Efectos de la termohumidificación sobre la interacción mecánica interfase–superficie facial durante ventilación mecánica no invasiva: un estudio experimental en modelo bench

Abstract

Background

Noninvasive ventilation (NIV) performance depends on effective mechanical coupling between the interface and the facial surface. However, the effects of thermohumidification on this interaction and its relationship with facial pressure redistribution, system leak, and ventilatory variables remain poorly characterized.

Objective

To evaluate the effect of thermohumidification on interface–facial surface mechanical interaction and its relationship with facial pressure redistribution, system leak, and ventilatory variables.

Methods

This controlled experimental bench study included 14 independent runs (7 per condition) comparing NIV with and without thermohumidification (35 °C). Experiments were performed under controlled environmental conditions (20 °C, 50% relative humidity, phantom surface temperature 36 °C). Interface–facial surface temperature (IFST), the Pressure Redistribution Index (PRI), system leak, and ventilatory variables were assessed. Group, time, and interaction effects were analyzed using linear mixed-effects models.

Results

Thermohumidification increased IFST by 4–5 °C (p < 0.001), progressively increased PRI (group × time interaction, p < 0.01), and reduced system leak by 11.5–12.4 l/min. During the final phase of the protocol (45–60 min), tidal volume increased by 58–61 ml and peak inspiratory flow by 5.9–6.3 l/min. Post-baseline changes in IFST correlated positively with changes in PRI (ρ=0.81, p < 0.001), whereas changes in PRI correlated inversely with system leak (ρ= − 0.74, p = 0.002).

Conclusions

Thermohumidification was associated with facial pressure redistribution, reduced system leak, and changes in ventilatory variables. These findings are consistent with the hypothesis that thermohumidification may influence the mechanical interaction between the interface and the facial surface. However, the underlying mechanisms were not directly evaluated and require confirmation in dedicated experimental and clinical studies.