Infrared Red Intubation System (IRRIS) guided flexile videoscope assisted difficult airway management

Infrared flashing light through the cricothyroid membrane as guidance to awake intubation with a flexible bronchoscope: A randomised cross-over study

BACKGROUND

In case of distorted airway anatomy, awake intubation with a flexible bronchoscope can be extremely difficult or even impossible. To facilitate this demanding procedure, an infrared flashing light source can be placed on the patient's neck superficial to the cricothyroid membrane. The light travels through the skin and tissue to the trachea, from where it can be registered by the advancing bronchoscope in the pharynx and seen as flashing white light on the monitor. We hypothesised that the application of this technique would allow more proximal and easier identification of the correct pathway to the trachea in patients with severe airway pathology.

METHODS

As part of awake intubation, patients underwent insertion of a flexible video bronchoscope via the mouth into the trachea. The procedure was performed twice, in random order in each patient, with and without the aid of the transcutaneous flashing infrared light. All insertions were video recorded to determine at which anatomical landmark within the airway the correct pathway was identified. The videos are accessible via this link: https://airwaymanagement.dk/infrared_comparative. The predefined landmarks were in successive order: oral cavity, oro-pharynx, tip of epiglottis, arytenoid cartilages, false cords, vocal cords and trachea, as well as the spaces between them.

RESULTS

Twenty-two patients had a total of 44 awake insertions with the flexible bronchoscope. The median anatomical level, at which correct identification of the trachea was obtained on the monitor, was, past the epiglottis, with the conventional technique, and at the level of the oropharynx, when using the infrared flashing light (p = .005). The time until the flashing light or the vocal cords were seen was 21 (22) S, mean (SD), and 48 (62) S, during the insertion with and without infrared flashing light activated, respectively (p = .005). Endoscopists rated it easier (p = .001) to recognise the entrance to the trachea in the infrared-group.

CONCLUSION

During awake intubation of patients with airway pathology, the application of trans-cricothyroid infrared flashing light to guide the insertion of a flexible bronchoscope significantly facilitated the recognition of the pathway into the trachea and the correct advancement of the flexible endoscope.

REGISTRATION OF CLINICAL TRIAL

NCT03930550.

Managing Known Difficult Airways in Obstetric Patients Using a Flexible Bronchoscope and IRRIS: A Case-Illustrated Guide for Nonexpert Anesthesiologists, without Surgical Backup

Pregnancy is associated with anatomical and physiological changes leading to potential difficult airway management. Some pregnant women have known difficult airways and cannot be intubated even with a hyperangulated videolaryngoscope. If neuraxial techniques are also impossible, awake tracheal intubation with a flexible bronchoscope may be one of the few available options to avoid more invasive techniques. The Infrared Red Intubation System (IRRIS) may help nonexpert anesthesiologists in such situations and may enhance the chance of successful intubation increasing safety for the mother and the fetus, especially in hospitals without the ear, nose, and throat surgical backup.

Infrared flashing light through the cricothyroid membrane to guide flexible bronchoscopic tracheal intubation

Flexible bronchoscopic tracheal intubation is a fundamental technique in the management of the difficult airway but requires specific skills which may be both difficult to achieve and maintain. Therefore, techniques to improve its success should be developed. We present two cases, one where the ear, nose and throat surgeon could not view the glottis due to laryngeal pathology, and one where pathology in the oropharynx obscured access to the trachea during attempts at flexible bronchoscopic and videolaryngoscopic tracheal intubation. In both cases, tracheal intubation was subsequently successful due to the use of the Infrared Red Intubation System. This is an infrared light source that is secured to the anterior neck. It emits a flashing infrared light that is captured by the flexible bronchoscope, thus guiding the way to the trachea. These are the first reports of this technology being used for flexible bronchoscopic tracheal intubation in patients with severe airway pathology where conventional approaches had failed. Both cases emphasise that this technique can be of benefit in avoiding a surgical airway.

Impact of retrograde transillumination while securing the airway in obese patients undergoing bariatric surgery

Video laryngoscopy (VL) is a well-established technique used in anaesthetising obese patients who present with higher risks of airway-related difficulties and desaturations due to shorter safe apnoea periods. However, VL has certain limitations and may fail. We present the Infrared Red Intubation System (IRRIS), a new technique facilitating glottis identification in severely obese patients undergoing anaesthesia for bariatric surgery. This single-centre, prospective trial assessed the efficacy of the IRRIS for VL tracheal intubation in 20 severely obese adult patients undergoing elective bariatric surgery under general anaesthesia. We assessed the ability of the IRRIS to differentiate the transilluminated glottis from the oesophagus and laryngeal folds and evaluated the ease of intubation. The average weight in the investigated patient cohort was 145 ± 29 kg, the suprasternal tissue thickness was 12 ± 4 mm. The median IQR [range] larynx recognition time was 10 [2-50] s, which was similar to that of lean patients. The degree of obesity correlated with the duration to achieve optimal laryngoscopic view and complete the intubation procedure. We achieved successful VL insertion on the first attempt in 13 of 20 cases (65%), and on the second attempt in 7 cases (35%), emphasising the increased probability of successful intubation on the first attempt. Tracheal intubation with the IRRIS lasted 50 [IQR 20-100] s. The lowest SpO₂ during intubation was 98 [IQR 83-100] %. Addition of IRRIS to VL insertion facilitated the intubation of difficult airways in severely obese patients. IRRIS improves the visualization of the intubation pathway by selectively highlighting the airway entrance and shortens the time to successfully conclude the intubation procedure.

A new retrograde transillumination technique for videolaryngoscopic tracheal intubation

This single-centre, prospective trial was designed to assess the efficacy of a new retrograde transillumination device called the 'Infrared Red Intubation System' (IRRIS) to aid videolaryngoscopic tracheal intubation. We included 40 adult patients, who were undergoing elective urological surgery under general anaesthesia. We assessed the ability to differentiate the transilluminated glottis from other structures and found a median (IQR [range]) larynx recognition time of 8 (5-14 [3-28]) s. The difference in laryngeal visibility on the screen between the deactivated vs. activated device expressed on a visual analogue scale was significant (6 (4-7 [2-10]) vs. 10 (8-10 [4-10]); p < 0.001). The number of laryngoscope insertions was 1 (1-2 [1-3]) and the device showed high values on a visual analogue scale ranging from 0 (lowest score) to 10 (highest score) for helpfulness (6 (5-7 [2-10])), credibility (10 (8-10 [5-10])) and ease of use (10 (9-10 [8-10])). Tracheal intubation with the system lasted 26 (16-32 [6-89]) s. No alternative technique of securing the airway was necessary. The lowest SpO₂ during intubation was 98 (97-99 [91-100])%. We conclude that this method of retrograde transillumination can assist videolaryngoscopy.