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

Protective potential of different mouthguard thicknesses against perianaesthetic dental trauma: a patient specific-finite element study

Perianaesthetic dental trauma is a common anaesthesia-related complication. Theprevious studies have shown a lack of knowledge regarding mouthguard usage and controversial results related to perianaesthetic dental trauma prevention. This study aimed to conduct a finite element analysis of the compressive and tensile stresses on the tooth-periodontal ligament-bone complex using custom-made mouthguards of different thicknesses and glass fibre splints to prevent perianaesthetic dental trauma. Custom-fitted ethylene-vinyl acetate mouthguards of two different thicknesses (2 and 3 mm) and glass fibre splint were modelled. A linear static finite element analysis was performed by applying a rigid Macintosh laryngoscope to the palatal surface of the maxillary central incisors at 150 N. The model without a mouthguard and glass fibre splint showed the highest stress values at the palatinal root surfaces during the impact. Increasing the mouthguard thickness significantly decreased the stress-strain values regardless of the presence of the glass fibre splint. Maximum stresses in the group using the 3 mm mouthguard were the lowest compared with the other groups.

Comparison of Macintosh Laryngoscope, King Vision®, VividTrac®, AirAngel Blade®, and a Custom-Made 3D-Printed Video Laryngoscope for Difficult and Normal Airways in Mannequins by Novices-A Non-Inferiority Trial

Background: Endotracheal intubation (ETI) is a cornerstone of airway management. The gold standard device for ETI is still the direct laryngoscope (DL). However, video laryngoscopes (VLs) are now also widely available and have several proven advantages. The VL technique has been included in the major airway management guidelines. During the COVID-19 pandemic, supply chain disruption has raised demand for 3D-printed medical equipment, including 3D-printed VLs. However, studies on performance are only sparsely available; thus, we aimed to compare 3D-printed VLs to the DL and other VLs made with conventional manufacturing technology. Methods: Forty-eight medical students were recruited to serve as novice users. Following brief, standardized training, students executed ETI with the DL, the King Vision® (KV), the VividTrac® (VT), the AirAngel Blade® (AAB), and a custom-made 3D-printed VL (3DVL) on the Laerdal® airway management trainer in normal and difficult airway scenarios. We evaluated the time to and proportion of successful intubation, the best view of the glottis, esophageal intubation, dental trauma, and user satisfaction. Results: The KV and VT are proved to be superior (p < 0.05) to the DL in both scenarios. The 3DVL's performance was similar (p > 0.05) or significantly better than that of the DL and mainly non-inferior (p > 0.05) compared to the KV and VT in both scenarios. Regardless of the scenario, the AAB proved to be inferior (p < 0.05) even to the DL in the majority of the variables. The differences between the devices were more pronounced in the difficult airway scenario. The user satisfaction scores were in concordance with the aforementioned performance of the scopes. Conclusions: Based upon our results, we cannot recommend the AAB over the DL, KV, or VT. However, as the 3DVL showed, 3D printing indeed can provide useful or even superior VLs, but prior to clinical use, meticulous evaluation might be recommended.

Styletubation in Bariatric Surgery: A Case Report

Direct laryngoscopes and videolaryngoscopes are the dominant endotracheal intubation tools. The styletubation technique (using a video-assisted intubating stylet) has shown its advantages in terms of short intubation time, high success rate, less required stimulation, and operator satisfaction. The learning curve can be steep but is easily overcome if technical pitfalls are avoided. Conditions that make styletubation challenging include secretions/blood, short/stiff neck, restricted mouth opening and cervical spine mobility, anatomical abnormalities over head and neck regions, obesity, etc. In this clinical report, we present the effectiveness and efficiency of the routine use of the styletubation for tracheal intubation in a super-super-obese patient (BMI 103 kg/m2) undergoing bariatric surgery with laparoscopic sleeve gastrectomy.

Comparison of a tube core and Magill forceps for nasotracheal intubation: a randomised controlled trial

Background

Magill forceps are frequently used to complete nasotracheal intubation (NTI). We aimed to identify a tube core that could conveniently facilitate the NTI process without using Magill forceps.

Methods

Sixty patients scheduled for oral and maxillofacial surgeries were enrolled in our study and divided into two groups (30 per group) with no differences with regard to demographic data. In the Magill forceps group (Group M), a wire-reinforced endotracheal catheter was inserted into the trachea using Magill forceps. However, in the tube core group (Group T), a tube core bent to the physiological curve of the nasal cavity and lubricated with aseptic paraffin oil was inserted into the endotracheal catheter and was then withdrawn after the endotracheal catheter was advanced through the glottis under direct vision.

Results

All NTIs were completed successfully, and Magill forceps were not used on any patient in Group T. There was a significant difference in total NTI time between the two groups (Group M, 59.7 (5.1) s vs Group T, 52.4 (3.1) s). Mild epistaxis was observed in 6 patients in Group M and 5 patients in Group T (6/30 vs 5/30, respectively). No damage to oral tissue or teeth was observed in either group.

Conclusions

We conclude that using a tube core, consisting of a disposable sterilised stylet, is a convenient choice for NTI.

Trial registration

Patient enrolment was conducted after registration in the Chinese Clinical Trial Registry (www.Chictr.org.cn, ChiCTR190002 7387). This trial was prospectively registered on 11 November 2019.

Does seniority always correlate with simulated intubation performance? Comparing endotracheal intubation performance across medical students, residents, and physicians using a high-fidelity simulator

Background

Endotracheal intubation is crucial in emergency medical care and anaesthesia. Our study employed a high-fidelity simulator to explore differences in intubation success rate and other skills between junior and senior physicians.

Methods

We examined the performance of 50 subjects, including undergraduate students (UGY), postgraduate trainees (PGY), residents (R), and attending physicians (VS). Each participant performed 12 intubations (i.e. 3 devices x 4 scenarios) on a high-fidelity simulator. Main outcome measures included success rate, time for intubation, force applied on incisor and tongue, and Cormack Lehane grades.

Results

There was no primary effect of seniority on any outcome measure except success rate and Cormack Lehane grades. However, VS demonstrated shorter duration than medical students using Glidescope and direct laryngoscopy, whereas VS and R applied significantly more force on the incisor in the normal airway and rigid neck scenario respectively.

Discussion

Seniority does not always correlate with skill perfection in detailed processes. Our study suggests that the use of video laryngoscopy enhances the intubation success rate and speed, but the benefit only accrues to senior learners, whereby they applied more force on the incisor at a single peak under difficult scenarios. These findings are discussed in terms of psychological and cognitive perspectives.

Conclusion

Speed and safety are essential for high quality critical medical procedures. A tool should be designed and implemented to educate junior physicians with an emphasis on practice and efficiency, which should also contribute to updating senior physicians’ knowledge and competence by providing instant feedback on their performance. This type of fine-grained feedback could serve as a complement to traditional training and provide a sustainable learning model for medical education.

Radiological indicators to predict the application of assistant intubation techniques for patients undergoing cervical surgery

Background

We aimed to distinguish the preoperative radiological indicators to predict the application of assistant techniques during intubation for patients undergoing selective cervical surgery.

Methods

A total of 104 patients were enrolled in this study. According to whether intubation was successfully accomplished by simple Macintosh laryngoscopy, patients were divided into Macintosh laryngoscopy group (n = 78) and Assistant technique group (n = 26). We measured patients’ radiographical data via their preoperative X-ray and MRI images, and compared the differences between two groups. Binary logistic regression model was applied to distinguish the meaningful predictors. Receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to describe the discrimination ability of indicators. The highest Youden’s index corresponded to an optimal cut-off value.

Results

Ten variables exhibited significant statistical differences between two groups (P <  0.05). Based on logistic regression model, four further showed correlation with the application of assistant techniques, namely, perpendicular distance from hard palate to tip of upper incisor (X2), atlanto-occipital gap (X9), angle between a line passing through posterior-superior point of hard palate and the lowest point of the occipital bone and a line passing through the anterior-inferior point and the posterior-inferior point of the second cervical vertebral body (Angle E), and distance from skin to hyoid bone (MRI 7). Angle E owned the largest AUC (0.929), and its optimal cut-off value was 19.9° (sensitivity = 88.5%, specificity = 91.0%). the optimal cut-off value, sensitivity and specificity of other three variables were X2 (30.1 mm, 76.9, 76.9%), MRI7 (16.3 mm, 69.2, 87.2%), and X9 (7.3 mm, 73.1, 56.4%).

Conclusions

Four radiological variables possessed potential ability to predict the application of assistant intubation techniques. Anaesthesiologists are recommended to apply assistant techniques more positively once encountering the mentioned cut-off values.

Comparison of Glidescope® Go™, King Vision™, Dahlhausen VL, I‑View™ and Macintosh laryngoscope use during difficult airway management simulation by experienced and inexperienced emergency medical staff: A randomized crossover manikin study

Background

In pre-hospital emergency care, video laryngoscopes (VLs) with disposable blades are preferably used due to hygienic reasons. However, there is limited existing data on the use of VLs with disposable blades by emergency medical staff. Therefore, the aim of this study was to compare the efficacy of four different VLs with disposable blades and the conventional standard Macintosh laryngoscope, when used by anesthetists with extensive previous experience and paramedics with little previous experience in endotracheal intubation (ETI) in a simulated difficult airway.

Methods

Fifty-eight anesthetists and fifty-four paramedics participated in our randomized crossover manikin trial. Each performed ETI with the new Glidescope^® Go^™, the Dahlhausen VL, the King Vision^™, the I-View^™ and the Macintosh laryngoscope. “Time to intubate” was the primary endpoint. Secondary endpoints were “time to vocal cords”, “time to ventilate”, overall success rate, number of intubation attempts and optimization maneuvers, Cormack-Lehane score, severity of dental compression and subjective impressions.

Results

The Glidescope^® Go^™, the Dahlhausen VL and the King Vision^™ provided superior intubation conditions in both groups without affecting the number of intubation attempts or the time required for successful intubation. When used by anesthetists with extensive experience in ETI, the use of VLs did not affect the overall success rate. In the hands of paramedics with little previous experience in ETI, the failure rate with the Macintosh laryngoscope (14.8%) decreased to 3.7% using the Glidescope^® Go^™ and the Dahlhausen VL. Despite the advantages of hyperangulated video laryngoscopes, the I-View^™ performed worst.

Conclusions

VLs with hyperangulated blades facilitated ETI in both groups and decreased the failure rate by an absolute 11.1% when used by paramedics with little previous experience in ETI. Our results therefore suggest that hyperangulated VLs could be beneficial and might be the method of choice in comparable settings, especially for emergency medical staff with less experience in ETI.