Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin - Madison, WI, USA.
BluePearl Veterinary Partners, Waltham, MA, USA.
Vet Anaesth Analg. 2021 Nov;48(6):891-899. doi: 10.1016/j.vaa.2021.08.046. Epub 2021 Sep 16.
To assess the effects of two sizes of silicone endotracheal tubes with internal diameter 26 mm (ETT) and 30 mm (ETT) inflated to minimum occlusive volume on tracheal and laryngeal mucosa of adult horses anesthetized for 2 hours with isoflurane.
Prospective, randomized, blinded, crossover experimental study.
A total of eight healthy adult mares.
Upper airway endoscopy and ultrasound measurements of internal tracheal diameter were performed the day before anesthesia. Horses were anesthetized and orotracheally intubated with ETT or ETT. Ease of intubation was scored. The cuff was inflated in 10 mL increments to produce a seal. Final volume of air used and intracuff (IC) pressure (measured by pressure transducer) were recorded. At the end of anesthesia, a manometer was used to measure IC pressure and these measurements compared against measurements from the pressure transducer. Laryngeal and tracheal mucosa were assessed via endoscopy and assigned a score 0-3 before anesthesia, and at 2 and 24 hours following extubation.
Data are from seven horses because one horse with laryngeal hemiplegia was excluded. Mean tracheal ultrasound measurement was 3.5 ± 0.4 cm. No significant differences were noted between endotracheal tube sizes for intubation score, IC pressures, inflation volumes or tracheal or laryngeal injury scores at any time point. IC pressure measured by manometer was slightly higher than that by transducer (+1.0 ± 2.8 mmHg).
Results identified no clear advantage of one endotracheal tube size over the other in the population of horses studied, when endotracheal intubation is properly applied and IC pressure is carefully monitored. However, given that ETT was associated with the highest observed IC pressures and the only observed incidents of tracheal circumferential erythema, the larger ETT may be the better choice in most cases where tracheal size is sufficient.
评估两种内径为 26 毫米（ETT）和 30 毫米（ETT）的硅酮气管内导管在异氟醚麻醉 2 小时的成年马的气管和喉黏膜上的最小闭塞容积充气的效果。
前瞻性、随机、盲法、交叉实验研究。
总共 8 匹健康成年母马。
在上麻醉前一天进行上气道内窥镜检查和气管内直径的超声测量。马匹用 ETT 或 ETT 进行全身麻醉和经口气管插管。对插管的难易程度进行评分。将套囊充气 10 毫升增量以形成密封。记录最终使用的空气量和套囊内（IC）压力（通过压力传感器测量）。麻醉结束时，使用压力计测量 IC 压力，并将这些测量值与压力传感器的测量值进行比较。在麻醉前、拔管后 2 小时和 24 小时，通过内窥镜检查评估喉和气管黏膜，并给予 0-3 分的评分。
由于一只患有喉麻痹的马被排除在外，因此只有七匹马的数据。气管超声测量的平均值为 3.5±0.4 厘米。在任何时间点，气管内导管大小对插管评分、IC 压力、充气量或气管或喉损伤评分均无显著差异。压力计测量的 IC 压力略高于传感器（+1.0±2.8mmHg）。
在研究的马匹群体中，当正确进行气管插管并仔细监测 IC 压力时，未发现一种气管内导管尺寸明显优于另一种，因此没有明显优势。然而，由于 ETT 与观察到的最高 IC 压力和唯一观察到的气管周径红斑有关，在大多数情况下，当气管大小足够时，较大的 ETT 可能是更好的选择。
