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Imposed Work of Breathing for Flow Meters with In-Line versus Flow-Through Technique during Simulated Neonatal Breathing.

Donaldsson S, Falk M, Jonsson B, Drevhammar T - PLoS ONE (2015)

Bottom Line: The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing.The quality of the recorded signals was compared graphically.The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates.

View Article: PubMed Central - PubMed

Affiliation: Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.

ABSTRACT

Background: The ability to determine airflow during nasal CPAP (NCPAP) treatment without adding dead space or resistance would be useful when investigating the physiologic effects of different NCPAP systems on breathing. The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing.

Methods: Six different flow measure devices were evaluated by recording pressure changes and imposed work of breathing for breaths with 16 and 32 ml tidal volumes. The tests were performed initially with the devices in an in line position and with 5 and 10 L/min using flow through technique, without CPAP. The flow meters were then subsequently tested with an Infant Flow CPAP system at 3, 5 and 8 cm H2O pressure using flow through technique. The quality of the recorded signals was compared graphically.

Results: The resistance of the measuring devices generated pressure swings and imposed work of breathing. With bias flow, the resistance also generated CPAP pressure. Three of the devices had low resistance and generated no changes in pressure stability or CPAP pressure. The two devices intended for neonatal use had the highest measured resistance.

Conclusion: The importance of pressure stability and increased work of breathing during non-invasive respiratory support are insufficiently studied. Clinical trials using flow-through technique have not focused on pressure stability. Our results indicate that a flow-through technique might be a way forward in obtaining a sufficiently high signal quality without the added effects of rebreathing and increased work of breathing. The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates.

No MeSH data available.


Related in: MedlinePlus

Graphic quality of signal at three levels of CPAP.Recordings from simulations with flow meters connected to the expiratory limb of an Infant Flow device at three levels of CPAP with simulated sinusoidal breathing (32 ml tidal volume, 60 breaths/minute). The colors indicate CPAP level; blue 3.0 cm H2O, red 5.0 cm H2O and green 8.0 cm H2O. The graphs represent one breath (1.0 s).
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pone.0133432.g009: Graphic quality of signal at three levels of CPAP.Recordings from simulations with flow meters connected to the expiratory limb of an Infant Flow device at three levels of CPAP with simulated sinusoidal breathing (32 ml tidal volume, 60 breaths/minute). The colors indicate CPAP level; blue 3.0 cm H2O, red 5.0 cm H2O and green 8.0 cm H2O. The graphs represent one breath (1.0 s).

Mentions: A graphical comparison between all flow recordings is presented in Figs 8 and 9. The SpiroQuant A had artifacts at flows close to zero. The other techniques showed similar graphic quality but with different levels of noise. All recordings from Infant Flow with flow-through technique showed increased levels of noise (Fig 9).


Imposed Work of Breathing for Flow Meters with In-Line versus Flow-Through Technique during Simulated Neonatal Breathing.

Donaldsson S, Falk M, Jonsson B, Drevhammar T - PLoS ONE (2015)

Graphic quality of signal at three levels of CPAP.Recordings from simulations with flow meters connected to the expiratory limb of an Infant Flow device at three levels of CPAP with simulated sinusoidal breathing (32 ml tidal volume, 60 breaths/minute). The colors indicate CPAP level; blue 3.0 cm H2O, red 5.0 cm H2O and green 8.0 cm H2O. The graphs represent one breath (1.0 s).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507850&req=5

pone.0133432.g009: Graphic quality of signal at three levels of CPAP.Recordings from simulations with flow meters connected to the expiratory limb of an Infant Flow device at three levels of CPAP with simulated sinusoidal breathing (32 ml tidal volume, 60 breaths/minute). The colors indicate CPAP level; blue 3.0 cm H2O, red 5.0 cm H2O and green 8.0 cm H2O. The graphs represent one breath (1.0 s).
Mentions: A graphical comparison between all flow recordings is presented in Figs 8 and 9. The SpiroQuant A had artifacts at flows close to zero. The other techniques showed similar graphic quality but with different levels of noise. All recordings from Infant Flow with flow-through technique showed increased levels of noise (Fig 9).

Bottom Line: The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing.The quality of the recorded signals was compared graphically.The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates.

View Article: PubMed Central - PubMed

Affiliation: Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.

ABSTRACT

Background: The ability to determine airflow during nasal CPAP (NCPAP) treatment without adding dead space or resistance would be useful when investigating the physiologic effects of different NCPAP systems on breathing. The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing.

Methods: Six different flow measure devices were evaluated by recording pressure changes and imposed work of breathing for breaths with 16 and 32 ml tidal volumes. The tests were performed initially with the devices in an in line position and with 5 and 10 L/min using flow through technique, without CPAP. The flow meters were then subsequently tested with an Infant Flow CPAP system at 3, 5 and 8 cm H2O pressure using flow through technique. The quality of the recorded signals was compared graphically.

Results: The resistance of the measuring devices generated pressure swings and imposed work of breathing. With bias flow, the resistance also generated CPAP pressure. Three of the devices had low resistance and generated no changes in pressure stability or CPAP pressure. The two devices intended for neonatal use had the highest measured resistance.

Conclusion: The importance of pressure stability and increased work of breathing during non-invasive respiratory support are insufficiently studied. Clinical trials using flow-through technique have not focused on pressure stability. Our results indicate that a flow-through technique might be a way forward in obtaining a sufficiently high signal quality without the added effects of rebreathing and increased work of breathing. The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates.

No MeSH data available.


Related in: MedlinePlus