Invasive Techniken in der Notfallmedizin

[Ultrasound supported identification of the ligamentum conicum in teaching head and neck sonography]

OBJECTIVE

Upper airway obstructions are usually acute emergencies. Coniotomy is the last option to secure the airway and can be supported by sonography. The aim of this study was to establish a training program to teach these skills.

MATERIAL AND METHODS

The training consisted of theoretical training with an additional video presentation (10 minutes each) and practical training (45 minutes). Evaluations were completed before (T1) and after (T2) the training to measure prior experience and satisfaction with the training as well as subjective and objective competence levels. At T2, a practical test was also completed by n=113 participants. A standardized evaluation form was used to document the results of the practical test.

RESULTS

A large proportion of the participants had neither seen a coniotomy (64.6%) nor performed one independently (79.6%). Significant improvement (T1 to T2) was measured with regard to the subjective assessment of competence (p<0.001). The training received positive ratings for all items tested (scale ranges 1-2). During practical tests, the participants achieved an average of 89.2% of the possible points and needed a mean of 101 ±23 seconds to identify the conic ligament.

CONCLUSION

Structured training for sonographic identification of the conic ligament leads to significant improvement in the subjective assessment of competence and a high objective competence level in a short period of time. This type of training should be standardized in head and neck ultrasound training in the future.

[Comparison of ready-to-use devices for emergency cricothyrotomy : randomized and controlled feasibility study on a mannequin]

BACKGROUND

According to various algorithms of airway management, emergency cricothyrotomy (coniotomy) represents the ultimate step for managing the difficult airway. As most physicians have limited experience with this technique several ready-to-use devices have emerged on the market with the aim of simplifying the procedure. However, they differ in details, such as configuration or the order of particular steps. Therefore, the intention of this randomized and controlled feasibility study was to test various sets and compare them to the classical surgical approach.

METHODS

After obtaining informed consent German anesthesiologists who were also board-certified emergency physicians were asked to perform the cricothyrotomy procedure in a cervical mannequin (Frova Crico-Trainer, VBM Medizintechnik) in a randomized order using a scalpel, peripheral intravenous cannula and the commercial devices TracheoQuick, Airfree, Portex-Crico-Kit, Quicktrach I and Quicktrach II. Handling and duration of the procedures were analyzed utilizing the Wilcoxon signed-rank test. A p-value  < 0.05 was considered significant.

RESULTS

A total of 20 anesthesiologists (11 residents and 9 specialists) with a mean age of 34 years were included in this study and all had the additional qualification of emergency physician, which enabled them to work in prehospital emergency medicine in Germany. Participants had been working in this field for an average of 29.9 months (range 6-84 months) performing a mean of 1.9 24 h shifts per month (range 1-6 shifts/month). Of the participants only 2 (10%) had performed a coniotomy in reality before. In this study surgical coniotomy required a median time of 35.4 s (range 30.0-61.8 s). No significant differences were seen when the cuffed devices Quicktrach II (median: 29.9 s, range 25.0-50.5 s) and Portex-Crico-Kit (median: 46.7 s, range 37.0-67.3 s) were used. A significantly faster airway was established using the non-cuffed devices TracheoQuick (median: 20.2 s, range 11.4-44.7 s), Airfree (median: 22.8 s, range 14.3-33.2 s), Quicktrach I (median: 21.1 s, range 14.5-32.4 s) and the peripheral intravenous cannula (median: 19.2 s, range 10.8-27.8 s). Incorrect tube placements were not observed.

CONCLUSION

This study allowed the comparison of surgical coniotomy to several ready-to-use devices in a standardized setting utilizing a reusable plastic mannequin. The interpretation for real emergency conditions is limited as individual anatomy, traumatic alterations of the neck or complications, such as bleeding or damage of important structures were not part of the study objectives. However, all participating emergency physicians successfully used the coniotomy sets provided at the first attempt. No device required significantly more time than the surgical approach. The procedures using cuffed devices lasted longer in comparison to procedures using uncuffed ones; however, this difference would only play a minor role in reality as effective ventilation with minute volumes greater than 7 l/min will only be achieved by a cuffed cannula with a minimum internal diameter of 4 mm. Devices with no cuff or with tube diameters smaller than 4 mm will only allow oxygenation of the patient, which in turn requires an inspiratory oxygen concentration of 100% and a relatively high ventilation frequency.

Emergency cricothyrotomy in infants--evaluation of a novel device in an animal model

BACKGROUND

According to different algorithms of airway management, emergency cricothyrotomy is the final step in managing an otherwise not accessible airway. As an alternative to an open surgical procedure, minimally invasive approaches exist. Quicktrach baby™ is a commercially available set for a minimal invasive cricothyrotomy in infants. The set consists of a plastic cannula over a metal needle for direct placement in the trachea. So far, this device has not been evaluated for its intended use.

OBJECTIVES

We hypothesize that Quicktrach baby™ allows the establishment of an emergency airway. The aim was to prove that the device is easy to handle and the cricothyrotomy fast to perform.

METHODS

After approval of the local ethics committee, the study was performed on the cadavers of 10 adult rabbits. Cricothyrotomy was performed with Quicktrach baby™. Successful placement, performance time, and complication rate were documented. Possible ventilation with a breathing bag was evaluated. Data are reported as mean and interquartile range.

RESULTS

Successful placement of Quicktrach baby™ was possible in all attempts. The placement took 31 [23-43] s. In two cases, a fracture of the cricoid's cartilage was seen. In one animal, damage to the posterior wall mucosa was observed. In all cases, sufficient ventilation was possible.

CONCLUSIONS

Quicktrach™ baby proved to be a reliable technique. In the animal model, it is easy and fast to perform. Only a few minor complications occurred. Sufficient ventilation was possible in all attempts.

Surgical approach in difficult airway management

In all difficult airway algorithms, cricothyroidotomy is the life-saving procedure and is the final 'cannot ventilate, cannot intubate' option, whether in pre-hospital, emergency department, intensive care unit, or operating room patients. Cricothyroidotomy is a relatively safe and rapid means of securing an emergency airway. As with all other critical procedures in emergency medicine, a thorough knowledge of the technique and adequate practice prior to attempting to perform an emergency cricothyroidotomy are essential.