An unusual site of an occult air leak in an armoured endotracheal tube in the midst of surgery

Abstract

Sir, Even after a recommended check of the anaesthesia equipments, we may sometimes face some intriguing problems during the surgical interventions. We describe an unusual site of an air leak in an armoured endotracheal tube (ETT) in the midst of the surgical procedure involving the trachea. A 35-year-old male, ASA class 1 patient with a history of tracheal injury was posted for Montgomery T-tube insertion through the tracheostomy site. After administration of general anaesthesia, the tracheostomy tube was removed and the patient was intubated with a 38FG Rusch® armoured ETT through the tracheostomy site. Before insertion, a recommended check of cuff and cuff inflation assembly was performed, with no leaks detected.[12] Instead of using an adhesive tape for securing the ETT in place, the surgeon insisted on application of a stay suture over the sternal skin and to tie it with the ETT. We noticed the leak pressure alarm displayed on the screen of the anaesthesia machine (GE Datex Ohmeda Aestiva 5®) nearly 20 min after the start of the surgical procedure. The surgeons also noticed the leak around the cuff and immediately alarmed us. The cuff was reinflated and surgery started, but again the same leak pressure alarm was displayed on the monitor after 10 min of the commencement of surgery. We decided to stop the surgery and replace the armoured ETT with fresh armoured ETT. Meanwhile, we carried out an in vitro check for patency of cuff, which showed no air leak, and, therefore, we decided to put whole tube in water to check the leak in the inflation tube assembly. To our surprise, we found a leak from the site where the surgeons had applied the stay suture near the 20 cm mark where the inflation tube was embedded in the ETT [Figure 1].Figure 1: Air leak site from the inflation tube assemblyWe concluded that applying a stay suture might have breached the integrity of the inflation tube that was embedded in the armoured ETT, leading to occult air leak. A similar observation with resterlized armoured ETT had been noted before when these tubes were stretched during the surgical procedure, allowing air to leak if any cuts or holes were present in the ETT, which usually get missed on routine check.[34] We observed that the inflation tube assembly of the armoured ETT is more superficially embedded in the wall of the ETT as compared with the poly vinyl chloride ETT; therefore, the chances of its damage are greater. The surgeons should be discouraged to apply stay suture on these ETTs for securing it in place. In certain situations, if the stay suture is necessary for securing the tube, then certain simple yet effective maneuvers can be done to avoid damage to the inflation tube assembly. The ETT should be placed in such a way that the tangential force of the stay suture should not directly be applied on the wall of the ETT where the inflation tube assembly is embedded. For that, the ETT with the inflation tube assembly should be facing downward and away from the contact point of the suture. If required, we can also apply a sterilized adhesive tape or an aluminium foil circumferentially in that area where the stay suture is tied onto the ETT, which will negate the effects of that tangential force and hence avoiding the breach in the inflation tube assembly.