Eichler Lars, Mueller Jakob, Grensemann Jörn, Frerichs Inez, Zöllner Christian, Kluge Stefan
Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20251, Hamburg, Germany.
Section of Anesthesiology, Tabea Hospital, Hamburg, Germany.
Ann Intensive Care. 2018 Nov 15;8(1):110. doi: 10.1186/s13613-018-0454-y.
Percutaneous dilatational tracheotomy (PDT) may lead to transient impairment of pulmonary function due to suboptimal ventilation, loss of positive end-expiratory pressure (PEEP) and repetitive suction maneuvers during the procedure. Possible changes in regional lung aeration were investigated using electrical impedance tomography (EIT), an increasingly implied instrument for bedside monitoring of pulmonary aeration.
With local ethics committee approval, after obtaining written informed consent 29 patients scheduled for elective PDT under bronchoscopic control were studied during mechanical ventilation in supine position. Anesthetized patients were monitored with a 16-electrode EIT monitor for 2 min at four time points: (a) before and (b) after initiation of neuromuscular blockade (NMB), (c) after dilatational tracheostomy (PDT) and (d) after a standardized recruitment maneuver (RM) following surgery, respectively. Possible changes in lung aeration were detected by changes in end-expiratory lung impedance (Δ EELI). Global and regional ventilation was characterized by analysis of tidal impedance variation.
While NMB had no detectable effect on EELI, PDT led to significantly reduced EELI in dorsal lung regions as compared to baseline, suggesting reduced regional aeration. This effect could be reversed by a standardized RM. Mean delta EELI from baseline (SE) was: NMB - 47 ± 62; PDT - 490 ± 180; RM - 89 ± 176, values shown as arbitrary units (a.u.). Analysis of regional tidal impedance variation, a robust measure of regional ventilation, did not show significant changes in ventilation distribution.
Though changes of EELI might suggest temporary loss of aeration in dorsal lung regions, PDT does not lead to significant changes in either regional ventilation distribution or oxygenation.
经皮扩张气管切开术（PDT）可能会因通气不佳、呼气末正压（PEEP）丧失以及手术过程中的反复吸引操作而导致肺功能暂时受损。使用电阻抗断层扫描（EIT）研究了局部肺通气的可能变化，EIT是一种越来越多地用于床边肺通气监测的仪器。
经当地伦理委员会批准，在获得书面知情同意后，对29例计划在支气管镜控制下进行择期PDT的患者在仰卧位机械通气期间进行研究。在四个时间点用16电极EIT监测仪对麻醉患者进行2分钟监测：（a）神经肌肉阻滞（NMB）开始前和（b）后，（c）扩张气管切开术（PDT）后，以及（d）手术后标准化肺复张手法（RM）后。通过呼气末肺阻抗（ΔEELI）的变化检测肺通气的可能变化。通过分析潮气阻抗变化来表征整体和局部通气。
虽然NMB对EELI没有可检测到的影响，但与基线相比，PDT导致背部肺区域的EELI显著降低，提示局部通气减少。这种效应可通过标准化的RM逆转。与基线相比的平均ΔEELI（SE）为：NMB - 47±62；PDT - 490±180；RM - 89±176，值以任意单位（a.u.）表示。作为局部通气可靠指标的局部潮气阻抗变化分析未显示通气分布有显著变化。
虽然EELI的变化可能提示背部肺区域暂时通气丧失，但PDT不会导致局部通气分布或氧合的显著变化。
