title: 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.
authors.affiliation: University of Porto, Faculty of Engineering, Porto, Portugal. Faculdade de Engenharia da Universidade do Porto - FEUP, University of Porto Faculty of Engineering - Porto, Portugal.
authors.forename: Luana Souto
authors.initials: LS
authors.lastname: Barros
authors.affiliation: University of Porto, Faculty of Engineering, Porto, Portugal. Faculdade de Engenharia da Universidade do Porto - FEUP, University of Porto Faculty of Engineering - Porto, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Talaia
authors.affiliation: University of Porto, Faculty of Medicine, Porto, Portugal. Faculdade de Medicina da Universidade do Porto - FEUP, University of Porto Faculty of Medicine - São João Hospital, Porto, Portugal.
authors.forename: Marta
authors.initials: M
authors.lastname: Drummond
authors.affiliation: University of Porto, Faculty of Engineering, Porto, Portugal. Mechanical Engineering Institute, University of Porto Faculty of Engineering, Porto, Portugal.
authors.forename: Renato
authors.initials: R
authors.lastname: Natal-Jorge
mesh_terms: D000208:Acute Disease; D003198:Computer Simulation; D004867:Equipment Design; D005145:Face / Q000033:anatomy & histology*; D005151:Facial Injuries / Q000517:prevention & control; D006801:Humans; D008397:Masks; D063087:Noninvasive Ventilation / Q000295:instrumentation* / Q000379:methods; D011175:Positive-Pressure Respiration / Q000295:instrumentation / Q000379:methods; D012131:Respiratory Insufficiency / Q000628:therapy*
keywords: Computer simulation; Noninvasive ventilation; Respiration, artificial