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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

Imposed WOB for Infant Flow with flow meters.Simulations using flow-through measurement at three levels of CPAP for simulated breathing with 32 ml tidal volume. Bars show mean imposed WOB (Total iWOB) for twenty consecutive breaths with 95% CI.
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pone.0133432.g007: Imposed WOB for Infant Flow with flow meters.Simulations using flow-through measurement at three levels of CPAP for simulated breathing with 32 ml tidal volume. Bars show mean imposed WOB (Total iWOB) for twenty consecutive breaths with 95% CI.

Mentions: The differences in pressure stability between SpiroQuant A, SFM3200 or the Vitalograph Fleisch pneumotachograph, in combination with Infant Flow, were very small (Figs 6 and 7). As an example, the differences in pressure swings were below 0.1 cm H2O (not statistically significant in several comparisons). Infant flow used with Fleisch 0, Florian or NDD increased imposed WOB and pressure swings (p <0.05 in all comparisons). Complete data and statistical comparisons are available as supplementary information (S2 Table).


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)

Imposed WOB for Infant Flow with flow meters.Simulations using flow-through measurement at three levels of CPAP for simulated breathing with 32 ml tidal volume. Bars show mean imposed WOB (Total iWOB) for twenty consecutive breaths with 95% CI.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0133432.g007: Imposed WOB for Infant Flow with flow meters.Simulations using flow-through measurement at three levels of CPAP for simulated breathing with 32 ml tidal volume. Bars show mean imposed WOB (Total iWOB) for twenty consecutive breaths with 95% CI.
Mentions: The differences in pressure stability between SpiroQuant A, SFM3200 or the Vitalograph Fleisch pneumotachograph, in combination with Infant Flow, were very small (Figs 6 and 7). As an example, the differences in pressure swings were below 0.1 cm H2O (not statistically significant in several comparisons). Infant flow used with Fleisch 0, Florian or NDD increased imposed WOB and pressure swings (p <0.05 in all comparisons). Complete data and statistical comparisons are available as supplementary information (S2 Table).

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