Tütüncü A S, Cakar N, Camci E, Esen F, Telci L, Akpir K
Department of Anesthesiology and Intensive Care, Medical Faculty, University of Istanbul, Turkey.
Crit Care Med. 1997 May;25(5):756-60. doi: 10.1097/00003246-199705000-00008.
To compare the effects of pressure- and flow-triggered pressure-support ventilation on weaning parameters during recovery from acute respiratory failure.
Prospective, randomized, clinical trial.
Intensive care unit in a university hospital.
Sixteen orotracheally intubated adult patients recovering from acute respiratory failure of various etiologies, without chronic obstructive pulmonary disease.
Randomized application of pressure- and flow-triggered pressure-support ventilation at 100% and 75% ventilatory support levels in each triggering system. A total of four conditions were applied for 30 mins each in all patients.
Ventilatory, respiratory, and hemodynamic data were measured. For the measurement of weaning parameters, pressure and volume signals were directed to a computerized respiratory monitor by means of an esophageal probe and a flow sensor between the "Y" piece of the ventilatory circuit and the endotracheal tube. During both pressure-triggered (trigger sensitivity of -1 cm H2O) and flow-triggered (trigger sensitivity of 0.7 to 2.0 L/min) pressure-support ventilation with a ventilator, peak airway pressures were applied so as to decrease the work of breathing performed by the patient to zero (full ventilatory support). Partial ventilatory support was applied at 75% of the peak airway pressures achieved during full ventilatory support with each triggering system. A total of four experimental conditions were evaluated at identical FiO2 and positive and-expiratory pressure levels during pressure-support ventilation in each patient. Total ventilation volumes, arterial blood gas data, and hemodynamics did not differ among the four experimental conditions. During partial ventilatory support, the work of breathing, rapid shallow breathing index, and esophageal pressure increased significantly with both triggering systems when compared with data obtained at full ventilatory support. The mean data for the weaning parameters during the condition of partial ventilatory support were comparable between pressure- and flow-triggered pressure-support ventilation (i.e., 0.38 +/- 0.24 vs. 0.42 +/- 0.26 joule/L for work of breathing, 2.6 +/- 1.6 vs. 3.3 +/- 1.7 cm H2O for tracheal occlusion pressure, and 40.2 +/- 12.9 vs. 50.4 +/- 18.3 breaths/min/L for rapid shallow breathing index, respectively).
The application of either a pressure- or flow-triggered system during pressure-support ventilation with the ventilator did not significantly affect short-term changes in gas exchange, respiratory mechanics, and inspiratory workload in patients recovering from acute respiratory failure of various etiologies without chronic obstructive pulmonary disease.
比较压力触发和流量触发的压力支持通气对急性呼吸衰竭恢复期撤机参数的影响。
前瞻性、随机、临床试验。
大学医院的重症监护病房。
16例经口气管插管的成年患者，因各种病因导致急性呼吸衰竭正在恢复，无慢性阻塞性肺疾病。
在每个触发系统中，以100%和75%的通气支持水平随机应用压力触发和流量触发的压力支持通气。所有患者共进行四种情况的通气，每种情况持续30分钟。
测量通气、呼吸和血流动力学数据。为测量撤机参数，通过食管探头和通气回路“Y”形接头与气管内导管之间的流量传感器，将压力和容积信号传输至计算机化呼吸监测仪。在使用呼吸机进行压力触发（触发灵敏度为-1 cm H₂O）和流量触发（触发灵敏度为0.7至2.0 L/min）的压力支持通气时，均施加峰值气道压力，以使患者的呼吸功降至零（完全通气支持）。在每种触发系统的完全通气支持期间达到的峰值气道压力的75%水平上应用部分通气支持。在压力支持通气期间，对每位患者在相同的FiO₂以及呼气末正压水平下评估总共四种实验情况。四种实验情况之间的总通气量、动脉血气数据和血流动力学无差异。在部分通气支持期间，与完全通气支持时获得的数据相比，两种触发系统的呼吸功、快速浅呼吸指数和食管压力均显著增加。在部分通气支持情况下，压力触发和流量触发的压力支持通气的撤机参数平均数据相当（即呼吸功分别为0.38±0.24与0.42±0.26焦耳/升，气管闭塞压力分别为2.6±1.6与3.3±1.7 cm H₂O，快速浅呼吸指数分别为40.2±12.9与50.4±18.3次呼吸/分钟/升）。
对于因各种病因导致急性呼吸衰竭且无慢性阻塞性肺疾病正在恢复的患者，在使用呼吸机进行压力支持通气期间应用压力触发或流量触发系统，对气体交换、呼吸力学和吸气负荷的短期变化无显著影响。
