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Effects of different flow patterns and end-inspiratory pause on oxygenation and ventilation in newborn piglets: an experimental study.

Ferrando C, García M, Gutierrez A, Carbonell JA, Aguilar G, Soro M, Belda FJ - BMC Anesthesiol (2014)

Bottom Line: However, the superiority of DF compared with SF has not yet been demonstrated during ventilation in small infants.The inspiratory flow waveform had no effect on arterial oxygenation pressure (PaO2) (276 vs. 278 mmHg, p = 0.77), alveolar dead space to alveolar tidal volume (VDalv/VTalv) (0.21 vs. 0.19 ml, p = 0.33), mean airway pressure (Pawm) (13.1 vs. 14.0 cmH2O, p = 0.69) and compliance (Crs) (3.5 vs. 3.5 ml cmH2O(-1), p = 0.73) when comparing SF and DF.A short EIP (10%) did not produce changes in the results.

View Article: PubMed Central - PubMed

Affiliation: Anesthesiology and Critical Care Department, Hospital Clínico Universitario of Valencia, Av. Blasco Ibañez, 17, CP: 46010 Valencia, Spain.

ABSTRACT

Background: Historically, the elective ventilatory flow pattern for neonates has been decelerating flow (DF). Decelerating flow waveform has been suggested to improve gas exchange in the neonate when compared with square flow (SF) waveform by improving the ventilation perfusion. However, the superiority of DF compared with SF has not yet been demonstrated during ventilation in small infants. The aim of this study was to compare SF vs. DF, with or without end-inspiratory pause (EIP), in terms of oxygenation and ventilation in an experimental model of newborn piglets.

Methods: The lungs of 12 newborn Landrace/LargeWhite crossbred piglets were ventilated with SF, DF, SF-EIP and DF-EIP. Tidal volume (VT), inspiratory to expiratory ratio (I/E), respiratory rate (RR), and FiO2 were keep constant during the study. In order to assure an open lung during the study while preventing alveolar collapse, a positive end-expiratory pressure (PEEP) of 6 cmH2O was applied after a single recruitment maneuver. Gas exchange, lung mechanics and hemodynamics were measured.

Results: The inspiratory flow waveform had no effect on arterial oxygenation pressure (PaO2) (276 vs. 278 mmHg, p = 0.77), alveolar dead space to alveolar tidal volume (VDalv/VTalv) (0.21 vs. 0.19 ml, p = 0.33), mean airway pressure (Pawm) (13.1 vs. 14.0 cmH2O, p = 0.69) and compliance (Crs) (3.5 vs. 3.5 ml cmH2O(-1), p = 0.73) when comparing SF and DF. A short EIP (10%) did not produce changes in the results.

Conclusion: The present study showed that there are no differences between SF, DF, SF-EIP and DF-EIP in oxygenation, ventilation, lung mechanics, or hemodynamics in this experimental model of newborn piglets with healthy lungs.

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Representative flow patterns studied with their respective pressure–time curve, all at the same tidal volumen, respiratory rate, positive end-expiratory pressure and inspiratory to expiratory ratio. DF-EIP: decelerating flow with 10% end-inspiratory pressure, DF: decelerating flow, SF-EIP: square flow with 10% end-inspiratory pressure, SF: square flow. TI: Inspiratory time.
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Fig1: Representative flow patterns studied with their respective pressure–time curve, all at the same tidal volumen, respiratory rate, positive end-expiratory pressure and inspiratory to expiratory ratio. DF-EIP: decelerating flow with 10% end-inspiratory pressure, DF: decelerating flow, SF-EIP: square flow with 10% end-inspiratory pressure, SF: square flow. TI: Inspiratory time.

Mentions: For mechanical ventilation, a Galileo gold (Hamilton, Bonaduz, Switzerland) was used in the pediatric mode. The ventilator allows square and decelerating flow, and end-inspiratory pause can be adjusted for a constant I/E relationship in VCV. The following ventilatory modes were compared in the study (Figure 1):Figure 1


Effects of different flow patterns and end-inspiratory pause on oxygenation and ventilation in newborn piglets: an experimental study.

Ferrando C, García M, Gutierrez A, Carbonell JA, Aguilar G, Soro M, Belda FJ - BMC Anesthesiol (2014)

Representative flow patterns studied with their respective pressure–time curve, all at the same tidal volumen, respiratory rate, positive end-expiratory pressure and inspiratory to expiratory ratio. DF-EIP: decelerating flow with 10% end-inspiratory pressure, DF: decelerating flow, SF-EIP: square flow with 10% end-inspiratory pressure, SF: square flow. TI: Inspiratory time.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4216830&req=5

Fig1: Representative flow patterns studied with their respective pressure–time curve, all at the same tidal volumen, respiratory rate, positive end-expiratory pressure and inspiratory to expiratory ratio. DF-EIP: decelerating flow with 10% end-inspiratory pressure, DF: decelerating flow, SF-EIP: square flow with 10% end-inspiratory pressure, SF: square flow. TI: Inspiratory time.
Mentions: For mechanical ventilation, a Galileo gold (Hamilton, Bonaduz, Switzerland) was used in the pediatric mode. The ventilator allows square and decelerating flow, and end-inspiratory pause can be adjusted for a constant I/E relationship in VCV. The following ventilatory modes were compared in the study (Figure 1):Figure 1

Bottom Line: However, the superiority of DF compared with SF has not yet been demonstrated during ventilation in small infants.The inspiratory flow waveform had no effect on arterial oxygenation pressure (PaO2) (276 vs. 278 mmHg, p = 0.77), alveolar dead space to alveolar tidal volume (VDalv/VTalv) (0.21 vs. 0.19 ml, p = 0.33), mean airway pressure (Pawm) (13.1 vs. 14.0 cmH2O, p = 0.69) and compliance (Crs) (3.5 vs. 3.5 ml cmH2O(-1), p = 0.73) when comparing SF and DF.A short EIP (10%) did not produce changes in the results.

View Article: PubMed Central - PubMed

Affiliation: Anesthesiology and Critical Care Department, Hospital Clínico Universitario of Valencia, Av. Blasco Ibañez, 17, CP: 46010 Valencia, Spain.

ABSTRACT

Background: Historically, the elective ventilatory flow pattern for neonates has been decelerating flow (DF). Decelerating flow waveform has been suggested to improve gas exchange in the neonate when compared with square flow (SF) waveform by improving the ventilation perfusion. However, the superiority of DF compared with SF has not yet been demonstrated during ventilation in small infants. The aim of this study was to compare SF vs. DF, with or without end-inspiratory pause (EIP), in terms of oxygenation and ventilation in an experimental model of newborn piglets.

Methods: The lungs of 12 newborn Landrace/LargeWhite crossbred piglets were ventilated with SF, DF, SF-EIP and DF-EIP. Tidal volume (VT), inspiratory to expiratory ratio (I/E), respiratory rate (RR), and FiO2 were keep constant during the study. In order to assure an open lung during the study while preventing alveolar collapse, a positive end-expiratory pressure (PEEP) of 6 cmH2O was applied after a single recruitment maneuver. Gas exchange, lung mechanics and hemodynamics were measured.

Results: The inspiratory flow waveform had no effect on arterial oxygenation pressure (PaO2) (276 vs. 278 mmHg, p = 0.77), alveolar dead space to alveolar tidal volume (VDalv/VTalv) (0.21 vs. 0.19 ml, p = 0.33), mean airway pressure (Pawm) (13.1 vs. 14.0 cmH2O, p = 0.69) and compliance (Crs) (3.5 vs. 3.5 ml cmH2O(-1), p = 0.73) when comparing SF and DF. A short EIP (10%) did not produce changes in the results.

Conclusion: The present study showed that there are no differences between SF, DF, SF-EIP and DF-EIP in oxygenation, ventilation, lung mechanics, or hemodynamics in this experimental model of newborn piglets with healthy lungs.

Show MeSH