Effectiveness of the endotracheal tube cuff on the trachea: physical and mechanical aspects

Introduction

The inflation pressure of the endotracheal tube cuff can cause ischemia of the tracheal mucosa at high pressures; thus, it can cause important tracheal morbidity and tracheal microaspiration of the oropharyngeal secretion, or it can even cause pneumonia associated with mechanical ventilation if the pressure of the cuff is insufficient.

Objective

In order to investigate the effectiveness of the RUSCH® 7.5 mm endotracheal tube cuff, this study was designed to investigate the physical and mechanical aspects of the cuff in contact with the trachea.

Methods

For this end, we developed an in vitro experimental model to assess the flow of dye (methylene blue) by the inflated cuff on the wall of the artificial material. We also designed an in vivo study with 12 Large White pigs under endotracheal intubation. We instilled the same dye in the oral cavity of the animals, and we analyzed the presence or not of leakage in the trachea after the region of the cuff after their deaths (animal sacrifice). All cuffs were inflated at the pressure of 30 cmH₂O.

Results

We observed the passage of fluids through the cuff in all in vitro and in vivo experimental models.

Conclusion

We conclude that, as well as several other cuff models in the literature, the RUSCH® 7.5 mm tube cuffs are also not able to completely seal the trachea and thus prevent aspiration of oropharyngeal secretions. Other prevention measures should be taken.     

Comparison of the TruView infant EVO2 PCD™ and C-MAC video laryngoscopes with direct Macintosh laryngoscopy for routine tracheal intubation in infants with normal airways

OBJECTIVE:

Videolaryngoscopy has mainly been developed to facilitate difficult airway intubation. However, there is a lack of studies demonstrating this method''s efficacy in pediatric patients. The aim of the present study was to compare the TruView infant EVO2 and the C-MAC videolaryngoscope with conventional direct Macintosh laryngoscopy in children with a bodyweight ≤10 kg in terms of intubation conditions and the time to intubation.

METHODS:

In total, 65 children with a bodyweight ≤10 kg (0-22 months) who had undergone elective surgery requiring endotracheal intubation were retrospectively analyzed. Our database was screened for intubations with the TruView infant EVO2, the C-MAC videolaryngoscope, and conventional direct Macintosh laryngoscopy. The intubation conditions, the time to intubation, and the oxygen saturation before and after intubation were monitored, and demographic data were recorded. Only children with a bodyweight ≤10 kg were included in the analysis.

RESULTS:

A total of 23 children were intubated using the C-MAC videolaryngoscope, and 22 children were intubated using the TruView EVO2. Additionally, 20 children were intubated using a standard Macintosh blade. The time required for tracheal intubation was significantly longer using the TruView EVO2 (52 sec vs. 28 sec for C-MAC vs. 26 sec for direct LG). However, no significant difference in oxygen saturation was found after intubation.

CONCLUSION:

All devices allowed excellent visualization of the vocal cords, but the time to intubation was prolonged when the TruView EVO2 was used. The absence of a decline in oxygen saturation may be due to apneic oxygenation via the TruView scope and may provide a margin of safety. In sum, the use of the TruView by a well-trained anesthetist may be an alternative for difficult airway management in pediatric patients.     

Using three-dimensional visualization as an optimal tool to plan and validate an aortopexy in a congenital heart disease patient with severe tracheal stenosis

We present a patient with severe tracheal stenosis resulting from a compression by the innominate artery 6 months after an arterial switch operation in a dextro-transposition of the great arteries. Segmentation and three-dimensional (3D) visualization were derived from a contrast-enhanced dual-source computed tomography and post-processing was performed using a dedicated open-source platform (3D Slicer). Post-processing allowed a comprehensible visualization of the relationship of the innominate artery to the trachea when compared to standard computer tomography reformations. Finally, the surgical approach to move the innominate artery anteriorly in order to relieve the tracheal obstruction was emphasized based on the improved 3D visualization of the actual pathology. An effective aortopexy could be performed and the postoperative result was confirmed by a second 3D visualization. About 3 months of follow-up, the patient is completely asymptomatic. Three-dimensional visualization offers excellent opportunities for diagnosis, treatment planning and follow-up in patients with a vascular-related tracheal stenosis in the context of congenital heart disease.     

术前连接气管插管下体位摆放的改进与护理

目的减少体位变动过程中增加气道阻力,防止术后麻醉恢复过程中气道损伤。方法将临床60例体位翻动患者按照体位翻动变化过程分为平卧搬动、侧卧搬动、俯卧搬动3阶段,分别比较改进前后体位移动时动态阻力变化隋况,比较改进前后体位移动后管道移位率及麻醉后护理评分。结果改进前后平卧搬动、侧卧搬动、俯卧搬动阶段分别比较体位移动前后安全纬度动态阻力、麻醉后护理评分及咽通气道使用率,差异均有统计学意义（P〈0.05）。结论术前连接气管插管下改进体位摆放方法可增加安全纬度,减少口咽通气道使用率。     

Critical importance of tracheal tube cuff pressure management

The ideal range for tracheal tube cuff pressures is usually taken to be between 20 to 30 cm H2 O. This is easily measured with a cuff pressure manometer and should be measured in each instance. The importanceof tracheal tube cuff pressures is highlighted by the spectrum of airway complications that can occur with incorrect cuff pressures. High cuff pressures can result in complications ranging from sore throat and hoarseness to tracheal stenosis, necrosis, and even rupture. In such cases, the postulated causative factor is diminished blood flow to tracheal mucosa due to excessive cuff pressure on the tracheal wall. This hypothesized ischemic injury then produces healing fibrosis months or even years later. On the other hand, cuff pressures that are too low place the patient at risk for aspiration of gastric contents and consequently, aspiration pneumonitis and pneumonia. This is why the authors recommend that cuff pressures be measured following all intubations.     

Symmetrical bronchial pattern with normal atrial morphology

An infant with trisomy 21 and tracheostenosis is described. Postmortem findings included symmetrical bronchi, normal atrial arrangement (“situs”) and anomalous thoracic vessels. The lack of concordance between the bronchial morphology and atrial arrangement supports the premise that atrial morphology is a more accurate predictor of the presence or absence of the isomerism syndromes.     

超声技术应用于气道管理的研究进展

背景 目前气道评估及管理仍然是一门不断更新的临床科学.近些年超声可视化技术的应用为围手术期、急诊及重症医学科患者的气道管理提供了一个动态的监测工具. 目的 针对超声技术在气道管理中的应用情况进行综述. 内容 描述呼吸道超声解剖结构,并概括超声在围手术期气道管理中的应用. 趋向 超声的应用使围手术期气道管理发生里程碑式的发展,未来将有更广阔的应用前景.     

氟比洛芬酯用于抑制神经外科气管拔管期不良反应的观察

目的探讨氟比洛芬酯用于抑制神经外科术后气管拔管期不良反应的有效性和可行性。方法ASAⅠ～Ⅱ级神经外科手术患者56例,随机分为观察组（氟比洛芬酯组）和对照组,2组分别在停用麻醉药前30min静注氟比洛芬酯注射液1.5mg/kg和加生理盐水5ml。在围拔管期观察并记录血压、心率、血氧饱和度、拔管时间、呼唤睁眼时间、躁动呛咳发生情况以及Ramsay镇静评分、VAS疼痛程度评分。结果围拔管期观察组的血压、心率均明显低于对照组,躁动和呛咳发生例数少,清醒度镇痛度明显优于对照组（P〈0.05）。结论氟比洛芬酯用于神经外科围拔管期可减轻气管拔管期不良反应,同时可产生良好的镇痛作用并维持满意的镇静度。