Facial pressure zones of an oronasal interface for noninvasive ventilation: a computer model analysis

Abstract

OBJECTIVE: To study the effects of an oronasal interface (OI) for noninvasive ventilation, using a three-dimensional (3D) computational model with the ability to simulate and evaluate the main pressure zones (PZs) of the OI on the human face. METHODS: We used a 3D digital model of the human face, based on a pre-established geometric model. The model simulated soft tissues, skull, and nasal cartilage. The geometric model was obtained by 3D laser scanning and post-processed for use in the model created, with the objective of separating the cushion from the frame. A computer simulation was performed to determine the pressure required in order to create the facial PZs. We obtained descriptive graphical images of the PZs and their intensity. RESULTS: For the graphical analyses of each face-OI model pair and their respective evaluations, we ran 21 simulations. The computer model identified several high-impact PZs in the nasal bridge and paranasal regions. The variation in soft tissue depth had a direct impact on the amount of pressure applied (438-724 cmH2O). CONCLUSIONS: The computer simulation results indicate that, in patients submitted to noninvasive ventilation with an OI, the probability of skin lesion is higher in the nasal bridge and paranasal regions. This methodology could increase the applicability of biomechanical research on noninvasive ventilation interfaces, providing the information needed in order to choose the interface that best minimizes the risk of skin lesion.

Randomized crossover trial of a pressure sensing visual feedback system to improve mask fitting in noninvasive ventilation

“…The pressures are slightly higher than the controversial values from the 1930s that are often quoted as tissue damaging, but they are in line with values measured in vivo by other groups or with other masks. [30][31][32][33] With the help of the real-time visual feedback, the participants were able to reduce the pressure exerted on the nasal bridge on average by 11% below the level of the standard mask fitting and achieved a better seal with less or similar air leak at the same time.…”

Associated factors of facial pressure ulcers in patients under non-invasive ventilation during hospital stay in an intermediate care facilities of a Portuguese hospital

“…The findings show that all PU developed in the nasal pyramid. In other studies, such as the one of Gregoretti et al (18) and Black et al (19), these wounds usually occur in the nasal pyramid, since there is less subcutaneous tissue in this area. Also, Barros, Talaia, Drummond, and Natal-Jorge (20) reported that the proportion of PU occurrence was higher in the nasal pyramid, and the variation of soft tissue depth had a direct influence on the amount of pressure applied.…”

“…Other studies attest to this result since in the study by Yamaguti et al (30) the mean number of NIV applications maintained for more than two hours was higher in individuals with facial lesions (mean: 7.1 SD: 13.3) that in individuals without facial lesion (mean: 4.4 SD: 7.5, p = 0.03), Carron et al 7also presented an incidence of facial lesion, after 2h of NIV, from 5 to 50 %, increasing dramatically after significant days of NIV. Furthermore, Gregoretti et al (18) demonstrated that the development of PU increased by 20% between 24h and 48h, suggesting that a period of NIV greater than 24h is associated with a higher risk of PU.…”

Year in Review 2014: Patient Safety

“…The objective of Barros et al 11 was to study the effects of an oronasal interface using a 3-dimensional computational model with the ability to simulate and evaluate the main pressure zones of the interface on the face. The model simulated soft tissues, skull, and nasal cartilage.…”