Malfunctioning pilot balloon assembly.

Sir,

Pilot balloon assembly malfunctions are quite common, necessitating pre-operative check of even new endotracheal tubes. We are reporting a case of a pilot balloon assembly, which was normal during the pre-operative check but malfunctioned during fiberoptic intubation, due to an unusual cause.

A 52-year-old ASA I male, chronic tobacco chewer, was scheduled for laparoscopic cholecystectomy. His pre-operative investigations were all within normal limits. Airway examination revealed restricted mouth opening (1 Finger, Mallampati grade IV) due to submucous fibrosis, with normal neck movements.

An elective awake nasal fiberoptic (FOB) intubation was planned, using ‘spray as you go’ technique with an endotracheal tube (ETT) of 7.5 mm internal diameter, which was pre-warmed by dipping in warm saline. When the pilot balloon was inflated, it was found that even after injecting 8 cc of air, there was a significant leak. Fearing cuff damage, ETT was removed and replaced with a fresh tube under FOB guidance. The rest of the intra-operative course was uneventful.

When the faulty tube was checked, the tubing from the pilot balloon to the cuff was found to be kinked at two places [Figure 1]. Therefore, while the pilot balloon was getting inflated on injecting air, there was no inflation of the distal cuff [Figures 2 and 3]. On checking, the temperature of the saline used for dipping the tube was found to be increased. It was presumed that the pilot balloon tubing had got soft and sticky due to hot saline and its walls had got adhered at two places, thus occluding the lumen. Retrospectively, we even realized that when we were railroading the tube, it had felt quite warm.

Figure 1

Kinking of the tubing at two places

Figure 2

Cuff and pilot balloon-both deflated

Figure 3

Pilot balloon inflated, cuff deflated still

Pre-operative check of ETT is essential to prevent equipment-related morbidity and mortality.[1] Most common cause of cuff leak is trauma to the cuff itself, which can occur during intubation. Damage to the nasotracheal tube pilot balloon has been reported; however, case reports on damage to the tubing from pilot balloon to ETT cuff are rare.[2]

Arya et al. have reported intra-operative cuff leak in previously checked flexometallic tube due to surface cuts over the embedded inflation tube, which became more prominent and gaped when the side of the tube on which they were present was made convex.[3]

We dipped the ETT in saline to soften it so as to decrease the chances of mucosal trauma and the incidence of epistaxis following nasotracheal intubation.[4] Pre-warming the tube also makes it more pliant to negotiate the abrupt curvature of the nasopharynx.[5] We erred in not checking the temperature of the saline solution, in which the tube was dipped, and also in not re-checking the ETT again. A re-check of ETT would have detected this and prevented re-intubation trauma to the patient.