基于Matlab无创正压通气下呼吸道气阻与顺应性的在线测算方法研究

Matlab-Based Study on Online Monitoring of Respiratory Resistance and Compliance under Noninvasive Positive Airway Pressure Ventilation

目的在无创正压通气下,避免对呼吸道内部进行操作以及自主呼吸和漏气的干扰等,研究有效在线动态测算呼吸道气阻(resistance,R)和顺应性(compliance,C)的方法。方法在呼气末气流为0时,控制呼气支持压(expiration positive airway pressure,EPAP)跃降1个幅度为Δp和时间宽度为Δt的负脉冲气压;在该负脉冲气压作用下,呼吸道出现短暂释放气流;通过获得Δt时间段的释放气流计算R和C。另外,基于Matlab建立通气模型,模拟正常成人、急性呼吸窘迫综合征(acute respiratory distress syndrome,ARDS)患者和慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)患者的呼吸,进行仿真实验,获取仿真数据并计算验证。结果根据仿真数据计算得到正常成人、ARDS患者、COPD患者R和C与实践赋值的误差分别为1.6%和-1.6%、1.21%和-1.19%、-12.53%和14.32%。结论该算法测算呼吸道R和C具有可行性和适应性。仿真研究结果有助于智能通气、比例辅助通气模式的研究与实现。

Objective Under noninvasive positive pressure ventilation,in view of inconvenient operations in human airway,and avoiding the interference of spontaneous breathing and the necessary leakage flow,the method for dynamic online monitoring of the respiratory resistance(R)and compliance(C)was studied.Methods At the end of expiration,when the exhaled flow was 0,relative to the expiration positive airway pressure(EPAP),a step-dropped pressure was produced with the amplitudeΔp and hold timeΔt.Under this dropped pressure,a short-time discharged flow was generated from the lung,and the discharged flow was applied to calculate the R and C.In addition,a respiratory model was developed in MATLAB to simulate the breaths of normal adult,acute respiratory distress syndrome(ARDS)patient and chronic obstructive pulmonary disease(COPD)patient.A serial of simulation experiments were carried out for obtaining data and verification.Results The calculated R and C from simulation for normal adult,ARDS patient,COPD patient,deviated from the actual value by 1.60%and-1.60%,1.21%and-1.19%,-12.53%and 14.32%,respectively.Conclusions The proposed algorithm is practicable and feasible for calculating the R and C.The simulation results are beneficial for studying and realizing the intelligent ventilation and proportional assist ventilation in respirator.