RT Journal Article
SR Electronic
T1 A Bench Study of 2 Ventilator Circuits During Helmet Noninvasive Ventilation
JF Respiratory Care
FD American Association for Respiratory Care
SP 1474
OP 1481
DO 10.4187/respcare.02060
VO 58
IS 9
A1 Giuliano Ferrone
A1 Flora Cipriani
A1 Giorgia Spinazzola
A1 Olimpia Festa
A1 Andrea Arcangeli
A1 Rodolfo Proietti
A1 Massimo Antonelli
A1 Giorgio Conti
A1 Roberta Costa
YR 2013
UL http://rc.rcjournal.com/content/58/9/1474.abstract
AB OBJECTIVE: To compare helmet noninvasive ventilation (NIV), in terms of patient-ventilator interaction and performance, using 2 different circuits for connection: a double tube circuit (with one inspiratory and one expiratory line) and a standard circuit (a Y-piece connected only to one side of the helmet, closing the other side). METHODS: A manikin, connected to a test lung set at 2 breathing frequencies (20 and 30 breaths/min), was ventilated in pressure support ventilation (PSV) mode with 2 different settings, randomly applied, of the ratio of pressurization time to expiratory trigger time (Tpress/Texp-trigger) 50%/25%, default setting, and Tpress/Texp-trigger 80%/60%, fast setting, through a helmet. The helmet was connected to the ventilator randomly with the double and the standard circuit. We measured inspiratory trigger delay (Tinsp-delay), expiratory trigger delay (Texp-delay), Tpress), time of synchrony (Tsynch), trigger pressure drop, inspiratory pressure-time product (PTP), PTP at 300 ms and 500 ms, and PTP at 500 ms expressed as percentage of an ideal PTP500 (PTP500 index). RESULTS: At both breathing frequencies and ventilator settings, helmet NIV with the double tube circuit showed better patient-ventilator interaction, with shorter Tinsp-delay, Texp-delay, and Tpress; longer Tsynch; and higher PTP300, PTP500, and PTP500 index (all P < .01). CONCLUSIONS: The double tube circuit had significantly better patient-ventilator interaction and a lower rate of wasted effort at 30 breaths/min.