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Jacques Rigo - One of the best experts on this subject based on the ideXlab platform.
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precision of continuous Neonatal Ventilator respiratory mechanics is improved with selected optimal respiratory cycles
European Journal of Pediatrics, 2012Co-Authors: Vincent Rigo, Estelle Graas, Jacques RigoAbstract:Given their high apparent variability, bedside continuous respiratory mechanics (RM) parameters [excepting tidal volume (V T)] remain infrequently used for adjustment of Neonatal Ventilatory settings. RM parameters provided by Ventilator (VRC) from ten recordings of newborns [10 min in synchronised intermittent mandatory ventilation and 10 min in assist/control (A/C)] were compared to those computed from visually selected assisted leak-free optimal respiratory cycles (SRC). Mean values, variability and ability to distinguish patients were compared between VRC and SRC. Dynamic resistances were more correlated (r 2 = 0.95) than compliances (r 2 = 0.42). V Ts were correlated only in A/C (r 2 = 0.78). C20/C was significantly higher in VRC (1.81 ± 0.67) than in SRC (1.23 ± 0.36) and frequently out of Neonatal reference range. In A/C ventilation, V T was higher in VRC (5.6 ± 1.8 ml/kg) than in SRC (4.8 ± 1.0 ml/kg) (p < 0.05). Displayed V Ts do not reflect those found in optimal assisted breaths and therefore have incomplete value in assessing adequacy of Ventilator settings. The variability of RM parameters provided by the Ventilator is large, and coefficients of variation were significantly lower with optimal respiratory cycles (for resistance, compliance, V T and C20/C; 27%, 26%, 18%, 24% in SRC and 36%, 35%, 40% and 33% in VRC). Selecting optimal cycles yields RM with two to three times higher discriminating power between patients. Conclusion: Current Ventilator’s RM parameters have limited clinical use. Using optimal breaths to calculate RM parameters improves precision and discriminating power. For integration to Ventilatory care, automation of this selection must be implemented first.
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validation of continuous Neonatal Ventilator respiratory mechanics and tidal volume by selected optimal respiratory cycles
Pediatric Research, 2011Co-Authors: Vincent Rigo, Estelle Graas, Jacques RigoAbstract:Validation of Continuous Neonatal Ventilator Respiratory Mechanics and Tidal Volume by Selected Optimal Respiratory Cycles
A. Harf - One of the best experts on this subject based on the ideXlab platform.
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Assessment of high-frequency Neonatal Ventilator performances
Intensive Care Medicine, 1997Co-Authors: P. Jouvet, P. Hubert, M. Cloup, D. Isabey, D. Pinquier, E. Dahan, A. HarfAbstract:Objective : To assess the efficacy and reliability of Neonatal high-frequency Ventilators. Design : Bench evaluation of Neonatal high-frequency Ventilators. Setting : Physiology department and university hospital Neonatal intensive care unit. Interventions : HFV-Babylog 8000 (Dräger Medical), OHF 1 (Dufour), and SensorMedics 3100A (SensorMedics) Ventilators were connected to a Neonatal test-lung. Tidal volume, peak-to-peak pressure amplitude, and mean airway pressure were measured for several Ventilator settings, endotracheal tube sizes, and lung compliances. Measurements and results : Increasing peak-to-peak pressure resulted in a linear increase in tidal volume delivery in the 0–30% range of maximum amplitude. No significant increase in tidal volume was observed with the HFV-Babylog8000 when pressure amplitude was above 50%. The maximum tidal volume delivered was substantially smaller with the HFV-Babylog8000 than with the OHF1 or SensorMedics3100A. Tidal volume increased with endotracheal tube size with all three Ventilators. Increasing test-lung compliance resulted in lower tidal volumes only with OHF1. Decreasing mean airway pressure was responsible for a decrease in tidal volume delivery with HFV-Babylog8000. Conclusion : We found that under our test conditions two of the three Ventilators delivered adequate tidal volumes at the usual frequency of 15Hz, regardless of the size of the endotracheal tube and of the mechanical properties of the respiratory system. When lung compliance increased or mean airway pressure decreased, both of which are common events during the recovery phase of hyaline membrane disease, we found that the intrinsic properties of two of the Ventilators tested were responsible for a decrease in tidal volume. This decrease may account for some cases of heretofore unexplained hypercapnia.
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Assessment of Neonatal Ventilator performances
Intensive Care Medicine, 1995Co-Authors: P. Jouvet, P. Hubert, P. H. Jarreau, F. Lofaso, M. Cloup, A. HarfAbstract:Objective To analyze efficiency and reliability of 4 modern Neonatal Ventilators under difficult test conditions. The Ventilators tested were: Babylog 8000 (Dräger Medical), BP 2001 (Bear Medical Systems), Sechrist IV 100 B (Sechrist Industries), Infant Star (Infrasonics INC). Measurements and results Gas flow generation was tested by comparison of preset flow values with no resistance in the circuit to flow values obtained during interposition of a resistance in the inspiratory circuit. A decrease in gas flow was observed when interposition of a resistance in the inspiratory circuit increased peak inspiratory pressure to 60 cmH_2O (gas flow decreased by 8% to 24% depending on the Ventilator tested). The pressure limiting valve and the positive end-expiratory pressure valve were also evaluated in order to test their behaviour under different flow conditions. Flow-dependence of the pressure was noted for all Ventilators except Babylog 8000. Assessment of the reliability of pressure monitoring revealed either ‘under’ or ‘over’ estimation of peak inspiratory pressure and positive end-expiratory pressure depending on the Ventilator tested. Conclusion For the best clinical use of mechanical Ventilators, neonatologists should be aware of these limitations. Therefore a regular assessment of Ventilator performance and monitoring reliability is recommended.
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Assessment of Neonatal Ventilator performances
Intensive care medicine, 1995Co-Authors: P. Jouvet, P. Hubert, P. H. Jarreau, F. Lofaso, M. Cloup, A. HarfAbstract:Objective To analyze efficiency and reliability of 4 modern Neonatal Ventilators under difficult test conditions. The Ventilators tested were: Babylog 8000 (Drager Medical), BP 2001 (Bear Medical Systems), Sechrist IV 100 B (Sechrist Industries), Infant Star (Infrasonics INC).
M Silverman - One of the best experts on this subject based on the ideXlab platform.
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delivery of micronized budesonide suspension by metered dose inhaler and jet nebulizer into a Neonatal Ventilator circuit
Pediatric Pulmonology, 1992Co-Authors: S Arnon, Kurt Verner Holger Nikander, Jonathan Grigg, M SilvermanAbstract:We compared the delivery of a micronized suspension of budesonide by a metered dose inhaler (MDI) with two different spacers (Aerochamber and Aerovent) and by two jet nebulizers (MAD2 and Ultravent) to a ventilated Neonatal test-lung using a standard Neonatal Ventilator circuit. The combination of MDI and Aerochamber was significantly better at delivering budesonide to a filter in front of the test lung (14.2% of aerosolized dose) than were either the MDI and Aerovent (3.6%) or the Ultravent or MAD2 jet nebulizers (0.02% and 0.68% of initial reservoir dose). Of the droplets emerging from the MDI, Aerochamber, and ET tube, 18% of the initial dose was in droplets < 4.7 μm. Assuming that the test-lung model accurately reflects in vivo deposition, the combination of MDI and Aerochamber appears to be an extremely effective way of delivering budesonide aerosol to ventilated newborn infants. © 1992 Wiley-Liss, Inc.
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Aerosol delivery in Neonatal Ventilator circuits: a rabbit lung model.
Pediatric pulmonology, 1991Co-Authors: Duncan Cameron, Michelle Clay, Rosemary Arnot, M SilvermanAbstract:The benefits of inhaled therapy in ventilated neonates are recognized, but the reliability of drug delivery in nebulizer-Ventilator circuits is uncertain. We quantified the effect of changing variables. Twenty-three freshly killed rabbits (1.15–1.9 kg) were ventilated via a tracheostomy by a pressure-limited, time-cycled Ventilator (Neovent). A radioaerosol of 99Tcm pertechnetate from an Ultravent nebulizer (Mallinkrodt) was fed into the proximal Ventilator tubing. Two 3-minute nebulizations at “standard settings” were followed by 2 at altered pressure, frequency, gas flow, I:E ratio, or position of the nebulizer in the circuit. Each nebulization was followed by a 3-minute gamma camera image and total deposited radioactivity was measured in excised lungs and trachea. Images demonstrated good peripheral aerosol deposition. At standard settings, lung deposition averaged 2.8% of the aerosol released. This was decreased markedly by reducing tidal volume (Ventilator pressures) and residence time of aerosol (I:E ratio). Reduced gas flow decreased deposition slightly, presumably by increased particle size and marginally reduced tidal volume. Deposition did not change with increased frequency; increased minute ventilation was offset by decreased residence time of the aerosol. We conclude that the Ultravent nebulizer can be used to nebulize drugs in a standard Neonatal circuit, although the dose delivered is small. Tidal volume and aerosol residence time are important determinants of aerosol delivery. Pediatr Pulmonol 1991; 10:208–213.
Vincent Rigo - One of the best experts on this subject based on the ideXlab platform.
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precision of continuous Neonatal Ventilator respiratory mechanics is improved with selected optimal respiratory cycles
European Journal of Pediatrics, 2012Co-Authors: Vincent Rigo, Estelle Graas, Jacques RigoAbstract:Given their high apparent variability, bedside continuous respiratory mechanics (RM) parameters [excepting tidal volume (V T)] remain infrequently used for adjustment of Neonatal Ventilatory settings. RM parameters provided by Ventilator (VRC) from ten recordings of newborns [10 min in synchronised intermittent mandatory ventilation and 10 min in assist/control (A/C)] were compared to those computed from visually selected assisted leak-free optimal respiratory cycles (SRC). Mean values, variability and ability to distinguish patients were compared between VRC and SRC. Dynamic resistances were more correlated (r 2 = 0.95) than compliances (r 2 = 0.42). V Ts were correlated only in A/C (r 2 = 0.78). C20/C was significantly higher in VRC (1.81 ± 0.67) than in SRC (1.23 ± 0.36) and frequently out of Neonatal reference range. In A/C ventilation, V T was higher in VRC (5.6 ± 1.8 ml/kg) than in SRC (4.8 ± 1.0 ml/kg) (p < 0.05). Displayed V Ts do not reflect those found in optimal assisted breaths and therefore have incomplete value in assessing adequacy of Ventilator settings. The variability of RM parameters provided by the Ventilator is large, and coefficients of variation were significantly lower with optimal respiratory cycles (for resistance, compliance, V T and C20/C; 27%, 26%, 18%, 24% in SRC and 36%, 35%, 40% and 33% in VRC). Selecting optimal cycles yields RM with two to three times higher discriminating power between patients. Conclusion: Current Ventilator’s RM parameters have limited clinical use. Using optimal breaths to calculate RM parameters improves precision and discriminating power. For integration to Ventilatory care, automation of this selection must be implemented first.
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validation of continuous Neonatal Ventilator respiratory mechanics and tidal volume by selected optimal respiratory cycles
Pediatric Research, 2011Co-Authors: Vincent Rigo, Estelle Graas, Jacques RigoAbstract:Validation of Continuous Neonatal Ventilator Respiratory Mechanics and Tidal Volume by Selected Optimal Respiratory Cycles
Gusztav Belteki - One of the best experts on this subject based on the ideXlab platform.
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Computational analysis of Neonatal Ventilator waveforms and loops
Pediatric Research, 2020Co-Authors: David Chong, Colin J. Morley, Gusztav BeltekiAbstract:Background Modern Neonatal Ventilators allow the downloading of their data with a high sampling rate. We wanted to develop an algorithm that automatically recognises and characterises Ventilator inflations from Ventilator pressure and flow data. Methods We downloaded airway pressure and flow data with 100 Hz sampling rate from Dräger Babylog VN500 Ventilators ventilating critically ill infants. We developed an open source Python package, Ventiliser , that includes a rule-based algorithm to automatically discretise Ventilator data into a sequence of flow and pressure states and to recognise Ventilator inflations and an information gain approach to identify inflation phases (inspiration, expiration) and sub-phases (pressure rise, pressure plateau, inspiratory hold etc.). Results Ventiliser runs on a personal computer and analyses 24 h of ventilation in 2 min. With longer recordings, the processing time increases linearly. It generates a table reporting indices of each breath and its sub-phases. Ventiliser also allows visualisation of individual inflations as waveforms or loops. Ventiliser identified >97% of Ventilator inflations and their sub-phases in an out-of-sample validation of manually annotated data. We also present detailed quantitative analysis and comparison of two 1-hour-long ventilation periods. Conclusions Ventiliser can analyse ventilation patterns and Ventilator–patient interactions over long periods of mechanical ventilation. Impact We have developed a computational method to recognize and analyse Ventilator inflations from raw data downloaded from Ventilators of preterm and critically ill infants. There have been no previous reports on the computational analysis of Neonatal Ventilator data. We have made our program, Ventiliser , freely available. Clinicians and researchers can use Ventiliser to analyse Ventilator inflations, waveforms and loops over long periods. Ventiliser can also be used to study Ventilator–patient interactions.
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Leak Compensation During Volume Guarantee With the Dräger Babylog VN500 Neonatal Ventilator.
Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Car, 2018Co-Authors: Eniko Szakmar, Colin J. Morley, Gusztav BeltekiAbstract:Objectives To investigate how compensating for endotracheal tube leaks by targeting the leak-compensated tidal volume affects measured physiologic and Ventilator variables during Neonatal mechanical ventilation. Design Retrospective observational study. Setting A level III Neonatal ICU. Patients We enrolled 30 neonates who were ventilated using synchronized intermittent positive pressure mode with volume guarantee and had at least 12 hours of continuous detailed recording of ventilation variables. Interventions Infants were treated using the Drager VN500 Ventilator (Drager, Lubeck, Germany), which uses a proprietary algorithm to measure and compensate for endotracheal tube leaks. Eleven were ventilated without leak compensation and 19 with leak compensation. Measurements and main results Detailed ventilation data were collected and analyzed at 1 Hz, with intermittent blood gas values. The percentage of leak was less than 20% in 73% of leak-compensated inflations, and the volume of the leak compensation was less than 1 mL/kg in 97.3% of inflations. Between the two groups, ventilation variables were comparable, except the percentage of leak that was significantly (p = 0.005) higher in the recordings with leak compensation. Without leak compensation, the mean expired tidal volume was maintained very close to the set level up to 50% leak, but with leaks greater than 50%, it declined progressively. With leak compensation, the mean leak-compensated expired tidal volume was well maintained even with leak greater than 90% although with large variability. Without leak compensation, the difference between the maximum allowed inflating pressure and the peak inflating pressure decreased progressively as the leak increased. This did not occur with leak compensation. The median PCO2 was slightly higher with leak compensation. Conclusions During volume guarantee ventilation with a Drager VN500 Ventilator, without leak compensation the expired tidal volume declined after 50% leak. With leak compensation, the tidal volume was maintained even with a large leak. With leak compensation, there was a more stable peak inflating pressure, although the PCO2 was slightly higher.
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Frequency, duration and cause of Ventilator alarms on a Neonatal intensive care unit.
Archives of disease in childhood. Fetal and neonatal edition, 2017Co-Authors: Gusztav Belteki, Colin J. MorleyAbstract:Objective To investigate the frequency and cause of Neonatal Ventilator alarms. Neonatal Ventilators frequently alarm and also disturb babies, parents and nurses. If frequent they may cause alarm fatigue and be ignored. The number, frequency and details of Neonatal Ventilator alarms are unreported. Methods We developed programs for retrieving and analysing Ventilator data each second on alarms and ventilation parameters from 46 babies ventilated with Drager Babylog VN500 Ventilators using various modes. Results A mean of 60 hours was recorded per baby. Over 116 days, 27 751 alarms occurred. On average, that was 603 per baby and 10 per hour. Median (IQR) alarm duration was 10 (4–21) s. Type, frequency and duration varied between infants. Some babies had >10% of their time with alarms. Eight alarm types caused ~99% of all alarms. Three alarms, ‘MV high limit’ and ‘respiratory rate >high limit’, caused 46.6%, often due to inappropriate settings. 49.9% were due to a low expired tidal volume during volume guarantee ventilation, often due to the maximum pressure being set too low. 26 106 (94.1%) of all alarms lasted 10 min and 16 alarms >1 hour. Similar alarms were frequently clustered, sometimes >100/hour. Conclusions Frequent Ventilator alarms are caused by physiological variability in the respiratory rate or minute volume, inappropriate alarm limits or too low maximum peak inflating pressure during volume-targeted ventilation. While most alarms were very short, sometimes alarms were ignored by Neonatal intensive care unit staff for long periods.
