			Home About us Contact

Lung Model (lung + model)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Validation and clinical feasibility of nitrogen washin/washout functional residual capacity measurements in children

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 3 2010
C. OLEGÅRD
Background: The functional residual capacity (FRC) is an important parameter in pediatric respiratory monitoring but it is difficult to assess in the clinical setting. We have introduced a modified N2 washout method utilizing a change of FIO2 of 0.1 for FRC measurement in adult respiratory monitoring. This study validated the algorithm in a pediatric lung model and investigated the stability and feasibility in a pediatric peri-operative and intensive care setting. Methods: The lung model was ventilated in combinations of ventilatory modes, CO2 production, model FRC and respiratory rates. Sixteen children from 10 days to 5 years were studied peri-operatively with controlled ventilation using a Mapleson D system and in the intensive care unit using a Servo-i ventilator in a supported spontaneous mode. FRC was measured during stable metabolic, respiratory and circulatory periods at positive end expiratory pressure of 3,4 and 7,8 cmH2O. Results: In the model and in the clinical setting, we found an excellent agreement between washout and washin measurements of FRC as well as acceptable coefficients of repeatability. Conclusion: FRC was satisfactorily measured by a modified N2 algorithm and may be included as a monitoring variable in pediatric respiratory care. Pediatric FRC monitoring demands strictly stable conditions as measurements are performed close to the limits of the monitor's specifications. [source]

A low oxygen consumption pneumatic ventilator for emergency construction during a respiratory failure pandemic,

ANAESTHESIA, Issue 3 2010
D. Williams
Summary The UK influenza pandemic plan predicts up to 750 000 additional deaths with hospitals prioritising patients against inadequate resources. We investigated three prototype low-cost, gas-efficient, pneumatic ventilators in a test lung model at different compliance and rate settings. Mean (SD) oxygen consumption was 0.913 (0.198) and 1.119 (0.267) l.min,1 at tidal volumes of 500 ml and 700 ml respectively. Values of FIo2 increased marginally as lung compliance reduced, reflecting the increased ventilator workload and consequent increased enrichment of breathing gas by waste oxygen from the pneumatic mechanism. We also demonstrated that a stable nitric oxide concentration could be delivered by this design following volumetric principles. It is possible to make a gas-efficient ventilator costing less than £200 from industrial components for use where oxygen is available at 2-4 bar, with no pressurised air or electrical requirements. Such a device could be mass-produced for crises characterised by an overwhelming demand for mechanical ventilation and a limited oxygen supply. [source]

Relationship between endotracheal tube leakage and under-reading of tidal volume in neonatal ventilators

ACTA PAEDIATRICA, Issue 7 2009
RA Mahmoud
Abstract Aim:, Protective ventilation in neonates requires careful volume monitoring to prevent ventilator-induced lung injury caused by baro/volutrauma and hence chronic lung disease. This study investigated the effect of endotracheal tube (ET) leakage on the displayed tidal volume using an in vitro model. Methods:, A neonatal lung model was ventilated via a 3 mm ET using three ventilators [Babylog 8000 (BL), Leoni (LE) and Stephanie (ST)]. Tidal volume was measured by each ventilator at the Y-piece and by a pneumotach (CO2SMO+) in the model. ET leaks were simulated by open tubes of different lengths. PIP (20 cmH2O) and PEEP (5 cmH2O) were kept constant, and the respiratory rate (RR) was varied between 20/min and 70/min (Ti:Te = 1:1). Results:, Tidal volume displayed by a ventilator decreased independently of RR with increasing leakage up to 21% (BL), 30% (LE) and 33% (ST). However, the volume delivered to the lung was nearly constant. The displayed leakage varied between 0 and 78% and was dependent on RR and leakage resistance. There were distinct differences between the three ventilators in the relationship between displayed leakage and volume error. Accepting a volume error <10% for RR between 20 and 70/min, ET leakage of up to 20% for BL, 12% for LE, but only <5% for ST, was acceptable. Conclusion:, Tidal volume underestimation arising from ET leakage depends on ventilator pressures, timing parameters and ventilator-specific algorithms for signal processing. Therefore, neonatologists should be aware of these issues to prevent lung over-inflation when adjusting target volume in the presence of ET leakage. [source]

Performance of neonatal ventilators in volume targeted ventilation mode

ACTA PAEDIATRICA, Issue 2 2007
Atul Sharma
Abstract Aim: To test the hypothesis that in volume targeted ventilation modes, ventilator performance would vary according to ventilator type. Methods: Four neonatal ventilators: Draeger Babylog 8000 (Draeger Medical, Germany), SLE 5000 infant ventilator (SLE systems, UK), Stephanie paediatric ventilator (F. Stephan Biomedical, German) and V.I.P. Bird gold (Viasys Healthcare, USA) were assessed using a lung model. Delivered peak pressure, inflation time, mean airway pressure (MAP) and volume were measured. Results: At the same preset ventilator settings, the Stephanie and V.I.P. Bird ventilators delivered significantly lower peak pressures and tended to deliver lower MAPs than the other two ventilators. At a volume targeted ventilation level of 5 mL, the SLE and the V.I.P. Bird delivered significantly shorter inflation times. The above differences related to differences in the airway pressure waveforms delivered by the four ventilators. The V.I.P. Bird had a less variable volume delivery, but this was always significantly lower than the preset volume guarantee level but higher than the volume displayed by the ventilator. Conclusion: In volume targeted ventilation modes, performance differs between neonatal ventilator types; these results may have implications for clinical practise. [source]

Exhaled and nasal nitric oxide in mechanically ventilated preterm and term newborns

ACTA PAEDIATRICA, Issue 10 2002
O Aikio
Aim: Nitric oxide (NO) is an important mediator required for neonatal pulmonary circulatory adaptation and for pulmonary defence. Both deficient and excessive NO production have been proposed to play a role in neonatal lung disease. This study aimed to establish a method that allows direct measurement of exhaled and nasal NO concentrations in newborn infants who require intubation and ventilation. Methods: A rapid-response chemiluminescence NO analyser was used. Gas was sampled from the endotracheal intubation tube, and tidal volumes and flow rates were measured. The nasal NO was sampled from the non-intubated nostril. The accuracy of the method was validated using a lung model. NO levels from six preterm and six term/near-term newborns were studied. Measurements were performed on a daily basis during the first week. Results: An expiration >0.2 s in duration with a flow rate >1.7mls,1 could be accurately analysed for the presence of >1 parts per billion of NO. The very preterm infants with neonatal lung disease had a different postnatal NO output pattern from the lower and upper airways compared with the ventilated term/near-term infants. Conclusion: A novel method for measurement of exhaled NO of an intubated newborn is presented. The possible association of exhaled NO concentration with the development of chronic lung disease remains to be studied. [source]