Measurement of Entrainment Ratio During High Frequency Jet Ventilation

Jones, Michael; Mottram, S.D.; Lin, E.S.; Smith, G.

doi:10.1093/bja/65.2.197

Cited by 13 publications

(9 citation statements)

References 9 publications

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“…When the duty cycle was doubled from 20 to 40%, gas exchange improved. The same trend in results, which have already been described (8), was seen after reduction of thorax-and lung compliance. .…”

Section: Resultssupporting

confidence: 85%

“…As soon as PAW was higher than 0. 8 and expiratory flow reached a highcr level and ncrdrd less time to reach the zero line. Fig.…”

Section: Resultsmentioning

confidence: 88%

“…Several rectmt reports indicate that HFJV may fail to deliver adequate gas exchange in pathological conditions (3ti). It has been suggested that factors implicated in this failure are increased airway resistance and reduced conipliance (7,8). We were especially interested in the last factor and are not aware of authors presenting reltwant quantitative data.…”

mentioning

confidence: 99%

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Gas flow distribution in distal high frequency jet ventilation and lung thorax compliance

Spoelstra

Tamsma²

1991

Acta Anaesthesiol Scand

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To investigate the influence of changes in thorax and lung compliance on ventilation during distal High Frequency Jet Ventilation (HFJV), similar ventilator settings were compared before and after changing the compliance in two groups of anaesthetized mongrel dogs. Each period of distal HFJV was preceded by adequate Intermittent Positive Pressure Ventilation (IPPV) to assure a start with baseline values. In Group 1 (n = 7), thorax compliance was changed by chest strapping, while in Group 2 (n = 7) lung compliance was changed by inducing acute lung injury by injection of oleic acid into the right atrium. Gas flow distribution in the ventilatory circuit during distal HFJV was determined before and after the changes in compliance were induced. Comparing similar ventilator settings during distal HFJV in the same dog, a decrease in lung or thorax compliance led to changes in gas flow distribution in the ventilatory circuit. Entrainment was decreased and bypass increased with a negative effect on the gas volume entering the lungs and on gas exchange. The results indicate that distal HFJV should be regarded as pressure-limited ventilation.

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Section: Resultssupporting

confidence: 85%

“…As soon as PAW was higher than 0. 8 and expiratory flow reached a highcr level and ncrdrd less time to reach the zero line. Fig.…”

Section: Resultsmentioning

confidence: 88%

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Gas flow distribution in distal high frequency jet ventilation and lung thorax compliance

Spoelstra

Tamsma²

1991

Acta Anaesthesiol Scand

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“…Je nach Katheter-oder Düsenkonfiguration wird Umgebungsluft mitgerissen (Venturi-Effekt oder ᭤ "air entrainment"), so daß eine Vergrößerung des vom Ventilator abgegebenen Beatmungsvolumens resultiert [18]. Die Größenordnung des Entrainments (V e ) ist im Verlauf eines Eingriffs großen Schwankungen unterworfen, da es von einer Vielzahl wechselnder Faktoren abhängt.…”

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Jetventilation und Anästhesie für diagnostische und therapeutische Eingriffe an den Atemwegen

Bíró

Wiedemann²

1999

Anaesthesist

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Jetventilation und Anästhesie für diagnostische und therapeutische Eingriffe an den Atemwegen Unter dem Oberbegriff Hoch-Frequenz Ventilation (HFV) findet sich eine heterogene Gruppe von Beatmungstechniken, denen allen eine mindestens 4mal höhere Beatmungsfrequenz gemeinsam ist, als sie bei normaler Spontanatmung vorliegt. Sie unterscheiden sich unter anderem durch den Frequenzbereich, welchen sie innerhalb des Spektrums von 60-2400 Impulsen pro Minute abdecken:"High Frequency Positive Pressure Ventilation" (HFPPV), "High Frequency Jet Ventilation" (HFJV),"High Frequency Pulsation" (HFP),"High Frequency Jet Oscillation" (HFJO), "Forced Diffusion Ventilation" (FDO) und "High Frequency Oscillation" (HFO) [2]. Der zweite Teil des Namens bezieht sich auf die stoßweise Applikation von Beatmungsgas unter hohem Druck durch dünne und ungeblockte Leitungen in die nach außen offenen Atemwege. Da relativ große Gasvolumina durch englumige Leitungen und Düsen hindurchfließen, werden die Gaspartikel auf sehr hohe Geschwindigkeiten beschleunigt. Dadurch entstehen die charakteristischen Strömungsgeräusche, welche die Einführung des ᭤ "Jet"-Begriffs begründeten. Im Zusammenhang mit der Beatmungsfrequenz hat es sich eingebürgert, bei <1 Hertz (Hz) von nieder-oder ᭤ normofrequenter Jetventilation (NFJV) und bei 1-10 Hz von ᭤ Hochfrequenz-Jetventilation (HFJV) zu sprechen. In der klinischen Praxis wird zumeist die HFJV verwendet, während die NFJV mit handgetriggerten Sauerstoffinjektoren für kurze Perioden im Rahmen der Notfalloxygenierung zum Einsatz gelangt. Eine Sonderform ist die Superponierte Hochfrequenz Jetventilation (SHFJV), bei welcher gleichzeitig je eine nieder-und hochfrequente Gasapplikation vorgenommen wird [17]. Mechanismen des GastransportsDie HFJV beruht auf der hochfrequenten Applikation kleiner Gasvolumina unter hohem Druck über englumige Kanülen. Die Gasportionen dürfen, im Gegensatz zur konventionellen Beatmung, nicht über ein abgeschlossenes System appliziert, sondern lediglich in die nach außen offenen Atemwege gerichtet werden. Das passiv exhalierte Gasvolumen muß möglichst ungehindert nach außen abfließen können. Um den inspiratorischen Widerstand der englumigen Jetkatheter oder Düsen Weiterbildung Jetventilation Anaesthesist 1999 · 48: 669-685 © Springer-Verlag 1999 Jet ventilation and anaesthesia for diagnostic and therapeutic interventions of the airway Die Beiträge der Rubrik "Weiterbildung" sollen dem Stand des zur Facharztprüfung für den Anästhesisten notwendigen Wissens entsprechen und zugleich dem Facharzt als Repetitorium dienen.Die Rubrik beschränkt sich auf gesicherte Aussagen zum Thema.

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“…Jones et al . measured the entrainment ratio during jet ventilation of anaesthetized patients using the Penlon Bromsgrave jet ventilator 17 . The highest entrainment ratio observed was 20% at a low inspiratory time–total time ratio (I : T) and this decreased to a negligible value as I : T and frequency increased.…”

Section: Discussionmentioning

confidence: 99%

The feasibility of nitric oxide delivery with high frequency jet ventilation

et al. 2005

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A 27-year-old female with acute monocytic leukaemia (M5) developed acute respiratory distress syndrome (ARDS). Because of refractory hypoxaemia and severe barotrauma during conventional mechanical ventilation, the patient was switched to high frequency jet ventilation (HFJV) as a salvage therapy. Her refractory hypoxaemia improved temporarily but worsened again. Approval of the Institutional Review Board and the Food and Drug Administration was obtained to use nitric oxide (NO) with HFJV on a compassionate basis considering the grave situation. The NO delivery system was connected to the secondary flow circuit of the HFJV immediately after the humidifier. We measured the concentration of NO at least every hour by inserting a 7-Fr catheter connected to a McNeill analyzer into the endotracheal tube. Despite improvement of oxygenation, the patient's respiratory status deteriorated further and she died. In this case we were able to achieve reliable and constant levels of NO. The purpose of this report is to discuss the technical aspects and pitfalls of this method.

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Measurement of Entrainment Ratio During High Frequency Jet Ventilation

Cited by 13 publications

References 9 publications

Gas flow distribution in distal high frequency jet ventilation and lung thorax compliance

Gas flow distribution in distal high frequency jet ventilation and lung thorax compliance

Jetventilation und Anästhesie für diagnostische und therapeutische Eingriffe an den Atemwegen

The feasibility of nitric oxide delivery with high frequency jet ventilation

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