The effect of i-gel® insertion on the accuracy of cricothyroid membrane identification in adult females: a prospective observational study

Tracheal Deviation and Airway Management: Clinical Considerations From a Cadaver

Severe tracheal deviation detected on preoperative chest radiographs is one of the risk factors for difficult tracheal intubation and difficulty in ventilation using an endotracheal tube after tracheal intubation when managing the airway through tracheal intubation under general anesthesia. In this report, we describe the cadaver of an 81-year-old woman with marked tracheal deviation due to meandering multiple aortas. This report details the importance of anatomical knowledge in developing a detailed airway management plan. The deviated trachea was removed from the cadaver and the tracheal tube was inserted at the glottis to the proximal end of the glottal marker. The tube tip was in contact with the tracheal wall, suggesting ventilation difficulty during intubation. The tortuous brachiocephalic artery passed in front of the trachea, which posed a risk of massive aortic hemorrhage and postoperative trachea-brachiocephalic artery fistula during percutaneous tracheostomy for emergency airway management. The anatomical location of the trachea and carotid artery must be confirmed before surgery/anesthesia to ensure safe airway management.

Evaluation of a novel emergency front of neck access device in a benchtop model of obesity

BACKGROUND

Emergency front of neck access (eFONA) is a critical step in oxygenation in cases of unrelieved airway obstruction. Multiple techniques are used in clinical practice without agreement regarding the optimal approach. We evaluated a novel device, the Cric-Guide (CG), a channelled bougie introducer that enters the airway in a single action and compared it with a scalpel-bougie-tube (SBT) technique in laboratory benchtop model.

METHODS

Seven anaesthesiologists attempted eFONA on both obese and non-obese models using both techniques in randomized order on an excised porcine trachea with an intact larynx with variable subcutaneous tissue depth. The primary outcome was successful tracheal cannulation. Secondary outcomes included false passage rate, time and tissue injury.

RESULTS

Anaesthesiologists performed 4 cricothyroidotomies on each model with each device. The CG was more successful in airway cannulation (47/56 [89.4%] vs. 33/56 [58.9%], P = 0.007). This difference was observed in the obese model only. The CG was associated with fewer false passages than the standard technique in the obese model (8/56 [14.3%] vs. 23/56 [41.1%], P = 0.006). There were no significant differences in time to completion or injury patterns between the techniques in the obese model, but the SBT was faster in the non-obese model. There was no difference in the proportion of specimens injured.

CONCLUSION

The Cric-Guide device was more successful than the standard SBT technique in airway cannulation in an obese neck model and with equivalent frequency and distribution of injury but performed equivalently in the non-obese model.

Effect of different types of laryngeal mask airway placement on the right internal jugular vein: A prospective randomized controlled trial

BACKGROUND

In recent years, with the popularity of laryngeal mask airway (LMA) for the management of clinical anesthesia, the influence of the LMA on the position and blood flow of the internal jugular vein (IJV) has attracted an increasing amount of attention.

AIM

To investigate the effect of placement of different types of LMA (Supreme LMA, Guardian LMA, I-gel LMA) on the position and blood flow of the right IJV.

METHODS

This was a prospective randomized controlled trial. A total of 102 patients aged 18-75 years who were scheduled to undergo laparoscopic abdominal surgery with general anesthesia were randomly assigned to three groups: Supreme LMA (group 1), Guardian LMA (group 2), and I-gel LMA (group 3) groups. The main indicator was the overlap index (OI) of IJV and the common carotid artery (CCA) at the high, middle, and low points before and after the placement of the LMA. The second indicators were the proportion of ultrasound-simulated needle crossing the IJV and CCA, and the cross-sectional area and blood flow velocity of the IJV before and after placement of the LMA at the middle point.

RESULTS

Data from 100 patients were included in the statistical analysis. The OI increased significantly after placement of the LMA in the three groups at the three points (P < 0.01), except group 2 at the low point. In group 2 and group 3, the OI was lower than that in group 1 after LMA insertion at the high point (P < 0.0167). At the middle point, after LMA insertion, the proportion of simulated needle crossing the IJV significantly decreased in all three groups (P < 0.05), and the proportion in group 2 was higher than that in group 3 (P < 0.0167). The proportion of simulated needle crossing the CCA or both the IJV and CCA significantly increased in group 1 and group 2 (P < 0.05), which increased with no statistical significance in group 3. After LMA insertion, the cross-sectional area of ​​the IJV significantly increased, while the blood flow velocity significantly decreased (P < 0.01). There was no significant difference among the three groups.

CONCLUSION

The placement of Supreme, Guardian, and I-gel LMA can increase the OI, reduce the success rate of IJV puncture, increase the incidence of arterial puncture, and cause congestion of IJV. Type of LMA did not influence the difficulty of IJV puncture. Therefore when LMA is used, ultrasound is recommended to guide the IJV puncture.

Accuracy of ultrasound in measurement of the pediatric cricothyroid membrane

BACKGROUND

Emergency front of neck airway is a recommended airway rescue strategy in children over 1 year old. Surgical tracheostomy is advocated as the first-line technique, but in the absence of an ear, nose and throat surgeon cricothyroidotomy or tracheostomy is proposed. Recent research shows that clinical identification of the cricothyroid membrane is frequently inaccurate in older children and adults and has prompted investigation of ultrasound as a potential clinical tool for emergency front of neck airway. Advance knowledge of the dimensions of the pediatric cricothyroid membrane may assist clinicians in determining the feasibility of emergency front of neck airway, optimum technique, and equipment.

AIMS

The aim of this study was to assess the accuracy of ultrasound-assisted pediatric cricothyroid membrane localization and dimension measurement using magnetic resonance imaging as the reference standard.

METHODS

After structured training, two pediatric anesthesiology trainees used ultrasound to identify and measure the dimensions of the cricothyroid membrane in pediatric patients undergoing elective magnetic resonance imaging of the head and neck under general anesthesia. A pediatric radiologist reviewed the corresponding magnetic resonance imaging scans and measured the height of the cricothyroid membrane. The accuracy of the cricothyroid membrane height as measured by ultrasound was compared to that measured by magnetic resonance imaging.

RESULTS

Twenty-two patients were included in the study. The cricothyroid membrane was accurately identified by ultrasound in all cases. The correlation coefficient for cricothyroid membrane height measured by ultrasound and that measured by magnetic resonance imaging was 0.98 (95% C.I 0.95-0.99, P < 0.0001). The bias was -0.16 mm and the precision was 0.19 mm. All differences were within the a priori limits of agreement. The 95% limits of agreement were -0.54 to 0.22 mm.

CONCLUSION

Ultrasound can be used to accurately identify and measure cricothyroid membrane height in pediatric patients. This approach could have clinical and research utility.