The Combitube™ (Sheridan Catheter Corporation, USA) has been extensively used for airway management in emergency situations . It has been included in the Advanced Cardiac Life Support guidelines of the American Heart Association , as well as in the Practice Parameter on Guidelines for the Management of the Difficult Airway of the American Society of Anesthesiologists . It has characteristics which would suggest its suitability for airway management during percutaneous tracheostomy.
The Combitude is a double lumen airway with one lumen serving as a 'tracheal' channel comparable with a conventional endotracheal tube with a distal open end. The second lumen acts as an oesophageal obturator with a blocked distal end and perforations at the level of the pharynx. At the distal end, the airway is surrounded by an inflatable cuff, which when inflated obturates either the trachea or the oesophagus. In the oropharyngeal section, there is a large elastic balloon, which when inflated presses against the base of the tongue and closes the soft palate, thereby sealing the hypopharynx against the oral and nasal cavities. The airway is correctly positioned when the ventral part of the oropharyngeal balloon reaches the posterior part of the hard palate, thus ensuring a firm position.
The Combitube can be inserted blindly without the use of a laryngoscope, and the elastic pharyngeal balloon self adjusts the airway to the optimal position during inflation. With the Combitube in the oesophageal position, such that the distal end and the inflated distal cuff lies within the oesophagus, the ventilatory gases pass via the perforations at the pharyngeal level into the trachea via the larynx. This therefore allows ventilation of the lungs, whilst the trachea remains free of ventilatory tubing.
Bedside percutaneous dilatational tracheostomy is increasingly practised in intensive care units (ICU) for airway management and has a low incidence of complications [4,5]. However, technical problems can be caused by the cannula hitting the endotracheal tube and either impinging on the tube, deflating the cuff or passing through Murphy's eye . Accidental extubation can also occur when repositioning the endotracheal tube to avoid cuff perforation. The use of the laryngeal mask for airway management during percutaneous tracheostomy  has been suggested in order to free the trachea and ease insertion of the percutaneous tracheostomy. However, situations in which higher than normal ventilatory pressures are required, or the possibility of gastric reflux and aspiration, may preclude ventilation via the laryngeal mask. The multiluminal Combitube, when used in the oesophageal position, offers the advantages of a free trachea and protected airway, and enables ventilation of the patient.
The Combitube has been used for airway management during formal surgical tracheostomy  and we have undertaken a pilot study to evaluate its use during percutaneous tracheostomy. However, we wish to report a complication which occurred during a percutaneous tracheostomy with the patient ventilated via a Combitube, which raises doubt as to the inherent safety of this approach.
A 71-year-old male was admitted to the ICU in respiratory and hepatorenal failure. Ten days into his admission a percutaneous dilatational tracheostomy was undertaken. A commercially available kit (Cook Critical Care Ltd, USA) was used, and the procedure was performed at the patients bedside in the ICU. The nasogastric tube was aspirated and removed, and to enable ventilation during the procedure, the endotracheal tube was replaced by a Combitube. This was positioned according to the manufacturers recommendations, such that the distal cuff was positioned in the oesophagus, so freeing the trachea of airway devices. No significant change in tidal volume was noted on changing from endotracheal to Combitube.
The skin overlying the first three tracheal rings was infiltrated with bupivacaine and adrenaline, and the skin prepared and towelled in the usual manner. Following a superficial horizontal skin incision and dissection of the facia over the first and second tracheal rings, the trachea was palpated and punctured using a cannula. The position was confirmed by the aspiration of air through saline. A guidewire was subsequently passed through the cannula and sequential dilation was then undertaken over the guidewire, in order to permit the final placement of a cuffed tracheostomy tube size 8, which was fed over the guidewire.
On connecting the ventilatory circuit to the tracheostomy, it was noted that the lungs were not inflating and that the abdomen was becoming distended. This suggested that air confirmed by auscultation was entering the stomach. A diagnosis of oesophageal intubation was made and the tracheostomy tube was immediately removed and the patient reintubed using an endotracheal tube. The percutaneous dilatational tracheostomy was then repeated under direct fibreoptic vision, during which airway control was obtained using the endotracheal tube pulled as far back in the trachea as possible. Rigid oesophagoscopy later revealed a 3 cm tear in the anterior oesophageal wall at a level corresponding with the tracheal puncture where the tracheostomy tube had passed into the oesophagus. This was treated conservatively. The patient subsequently died from hepatorenal failure that failed to respond to treatment.
Percutaneous tracheostomy by the dilatational technique has been shown to compare favourably in terms of safety and technical ease with conventional methods of tracheostomy . Recently, the use of the laryngeal mask airway has been advocated during endoscopically guided percutaneous tracheostomy in selected patients . The laryngeal mask allows ventilation and synchronous views of the trachea without interfering with the surgical field. However, the use of the laryngeal mask is contraindicated in patients who are at risk of aspiration or who require high inflation pressures. The Combitube theoretically offers similar advantages of a free surgical field, but with increased airway protection from aspiration.
To confirm tracheal placement of the cannula during percutaneous tracheostomy, air is aspirated . Normally air can only be aspirated from the non-collapsible trachea and not from the flaccid walled oesophagus. However, with the Combitube in-situ, the distal cuff lies within the oesophagus, such that the proximal end of the oesophagus is inflated with ventilating gases. Therefore, if the cannula is accidentally passed through the posterior wall of the trachea and enters the upper part of the oesophagus proximal to the distal cuff of the Combitube, air can be aspirated leading to a false positive test for tracheal position. Subsequent dilatation over the guidewire would then lead to oesophageal dilatation and intubation.
It is conceivable that during this case the cannula could have been in the trachea when aspiration was performed, and the oesophagus could have been perforated subsequently during the procedure, either by the cannula or guidewire. In order to ensure correct placement of the cannula and guidewire when undertaking percutaneous tracheostomy, direct visualization has been recommended , using a fibreoptic laryngoscope passed through the endotracheal tube. However, the perforations in the oesophageal lumen of the Combitube are not of sufficient diameter to allow the passage of a fibreoptic laryngoscope, so preventing visual confirmation of the correct placement of the cannula and guidewire in the trachea.
This case demonstrates the complication of oesophageal dilatation and intubation during attempted percutaneous tracheostomy. The possibility of accidental oesophageal cannulation being misinterpreted as tracheal owing to the possible aspiration of air from the oesophagus. The inability to pass a fibreoptic laryngoscope into the trachea via the oesophageal lumen of the Combitube prevents direct visualization and reduces the safety of the technique when such an airway is used. We would therefore not recommend the use of the Combitube for airway control when undertaking a percutaneous tracheostomy.
1 Frass M, Frenzer R, Rauscha F, Schuster E, Glogar D. Ventilation with the oesophageal tracheal Combitube in cardiopulmonary resuscitation. Promptness and effectiveness. Chest
2 Emergency Cardiac Care Committee. Combination oesophageal-tracheal tube. In: Guidelines for cardiopulmonary resuscitation and emergency cardiac care. Recommendations of the 1992 National Conference of the American Heart Association. JAMA
3 Practice parameters on guidelines for the management of the difficult airway. American Society of Anaesthesiologists, New Orleans, LA, October 1992.
4 Friedman Y, Mayer AD. Bedside percutaneous tracheostomy in critically ill patients. Chest
5 Hazard P, Jones C, Benitone J. Comparative clinical trial of standard operative tracheostomy with percutaneous tracheostomy. Crit Care Med
6 Bodenham AR. Percutaneous dilational tracheostomy. Completing the anaesthetist's range of airway techniques. Anaesthesia
7 Dexter TJ. The laryngeal mask airway: a method to improve visualisation of the trachea and larynx during fibreoptic assisted percutaneous tracheostomy. Anaesth Intens Care
8 Wiltschke C, Kmet G, Swobodah et al.
Ventilation with the Combitube during tracheostomy. Laryngoscope
9 Marelli D, Paul A, Manolidis S et al.
Endoscopic guided percutaneous tracheostomy: early results of a consecutive trial. J Trauma
10 Wilson RC, Bodenham AR. Percutaneous tracheostomy. Br J Hosp Med