Department of Anaesthesia, Maastricht University Medical Centre, PO Box 5800, 6202 AZ Maastricht, The Netherlands.
Br J Anaesth. 2011 Mar;106(3):403-9. doi: 10.1093/bja/aeq364. Epub 2010 Dec 22.
Emergency ventilation through a small-bore transtracheal catheter can be lifesaving in a 'cannot intubate, cannot ventilate' situation. Ejectors, capable of creating suction by the Bernoulli principle, have been proposed to facilitate expiration through small-bore catheters. In this bench study, we compared a novel, purpose-built ventilation ejector (DE 5) with a previously proposed, modified industrial ejector (SBP 07).
The generated insufflation pressures, suction pressures in static and dynamic situations, and also suction capacities and entrainment ratios of the SBP 07 and the DE 5 were determined. The DE 5 was also tested in a lung simulator with a simulated complete upper airway obstruction. Inspiratory and expiratory times through a transtracheal catheter were measured at various flow rates and achievable minute volumes were calculated.
In a static situation, the SBP 07 showed a more negative pressure build-up compared with the DE 5. However, in a dynamic situation, the DE 5 generated a more negative pressure, resulting in a higher suction capacity. Employment of the DE 5 at a flow rate of 18 litre min(-1) allowed a minute volume through the transtracheal catheter of up to 8.27 litre min(-1) at a compliance of 100 ml cm H(2)O(-1). The efficiency of the DE 5 depended on the flow rate of the driving gas and the compliance of the lung simulator.
In laboratory tests, the DE 5 is an optimized ventilation ejector suitable for applying expiratory ventilation assistance. Further research may confirm the clinical applicability as a portable emergency ventilator for use with small-bore catheters.
在“无法插管、无法通气”的情况下，通过小口径经气管导管进行紧急通气可挽救生命。喷射器可利用伯努利原理产生吸力，有人提议利用它通过小口径导管来辅助呼气。在这项基础研究中，我们比较了一种新型、专用的通气喷射器（DE5）和以前提出的、经改良的工业喷射器（SBP07）。
确定了 SBP07 和 DE5 的充气压力、静态和动态条件下的抽吸压力、抽吸能力和夹带比。还在具有模拟完全上呼吸道阻塞的肺模拟器中对 DE5 进行了测试。在各种流速下测量经气管导管的吸气和呼气时间，并计算可实现的分钟通气量。
在静态情况下，SBP07 显示出比 DE5 更负的压力增加。然而，在动态情况下，DE5 产生了更大的负压，从而产生了更高的抽吸能力。在 18 升/分钟的流速下使用 DE5 时，在顺应性为 100ml cm H2O(-1)的情况下，经气管导管的分钟通气量可达 8.27 升/分钟。DE5 的效率取决于驱动气体的流速和肺模拟器的顺应性。
在实验室测试中，DE5 是一种适合应用呼气通气辅助的优化通气喷射器。进一步的研究可能会证实其作为一种便携式紧急呼吸机，与小口径导管一起使用的临床适用性。
