Design and simulation-based evaluation of a novel tracheostomy high-flow therapy device interface: a preclinical...

High-flow tracheal oxygen (HFTO) does not generate significant positive end-expiratory pressure (PEEP), which may limit its clinical applicability. We designed a novel high-flow tracheal interface (nHFTI) and compared the PEEP and other respiratory parameters it generated with those of the traditional high-flow tracheal interface (tHFTI) across a range of flow rates.

We conducted a randomized crossover bench study. A size 8 cuffed tracheostomy tube was connected to the high-flow therapy (HFT) device using two different interfaces. A high-fidelity lung simulator was used to model normal lung mechanics. Gas flow rates were set from 10 to 80 L/min at a gradient of 10 L/min, and the sequence was randomized. At each flow setting, the following parameters were recorded: PEEP, peak inspiratory pressure (PIP), peak expiratory pressure (PEP), end-inspiratory transpulmonary pressure (Ptp-EI), end-expiratory transpulmonary pressure (Ptp-EE), end-inspiratory cardiac pressure (PEIC) and end-expiratory cardiac pressure (PEEC), functional residual capacity (FRC), tidal volume (Vt) and fraction of inspired oxygen (FiO₂).

As the HFT flow rate increased, PEEP increased significantly with both the tHFTI and nHFTI (P < 0.001). Compared with the tHFTI, the nHFTI generated significantly higher PEEP across most flow rates (e.g., 3.4 vs. 1.0 cmH₂O at 40 L/min; 7.3 vs. 3.1 cmH₂O at 60 L/min, nHFTI vs. tHFTI, mean values). The nHFTI also generated higher PIP, PEP, Ptp-EI, Ptp-EE, PEIC, and PEEC, and resulted in a greater increase in FRC (P < 0.010). Compared with the tHFTI, the nHFTI maintained a relatively constant FiO₂ and slightly reduced Vt at the same flow rate level.

The nHFTI generated a modest level of PEEP, increased FRC and slightly reduced Vt at flow rates of 40-60 L/min. This physiological profile suggests potential for maintaining lung expansion and improving cardiac function in heart failure. Further in vivo studies are needed to evaluate the clinical impact of nHFTI-mediated PEEP augmentation and determine whether it can lead to improved clinical outcomes, particularly in patients requiring prolonged mechanical ventilation during the weaning process.