An alternative technique for retrograde intubation

Abstract

Retrograde intubation is one of the techniques used for intubation in patients with difficult airway. It necessitates retrograde passage of an introducer cranially from a cricothyroid puncture. The introducer is retrieved from mouth or nares, over which a tracheal tube is guided into the trachea. A common problem with this technique is that the tip of the tracheal tube may catch at the epiglottis or arytenoids, thereby preventing its passage into the trachea. We describe a technique to circumvent this problem. A 19-year-old girl was scheduled for bilateral genioplasty for temporomandibular joint ankylosis. Physical examination revealed a 35-kg girl with profound micrognathia, retrognathia and deviation of the chin towards the left side due to earlier surgery for the same problem. Mouth opening was restricted to 2.5 cm. She had buck teeth and a high arched palate. Examination of the neck revealed a central trachea and a superior larynx. Mentohyoid and mentothyroid distances were 2 and 3.5 cm, respectively (Fig. 3). Profile of the patient. The patient was premedicated with oral diazepam 5 mg, metoclopramide 5 mg, ranitidine 150 mg and intramuscular glycopyrronium 0.2 mg. Inhalation induction was carried out with halothane in oxygen. Direct laryngoscopy revealed only the tip of the epiglottis and intubation of the trachea was unsuccessful. Four attempts at blind nasotracheal intubation were also unsuccessful. A nasopharyngeal airway was used to maintain anaesthesia with halothane and retrograde intubation was planned. An 18 G epidural catheter was introduced through a cricothyroid puncture and was retrieved via the right nostril. A lubricated cuffed 6-mm ID tracheal tube was threaded over the catheter. The catheter was made taut by pulling both its ends and the tube was guided over it. However, the tube could not be negotiated into the trachea despite repeated attempts. Intubation was also tried by passing the catheter through the Murphy's eye of the tracheal tube but this also failed. Subsequently, we used the following technique. The nasal end of the catheter was tied to the Murphy's eye with a knot inside the lumen of the tracheal tube (Fig. 4). The tube was introduced into the nasopharynx and a gentle downward pressure was applied on the tube guided by the traction at the distal end of the catheter; this led to successful passage of the tracheal tube into the trachea. The position of the tube was confirmed and it was then secured. The introducer was left in situ. Surgery lasted for 5 h. Extubation was planned for the next morning. Prior to extubation, the tube was withdrawn into the posterior pharynx. After demonstrating the ability to maintain an adequate airway, both catheter and tracheal tube were removed together. The rest of the stay in hospital was uneventful. The patient was discharged on the 6th postoperative day. Epidural catheter tied to Murphy's eye of the tracheal tube. In the conventional method of retrograde intubation, the introducer traverses the entire length of the tracheal tube, i.e. from the bevelled end/Murphy's eye to the proximal end of the tube [1-3]. To assist guiding the tube over the introducer, the latter is made taut by pulling at both its ends. In doing so, the introducer moves anteriorly towards the narrowest portion of the glottis. When a tracheal tube is guided over this taut introducer, the tip of the tube that is free to move may get caught on the epiglottis or the arytenoid cartilage and may fail to enter the trachea [4, 5]. In our technique, the introducer tied to the Murphy's eye acted as an anchor to guide the bevelled end of the tube into the glottic aperture, thereby avoiding its impingement on epiglottis or arytenoids. The knot made with the epidural catheter was kept on the inner aspect of the tube to avoid any tracheal injury. The knot was small and did not interfere with suction. The introducer when left in situ can help in re-introducing the tube if re-intubation is required. This case report provides an alternative method of retrograde intubation when conventional techniques fail.