The Experts below are selected from a list of 933 Experts worldwide ranked by ideXlab platform
Gary Stahl - One of the best experts on this subject based on the ideXlab platform.
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work of breathing using high flow nasal cannula in preterm infants
Journal of Perinatology, 2006Co-Authors: J G Saslow, Zubair H. Aghai, T A Nakhla, J J Hart, R Lawrysh, Gary StahlAbstract:To compare the work of breathing (WOB) in premature neonates supported with high-flow nasal cannula (HFNC) and nasal continuous positive airway pressure (NCPAP). Eighteen preterm neonates <2.0 kg on HFNC or NCPAP support were studied in a random order. A ventilator was used to deliver 6 cm H2O of NCPAP with nasal prongs. High-flow nasal cannula delivered with Vapotherm (VAPO) at 3, 4 and 5 l/min was used. Tidal ventilation was obtained using respiratory inductance plethysmography calibrated with face-mask Pneumotachography. An esophageal balloon estimated pleural pressure from which changes in end distending pressure were calculated. Inspiratory, elastic and resistive WOB and respiratory parameters were calculated. No differences were found in the WOB for all settings. Changes in end distending pressure did not vary significantly over all device settings except VAPO at 5 l/min. In these preterm infants with mild respiratory illness, HFNC provided support comparable to NCPAP.
M R Miller - One of the best experts on this subject based on the ideXlab platform.
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peak expiratory flow profiles delivered by pump systems limitations due to wave action
American Journal of Respiratory and Critical Care Medicine, 2000Co-Authors: M R Miller, Barrie Jones, Yong Xu, Philip H QuanjerAbstract:Pump systems are currently used to test the performance of both spirometers and peak expiratory flow (PEF) meters, but for certain flow profiles the input signal (i.e., requested profile) and the output profile can differ. We developed a mathematical model of wave action within a pump and compared the recorded flow profiles with both the input profiles and the output predicted by the model. Three American Thoracic Society (ATS) flow profiles and four artificial flow-versus-time profiles were delivered by a pump, first to a Pneumotachograph (PT) on its own, then to the PT with a 32-cm upstream extension tube (which would favor wave action), and lastly with the PT in series with and immediately downstream to a mini-Wright peak flow meter. With the PT on its own, recorded flow for the seven profiles was 2.4 ± 1.9% (mean ± SD) higher than the pump's input flow, and similarly was 2.3 ± 2.3% higher than the pump's output flow as predicted by the model. With the extension tube in place, the recorded flow was 6.6...
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peak expiratory flow and the resistance of the mini wright peak flow meter
European Respiratory Journal, 1996Co-Authors: O F Pedersen, Philip H Quanjer, Torben Riis Rasmussen, Oyvind Omland, Torben Sigsgaard, M R MillerAbstract:The purpose of this study was to examine whether the resistance of the peak flow meter influences its recordings. One hundred and twelve subjects, (healthy nonsmokers and smokers and subjects with lung diseases) performed three or more peak expiratory flow (PEF) manoeuvres through a Fleisch Pneumotachograph with and without a mini-Wright peak flow meter added in random order as a resistance in series. The results were as follows. In comparison with a Pneumotachograph alone, peak flow measured with an added mini-Wright meter had a smaller within-test variation, defined as the difference between the highest and second highest values of PEF in a series of blows. The mean (SE) variation was 14 (1.3) L.min-1 and 19 (1.5) L.min-1 with and without meter added, respectively. In comparison with the Pneumotachograph alone, the addition of the mini-Wright meter caused PEF to be underread, especially at high flows. The difference (PEF with meter minus PEF without meter) = -0.064 (average PEF) -8 L.min-1; R2 = 0.13. The mean difference was -7.8 (1.1) %, and increased numerically for a given PEF, when maximal expiratory flow when 75% forced vital capacity remains to be exhaled (MEF75%FVC) decreased. The reproducibility criteria for repeated measurements of peak flow are more appropriately set at 30 L.min-1 than the commonly used 20 L.min-1, because a within-test variation of less than 30 L.min-1 was achieved in 76% of the subjects without PEF meter inserted and in 88% with meter inserted, with no difference between healthy untrained subjects and patients. The resistance of the peak expiratory flow meter causes less variation in recordings but reduces peak expiratory flow, especially at high values and when the peak is large as compared with the rest of the maximal expiratory flow-volume curve.
J G Saslow - One of the best experts on this subject based on the ideXlab platform.
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work of breathing using high flow nasal cannula in preterm infants
Journal of Perinatology, 2006Co-Authors: J G Saslow, Zubair H. Aghai, T A Nakhla, J J Hart, R Lawrysh, Gary StahlAbstract:To compare the work of breathing (WOB) in premature neonates supported with high-flow nasal cannula (HFNC) and nasal continuous positive airway pressure (NCPAP). Eighteen preterm neonates <2.0 kg on HFNC or NCPAP support were studied in a random order. A ventilator was used to deliver 6 cm H2O of NCPAP with nasal prongs. High-flow nasal cannula delivered with Vapotherm (VAPO) at 3, 4 and 5 l/min was used. Tidal ventilation was obtained using respiratory inductance plethysmography calibrated with face-mask Pneumotachography. An esophageal balloon estimated pleural pressure from which changes in end distending pressure were calculated. Inspiratory, elastic and resistive WOB and respiratory parameters were calculated. No differences were found in the WOB for all settings. Changes in end distending pressure did not vary significantly over all device settings except VAPO at 5 l/min. In these preterm infants with mild respiratory illness, HFNC provided support comparable to NCPAP.
Philip H Quanjer - One of the best experts on this subject based on the ideXlab platform.
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peak expiratory flow profiles delivered by pump systems limitations due to wave action
American Journal of Respiratory and Critical Care Medicine, 2000Co-Authors: M R Miller, Barrie Jones, Yong Xu, Philip H QuanjerAbstract:Pump systems are currently used to test the performance of both spirometers and peak expiratory flow (PEF) meters, but for certain flow profiles the input signal (i.e., requested profile) and the output profile can differ. We developed a mathematical model of wave action within a pump and compared the recorded flow profiles with both the input profiles and the output predicted by the model. Three American Thoracic Society (ATS) flow profiles and four artificial flow-versus-time profiles were delivered by a pump, first to a Pneumotachograph (PT) on its own, then to the PT with a 32-cm upstream extension tube (which would favor wave action), and lastly with the PT in series with and immediately downstream to a mini-Wright peak flow meter. With the PT on its own, recorded flow for the seven profiles was 2.4 ± 1.9% (mean ± SD) higher than the pump's input flow, and similarly was 2.3 ± 2.3% higher than the pump's output flow as predicted by the model. With the extension tube in place, the recorded flow was 6.6...
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peak expiratory flow and the resistance of the mini wright peak flow meter
European Respiratory Journal, 1996Co-Authors: O F Pedersen, Philip H Quanjer, Torben Riis Rasmussen, Oyvind Omland, Torben Sigsgaard, M R MillerAbstract:The purpose of this study was to examine whether the resistance of the peak flow meter influences its recordings. One hundred and twelve subjects, (healthy nonsmokers and smokers and subjects with lung diseases) performed three or more peak expiratory flow (PEF) manoeuvres through a Fleisch Pneumotachograph with and without a mini-Wright peak flow meter added in random order as a resistance in series. The results were as follows. In comparison with a Pneumotachograph alone, peak flow measured with an added mini-Wright meter had a smaller within-test variation, defined as the difference between the highest and second highest values of PEF in a series of blows. The mean (SE) variation was 14 (1.3) L.min-1 and 19 (1.5) L.min-1 with and without meter added, respectively. In comparison with the Pneumotachograph alone, the addition of the mini-Wright meter caused PEF to be underread, especially at high flows. The difference (PEF with meter minus PEF without meter) = -0.064 (average PEF) -8 L.min-1; R2 = 0.13. The mean difference was -7.8 (1.1) %, and increased numerically for a given PEF, when maximal expiratory flow when 75% forced vital capacity remains to be exhaled (MEF75%FVC) decreased. The reproducibility criteria for repeated measurements of peak flow are more appropriately set at 30 L.min-1 than the commonly used 20 L.min-1, because a within-test variation of less than 30 L.min-1 was achieved in 76% of the subjects without PEF meter inserted and in 88% with meter inserted, with no difference between healthy untrained subjects and patients. The resistance of the peak expiratory flow meter causes less variation in recordings but reduces peak expiratory flow, especially at high values and when the peak is large as compared with the rest of the maximal expiratory flow-volume curve.
Christopher J. L. Newth - One of the best experts on this subject based on the ideXlab platform.
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total lung capacity by n2 washout from high and low lung volumes in ventilated infants and children
American Journal of Respiratory and Critical Care Medicine, 1998Co-Authors: Jürg Hammer, Andrew Numa, Christopher J. L. NewthAbstract:Although there is a strong rationale for the assessment of the subdivisions of lung volume, lung function testing has focused on the measurement of FRC alone in ventilated infants and children. To assess the feasibility, reproducibility, and accuracy of measurements of total lung capacity (TLC), FRC, and their ratio, we determined both lung volumes in 50 critically ill, intubated, and paralyzed infants (mean age [SEM]), 19.9 [4.6] mo) with a variety of lung diseases, by a modified N2 washout technique from end-exhalation and from + 40 cm H2O inspiratory pressure, respectively. In the same infants, we also defined TLC by adding inspiratory capacity, measured by Pneumotachograph during a passive exhalation from + 40 cm H2O to FRC measured by N2 washout. Respiratory mechanics were measured by single-breath occlusion, and the patients were classified according to clinical picture and lung function into groups without lung disease or with restrictive or obstructive disease. The TLC data obtained by both method...