El Masry Ashraf, Williams Purris F, Chipman Daniel W, Kratohvil Joseph P, Kacmarek Robert M
Department of Anesthesia and Critical Care, Massachusetts General Hospital, Boston 02114, USA.
Respir Care. 2005 Mar;50(3):345-53.
Closed endotracheal suctioning during mechanical ventilation is increasingly used, but its impact on ventilator function has not been fully studied.
We evaluated the impact of closed suctioning with 11 critical-care ventilators, during assisted ventilation in pressure-support mode, pressure-assist/control mode, volume-assist/control mode, and during continuous positive airway pressure, with 2 suctioning pressures (-120 mm Hg and approximately -200 mm Hg), and with 2 tidal volumes (450 mL and 900 mL). We continuously measured airway pressure, flow at the airway, and pressure distal to the catheter tip, before, during, and after a single 15-second period of continuous suctioning.
No ventilator malfunctioned as a result of the closed suctioning. During suctioning, end-expiratory pressure markedly decreased in all modes, and peak flow increased in all modes except volume-assist/control (p < 0.001). Respiratory rate increased during suctioning in pressure- and volume-assist/control (p < 0.001) but not during pressure support or continuous positive airway pressure. Gas delivery was most altered during volume-assist/control with the smaller tidal volume (p < 0.05) and least altered during pressure-assist/control with the larger tidal volume.
There are large differences between the ventilators evaluated (p < 0.001). Closed suctioning does not cause mechanical ventilator malfunction. Upon removal of the suction catheter, these ventilators resumed their pre-suctioning-procedure gas delivery within 2 breaths, and, during all the tested modes, all the ventilators maintained gas delivery. However, closed suctioning can decrease end-expiratory pressure during suctioning.
机械通气期间的密闭式气管内吸痰应用日益广泛，但其对呼吸机功能的影响尚未得到充分研究。
我们使用11台重症监护呼吸机，在压力支持模式、压力辅助/控制模式、容量辅助/控制模式下的辅助通气期间以及持续气道正压通气期间，以2种吸痰压力（-120 mmHg和约-200 mmHg）和2种潮气量（450 mL和900 mL）评估密闭式吸痰的影响。在单次持续15秒吸痰的前、中、后，我们持续测量气道压力、气道流量以及导管尖端远端的压力。
未因密闭式吸痰导致呼吸机故障。吸痰期间，所有模式下呼气末压力均显著降低，除容量辅助/控制模式外，所有模式下峰值流量均增加（p < 0.001）。压力辅助/控制和容量辅助/控制模式下吸痰期间呼吸频率增加（p < 0.001），但压力支持或持续气道正压通气期间呼吸频率未增加。在较小潮气量的容量辅助/控制模式下气体输送变化最大（p < 0.05），在较大潮气量的压力辅助/控制模式下气体输送变化最小。
所评估的呼吸机之间存在很大差异（p < 0.001）。密闭式吸痰不会导致机械呼吸机故障。移除吸痰导管后，这些呼吸机在2次呼吸内恢复吸痰前的气体输送，并且在所有测试模式下，所有呼吸机均维持气体输送。然而，密闭式吸痰可在吸痰期间降低呼气末压力。
