Comparison of forces acting on maxillary incisors during tracheal intubation with different laryngoscopy techniques: a blinded manikin study

Dental trauma is a common complication of tracheal intubation. As existing evidence is insufficient to validly assess the impact of different laryngoscopy techniques on the incidence of dental trauma, the force exerted onto dental structures during tracheal intubation was investigated. An intubation manikin was equipped with hidden force sensors in all maxillary incisors. Dental force was measured while 104 anaesthetists performed a series of tracheal intubations using direct laryngoscopy with a Macintosh blade, and videolaryngoscopy with a C-MAC^®, or the hyperangulated GlideScope^® or KingVision^® laryngoscopes in both normal and difficult airway conditions. A total of 624 tracheal intubations were analysed. The median (IQR [range]) peak force of direct laryngoscopy in normal airways was 21.1 (14.0–32.8 [2.3–127.6]) N and 29.3 (17.7–44.8 [3.3–97.2]) N in difficult airways. In normal airways, these were lower with the GlideScope and KingVision hyperangulated laryngoscopes, with a reduction of 4.6 N (p = 0.006) and 10.9 N (p < 0.001) compared with direct laryngoscopy, respectively. In difficult airways, these were lower with the GlideScope and KingVision hyperangulated laryngoscopes, with a reduction of 9.8 N (p < 0.001) and 17.6 N (p < 0.001) compared with direct laryngoscopy, respectively. The use of the C-MAC did not have an impact on the median peak force. Although sex of anaesthetists did not affect peak force, more experienced anaesthetists generated a higher peak force than less experienced providers. We conclude that hyperangulated videolaryngoscopy was associated with a significantly decreased force exerted on maxillary incisors and might reduce the risk for dental injury in clinical settings.     

Removal methods of rigid stylets to minimise adverse force and tracheal tube movement: a mathematical and in-vitro analysis in manikins

This study investigated displacement of the tracheal tube caused by different methods of intubating stylet removal, using in-vitro experiments and mathematical analysis. In the first in-vitro experiment, we measured the distance travelled by the tube tip during stylet extraction. Then, we investigated the ideal technique for stylet extraction using mathematical analysis, which would cause minimal tube displacement. Then, using a training manikin, we measured the force applied to the vocal cords and stylet extraction force during tracheal intubation. When the stylet was extracted along a straight path towards the stylet end, the distance travelled by the tube tip significantly increased as the bending angle increased. Mathematical analysis revealed that the stylet should be diagonally extracted (in the sagittal plane) at an appropriate angle, rather than along a straight path towards the direction of the stylet end. In simulated tracheal intubation, extraction force and force applied to the vocal cords both significantly increased as the bending angle increased. Compared with the ‘hockey stick’-shaped stylet, the arcuate-shaped stylet resulted in reduced force. Our results indicate the potential risk for vocal cord injury when using hockey stick-shaped stylets with large bending angles.     

Assessment and management of the predicted difficult airway in babies and children

Although it is essential to take a history and examine every child prior to airway management, preoperative anticipation of a difficult airway is not totally reliable and therefore it is wise to be prepared for the unexpected difficult airway. Information about the airway can be gained from previous medical records, current history, physical examination and other tests. A natural consequence of airway assessment is development of an airway plan. Important anatomical and physiological features may be identified in an airway assessment which can then have a direct influence on the subsequent airway plan. Managing the predicted difficult airway is usually elective. This allows proper preparation of equipment, assistants, expertise and the environment required for the airway plan. This article will discuss paediatric airway assessment, outline those features that contribute to airway difficulty, and identify indications and risk factors associated with various airway techniques. Key objectives for an airway management plan are to maintain oxygenation and avoid trauma. This involves adopting techniques that avoid hypoxia and provide a high success rate with minimum attempts.     

Tracheal intubation

Tracheal intubation is the act of placing a tube into the trachea. The tube enables oxygen delivery and removal of carbon dioxide, while also allowing for the administration of pharmacological agents. Intubation is the most reliable method of maintaining an airway under anaesthesia, and for protection against aspiration of stomach contents. Traditionally, intubation is achieved by direct visualization of the glottis, but now indirect laryngoscopy (via a videolaryngoscope) is a common alternative. Prior to embarking upon intubation, a thorough patient history and examination must be undertaken by the laryngoscopist; equipment must be prepared and checked; a trained assistant present; and an experienced anaesthetist available in case assistance is required. Once the endotracheal tube has been placed, correct positioning must be confirmed via both clinical examination and monitoring, including capnography. Tracheal intubation is a procedure that should only be undertaken by trained operators and is not without risk. It is important to note that it is failure to oxygenate patients rather than failure to intubate that ultimately leads to serious morbidity and mortality. The Difficult Airway Society has produced guidelines on how to manage unanticipated difficulty in tracheal intubation; it is essential that every practitioner trained to intubate patients is familiar with these algorithms and the key principles of safe airway management.     

‘Where did the tube go?’ A case of retropharyngeal submucosal false passage during nasal intubation

Nasotracheal intubation could be associated with a variety of complications, of which traumatic complications are commonly encountered. We present a rare case of retropharyngeal submucosal false passage which occurred during nasotracheal intubation inspite of avoiding potential risk factors known for causing nasopharyngeal trauma. Risk factors, preventive measures and probable reason for this complication have been discussed.     

Understanding and improving airway management in companion animals - part 1

Airway Management, briefly taught within the veterinary nursing curriculum, is performed many times a day and a vital part of the anaesthesia process. Students are shown how to place an endotracheal tube, taught little about dead-space and airway resistance but, although there are many publications on the pitfalls of intubation, it is often sub-optimally managed in a busy clinic. To provide excellent, safe airway management for our patients, we must understand the history, mechanics and pitfalls about the process: It is only then can we truly apply better techniques in order to improve both care and safety to our patients.     

持续质量改进在小儿气管插管非计划性拔管中的应用

目的 探讨小儿气管插管非计划性拔管的危险因素,采取针对性措施,以降低小儿气管插管非计划性拔管的发生率.方法 应用持续质量改进的方法,对小儿发生非计划性拔管的原因进行分析,确定改进目标,制订改进计划并实施,评价改进效果.结果 小儿气管插管非计划性拔管的发生率下降(P<0.01).结论 遵循质量持续改进原则实施管理,...