Use of Combitube airway to protect the airway from methylene blue dye

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Introduction

The Combitube airway (Kendall UK Ltd., Basingstoke, England) is included in the European Resuscitation guidelines for the management of the emergency airway [1]. In the trauma patient tracheal soiling is usually from the upper airway [2]. Although the proximal, large cuff of the Combitube may protect the airway, this has not been formally assessed.

Method

After local ethics committee approval, 10 ASA 1 and 2, starved patients undergoing routine elective general anaesthesia involving non-depolarising neuromuscular blockade and mechanical ventilation of the lungs gave informed consent. Only patients with grade 1 direct laryngoscopic views were included to ensure adequate views of the vocal cords. The small adult sized Combitube was placed into the oesophagus, all patients being of the appropriate height, and the cuffs inflated. 10 ml of 0.1% methylene blue dye was instilled into the mouth. Full monitoring was used, and adequate ventilation ensured throughout. At the end of surgery all dye was suctioned away and the oral cavity and proximal Combitube cuff manually cleaned with absorbent gauze. The Combitube was removed and the airway examined laryngoscopically.

Results

One patient had an initial airway leak that settled with minor Combitube realignment prior to dye instillation. No laryngeal dye was detected in 9 patients. One patient had significant blue staining of the vocal cords.

Conclusion

The Combitube therefore protects the majority of patients airways from aspiration of dye from the oral cavity. In the trauma setting blood and oral debris may therefore be prevented from entering the trachea. The one failure was probably a result of patient movement by surgeons as this same patient developed a ventilatory leak mid-operation. However, patient movement would be expected in the trauma population.