Hess D, Simmons M, Slikkers F, Dickerson R
York Hospital, PA.
Respir Care. 1993 Feb;38(2):183-8.
We conducted this study to determine the inspiratory and expiratory flow resistance of the valves of eight commercially available mouth-to-mask ventilation devices.
METHODS & MATERIALS: We evaluated the valves of Intertech, Laerdal, Life Design Systems (LDS), Res-Q, Respironics, Rondex, Vital Signs, and White. The devices were supplied by the manufacturers and included the valve and any filter or extension tube supplied with the valve. Expiratory resistance was evaluated by directing air through the valve in the direction of flow when the patient exhales. Inspiratory resistance was evaluated by directing air through the valve in the direction of flow when a breath is delivered to the patient. Flow was controlled by a Timeter 0-75 flowmeter and measured using a calibrated Timeter RT-200. Flows of 10, 20, 30, 40, 50, 60, 70, 80, and 90 L/min were used. 'Back' pressure due to the resistance of the valves was measured using a calibrated Timeter RT-200. Resistance was calculated by dividing back pressure by flow. Five measurements were made at each flow setting for each valve.
We observed significant differences in back pressures and resistances between the flows evaluated (p < 0.001 for both inspiratory and expiratory flows), and between the commercially available devices (p < 0.001 for both inspiratory and expiratory flows). At a flow of 50 L/min, the inspiratory back pressures produced by the devices were [mean (SD) in cm H2O] Intertech 5.2 (0.06), Laerdal 4.6 (0.09), LDS 4.7 (0.03), Res-Q 3.1 (0.04), Respironics 3.3 (0.04), Rondex 1.1 (0.02), Vital Signs 4.0 (0.06), and White 4.3 (0.10). At this same flow, the expiratory back pressures were Intertech 4.8 (0.30), Laerdal 9.1 (0.10), LDS 3.3 (0.02), Res-Q 3.7 (0.35), Respironics 0.5 (0.01), Rondex 1.4 (0.01), Vital Signs 3.6 (0.05), and White 13.7 (0.48).
In some cases, the resistance through these devices might be considered excessive; however, most of the devices meet the International Standards Organization (ISO) standard (back pressure < 5 cm H2O at 50 L/min).
我们开展这项研究以确定8种市售口对面罩通气设备阀门的吸气和呼气流动阻力。
我们评估了Intertech、Laerdal、生命设计系统（LDS）、Res-Q、瑞思迈、Rondex、伟伦和White的阀门。这些设备由制造商提供，包括阀门以及随阀门配备的任何过滤器或延长管。呼气阻力通过在患者呼气时使空气沿气流方向通过阀门来评估。吸气阻力通过在向患者输送呼吸时使空气沿气流方向通过阀门来评估。气流由Timeter 0 - 75流量计控制，并使用校准后的Timeter RT - 200进行测量。使用的气流速度为10、20、30、40、50、60、70、80和90升/分钟。由阀门阻力产生的“背”压使用校准后的Timeter RT - 200进行测量。阻力通过背压除以气流速度来计算。每个阀门在每个气流设置下进行5次测量。
我们观察到在评估的气流之间（吸气和呼气气流的p均<0.001）以及市售设备之间（吸气和呼气气流的p均<0.001），背压和阻力存在显著差异。在50升/分钟的气流速度下，各设备产生的吸气背压为[以厘米水柱计的均值（标准差）]Intertech 5.2（0.06）、Laerdal 4.6（0.09）、LDS 4.7（0.03）、Res-Q 3.1（0.04）、瑞思迈3.3（0.04）、Rondex 1.1（0.02）、伟伦4.0（0.06）和White 4.3（0.10）。在相同气流速度下，呼气背压分别为Intertech 4.8（0.30）、Laerdal 9.1（0.10）、LDS 3.3（0.02）、Res-Q 3.7（0.35）、瑞思迈（0.5）（0.01）、Rondex 1.4（0.01）、伟伦3.6（0.05）和White 13.7（0.48）。
在某些情况下，通过这些设备的阻力可能被认为过大；然而，大多数设备符合国际标准化组织（ISO）标准（在50升/分钟时背压<5厘米水柱）。
