Krishna Senthil G, Hakim Mumin, Sebastian Roby, Dellinger Heather L, Tumin Dmitry, Tobias Joseph D
Department of Anesthesiology & Pain Medicine, Nationwide Children's Hospital, Columbus, OH, USA.
Department of Anesthesiology & Pain Medicine, The Ohio State University, Columbus, OH, USA.
Paediatr Anaesth. 2017 May;27(5):494-500. doi: 10.1111/pan.13099. Epub 2017 Feb 15.
In children, the size of the cuffed endotracheal tube is based on various age-based formulas. However, such formulas may over or underestimate the size of the cuffed endotracheal tube. There are no data on the impact of different-sized cuffed endotracheal tubes (ETT) on the intracuff pressure in children.
The current study measures intracuff pressure with different-sized cuffed ETT.
The study was conducted in an in vitro and in vivo phase. For the in vitro phase, 10 cuffed ETT of size 4.0, 4.5, and 5 mm internal diameter (ID) each were randomly placed inside a 1.0 cm ID plastic tube (mimicking the trachea), which was in turn connected to a 1 l test lung. After inflation of the cuff using the air leak test at a continuous positive airway pressure of 20 cmH O, the intracuff pressure was measured. The in vivo phase was conducted in 100 children (4-8 years) and were randomly divided into two groups to receive either a cuffed endotracheal tube based on the Khine formula (Group R) or a cuffed endotracheal tube that was a half-size (0.5 mm ID) smaller (Group S). Following the inflation of the cuff to seal the trachea, the intracuff pressure was measured.
In the in vitro phase, the intracuff pressure was 45 ± 6, 23 ± 1, and 14 ± 6 cmH O with size 4.0, 4.5, and 5 mm ID cuffed ETT, respectively (F-test P < 0.001 for difference among three groups). In the in vivo phase, the mean intracuff pressure in Group R was 25 ± 19 cmH O vs 37 ± 35 cmH O in Group S (95% CI of difference: 1, 23; P = 0.039).
If the cuffed endotracheal tube is too small, the trachea can still be sealed by inflating the cuff with additional air. However, this transforms the cuff from the intended high-volume, low-pressure cuff to an undesirable high-volume, high-pressure cuff.
在儿童中，带套囊气管内导管的尺寸是根据各种基于年龄的公式来确定的。然而，这些公式可能会高估或低估带套囊气管内导管的尺寸。关于不同尺寸的带套囊气管内导管（ETT）对儿童套囊内压力的影响，目前尚无相关数据。
本研究测量不同尺寸带套囊ETT的套囊内压力。
本研究分为体外和体内两个阶段。在体外阶段，将内径（ID）分别为4.0、4.5和5mm的10根带套囊ETT随机放置在一根内径为1.0cm的塑料管内（模拟气管），该塑料管再连接到一个1L的测试肺上。在气道持续正压20cmH₂O下采用漏气试验对套囊充气后，测量套囊内压力。体内阶段在100名4至8岁的儿童中进行，他们被随机分为两组，分别接受基于Khine公式的带套囊气管内导管（R组）或尺寸小半号（ID小0.5mm）的带套囊气管内导管（S组）。套囊充气以封闭气管后，测量套囊内压力。
在体外阶段，内径为4.0、4.5和5mm的带套囊ETT的套囊内压力分别为45±6、23±1和14±6cmH₂O（三组间差异的F检验P<0.001）。在体内阶段，R组的平均套囊内压力为25±19cmH₂O，而S组为37±35cmH₂O（差异的95%CI：1，23；P=0.039）。
如果带套囊气管内导管尺寸过小，通过向套囊额外充气仍可封闭气管。然而，这会将套囊从预期的大容量、低压套囊转变为不理想的大容量、高压套囊。
