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Intensive Care Med. 2008 Sep;34(9):1615-23. doi: 10.1007/s00134-008-1163-z. Epub 2008 May 30.

Subject-ventilator synchrony during neural versus pneumatically triggered non-invasive helmet ventilation.

Author information

1
Interdepartmental Division of Critical Care, St. Michael's Hospital, University of Toronto, Toronto, ON, Canada.

Abstract

OBJECTIVE:

Patient-ventilator synchrony during non-invasive pressure support ventilation with the helmet device is often compromised when conventional pneumatic triggering and cycling-off were used. A possible solution to this shortcoming is to replace the pneumatic triggering with neural triggering and cycling-off-using the diaphragm electrical activity (EA(di)). This signal is insensitive to leaks and to the compliance of the ventilator circuit.

DESIGN:

Randomized, single-blinded, experimental study.

SETTING:

University Hospital. PARTICIPANTS AND SUBJECTS: Seven healthy human volunteers.

INTERVENTIONS:

Pneumatic triggering and cycling-off were compared to neural triggering and cycling-off during NIV delivered with the helmet.

MEASUREMENTS AND RESULTS:

Triggering and cycling-off delays, wasted efforts, and breathing comfort were determined during restricted breathing efforts (<20% of voluntary maximum EA(di)) with various combinations of pressure support (PSV) (5, 10, 20 cm H(2)O) and respiratory rates (10, 20, 30 breath/min). During pneumatic triggering and cycling-off, the subject-ventilator synchrony was progressively more impaired with increasing respiratory rate and levels of PSV (p < 0.001). During neural triggering and cycling-off, effect of increasing respiratory rate and levels of PSV on subject-ventilator synchrony was minimal. Breathing comfort was higher during neural triggering than during pneumatic triggering (p < 0.001).

CONCLUSIONS:

The present study demonstrates in healthy subjects that subject-ventilator synchrony, trigger effort, and breathing comfort with a helmet interface are considerably less impaired during increasing levels of PSV and respiratory rates with neural triggering and cycling-off, compared to conventional pneumatic triggering and cycling-off.

PMID:
18512045
PMCID:
PMC2517084
DOI:
10.1007/s00134-008-1163-z
[Indexed for MEDLINE]
Free PMC Article

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