Authors' reply.

Sir,

Thanks for taking a keen interest in the article titled “Fibreoptic aided retrograde intubation in an oral cancer patient”.[1] As we all know, guidelines and protocols definitely do help in difficult airway situations, but the judgment of the attending anaesthesiologist at the warfront remains the principal factor to avoid airway accidents.

Despite of a good number of failures since 1983,[2] awake fibreoptic is still the gold standard for anticipated difficult intubation. However, the role of this procedure in compromised airway and limited mouth opening is not clear. Tissue oedema and immobility due to tumour, distorted airway, copious secretions and chances of bleeding contribute, at least in part, to its high failure rate.[3] Interarytenoid space and right arytenoids are common sites of resistance to tube advancement during awake fibreoptic intubation. Ovassapian et al.[3] had reported significant failures (as high as 66%) in awake fibreoptic bronchoscopic (FOB) nasotracheal intubation, but improved success rate has also been reported with a well-planned approach in expert hands even in a compromised airway.

Since retrograde intubation was originally described in 1960s, several modifications[45] of this technique have been done to augment the success rate. However, as it is a blind procedure, there is a chance of dislodgement or kinking of the endotracheal tube after the removal of the guide catheters[6] that contribute to its failure.

Therefore, to achieve safety, success and to lessen the time of awake flexible FOB intubation, we had combined both retrograde and fibreoptic intubation[7] while securing airway with nasotracheal intubation in a difficult airway situation compromised with tumour mass. When the guidewire introduced for retrograde intubation is retrieved through the mouth, it is fed through the working channel of the FOB from distal to proximal. The FOB is then fed over the wire through the glottis. After the wire is removed, the FOB acts as a visualizing guide catheter. This reduces the chance of the dislodgement of the tracheal tube as the glottis can be visualized throughout the procedure. Herein lies the advantage of using FOB over other items (such as suction catheter, guidewire sheath, multilumen catheter, tracheal tube exchanger) as an anterograde guide to facilitate retrograde intubation. On the other hand, the retrograde guidewire is utilized to guide the FOB through the vocal cord for speedy advancement across the oropharynx occupied with tumour. It hastens the advancement of the FOB in spite of the oral mass and the altered anatomy, which otherwise causes mechanical hindrance and also overcomes the loss of vision from small bleeding. As the time required is less, the patient tolerates the procedure well and the probability of desaturation during the procedure is also reduced.

Moreover, to reduce the chances of trauma and bleeding during the retrieval of the guidewire from the oral cavity occupied with tumour mass, a sterile Terumo guidewire was chosen for this technique. This guidewire has a unique property that its tip is very soft and it finds way even in a small opening, and any injury to the airway is very unlikely. Moreover, it becomes very slimy in presence of water, which eases the smooth threading of the guidewire.

To conclude, we suggest that the practice of this combination technique may offer benefit in patients with anticipated difficult intubation. However, the need for more equipments and the longer preparation time limits the utility of this technique in emergency settings. Last but not the least, one should use the procedure that one is most experienced and familiar with.