Abstract
Background At high ambient temperatures in ICU rooms, the humidification performances of heated wire humidifiers (HH) are significantly reduced, with delivered gas humidity well below 30 mgH2O/L leading to an increased risk of endo-tracheal occlusions, sub-occlusions or mucociliary dysfunction.
The objective of the study was to evaluate the humidity delivered at the Y-piece with new generation HH with advanced algorithm (FP950 and VHB20) while varying ambient temperatures.
Methods We measured on bench the hygrometry of inspiratory gases delivered by new generation of HH (i) FP950 (Fisher&Paykel Healthcare) (ii) VHB20 (Vincent Medical) and previous generation of HH (iii) MR850 with usual settings (37 at the chamber/40 at the Y piece) (iv) MR 850 with no temperature gradient (40/40), and (v) MR850 with automatic compensation algorithm activated. Hygrometry was measured with the psychrometric method after one hour of stability while varying the room temperature from 20 to 30°C.
Results Two hundred and ninety-four hygrometric bench measurements were performed at steady state for the different tested conditions. With the new HH (FP950 and VHB20), gas humidity delivered remained above 30 mgH2O/L in all tested conditions, even at high ambient temperatures (> 25°C). With previous generation of HH (MR850), at high ambient temperature, humidity delivered was adequate in only 26% (11/42) of the measurements when usual settings were used (37/40) and 30% (11/37) with automatic compensation. When no temperature gradient was set (40/40), humidity delivered was above 30 mgH2O/L in 91% (30/33) of the measurements at high ambient temperature. With ambient temperature below 25°C, almost all devices and settings provided adequate humidity.
Conclusion The new FP950 and VHB20 heated wire heated humidifiers using advanced algorithms have demonstrated stable performance while varying the ambient temperature by 20–30°C, better than the previous generation of heated humidifiers when ambient temperatures were high.
Footnotes
- Corresponding author:
François Lellouche, Laboratoire H2O-O2-CO2, Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec. 2725, Chemin Sainte-Foy. G1V4G5, Québec, QC, CANADA. E-mail: francois.lellouche{at}criucpq.ulaval.ca Tel: +1 418 656 8711 Ext 3298
- Received July 6, 2023.
- Accepted September 18, 2023.
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