Ambulance Victoria, Doncaster, Victoria, Australia.
Emerg Med Australas. 2009 Dec;21(6):449-54. doi: 10.1111/j.1742-6723.2009.01228.x.
The Valsalva manoeuvre (VM) continues to be first-line management for haemodynamically stable supraventricular tachycardia in the acute setting. 40 mmHg of intrathoracic pressure is seen as an essential component of the VM. Anecdotally, blowing into a 10 mL syringe to move the plunger is one method of pressure generation; however, to date its effectiveness has not been tested. The objective of the present study was to assess if blowing into a syringe sufficient to move the plunger could produce the required 40 mmHg of pressure.
A two-part experimental study tested the pressure required to move the plunger, and sustain that movement for 15 s, in a Terumo syringe. Part one tested a range of syringe sizes. Part two, a repeated measures study, tested the syringe to ascertain if a pressure reduction occurred after repeated use. A sphygmomanometer was attached to the syringe via a 10 cm length of tubing with another length of tubing attached to the sphygmomanometer enabling an investigator to blow into the syringe.
In part one, the 10 mL syringe was the only size noted to provide the required 40 mmHg pressure to move the plunger. In part two, the mean for each of the three tests per syringe varied between 37.0 mmHg (95% CI 34.2-39.8) and 40.2 mmHg (95% CI 37.5-43.0). There was no statistically significant fall noted over three uses of the same syringe.
The present study has demonstrated that blowing into a 10 mL Terumo syringe, to move the plunger, generated 40 mmHg intrathoracic pressure, thereby meeting the recommended intrathoracic pressure for optimum VM performance.
瓦尔萨尔瓦动作（VM）仍然是急性稳定型室上性心动过速的一线治疗方法。胸腔内压力达到 40mmHg 被认为是 VM 的一个重要组成部分。据推测，向 10ml 注射器吹气以推动柱塞是产生压力的一种方法；然而，迄今为止，其效果尚未得到验证。本研究的目的是评估向足以推动柱塞的注射器吹气是否可以产生所需的 40mmHg 压力。
一项两部分的实验研究测试了在 Terumo 注射器中推动柱塞所需的压力，并在 15 秒内维持该运动。第一部分测试了一系列注射器的尺寸。第二部分，一项重复测量研究，测试了注射器，以确定在重复使用后是否会出现压力下降。通过一段 10cm 长的管将血压计连接到注射器上，再将另一段管连接到血压计上，以便调查员可以向注射器吹气。
在第一部分中，只有 10ml 注射器被注意到可以提供所需的 40mmHg 压力来推动柱塞。在第二部分中，每个注射器的三次测试的平均值在 37.0mmHg（95%CI 34.2-39.8）和 40.2mmHg（95%CI 37.5-43.0）之间变化。在使用同一注射器三次后，没有发现统计学上显著的下降。
本研究表明，向 10ml Terumo 注射器吹气以推动柱塞可产生 40mmHg 的胸腔内压力，从而达到 VM 最佳性能所需的推荐胸腔内压力。
