Blanch Paul B
Department of Anesthesiology, University of Florida College of Medicine, Gainsville, Florida 32610-0254, USA.
Respir Care. 2004 Feb;49(2):166-73.
Routine measurement of endotracheal tube (ETT) cuff pressure is a standard in respiratory care, and several devices are available for measuring ETT cuff pressure. Yet an informed choice in the buying process is hindered by the present paucity of unbiased, comparative data.
Four brands of cuff inflator were tested: Posey Cufflator, DHD Cuff-Mate 2, Rüsch Endotest, and SIMS-Portex Cuff Pressure Indicator. Ten randomly selected 8.0-mm-inner-diameter ETTs were modified and tested in a trachea model. The cuffs were gradually inflated and deflated. After each sequential change in cuff volume, cuff pressure measurements were simultaneously recorded with the cuff inflator and with a calibration analyzer. These data were compared using limits-of-agreement analysis. Then, with each of the 10 ETTs, each cuff inflator was used to measure 3 known (ie, measured with the calibration analyzer) cuff pressures: 20, 40, and 60 cm H(2)O. Cuff pressure measurements were averaged, by brand, and compared to the respective baseline cuff pressure. Finally, using the 10 ETTs and trachea model, the ETT cuffs were inflated, in 0.25-mL increments, using only a syringe and the calibration analyzer. The cuff pressure and cuff volume data from that procedure were plotted and the best-fit regression line was determined.
There were differences in bias and precision among the tested cuff inflators. The Cuff-Mate 2 had the smallest bias and best precision. None of the cuff inflator brands accurately measured cuff pressure. In each case the Cuff-Mate 2 measured cuff pressures closest to actual. The Cuff-Mate 2 contains about half the compressible volume of that in the Endotest and Cufflator and < 20% of that in the Cuff Pressure Indicator. Regarding the relationship between cuff pressure and intracuff volume, the best-fit linear regression equation was: cuff volume = 0.05 x CP - 0.39 (r(2) = 0.96).
The 4 cuff inflators tested differ in bias and precision and none of the devices accurately measure cuff pressure. Cuff inflator manufacturers should design an accurate yet reasonably priced device to inflate ETT cuffs, and ideally that device should allow cuff-pressure checks without decreasing cuff pressure. In the meanwhile clinicians may opt to use my proposed cuff-pressure measurement technique, which minimizes the loss of cuff pressure during cuff-pressure checks and provides more accurate cuff-pressure measurements.
气管内插管（ETT）套囊压力的常规测量是呼吸护理的一项标准，有多种设备可用于测量ETT套囊压力。然而，目前缺乏无偏倚的比较数据，这阻碍了在购买过程中做出明智的选择。
对四个品牌的套囊充气器进行了测试：波西（Posey）套囊充气器、DHD袖带伴侣2（Cuff-Mate 2）、鲁施（Rüsch）气管测试器（Endotest）和西姆斯-波特克斯（SIMS-Portex）套囊压力指示器。随机选择10根内径为8.0毫米的ETT进行改良，并在气管模型中进行测试。套囊逐渐充气和放气。在套囊容积每次连续变化后，使用套囊充气器和校准分析仪同时记录套囊压力测量值。使用一致性界限分析对这些数据进行比较。然后，对每根10根ETT，使用每个套囊充气器测量3个已知（即使用校准分析仪测量）的套囊压力：20、40和60厘米水柱。按品牌对套囊压力测量值进行平均，并与各自的基线套囊压力进行比较。最后，使用10根ETT和气管模型，仅使用注射器和校准分析仪，以0.25毫升的增量对ETT套囊进行充气。绘制该过程的套囊压力和套囊容积数据，并确定最佳拟合回归线。
测试的套囊充气器在偏差和精度方面存在差异。袖带伴侣2的偏差最小，精度最佳。没有一个套囊充气器品牌能准确测量套囊压力。在每种情况下，袖带伴侣2测量的套囊压力最接近实际值。袖带伴侣2的可压缩容积约为气管测试器和套囊充气器的一半，小于套囊压力指示器的20%。关于套囊压力与套内容积之间的关系，最佳拟合线性回归方程为：套内容积 = 0.05×CP - 0.39（r² = 0.96）。
测试的4种套囊充气器在偏差和精度方面存在差异，且没有一种设备能准确测量套囊压力。套囊充气器制造商应设计一种准确且价格合理的设备来为ETT套囊充气，理想情况下，该设备应能在不降低套囊压力的情况下进行套囊压力检查。同时，临床医生可选择使用我提出的套囊压力测量技术，该技术可在套囊压力检查期间将套囊压力损失降至最低，并提供更准确的套囊压力测量值。
