Abstract:
Decongestion reduces blood flow in the nasal turbinates, enlarging the airway lumen. Although the enlarged airspace reduces the trans-nasal inspiratory pressure drop, symptoms of nasal obstruction may relate to nasal cavity air-conditioning. Thus, it is necessary to quantify the efficiency of nasal cavity conditioning of the inhaled air. This study quantifies both overall and regional nasal air-conditioning in a cohort of 10 healthy subjects using computational fluid dynamics simulations before and after nasal decongestion. The 3D virtual geometry model was segmented from magnetic resonance images (MRI). Each subject was under two MRI acquisitions before and after the decongestion condition. The effects of decongestion on nasal cavity air conditioning efficiency were modelled at two inspiratory flowrates: 15 and 30 L min-1 to represent restful and light exercise conditions. Results show inhaled air was both heated and humidified up to 90% of alveolar conditions at the posterior septum. The air-conditioning efficiency of the nasal cavity remained nearly constant between nostril and posterior septum but dropped significantly after posterior septum. In summary, nasal cavity decongestion not only reduces inhaled air added heat by 23% and added moisture content by 19%, but also reduces the air-conditioning efficiency by 35% on average.
摘要:
充血减少了鼻甲的血流量,扩大气道腔。虽然扩大的空气空间减少了经鼻吸气压降,鼻塞的症状可能与鼻腔空调有关。因此,有必要量化吸入空气的鼻腔调节效率。这项研究使用计算流体动力学模拟在鼻充血之前和之后对10名健康受试者的总体和区域鼻空调进行了量化。从磁共振图像(MRI)分割3D虚拟几何模型。每个受试者在充血状态之前和之后都进行了两次MRI采集。在两种吸气流速下:15和30Lmin-1模拟了充血对鼻腔空调效率的影响,以代表宁静和轻度运动条件。结果显示,吸入的空气在后隔被加热和加湿至90%的肺泡状况。鼻腔的空调效率在鼻孔和后隔之间几乎保持恒定,但在后隔之后显着下降。总之,鼻腔充血不仅减少了23%的吸入空气增加热量和增加19%的水分含量,而且空调效率平均降低了35%。