Biomechanical aspects of compliant airways due to mechanical ventilation.

Without proper knowledge of mechanical ventilation effects, physicians can aggravate an existing lung injury. A better understanding of the interaction between airflow and airway tissue during mechanical ventilation will be helpful to physicians so that they can provide appropriate ventilator parameters for intubated patients. In this study, a computational model incorporating the interactions between airflow and airway walls was developed to investigate the effects of airway tissue flexibility on airway pressure and stress. Two flow rates, 30 and 60 1/min, from mechanical ventilation were considered. The transient waveform was active inhalation with a constant flow rate and passive exhalation. Results showed that airway tissue flexibility decreased airway pressure at bifurcation sites by approximately 25.06% and 16.91% for 30 and 60 1/min, respectively, and increased wall shear stress (WSS) by approximately 74.00% and 174.91% for 30 and 60 1/min, respectively. The results from the present study suggested that it is very important to consider the interaction between airflow and airway walls when computational models are developed. Results of this study help to better quantify how the airflow rate used in mechanical ventilation, in conjunction with airway tissue flexibility, affects airway pressure and stresses.