Cardiovascular and Respiratory Physiology, Technical Medical Centre, University of Twente, Technohal 3184, P.O. Box 217, 7500 AE, Enschede, The Netherlands.
Intensive Care Centre, Medisch Spectrum Twente, Enschede, The Netherlands.
Crit Care. 2024 Jun 9;28(1):195. doi: 10.1186/s13054-024-04978-0.
Respiratory effort should be closely monitored in mechanically ventilated ICU patients to avoid both overassistance and underassistance. Surface electromyography of the diaphragm (sEMGdi) offers a continuous and non-invasive modality to assess respiratory effort based on neuromuscular coupling (NMCdi). The sEMGdi derived electrical activity of the diaphragm (sEAdi) is prone to distortion by crosstalk from other muscles including the heart, hindering its widespread use in clinical practice. We developed an advanced analysis as well as quality criteria for sEAdi waveforms and investigated the effects of clinically relevant levels of PEEP on non-invasive NMCdi.
NMCdi was derived by dividing end-expiratory occlusion pressure (Pocc) by sEAdi, based on three consecutive Pocc manoeuvres at four incremental (+ 2 cmH2O/step) PEEP levels in stable ICU patients on pressure support ventilation. Pocc and sEAdi quality was assessed by applying a novel, automated advanced signal analysis, based on tolerant and strict cut-off criteria, and excluding inadequate waveforms. The coefficient of variations (CoV) of NMCdi after basic manual and automated advanced quality assessment were evaluated, as well as the effect of an incremental PEEP trial on NMCdi.
593 manoeuvres were obtained from 42 PEEP trials in 17 ICU patients. Waveform exclusion was primarily based on low sEAdi signal-to-noise ratio (N = 155, 37%, N = 241, 51% waveforms excluded), irregular or abrupt cessation of Pocc (N = 145, 35%, N = 145, 31%), and high sEAdi area under the baseline (N = 94, 23%, N = 79, 17%). Strict automated assessment allowed to reduce CoV of NMCdi to 15% from 37% for basic quality assessment. As PEEP was increased, NMCdi decreased significantly by 4.9 percentage point per cmHO.
Advanced signal analysis of both Pocc and sEAdi greatly facilitates automated and well-defined identification of high-quality waveforms. In the critically ill, this approach allowed to demonstrate a dynamic NMCdi (Pocc/sEAdi) decrease upon PEEP increments, emphasising that sEAdi-based assessment of respiratory effort should be related to PEEP dependent diaphragm function. This novel, non-invasive methodology forms an important methodological foundation for more robust, continuous, and comprehensive assessment of respiratory effort at the bedside.
为避免过度辅助和辅助不足，应密切监测机械通气 ICU 患者的呼吸努力。膈肌表面肌电图（sEMGdi）提供了一种连续且非侵入性的方法，可根据神经肌肉耦联（NMCdi）评估呼吸努力。膈肌的 sEMGdi 衍生电活动（sEAdi）容易受到来自包括心脏在内的其他肌肉的串扰的扭曲，这阻碍了它在临床实践中的广泛应用。我们开发了一种高级分析方法和 sEAdi 波形的质量标准，并研究了临床相关水平的 PEEP 对非侵入性 NMCdi 的影响。
在压力支持通气的稳定 ICU 患者中，基于三个连续的 Pocc 操作，在四个递增（每步+2 cmH2O）PEEP 水平下，通过将终末呼气阻塞压（Pocc）除以 sEAdi 来获得 NMCdi。通过应用一种新的、自动的高级信号分析方法评估 Pocc 和 sEAdi 的质量，该方法基于宽容和严格的截止标准，并排除了不充分的波形。评估了基本手动和自动高级质量评估后的 NMCdi 变异系数（CoV），以及递增 PEEP 试验对 NMCdi 的影响。
从 17 名 ICU 患者的 42 个 PEEP 试验中获得了 593 个操作。波形排除主要基于低 sEAdi 信噪比（N=155，37%，N=241，51%波形排除）、Pocc 不规则或突然停止（N=145，35%，N=145，31%）和 sEAdi 基线下的高面积（N=94，23%，N=79，17%）。严格的自动评估允许将 NMCdi 的 CoV 从基本质量评估的 37%降低到 15%。随着 PEEP 的增加，NMCdi 每增加 1 cmHO 就会显著降低 4.9 个百分点。
对 Pocc 和 sEAdi 进行高级信号分析极大地促进了高质量波形的自动和明确定义的识别。在危重病患者中，这种方法证明了在增加 PEEP 时 NMCdi（Pocc/sEAdi）的动态降低，强调了基于 sEAdi 的呼吸努力评估应与 PEEP 依赖性膈肌功能相关。这种新的非侵入性方法为床边更强大、连续和全面的呼吸努力评估奠定了重要的方法学基础。
