新冠肺炎病人吸入药物肺内定向投递的数值模拟研究

Numerical simulations of the targeted delivery of the inhalable drug in pulmonary airway of a COVID-19 patient

新冠肺炎病毒席卷全球,世界范围内患病人数仍在迅速增加,新冠肺炎病人的治疗引起研究者的关注,我国新型冠状病毒感染的肺炎诊疗方案指出可采用雾化吸入α-干扰素进行抗病毒治疗。为探索提高雾化吸入治疗效果的方法,本文针对一中症新冠肺炎病例进行了计算流体力学数值模拟分析,分区域重建了病患肺部呼吸道几何结构,在低吸气流量条件下(15 L/min)开展了不同直径药物液滴的肺内投递数值模拟,统计了呼吸道内液滴沉积的数量和位置以及能够投递入肺段深处的液滴数量。揭示了肺段投递效率随Stokes数增大而降低,获得了液滴入口位置与去向间的关系,发现从主气管入口截面上两个圆形区域内释放药物液滴能够高效投递入严重病变肺段,证明了吸入药物定向投递的可能性。

The COVID-19 has spread throughout the world.The number of COVID-19 patients still increase rapidly worldwide.The treatment of the COVID-19 patients attracts attention of the researchers.Diagnosis and Treatment Protocol for COVID-19 indicates that atomization inhalation of Alpha-interferon could be used for the antiviral therapy.To explore the possible method for enhancing the effectiveness of the inhalation treatment,numerical simulation was applied to analyze the treatment of a patient with moderate COVID-19 symptoms.Based on the spiral CT scan images on admission,we analyzed the severity of the lung segments.The geometry of the lung was reconstructed according to the lung segmentations.Drug delivery simulations for droplets with different diameters were carried out at low inhalation flow rate(15 L/min).The numbers of the droplets deposited in the airway those delivered into the deeper lung regions were recorded.The relationship between the initial locations of the droplets and their final destinations were obtained.The results indicate that the overall deep lung delivery efficiency of the droplets decreases with the increase of the Stokes number.The delivery efficiency could be significantly increased,if the droplets could be released from two circular areas at the inlet.This investigation proves that the targeted delivery of the inhalable drug is possible.