Resistance of pediatric and neonatal endotracheal tubes: Influence of flow rate, size, and shape
Resistance of pediatric and neonatal endotracheal tubes: Influence of flow rate, size, and shape
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DOI：
10.1097/00003246-200005000-00056
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发表时间：
2000-05-01
影响因子：
8.8
通讯作者：
Rafferty, GF
中科院分区：
文献类型：
--
作者：
Manczur, T;Greenough, A;Rafferty, GF
目的：本研究的目的是确定新生儿和儿科重症监护病房常用的气管插管（ETT）的阻力以及阻力与流速、ETT尺寸和形状的关系。我们检查了内径在2.5和6 mm之间的直管和内径/外径在2，5/4和3.5/5 mm，我们评估了标准和“适合患者使用”长度下的ETT阻力，流速为0 L/min至30 L/min。我们使用校准的转子流量计控制气体流量，并使用工业通风计或压差传感器测量近端静压。ETT阻力的计算方法为近端ETT压力除以实测流量，并表示为每个流量下三次测量的平均值。在5 L/min和10 L/min的流量下，6 mm内径ETT的阻力分别为3.1 cm H2O/L/sec和4.6 cm H2O/L/sec，内径为2.5mm的ETT的阻力分别为81.2cm H2O/L/sec和139.4cm H2O/L/sec。将Err缩短到适合患者使用的长度（例如，内径为4.0 mm，从20.7 cm到11.3 cm），其阻力平均降低了22%。一个科尔管的阻力是类似的50%，低于一个直管的内径对应的狭窄部分的肩tube.Conclusions：我们的研究结果表明，使用一个小直径，直气管插管将显着增加呼吸的工作。
Objective: The aim of this study was to determine the resistances of endotracheal tubes (ETTs) commonly used in neonatal and pediatric intensive care units and the relationship of resistance to flow rate, size, and shape of ETT.Setting: Laboratory-based measurements.Evaluation: We examined straight tubes with inner diameters between 2.5 and 6 mm and shouldered (Cole) tubes with inner diameter/outer diameter between 2,5/4 and 3.5/5 mm, We assessed ETT resistance at standard and "appropriate for patient use" lengths at flow rates from 0 L/min to 30 L/min, We used calibrated rotameters to control the flow of gas and proximal static pressure measured by using either an industrial draft gauge or a differential pressure transducer. The ETT resistance was calculated by dividing the proximal ETT pressure by the measured flow and expressed as the mean of three measurements at each flow rate.Main Results: Resistance increased as ETT diameter decreased; at flows of 5 L/min and 10 L/min, the resistances of the 6 mm inner diameter ETT were 3.1 H2O/L/sec and 4.6 cm H2O/L/sec, respectively, and the resistances of the 2.5 mm inner diameter ETT were 81.2 H2O/L/sec and 139.4 cm H2O/L/sec, respectively. Shortening an Err to a length appropriate for patient use (e.g., a 4.0 mm inner diameter, from 20.7 to 11.3 cm) reduced its resistance on average by 22%. The resistance of a Cole tube was similar to 50% lower than that of a straight tube with an inner diameter corresponding to the narrow part of the shouldered tube.Conclusions: Our results suggest that the use of a small-diameter, straight ETT will significantly increase the work of breathing.