Parametric study of catheters for endotracheal aspiration

Endotracheal aspiration is a routine procedure for managing secretions in mechanically ventilated patients and other cases of secretion accumulation. However, this procedure can lead to hypoxemia and tracheobronchial mucosal injury, and patients describe it as painful and uncomfortable. An adequate design of the suction catheter can help to avoid the injuries, decrease the risk of hypoxemia and patient’s discomfort, and increase the efficiency of the procedure. The objective of this study is to evaluate the influence of the suction catheter design on suctioning efficiency of mucus with different properties, at different pressures, using computational fluid dynamics. Three concentrations of polyethylene glycol solution with molecular weight of 5,000,000 g/mol were prepared to simulate the airway mucus. Three parameters of catheter design related to the local pressure drop were defined for the analysis: mucus input area, distance between the lateral holes, and number of lateral holes. The influence of suction catheter length on the total pressure drop was also analyzed. The results of the study show that with the increase in the input area, the pressure drop decreases for all fluids and pressures. The suction catheter with aligned holes produced the largest pressure drop. As expected, catheter length had a critical influence on the pressure drop for all fluids and operational pressures, and therefore, it is advisable to use the shortest catheter possible.