Performance of a new oxygen delivery device for potentially infectious critically ill patients

In patients with highly contagious diseases that are spread by respiratory droplets or air-borne particles, the use of high-flow oxygen may carry a significant risk of nosocomial transmission. We tested a new oxygen delivery device designed to address these problems by simulating 108 patients with sepsis and respiratory failure. The device being tested consisted of an airtight mask, a bacterial and viral filter, a T-shaped reservoir (50 and 100 ml) and oxygen delivery tubing connected directly to the mask. When tested with a 50-ml reservoir, a high fractional oxygen concentration was achieved: mean (SD) 0.83 (0.11) at a flow of 15 l.min(-1) oxygen. The 50-ml reservoir, when compared with the 100-ml reservoir, was associated with reduced carbon dioxide rebreathing (mean (SD) inspired fractional carbon dioxide concentration 2.5 (1.0) vs 3.0 (1.1), respectively, p = 0.009) and reduced inspiratory resistive work of breathing (mean (SD) 1.0 (0.6) J.l(-1) vs 1.2 (0.5) J.l(-1), respectively, p = 0.028). However, rebreathing and work of breathing were relatively high if a high respiratory rate was simulated. We conclude that the novel oxygen device we describe, equipped with the 50-ml T-shaped reservoir, is suitable for potentially infectious patients with type-1 respiratory failure but without marked tachypnoea.