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

BACKGROUND

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.

METHODS

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).

RESULTS

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.

CONCLUSIONS

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.