PT  - JOURNAL ARTICLE
AU  - Giuliano Ferrone
AU  - Flora Cipriani
AU  - Giorgia Spinazzola
AU  - Olimpia Festa
AU  - Andrea Arcangeli
AU  - Rodolfo Proietti
AU  - Massimo Antonelli
AU  - Giorgio Conti
AU  - Roberta Costa
TI  - Comparative evaluation of two ventilator circuits during noninvasive ventilation (NIV) with Helmet: a bench study
AID  - 10.4187/respcare.02060
DP  - 2013 Feb 19
TA  - Respiratory Care
PG  - respcare.02060
4099  - http://rc.rcjournal.com/content/early/2013/02/19/respcare.02060.short
4100  - http://rc.rcjournal.com/content/early/2013/02/19/respcare.02060.full
AB  - Purpose The aim of this study was to compare helmet-NIV (non invasive ventilation), in terms of patientventilator interaction and performance, using two different circuits for connection: a double tube circuit (with one inspiratory and one expiratory line) and a standard circuit (an Y piece connected only to one side of the helmet, closing the other side). Methods A mannequin, connected to a test lung, set at two different respiratory rates (20 and 30 breaths/min), was ventilated in Pressure Support Ventilation (PSV) mode with two different settings, randomly applied: Pressurization time/Expiratory trigger (Timepress/Trexp) 50%/25%, Default setting and Timepress/Trexp 80%/60%, Fast setting, through a helmet. The helmet was connected to the ventilator randomly with the double and the standard circuit. Patient-ventilator interaction was evaluated measuring: Inspiratory trigger delay (Delaytrinsp), Expiratory trigger delay (Delaytrexp), Pressurization Time (Timepress), Time of synchrony (Timesyn). The performance was analyzed measuring: Trigger pressure drop, Inspiratory Pressure-Time Product (PTPt), Pressure Time Product at 300 ms and 500 ms (PTP 300 and PTP 500 respectively) and Pressure Time Product 500 ms expressed as percentage of an ideal PTP500 (PTP500 index). Results At both respiratory rates and ventilator settings helmet-NIV with the double tube circuit showed better interaction, with shorter Delaytrinsp, Delaytrexp and Timepress and longer Timesyn (p<0.01) compared to the standard circuit (p<0.01). Moreover, the helmet performance was significantly improved by the double tube circuit as shown by higher PTP 300, PTP500 and PTP 500 index (p<0.01). Conclusions Compared to the standard circuit, helmet-NIV with the double tube circuit showed a significantly better patient-ventilator interaction associated with a significantly better performance and a lower rate of wasted effort at30 breaths/min .