School of Engineering, Monash University, Subang Jaya, Malaysia.
Centre for Bioengineering, University of Canterbury, Christchurch, New Zealand.
Comput Methods Programs Biomed. 2018 Apr;157:217-224. doi: 10.1016/j.cmpb.2018.02.007. Epub 2018 Feb 3.
Respiratory mechanics estimation can be used to guide mechanical ventilation (MV) but is severely compromised when asynchronous breathing occurs. In addition, asynchrony during MV is often not monitored and little is known about the impact or magnitude of asynchronous breathing towards recovery. Thus, it is important to monitor and quantify asynchronous breathing over every breath in an automated fashion, enabling the ability to overcome the limitations of model-based respiratory mechanics estimation during asynchronous breathing ventilation.
An iterative airway pressure reconstruction (IPR) method is used to reconstruct asynchronous airway pressure waveforms to better match passive breathing airway waveforms using a single compartment model. The reconstructed pressure enables estimation of respiratory mechanics of airway pressure waveform essentially free from asynchrony. Reconstruction enables real-time breath-to-breath monitoring and quantification of the magnitude of the asynchrony (M).
Over 100,000 breathing cycles from MV patients with known asynchronous breathing were analyzed. The IPR was able to reconstruct different types of asynchronous breathing. The resulting respiratory mechanics estimated using pressure reconstruction were more consistent with smaller interquartile range (IQR) compared to respiratory mechanics estimated using asynchronous pressure. Comparing reconstructed pressure with asynchronous pressure waveforms quantifies the magnitude of asynchronous breathing, which has a median value M for the entire dataset of 3.8%.
The iterative pressure reconstruction method is capable of identifying asynchronous breaths and improving respiratory mechanics estimation consistency compared to conventional model-based methods. It provides an opportunity to automate real-time quantification of asynchronous breathing frequency and magnitude that was previously limited to invasively method only.
呼吸力学估计可用于指导机械通气（MV），但在发生异步呼吸时会严重受损。此外，MV 期间的异步通常不会被监测，并且对于异步呼吸对恢复的影响或程度知之甚少。因此，重要的是要以自动化的方式监测和量化每一次呼吸中的异步呼吸，从而能够克服在异步呼吸通气期间基于模型的呼吸力学估计的局限性。
使用迭代气道压力重建（IPR）方法来重建异步气道压力波形，以便使用单个隔室模型更好地匹配被动呼吸气道波形。重建压力可用于基本上不受异步影响的气道压力波形的呼吸力学估计。重建使能够实时逐呼吸监测和量化异步的幅度（M）。
分析了来自具有已知异步呼吸的 MV 患者的超过 100,000 个呼吸周期。IPR 能够重建不同类型的异步呼吸。与使用异步压力估计的呼吸力学相比，使用压力重建估计的呼吸力学更一致，其四分位距（IQR）更小。将重建压力与异步压力波形进行比较可量化异步呼吸的幅度，整个数据集的中位数 M 值为 3.8%。
与传统的基于模型的方法相比，迭代压力重建方法能够识别异步呼吸并提高呼吸力学估计的一致性。它提供了一个机会，可以自动实时量化以前仅限于侵入性方法的异步呼吸频率和幅度。
