Transillumination-assisted orotracheal intubation: a comparison of the Bonfils fibrescope and the lightwand (Trachlight)

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.

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.

A comparison of the transillumination-assisted technique versus midline approach technique in novices: a prospective randomized controlled trial about the Bonfils intubation fiberscope

Background

The present study aimed to compare the safety and efficacy for novices to conduct intubation with the Bonfils intubation fiberscope (BIF) using the transillumination-assisted or midline approach technique in patients with normal airways.

Methods

In this prospective randomized control study, 10 trainees were assigned to the transillumination-assisted technique group (T group) or the midline approach technique group (R group). Each trainee was required to conduct intubation in 50 patients. The primary outcome was intubation time. The secondary outcomes were success rate (%), number of attempts, and complications.

Results

Among the cases of successful intubation, the intubation time was not significantly different between the two groups (P > 0.05). The overall success rate of intubation was not significantly different between the two groups (P > 0.05). The intubation success rates at the first, second, and third attempts as well as the average intubation times were similar between the two groups (P > 0.05), but in patients receiving successful intubation at the second attempt, the intubation time was longer in the T group (P = 0.0006). The incidences of dry throat, sore throat, and hoarseness were higher in the T group (all P < 0.05).

Conclusions

For patients with a normal airway, the transillumination-assisted technique was unlikely to increase the success rate of intubation with the BIF compared with the midline approach technique, but led to more complications.

Trial registration

ChiCTR-INR-16009967, retrospectively registered on November 22, 2016

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-017-0322-6) contains supplementary material, which is available to authorized users.