[氦气对呼吸机参数的影响：使用Servoi呼吸机的体外研究]

López-Herce Cid J, Urbano Villaescusa J, Cidoncha Escobar E, Del Castillo Peral J, Santiago Lozano M J, Mencía Bartolomé S, Bellón Cano J M

Sección de Cuidados Intensivos Pediátricos. Hospital General Universitario Gregorio Marañón. Madrid. España.

An Pediatr (Barc). 2008 Apr;68(4):336-41. doi: 10.1157/13117703.

OBJECTIVE

To analyze the changes in respiratory parameters in a Servoi ventilator with heliox.

MATERIAL AND METHODS

In vitro study with a Servoi (Maquet) ventilator in volume controlled (VC), pressure controlled (PC) and volume control regulated by pressure (VCPR) modes connected to an artificial lung. A heliox tank with a fixed concentration of helium 70 % and oxygen 30 % was connected to the air inlet of the ventilator. The ventilator was set in VC mode with tidal volumes of 30, 50, 100, 250 and 500 ml; in PC mode with pressure of 20 and 30 cmH(2)O and in VCPR mode with tidal volume of 150 ml. In each case FiO(2) of 21, 30, 40, 50, 60, 70, 80, 90 and 100 % was used. The FiO(2), inspired and expired tidal volume and inspiratory pressure measured by the ventilator and a pitot spirometer (Datex_S5) were compared.

RESULTS

In VC and VCPR modes the increase in helium produced a progressive decrease in the pressure needed to administrate the set volume. Heliox also produced a decrease in the tidal volume measured by the spirometer and the tidal expired volume measured by the respirator. In PC mode, heliox produced a progressive increase in the inspired tidal volume, increasing the differences between inspired and expired tidal volumes.

CONCLUSIONS

Heliox used with Servoi ventilator produces a decrease in inspiratory pressures in VC and VCPR modes, and an increase in inspiratory tidal volume in PC mode. In all modes heliox reduced the expired tidal volume measured by the ventilator and the spirometer. These changes should be borne in mind if heliox is used with this ventilator.

目的

分析在Servoi呼吸机中使用氦氧混合气时呼吸参数的变化。

材料与方法

采用体外研究，将Servoi（迈柯唯）呼吸机设置为容量控制（VC）、压力控制（PC）和压力调节容量控制（VCPR）模式，连接至人工肺。将一个固定浓度为氦气70%和氧气30%的氦氧混合气罐连接至呼吸机的进气口。呼吸机在VC模式下设置潮气量为30、50、100、250和500 ml；在PC模式下设置压力为20和30 cmH₂O，在VCPR模式下设置潮气量为150 ml。每种情况下使用的FiO₂分别为21%、30%、40%、50%、60%、70%、80%、90%和100%。比较呼吸机和皮托管肺活量计（Datex_S5）测量的FiO₂、吸入和呼出潮气量以及吸气压力。