Wang J S, Hung W T, Lin C Y
Department of Anesthesia and Critical Care, University of Chicago, IL 60637.
J Clin Anesth. 1992 Mar-Apr;4(2):111-5. doi: 10.1016/0952-8180(92)90025-v.
To determine the sites and rates of the leakage of disposable breathing circuits.
Nonclinical, experimental study.
Experimental laboratory.
To identify in vitro the leakage sites by bubble test and to measure the leakage rate by the increased oxygen (O2) flow needed to maintain the circuit pressure provided by an anesthesia machine previously verified to have no leaks. Breathing circuit pressures measured with a sphygmomanometer of 30, 50, 70, and 100 mmHg were studied.
Ninety-seven disposable and three reusable breathing circuits from seven manufacturers were investigated for leakage. There was a linear relationship between the circuit pressure and O2 flow at which leaks occurred. No leakage was detected in reusable circuits at 30 mmHg of circuit pressure. Leakage was found in two of the six junctions between the patient adapter and the corrugated tubing in the reusable breathing circuits at a circuit pressure of 100 mmHg. In 90% of the disposable circuits tested, the leakage rate was less than 75 ml/min at 30 mmHg of circuit pressure, but there was a wide variation in the amount of leakage among the circuits of different companies. Almost all the leakage sites were located at connections in the circuit and not in the corrugated tubing. The most common site of leakage in the disposable circuits was the junction between the patient adapter end and the corrugated tubing (57%) rather than the swivel piece (40%).
Most disposable breathing circuits can be used safely for closed-circuit anesthesia, as the leakage volume is too small to be of clinical importance. The variation in the leakage rates stresses the importance of quality control of the connector seals.
确定一次性呼吸回路的泄漏部位及发生率。
非临床实验研究。
实验实验室。
通过气泡试验在体外识别泄漏部位，并通过维持先前验证无泄漏的麻醉机提供的回路压力所需的增加的氧气（O₂）流量来测量泄漏率。研究了用血压计测量的30、50、70和100 mmHg呼吸回路压力。
对来自7个制造商的97个一次性呼吸回路和3个可重复使用的呼吸回路进行了泄漏调查。泄漏发生时的回路压力与O₂流量之间存在线性关系。在回路压力为30 mmHg时，可重复使用的回路中未检测到泄漏。在回路压力为100 mmHg时，可重复使用的呼吸回路中患者适配器与波纹管之间的6个连接处中有2个发现泄漏。在测试的90%的一次性回路中，回路压力为30 mmHg时泄漏率小于75 ml/min，但不同公司的回路之间泄漏量差异很大。几乎所有的泄漏部位都位于回路中的连接处，而不是波纹管中。一次性回路中最常见的泄漏部位是患者适配器末端与波纹管之间的连接处（57%），而不是旋转接头（40%）。
大多数一次性呼吸回路可安全用于闭路麻醉，因为泄漏量太小，无临床意义。泄漏率的差异强调了连接器密封质量控制的重要性。
