Objective: To assess the behavior of different helmets after discontinuation of fresh gas flow by disconnection at the helmet inlet, flow generator, or gas source. Design and setting: Randomized physiological study in a university research laboratory. Patients: Five healthy volunteers. Intervention: CPAP (FIO<sub>2</sub> 50%, PEEP 5 cmH<sub>2</sub>O) delivered in random sequence with three different helmets: 4Vent (Rüsch), PN500 (Harol), CaStar (StarMed) with antisuffocation valve open or locked. For each helmet all three disconnections were randomly employed up to 4 min. Measurements and results: During flow disconnection we measured: respiratory rate and tidal volume by respitrace; inspiratory and expiratory CO<sub>2</sub> concentration, and FIO<sub>2</sub> from a nostril; SpO<sub>2</sub> by pulse oxymetry. Independently of the site of disconnection we observed a fast increase in CO<sub>2</sub> rebreathing and minute ventilation, associated with a decrease in inspired O<sub>2</sub> concentration. In the absence of an operational safety valve, larger helmet size and lower resistance of the inlet hose resulted in slower increase in CO<sub>2</sub> rebreathing. The presence of the safety valve limited the rebreathing of CO<sub>2</sub>, and the increase in minute ventilation but did not protect from a decrease in FIO<sub>2</sub> and loss of PEEP. Conclusions: While the use of a safety valve proved effective in limiting CO<sub>2</sub> rebreathing, it did not protect from the risk of hypoxia related to decrease in FIO<sub>2</sub> and loss of PEEP. In addition to a safety antisuffocation valve, a dedicated monitoring and alarming systems are needed to employ helmet CPAP safely. © 2006 Springer-Verlag.
Patroniti, N., Saini, M., Zanella, A., Isgrò, S., & Pesenti, A. (2006). Danger of helmet continuous positive airway pressure during failure of fresh gas source supply. INTENSIVE CARE MEDICINE, 33(1), 153-157.
Citazione: | Patroniti, N., Saini, M., Zanella, A., Isgrò, S., & Pesenti, A. (2006). Danger of helmet continuous positive airway pressure during failure of fresh gas source supply. INTENSIVE CARE MEDICINE, 33(1), 153-157. |
Tipo: | Articolo in rivista - Articolo scientifico |
Carattere della pubblicazione: | Scientifica |
Titolo: | Danger of helmet continuous positive airway pressure during failure of fresh gas source supply |
Autori: | Patroniti, N; Saini, M; Zanella, A; Isgrò, S; Pesenti, A |
Autori: | |
Data di pubblicazione: | gen-2006 |
Lingua: | English |
Rivista: | INTENSIVE CARE MEDICINE |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1007/s00134-006-0446-5 |
Appare nelle tipologie: | 01 - Articolo su rivista |