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


METHODS
Randomized, single-blinded, experimental study.


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


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


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.
Interdepartmental Division of Critical Care, St. Michael's Hospital, University of Toronto, Toronto, ON, Canada.
Onnen
O
Moerer
Jennifer
J
Beck
Lukas
L
Brander
Roberta
R
Costa
Michael
M
Quintel
Arthur S
AS
Slutsky
Fabrice
F
Brunet
Christer
C
Sinderby
D000328:Adult; D004867:Equipment Design; D005260:Female; D006260:Head Protective Devices; D006801:Humans; D008297:Male; D017060:Patient Satisfaction; D011175:Positive-Pressure Respiration / Q000295:instrumentation* / Q000379:methods; D012119:Respiration; D016037:Single-Blind Method