Sir,
Awake fibreoptic bronchoscopy (FOB) guided intubation is considered as the technique of choice for an anticipated difficult airway. However, video laryngoscopes are gaining popularity as first line devices in these scenarios.[1] Being similar to conventional direct laryngoscope with a short learning curve, C-MAC® video laryngoscope (Karl Storz, Tuttlingen, Germany) has got rapid acceptance among anaesthesiologists. Here, we describe the role of the angulated C-MAC® D-Blade for awake orotracheal intubation in restricted mouth opening situation.
A 28-year-old male with retinal haemorrhage was scheduled for vitreo-retinal surgery under general anaesthesia. The patient had a road traffic accident 10 days back. On examination, he had mouth opening of just 1.2 cm and the trismus was not due to pain [Figure 1a]. The computed tomography scan showed fractures of anterior cranial fossa, medial orbital wall and floor. Also, there were bilateral maxillary, nasal and left zygomatic bone fractures. There were no fractures of the mandible or dentition.
Figure 1.
(a) Patient with mouth opening of 1.2 cm. (b) C-MAC® D-Blade with a preshaped 7 size ETT well within the thickness of the blade
Our initial plan was awake orotracheal intubation with C-MAC® D-Blade. Senior anaesthesiologist experienced in performing FOB was present and difficult airway cart was kept ready. In the preanaesthesia room, the patient received inj. Glycopyrrolate 0.2 mg intramuscularly and oral cavity was anaesthetised by gargling with 2% lignocaine viscous. Inside the operation theatre, supplementary oxygen was provided through nasal prongs and inj. Fentanyl 50 mcg was given intravenously. Further airway anaesthesia was achieved with bilateral superior laryngeal nerve block using 2 ml of 2% lignocaine on each side and a transtracheal injection with 4 ml of 2% lignocaine. A 7-mm internal diameter cuffed endotracheal tube (ETT) with stylet was preshaped to the curvature of C-MAC® D-Blade.[2] The blade was inserted along the midline of the tongue till the vallecula, and the glottic aperture was visible (percentage of glottic opening score 60%) without much pressure. The preshaped ETT was passed along the curvature of the blade and glided smoothly into the glottis. Throughout the procedure the patient was comfortable and there was no coughing or gag response.
The American Society of Anaesthesiologists difficult airway algorithm advises considering video laryngoscopy as an initial approach for difficult intubation.[1] In our case, laryngeal mask airway placement was difficult with mouth opening of 1.2 cm. Likewise, FOB-guided nasal intubation was contraindicated, due to comminuted nasal and anterior cranial fossa fractures. The oral route for FOB is relatively difficult due to the tendency to go off midline and acute oral to laryngeal axis. This is especially true in restricted mouth opening patients where inserting an intubating oral airway is not possible.
We preferred D-Blade for its feasibility to use in a restricted mouth opening of 1.2 cm as it is slim and elliptically tapered.[3] D-Blade has space to accommodate ETT along its dorsal side. We chose 7 size cuffed ETT (9.6-mm outer diameter) so that it could be accommodated well within the dorsum of blade [Figure 1b]. The maximum thickness of D-Blade with the ETT alongside was just 1 cm. Furthermore, the D-Blade is hemi-moon shaped with a 40° curvature and 80° field of vision, making glottic visualisation easy without the need of undue pressure or lifting force.[4] We did not face any difficulty in gliding a preformed tube over the curvature of the blade in restricted mouth opening. But if any difficulty arises, the tube can be inserted with its curvature facing right and then rotated (90° anticlockwise) to align along the scope.[2] Along with the pertinent features of D-Blade, airway blocks made awake oral intubation smooth and tolerable.
This article highlights the feasibility of awake orotracheal intubation with D-Blade in a restricted mouth opening situation as a safe alternative to FOB.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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