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High flow biphasic positive airway pressure by helmet--effects on pressurization, tidal volume, carbon dioxide accumulation and noise exposure.

Moerer O, Herrmann P, Hinz J, Severgnini P, Calderini E, Quintel M, Pelosi P - Crit Care (2009)

Bottom Line: Pressurization during inspiration was more effective with pressure controlled modes compared to PSV (P < 0.001) at similar tidal volumes.At high level of asynchrony both HF-BiPAP and BiVent were less effective.Only HF-BiPAP ventilation effectively removed CO2 (P < 0.001) during all settings.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Anaesthesiology, Emergency and Critical Care Medicine, University of Göttingen, 37075 Göttingen, Germany. omoerer@gwdg.de

ABSTRACT

Introduction: Non-invasive ventilation (NIV) with a helmet device is often associated with poor patient-ventilator synchrony and impaired carbon dioxide (CO2) removal, which might lead to failure. A possible solution is to use a high free flow system in combination with a time-cycled pressure valve placed into the expiratory circuit (HF-BiPAP). This system would be independent from triggering while providing a high flow to eliminate CO2.

Methods: Conventional pressure support ventilation (PSV) and time-cycled biphasic pressure controlled ventilation (BiVent) delivered by an Intensive Care Unit ventilator were compared to HF-BiPAP in an in vitro lung model study. Variables included delta pressures of 5 and 15 cmH2O, respiratory rates of 15 and 30 breaths/min, inspiratory efforts (respiratory drive) of 2.5 and 10 cmH2O) and different lung characteristics. Additionally, CO2 removal and noise exposure were measured.

Results: Pressurization during inspiration was more effective with pressure controlled modes compared to PSV (P < 0.001) at similar tidal volumes. During the expiratory phase, BiVent and HF-BiPAP led to an increase in pressure burden compared to PSV. This was especially true at higher upper pressures (P < 0.001). At high level of asynchrony both HF-BiPAP and BiVent were less effective. Only HF-BiPAP ventilation effectively removed CO2 (P < 0.001) during all settings. Noise exposure was higher during HF-BiPAP (P < 0.001).

Conclusions: This study demonstrates that in a lung model, the efficiency of NIV by helmet can be improved by using HF-BiPAP. However, it imposes a higher pressure during the expiratory phase. CO2 was almost completely removed with HF-BiPAP during all settings.

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Related in: MedlinePlus

Effect of different ventilator respiratory settings on the mean airway pressure time product below PEEP (PTPPEEP) during HF-BiPAP, BiVent, and PSV ventilation. Data were measured in normal (compliance 90 ml/cmH2O, resistance 3 cm H2O/l/s), restrictive (compliance 30 ml/cmH2O, resistance 3 cmH2O/l/s), and obstructive lung conditions (compliance 90 ml/cmH2O, resistance 15 cmH2O/l/s) at low (2.5 cmH2O) and high inspiratory efforts (10 cmH2O) at a respiratory rate of 15 and 30 breaths per minute. BiVent = time-cycled pressure controlled switching between two continuous positive airway pressure levels; HF-BiPAP = high flow biphasic positive airway pressure; PEEP = positive end-expiratory pressure; PSV = pressure support ventilation.
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Figure 4: Effect of different ventilator respiratory settings on the mean airway pressure time product below PEEP (PTPPEEP) during HF-BiPAP, BiVent, and PSV ventilation. Data were measured in normal (compliance 90 ml/cmH2O, resistance 3 cm H2O/l/s), restrictive (compliance 30 ml/cmH2O, resistance 3 cmH2O/l/s), and obstructive lung conditions (compliance 90 ml/cmH2O, resistance 15 cmH2O/l/s) at low (2.5 cmH2O) and high inspiratory efforts (10 cmH2O) at a respiratory rate of 15 and 30 breaths per minute. BiVent = time-cycled pressure controlled switching between two continuous positive airway pressure levels; HF-BiPAP = high flow biphasic positive airway pressure; PEEP = positive end-expiratory pressure; PSV = pressure support ventilation.

Mentions: The pressure drop below PEEP (PTPPEEP) during unassisted breathing or at the lower Δ pressure is depicted in Figure 4. PTPPEEP was influenced by the Δ pressure (P < 0.001), the respiratory rate (P < 0.001), and the lung setting (P < 0.001). Overall mean PTPPEEP during HF-BiPAP was 0 ± 0.1 cmH2O/sec, compared with -0.13 ± 0.17 cmH2O/sec, and 0.23 ± 0.16 cmH2O/sec during BiVent and PSV respectively (P < 0.001). Mean fraction of PTPPEEP on PTPinsp accounted for 1.1 ± 3.3% (median 0%, 0/0.14%) during HF-BiPAP, while it was 3.4 ± 5.8% (median 0%, 0/4.8%) and 13.3 ± 30.9% (median 5.2%, 2.9/8.3%) during BiVent and PSV, respectively. In particular, at low inspiratory efforts the high flow during HF-BiPulse almost completely compensated the pressure drop, except for the normal lung condition. Even at high asynchrony setting (i.e. HF-BiPAP and BiVent at 15 breaths per minute, lung model rate 30 breaths per minute) the percentage of PTPPEEP in PTPinsp was lower during HF-BiPAP (mean 12.2 ± 46.8%, median 0%, 0/5.9%) when compared with PSV at 30 breaths per minute (mean 21.3 ± 41.9%, median 5.4%, 3.4/19.8%), but increased during BiVent (mean 30.1 ± 92%, median 0%, 0/10%).


High flow biphasic positive airway pressure by helmet--effects on pressurization, tidal volume, carbon dioxide accumulation and noise exposure.

Moerer O, Herrmann P, Hinz J, Severgnini P, Calderini E, Quintel M, Pelosi P - Crit Care (2009)

Effect of different ventilator respiratory settings on the mean airway pressure time product below PEEP (PTPPEEP) during HF-BiPAP, BiVent, and PSV ventilation. Data were measured in normal (compliance 90 ml/cmH2O, resistance 3 cm H2O/l/s), restrictive (compliance 30 ml/cmH2O, resistance 3 cmH2O/l/s), and obstructive lung conditions (compliance 90 ml/cmH2O, resistance 15 cmH2O/l/s) at low (2.5 cmH2O) and high inspiratory efforts (10 cmH2O) at a respiratory rate of 15 and 30 breaths per minute. BiVent = time-cycled pressure controlled switching between two continuous positive airway pressure levels; HF-BiPAP = high flow biphasic positive airway pressure; PEEP = positive end-expiratory pressure; PSV = pressure support ventilation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2717454&req=5

Figure 4: Effect of different ventilator respiratory settings on the mean airway pressure time product below PEEP (PTPPEEP) during HF-BiPAP, BiVent, and PSV ventilation. Data were measured in normal (compliance 90 ml/cmH2O, resistance 3 cm H2O/l/s), restrictive (compliance 30 ml/cmH2O, resistance 3 cmH2O/l/s), and obstructive lung conditions (compliance 90 ml/cmH2O, resistance 15 cmH2O/l/s) at low (2.5 cmH2O) and high inspiratory efforts (10 cmH2O) at a respiratory rate of 15 and 30 breaths per minute. BiVent = time-cycled pressure controlled switching between two continuous positive airway pressure levels; HF-BiPAP = high flow biphasic positive airway pressure; PEEP = positive end-expiratory pressure; PSV = pressure support ventilation.
Mentions: The pressure drop below PEEP (PTPPEEP) during unassisted breathing or at the lower Δ pressure is depicted in Figure 4. PTPPEEP was influenced by the Δ pressure (P < 0.001), the respiratory rate (P < 0.001), and the lung setting (P < 0.001). Overall mean PTPPEEP during HF-BiPAP was 0 ± 0.1 cmH2O/sec, compared with -0.13 ± 0.17 cmH2O/sec, and 0.23 ± 0.16 cmH2O/sec during BiVent and PSV respectively (P < 0.001). Mean fraction of PTPPEEP on PTPinsp accounted for 1.1 ± 3.3% (median 0%, 0/0.14%) during HF-BiPAP, while it was 3.4 ± 5.8% (median 0%, 0/4.8%) and 13.3 ± 30.9% (median 5.2%, 2.9/8.3%) during BiVent and PSV, respectively. In particular, at low inspiratory efforts the high flow during HF-BiPulse almost completely compensated the pressure drop, except for the normal lung condition. Even at high asynchrony setting (i.e. HF-BiPAP and BiVent at 15 breaths per minute, lung model rate 30 breaths per minute) the percentage of PTPPEEP in PTPinsp was lower during HF-BiPAP (mean 12.2 ± 46.8%, median 0%, 0/5.9%) when compared with PSV at 30 breaths per minute (mean 21.3 ± 41.9%, median 5.4%, 3.4/19.8%), but increased during BiVent (mean 30.1 ± 92%, median 0%, 0/10%).

Bottom Line: Pressurization during inspiration was more effective with pressure controlled modes compared to PSV (P < 0.001) at similar tidal volumes.At high level of asynchrony both HF-BiPAP and BiVent were less effective.Only HF-BiPAP ventilation effectively removed CO2 (P < 0.001) during all settings.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Anaesthesiology, Emergency and Critical Care Medicine, University of Göttingen, 37075 Göttingen, Germany. omoerer@gwdg.de

ABSTRACT

Introduction: Non-invasive ventilation (NIV) with a helmet device is often associated with poor patient-ventilator synchrony and impaired carbon dioxide (CO2) removal, which might lead to failure. A possible solution is to use a high free flow system in combination with a time-cycled pressure valve placed into the expiratory circuit (HF-BiPAP). This system would be independent from triggering while providing a high flow to eliminate CO2.

Methods: Conventional pressure support ventilation (PSV) and time-cycled biphasic pressure controlled ventilation (BiVent) delivered by an Intensive Care Unit ventilator were compared to HF-BiPAP in an in vitro lung model study. Variables included delta pressures of 5 and 15 cmH2O, respiratory rates of 15 and 30 breaths/min, inspiratory efforts (respiratory drive) of 2.5 and 10 cmH2O) and different lung characteristics. Additionally, CO2 removal and noise exposure were measured.

Results: Pressurization during inspiration was more effective with pressure controlled modes compared to PSV (P < 0.001) at similar tidal volumes. During the expiratory phase, BiVent and HF-BiPAP led to an increase in pressure burden compared to PSV. This was especially true at higher upper pressures (P < 0.001). At high level of asynchrony both HF-BiPAP and BiVent were less effective. Only HF-BiPAP ventilation effectively removed CO2 (P < 0.001) during all settings. Noise exposure was higher during HF-BiPAP (P < 0.001).

Conclusions: This study demonstrates that in a lung model, the efficiency of NIV by helmet can be improved by using HF-BiPAP. However, it imposes a higher pressure during the expiratory phase. CO2 was almost completely removed with HF-BiPAP during all settings.

Show MeSH
Related in: MedlinePlus