摘要：Cough is a defensive behavior that protects the respiratory system from infection and clears airway *** airflow dynamics have been analyzed by a variety of mathematical and experimental *** this paper,the cough airflow dynamics of 42 subjects were obtained and *** identification model based on piecewise Gauss function for cough airflow dynamics is proposed through the dimensionless method,which could achieve over 90%identification ***,an assisted cough system based on pneumatic flow servo system is *** vacuum situation and feedback control are used to increase the simulated peak cough flow rate,which are important for airway secretion clearance and to avoid airway collapse,*** simulated cough peak flow could reach 5 L/s without the external assistance such as manual pressing,patient cooperation and other ***,the backstepping control is developed to generate a simulated cough airflow that closely mimics the natural cough airflow of *** assisted cough system opens up wide opportunities of practical application in airway secretion clearance for critically ill patients with COVID 2019 and other pulmonary diseases.

摘要：目的探讨新一代比例辅助通气模式(PAV)对慢性阻塞性肺疾病(简称慢阻肺)急性加重患者提供辅助呼吸时,不同辅助比例(PA)对患者通气、氧合及呼吸功耗状况等相关生理学指标的影响。方法采用前瞻性自身交叉随机对照研究的设计方案,随机选取PAV模式中的三个辅助比例,即80%PA、60%PA、40%PA先后对患者进行辅助呼吸,每个辅助比例持续时间均为30 min;在应用不同辅助比例前均先给予压力支持通气模式(PSV)辅助呼吸,持续时间30 min。比较不同PA及PSV模式条件下通气、氧合及呼吸困难等相关指标的变化;比较不同PA时患者呼吸做功(WOBp)及呼吸机做功(WOBv)的变化。结果共28例患者入选。随着PA不断下调,气道峰压(PIP)、平均气道压(Pm)、潮气量(VT)逐渐降低(P0.05)。与在PSV模式时相比,PIP在80%PA时显著增高(P0.05),在60%PA及40%PA时显著降低(P0.05),在60%PA及40%PA时显著增高(P0.05),在60%PA及40%PA时显著降低(P0.05),在60%PA及40%PA时显著增加(P<0.05)。随着PA不断下调,WOBp不断增加,在40%PA时显著高于在60%PA(P=0.000)及80%PA时(P=0.000),在60%PA时显著高于80%PA(P=0.000);WOBv不断降低,在40%PA时显著低于在60%PA(P=0.004)及80%PA时(P=0.000),在60%PA时显著低于80%PA(P=0.000)。结论新一代PAV能够安全有效地为慢阻肺急性加重患者提供辅助呼吸。80%PA时患者呼吸形式、呼吸困难程度及辅助呼吸肌参与程度与基础PSV大致相似,随着辅助比例的逐渐降低,患者自主呼吸参与的程度逐渐增加,呼吸功耗增加,呼吸困难程度加重。PAV更能促进自主呼吸做功,防止呼吸肌废用性萎缩,应用不当也容易导致呼吸肌疲劳。