Limits...
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.

Show MeSH

Related in: MedlinePlus

Original tracing of helmet and airway (lung) flow and pressure during HF-BiPAP, BIVENT, and PSV. Compliance was 90 ml/cm H2O, resistance was 3 cm H2O/l/s, at high inspiratory effort, respiratory rate was 30 breaths per minute and delta pressure was 15 cmH2O. Note: During HF-BiPAP inspiratory flow to the helmet was constantly high at about 60 l/minute. Expiratory flow did not become zero due to the high constant free flow. BiVent = time-cycled pressure controlled switching between two continuous positive airway pressure levels; HF-BiPAP = high flow biphasic positive airway pressure; PSV = pressure support ventilation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2717454&req=5

Figure 3: Original tracing of helmet and airway (lung) flow and pressure during HF-BiPAP, BIVENT, and PSV. Compliance was 90 ml/cm H2O, resistance was 3 cm H2O/l/s, at high inspiratory effort, respiratory rate was 30 breaths per minute and delta pressure was 15 cmH2O. Note: During HF-BiPAP inspiratory flow to the helmet was constantly high at about 60 l/minute. Expiratory flow did not become zero due to the high constant free flow. BiVent = time-cycled pressure controlled switching between two continuous positive airway pressure levels; HF-BiPAP = high flow biphasic positive airway pressure; PSV = pressure support ventilation.

Mentions: Figure 3 shows an original tracing of flow and pressure during HF-BIPAP, BIVENT, and PSV at the helmet and airway level. Pressurization differed due to fixed inspiratory timing. During HF-BiPAP, there was a constant free inspiratory flow between 60 and 70 L/minute. Overall, the mean lower pressures (PEEP/P1) were 8.3 ± 0.4 cmH2O (PSV), 8.3 ± 0.6 cmH2O (BiVent), and 8.4 ± 0.7 cmH2O (HF-BiPAP; P = 0.26). There was no significant difference between the tested modes regarding the mean Δ pressure at low (PSV: 5.3 ± 0.4 cmH2O, BiVent: 5.4 ± 0.6 cmH2O, HF-BiPAP: 5.3 ± 0.9 cmH2O; P = 0.119) and high upper pressure (PSV: 15.2 ± 0.7 cmH2O, BiVent: 15 ± 1 cmH2O, HF-BiPAP; 15.1 ± 2.4 cmH2O; P = 0.308).


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)

Original tracing of helmet and airway (lung) flow and pressure during HF-BiPAP, BIVENT, and PSV. Compliance was 90 ml/cm H2O, resistance was 3 cm H2O/l/s, at high inspiratory effort, respiratory rate was 30 breaths per minute and delta pressure was 15 cmH2O. Note: During HF-BiPAP inspiratory flow to the helmet was constantly high at about 60 l/minute. Expiratory flow did not become zero due to the high constant free flow. BiVent = time-cycled pressure controlled switching between two continuous positive airway pressure levels; HF-BiPAP = high flow biphasic positive airway pressure; PSV = pressure support ventilation.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Original tracing of helmet and airway (lung) flow and pressure during HF-BiPAP, BIVENT, and PSV. Compliance was 90 ml/cm H2O, resistance was 3 cm H2O/l/s, at high inspiratory effort, respiratory rate was 30 breaths per minute and delta pressure was 15 cmH2O. Note: During HF-BiPAP inspiratory flow to the helmet was constantly high at about 60 l/minute. Expiratory flow did not become zero due to the high constant free flow. BiVent = time-cycled pressure controlled switching between two continuous positive airway pressure levels; HF-BiPAP = high flow biphasic positive airway pressure; PSV = pressure support ventilation.
Mentions: Figure 3 shows an original tracing of flow and pressure during HF-BIPAP, BIVENT, and PSV at the helmet and airway level. Pressurization differed due to fixed inspiratory timing. During HF-BiPAP, there was a constant free inspiratory flow between 60 and 70 L/minute. Overall, the mean lower pressures (PEEP/P1) were 8.3 ± 0.4 cmH2O (PSV), 8.3 ± 0.6 cmH2O (BiVent), and 8.4 ± 0.7 cmH2O (HF-BiPAP; P = 0.26). There was no significant difference between the tested modes regarding the mean Δ pressure at low (PSV: 5.3 ± 0.4 cmH2O, BiVent: 5.4 ± 0.6 cmH2O, HF-BiPAP: 5.3 ± 0.9 cmH2O; P = 0.119) and high upper pressure (PSV: 15.2 ± 0.7 cmH2O, BiVent: 15 ± 1 cmH2O, HF-BiPAP; 15.1 ± 2.4 cmH2O; P = 0.308).

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