man have not been reported in the literature. The authors measured resistance to translaryngeal Respiratory Airflow in inspiratory and expiratory phases of the Respiratory cycle of four healthy, awake men during nasal breathing. It was found that, during quiet breathing through a decongested nose, translaryngeal resistance was 1.245 cm H2O/L per second in expiration and 0.354 cm H2O/L per second in inspiration (.005 < P < or = .01), for a percentage of approximately 25% and 50% of extrathoracic expiratory and inspiratory resistances, respectively. Voluntary hyperventilation decreased expiratory resistance, and a partial nasal obstruction abolished the statistical difference between translaryngeal inspiratory and expiratory resistance. These results are in agreement with previous observations of vocal cord movement and are consistent with an expiratory braking effect on Airflow.
James S. J. Haight - One of the best experts on this subject based on the ideXlab platform.
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Comparison of direct and indirect measurements of Respiratory Airflow: implications for hypopneas.
Sleep, 1997Co-Authors: Søren Berg, James S. J. Haight, Victor Yap, Victor Hoffstein, Philip ColeAbstract:The purpose of this study was to compare indirect methods for measuring Respiratory Airflow, such as temperature difference between inspired and expired air, thoracoabdominal movements, and nasal Respiratory-Airflow pressures-with a more direct measurement of minute ventilation using a head-out body plethysmograph. Measurements were obtained in healthy, awake, seated subjects during sequences of different levels of voluntary hypoventilations at 20 breaths/minute and analyzed to determine how well different methods could identify hypopneas (defined as reduction in minute ventilation by 50% or more). The results varied widely between different methods. Sensitivities ranged from 0 to 1, specificity ranged from 0.33 to 1, positive predictive values (PPV) ranged from 0 to 0.73, negative predictive values (NPV) ranged from 0.68 to 0.93. Cohen's kappa varied between 0 and 0.65 The poorest agreement was for the thermistor method, and the best agreement was obtained when a combination of thoraco-abdominal movements and nasal Respiratory-Airflow pressure was employed (sensitivity = 0.86, specificity = 0.83, PPV = 0.71, NPV = 0.92, Cohen's kappa = 0.65). We conclude that none of the indirect methods investigated, individually or in combination, proved adequate for identification of voluntary hypopneas in awake individuals.
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Postural Changes in Respiratory Airflow Pressure and Resistance in Nasal, Hypopharyngeal, and Pharyngeal Airway in Normal Subjects:
The Annals of otology rhinology and laryngology, 1996Co-Authors: Magne Tvinnereim, Philip Cole, James S. J. Haight, Susan Mateika, Victor HoffsteinAbstract:We investigated the effect of posture on nasal and pharyngeal resistance in 12 healthy subjects studied during wakefulness. Airway pressure and Airflow were measured with subjects seated and in dorsal and left lateral recumbency, during inspiration and expiration. We found that pharyngeal resistance was approximately four to six times lower than the nasal resistance. Only pharyngeal resistance was significantly increased upon assumption of a supine posture, from 0.02 +/- 0.01 Pa/mL per second when seated to 0.06 +/- 0.05 Pa/mL per second in dorsal recumbency and to 0.05 +/- 0.04 Pa/mL per second in left lateral recumbency. Mean nasal and pharyngeal resistances doubled upon assumption of a supine posture, but this difference was not statistically significant. There was no significant difference in pharyngeal resistance between inspiration and expiration. Finally, there was a strong linear relationship between pharyngeal pressure and pharyngeal resistance (r = .98, p
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Resistance to Respiratory Airflow of the extrapulmonary airways.
The Laryngoscope, 1993Co-Authors: Philip Cole, Patrick Savard, Harald Miljeteig, James S. J. HaightAbstract:Resistances to Respiratory Airflow of nasal, pharyngeal, laryngeal, and tracheobronchial airway segments were determined by computer processing of digitized differential pressure and flow signals in four healthy, awake, male adults seated and breathing spontaneously at rest, exclusively through decongested noses. Resistances of the nasal and pharyngeal segments in Pa/cm3 per second averaged 0.139 (SD +/- 0.044) and 0.081 (SD +/- 0.051), respectively, with no resistive evidence of compliance with Airflow pressures. The laryngeal segment exhibited the reciprocal of compliance, expiratory resistances exceeded those of inspiration, averaging 0.125 (SD +/- 0.037) and 0.035 (SD +/- 0.013), respectively (.005 < P < .01). Tracheobronchial resistances during spontaneous resting breathing were too small to record reliably at the calibration used, and values augmented by voluntary hyperventilation averaged only 0.012 (SD +/- 0.004). Laryngeal expiratory resistance approximated one fifth of the sum total of Respiratory Airflow resistances (including the pulmonary airways) and the authors suggest that, in addition to contributing to expiratory Airflow braking, partial laryngeal closure induces orifice flow. This nonlaminar flow regime promotes the mucosal contact and mixing that enables greater than 30% of heat and water to be recovered from expiratory air by the human pharynx and nose.
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Laryngeal resistance to Respiratory Airflow in humans
The Laryngoscope, 1993Co-Authors: Patrick Savard, Philip Cole, Harald Miljeteig, James S. J. HaightAbstract:Although vocal cord adduction has been observed during expiration, measurements of absolute values of resistance changes in man have not been reported in the literature. The authors measured resistance to translaryngeal Respiratory Airflow in inspiratory and expiratory phases of the Respiratory cycle of four healthy, awake men during nasal breathing. It was found that, during quiet breathing through a decongested nose, translaryngeal resistance was 1.245 cm H2O/L per second in expiration and 0.354 cm H2O/L per second in inspiration (.005 < P < or = .01), for a percentage of approximately 25% and 50% of extrathoracic expiratory and inspiratory resistances, respectively. Voluntary hyperventilation decreased expiratory resistance, and a partial nasal obstruction abolished the statistical difference between translaryngeal inspiratory and expiratory resistance. These results are in agreement with previous observations of vocal cord movement and are consistent with an expiratory braking effect on Airflow.
Azadeh Yadollahi - One of the best experts on this subject based on the ideXlab platform.
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Relative tidal volume and Respiratory Airflow estimation using tracheal sound and movement during sleep.
Journal of sleep research, 2021Co-Authors: Nasim Montazeri Ghahjaverestan, Shumit Saha, Bojan Gavrilovic, M. Kabir, Kaiyin Zhu, Babak Taati, Hisham Alshaer, Azadeh YadollahiAbstract:Airflow is the reference signal to assess sleep Respiratory disorders, such as sleep apnea. Previous studies estimated Airflow using tracheal sounds in short segments with specific Airflow rates, while requiring calibration or a few breaths for tuning the relationship between sound energy and Airflow. Airflow-sound relationship can change by posture, sleep stage and Airflow rate or tidal volume. We investigated the possibility of estimating surrogates of tidal volume without calibration in the adult sleep apnea population using tracheal sounds and movements. Two surrogates of tidal volume: thoracoabdominal range of sum movement and Airflow level were estimated. Linear regression was used to estimate thoracoabdominal range of sum movement from sound energy and the range of movements. The sound energy lower envelope was found to correlate with Airflow level. The agreement between reference and estimated signals was assessed by repeated-measure correlation analysis. The estimated tidal volumes were used to estimate the Airflow signal. Sixty-one participants (30 females, age: 51 ± 16 years, body mass index: 29.5 ± 6.4 kg m-2 , and apnoea-hypopnea index: 20.2 ± 21.2) were included. Reference and estimated thoracoabdominal range of sum movement of whole night data were significantly correlated with the reference signal extracted from polysomnography (r = 0.5 ± 0.06). Similarly, significant correlations (r = 0.3 ± 0.05) were found for Airflow level. Significant differences in estimated surrogates of tidal volume were found between normal breathing and apnea/hypopnea. Surrogate of Airflow can be extracted from tracheal sounds and movements, which can be used for assessing the severity of sleep apnea and even phenotyping sleep apnea patients based on the estimated Airflow shape.
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EMBC - Removing of Snoring Segments from Tracheal Breathing Sounds using a Wavelet-based Algorithm
Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Inte, 2020Co-Authors: Nasim Montazeri Ghahjaverestan, Shumit Saha, Bojan Gavrilovic, Azadeh YadollahiAbstract:Tracheal sounds represent information about the upper airway and Respiratory Airflow, however, they can be contaminated by the snoring sounds. The sound of snoring has spectral content in a wide range that overlaps with that of breathing sounds during sleep. For assessing Respiratory Airflow using tracheal breathing sound, it is essential to remove the effect of snoring. In this paper, an automatic and unsupervised wavelet-based snoring removal algorithm is presented. Simultaneously with full-night polysomnography, the tracheal sound signals of 9 subjects with different levels of airway obstruction were recorded by a microphone placed over the trachea during sleep. The segments of tracheal sounds that were contaminated by snoring were manually identified through listening to the recordings. The selected segments were automatically categorized based on including discrete or continuous snoring pattern. Segments with discrete snoring were analyzed by an iterative wave-based filtering optimized to separate large spectral components related to snoring from smaller ones corresponded to breathing. Those with continuous snoring were first segmented into shorter segments. Then, each short segments were similarly analyzed along with a segment of normal breathing extracted from the recordings during wakefulness. The algorithm was evaluated by visual inspection of the denoised sound energy and comparison of the spectral densities before and after removing snores, where the overall rate of detectability of snoring was less than 2%.Clinical Relevance— The algorithm provides a way of separating snoring pattern from the tracheal breathing sounds. Therefore, each of them can be analyzed separately to assess Respiratory Airflow and the pathophysiology of the upper airway during sleep
Tiina M. Seppänen - One of the best experts on this subject based on the ideXlab platform.
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BIOSTEC (Selected Papers) - Continuous postoperative Respiratory monitoring with calibrated Respiratory effort belts : pilot study
Biomedical Engineering Systems and Technologies, 2017Co-Authors: Seppo Alahuhta, Merja Vakkala, Olli-pekka Alho, Tiina M. SeppänenAbstract:Postoperative Respiratory complications are common in patients after surgery. Respiratory depression and subsequent adverse outcomes can arise from pain, residual effects of drugs given during anaesthesia and administration of opioids for pain management. There is an urgent need for a continuous, real-time and non-invasive Respiratory monitoring of spontaneously breathing postoperative patients. For this purpose, we used rib cage and abdominal Respiratory effort belts for the Respiratory monitoring pre- and postoperatively, with a new calibration method that enables accurate estimates of the Respiratory Airflow waveforms even when breathing style changes. Five patients were measured with Respiratory effort belts and mask spirometer. Preoperative measurements were done in the operating room, whereas postoperative measurements were done in the recovery room. We compared five calibration models with pre- and postoperative training data. The postoperative calibration approach with two Respiratory effort belts produced the most accurate Respiratory Airflow waveforms and tidal volume, minute volume and Respiratory rate estimates. Average results for the best model were: coefficient of determination R2 was 0.91, tidal volume error 5.8%, minute volume error 8.5% and BPM (Breaths per Minute) error 0.21. The method performed well even in the following challenging Respiratory cases: low Airflows, thoracoabdominal asynchrony and hypopneic events. It was shown that a single belt measurement can be sufficient in some cases. The proposed method is able to produce estimates of postoperative Respiratory Airflow waveforms to enable accurate, continuous, real-time and non-invasive Respiratory monitoring postoperatively. It provides also potential to optimize postoperative pain management and enables timely interventions.
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HEALTHINF - Respiratory Effort Belts in Postoperative Respiratory Monitoring: Pilot Study with Different Patients
Proceedings of the 9th International Joint Conference on Biomedical Engineering Systems and Technologies, 2016Co-Authors: Seppo Alahuhta, Merja Vakkala, Olli-pekka Alho, Tiina M. SeppänenAbstract:Respiratory complications are common in patients after the general anaesthesia. Respiratory depression often occurs in association with postoperative opioid analgesia. Currently, there is a need for a continuous non-invasive Respiratory monitoring of spontaneously breathing postoperative patients. We used calibrated Respiratory effort belts for the Respiratory monitoring pre- and postoperatively. Used calibration method enables accurate estimates of the Respiratory Airflow waveforms. Five different patients were measured with the spirometer and Respiratory effort belts at the same time. Preoperative measurements were done in the operating room just before the operation, whereas postoperative measurements were done in the recovery room after the operation. We compared three calibration models pre- and postoperatively. Postoperative calibration produced more accurate Respiratory Airflows. Results show that not only the tidal volume, minute volume and Respiratory rate can be computed precisely from the estimated Respiratory Airflow, but also the Respiratory Airflow waveforms are very accurate. The method produced accurate estimates even from the following challenging Respiratory signals: low Airflows, COPD, hypopneic events and thoracoabdominal asynchrony. The presented method is able to produce estimates of postoperative Respiratory Airflow waveforms to enable accurate, continuous, non-invasive Respiratory monitoring postoperatively.
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Accurate measurement of Respiratory Airflow waveforms using depth data
2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015Co-Authors: Tiina M. Seppänen, Olli-pekka Alho, Janne Kananen, Kai Noponen, Tapio SeppänenAbstract:Respiratory disorders are a very common and growing health problem. Signal waveforms of Respiratory Airflow and volume may indicate pathological signs of several diseases and, thus, it would be important to measure them accurately. Currently, devices used in respiration measurements are mostly obtrusive in nature interfering with the natural respiration patterns. We used a depth camera for the continuous measurement of Respiratory function without contact on a subject. We propose a novel calibration method which enables accurate estimates of the Respiratory Airflow waveforms from the depth camera data. Eight subjects were measured with the depth camera and spirometer at the same time using different breathing styles. Results show that not only the Respiratory volume and Respiratory rate (RR) can be computed precisely from the estimated Respiratory Airflow, but also the Respiratory Airflow waveforms are very accurate. This offers interesting opportunities, e.g. in pulmonary and critical care medicine, when objective measurements are required.
Harald Miljeteig - One of the best experts on this subject based on the ideXlab platform.
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Resistance to Respiratory Airflow of the extrapulmonary airways.
The Laryngoscope, 1993Co-Authors: Philip Cole, Patrick Savard, Harald Miljeteig, James S. J. HaightAbstract:Resistances to Respiratory Airflow of nasal, pharyngeal, laryngeal, and tracheobronchial airway segments were determined by computer processing of digitized differential pressure and flow signals in four healthy, awake, male adults seated and breathing spontaneously at rest, exclusively through decongested noses. Resistances of the nasal and pharyngeal segments in Pa/cm3 per second averaged 0.139 (SD +/- 0.044) and 0.081 (SD +/- 0.051), respectively, with no resistive evidence of compliance with Airflow pressures. The laryngeal segment exhibited the reciprocal of compliance, expiratory resistances exceeded those of inspiration, averaging 0.125 (SD +/- 0.037) and 0.035 (SD +/- 0.013), respectively (.005 < P < .01). Tracheobronchial resistances during spontaneous resting breathing were too small to record reliably at the calibration used, and values augmented by voluntary hyperventilation averaged only 0.012 (SD +/- 0.004). Laryngeal expiratory resistance approximated one fifth of the sum total of Respiratory Airflow resistances (including the pulmonary airways) and the authors suggest that, in addition to contributing to expiratory Airflow braking, partial laryngeal closure induces orifice flow. This nonlaminar flow regime promotes the mucosal contact and mixing that enables greater than 30% of heat and water to be recovered from expiratory air by the human pharynx and nose.
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Laryngeal resistance to Respiratory Airflow in humans
The Laryngoscope, 1993Co-Authors: Patrick Savard, Philip Cole, Harald Miljeteig, James S. J. HaightAbstract:Although vocal cord adduction has been observed during expiration, measurements of absolute values of resistance changes in man have not been reported in the literature. The authors measured resistance to translaryngeal Respiratory Airflow in inspiratory and expiratory phases of the Respiratory cycle of four healthy, awake men during nasal breathing. It was found that, during quiet breathing through a decongested nose, translaryngeal resistance was 1.245 cm H2O/L per second in expiration and 0.354 cm H2O/L per second in inspiration (.005 < P < or = .01), for a percentage of approximately 25% and 50% of extrathoracic expiratory and inspiratory resistances, respectively. Voluntary hyperventilation decreased expiratory resistance, and a partial nasal obstruction abolished the statistical difference between translaryngeal inspiratory and expiratory resistance. These results are in agreement with previous observations of vocal cord movement and are consistent with an expiratory braking effect on Airflow.
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Nasal airway dilation and obstructed breathing in sleep
The Laryngoscope, 1992Co-Authors: Agnes Metes, Philip Cole, Victor Hoffstein, Harald MiljeteigAbstract:Nasal Respiratory Airflow resistances of awake snorers averaged 0.188 +/- 0.165 Pa/cm3/s (N = 306) and were not elevated beyond the normal range (less than 0.25 Pa/cm3/s). Resistances were decreased substantially from a mean of 0.164 +/- 0.128 to 0.065 +/- 0.037 Pa/cm3/s (N = 72) by a nasal vestibular dilator (Nozovent). Effects of the dilator on breathing disorders in sleep were determined by polysomnographic recordings that included frequency, duration and intensity of snoring, apneas, hypopneas, and oxygen saturation in 10 heavy snorers while asleep with and without the dilator in situ over periods of several hours. No significant changes were detected in these parameters in any stage of sleep.
