%0 Journal Article
%T Bench experiments comparing simulated inspiratory effort when breathing helium-oxygen mixtures to that during positive pressure support with air
%A Andrew R Martin
%A Ira M Katz
%A Katharina Jen£¿fi
%A Georges Caillibotte
%A Laurent Brochard
%A Jo£¿lle Texereau
%J BMC Pulmonary Medicine
%D 2012
%I BioMed Central
%R 10.1186/1471-2466-12-62
%X Patient breathing was simulated using a dual-chamber mechanical test lung, with the breathing compartment connected to an ICU ventilator operated in NIV mode with medical air or He/O2 (78/22 or 65/35%). Parabolic or linear resistances were inserted at the inlet to the breathing chamber. Breathing chamber compliance was also varied. The inspiratory effort was assessed for the different gas mixtures, for three breathing patterns, with zero pressure support (simulating unassisted spontaneous breathing), and with varying levels of pressure support.Inspiratory effort increased with increasing resistance and decreasing compliance. At a fixed resistance and compliance, inspiratory effort increased with increasing minute ventilation, and decreased with increasing pressure support. For parabolic resistors, inspiratory effort was lower for He/O2 mixtures than for air, whereas little difference was measured for nominally linear resistance. Relatively small differences in inspiratory effort were measured between the two He/O2 mixtures. Used in combination, reductions in inspiratory effort provided by He/O2 and pressure support were additive.The reduction in inspiratory effort afforded by breathing He/O2 is strongly dependent on the severity and type of airway obstruction. Varying helium concentration between 78% and 65% has small impact on inspiratory effort, while combining He/O2 with pressure support provides an additive reduction in inspiratory effort. In addition, breathing He/O2 alone may provide an alternative to pressure support in circumstances where NIV is not available or poorly tolerated.The effects of inhaling helium-oxygen mixtures (He/O2) during spontaneous breathing continue to be explored for the treatment of obstructive lung diseases, both during acute exacerbations of disease [1-7] and during the exercise component of rehabilitation programs [8-11]. When breathing He/O2, the low density of the mixture compared to air reduces airway resistance, specifically, de
%K Helium
%K Oxygen
%K Heliox
%K Inspiratory effort
%K Work of breathing
%K Airway resistance
%K Lung compliance
%K Non-invasive ventilation
%K Pressure support
%U http://www.biomedcentral.com/1471-2466/12/62