Clinical evaluation of the Combitube®

The Combitube® (CT), a twinlumen tube designed to provide ventilation after blind intubation, is either placed into the oesophagus or trachea. It has proved to be useful in establishing an airway during CPR and in patients with difficult airway situations. Aim of this study was to determine efficacy and safety of the CT for emergency airway management. To obtain reliable data, the CT was used during the controlled setting of elective general anaesthesia (GA). After approval of the Local Ethics Committee and informed consent, 50 patients (ASA grade I–II, Mallampati grade I) were included. Haemodynamic parameters, oxygen saturation, pCO2, ventilatory parameter complications were recorded. GA was induced with thiopentone, fentanyl, atracurium (0.5 mg kg−1) and maintained with enflurane, nitrous oxide/oxygen. For intubation the patients head remained in a neutral position and the CT was inserted blindly until the two markings on the CT were adjacent to the patients upper incisors. Ventilation was first checked with the head in the neutral position followed by a hyperextended position. All CTs were inserted within 12 to 23 s, always positioned in the oesophagus. In 47 patients a sufficient airway was established at the first attempt. In 3 applications the CT had to be withdrawn 1–2 cm from its initial position to achieve successful ventilation (obstruction of the glottic opening by the upper cuff). Better ventilation conditions were observed in all patients with the head placed in the hyperextended position compared with the neutral position. Major difficulties during ventilation occurred in 11 patients: 60 min after the initial neuromuscular blockade and beginning of positive pressure ventilation, peak pressures increased slightly, accompanied with a sound produced in the laryngeal region. Seconds later sufficient ventilation became impossible. After a repeated dose of atracurium airway pressure returned within 60 s to base-line values. Similar symptoms occurred during recovery from anaesthesia under positive pressure ventilation: sufficient ventilation could be maintained by elevating the jaw with the head in a hyperextended position. After return of spontaneous ventilation, there were no more signs of any airway obstruction. Mucosal bleeding was observed in 12 patients. There were no signs of gastric insufflation or regurgitation. The CT allowed a reliable airway to be established in all patients, but was always positioned in the oesophagus. The markings on the CT are not suitable for all patients and following the instruction manual (positioning the CT between both markings) led to airway obstruction in 3 cases. In 11 patients a closure of the vocal cords occurred due to obstruction of the glottic opening with impaired ventilation. During controlled ventilation neuromuscular blockade with a deep level of anaesthesia are necessary to prevent this complication. The CT can be regarded as an alternative airway management device during CPR or during emergency management of a difficult airway, if conventional endotracheal intubation can not be performed immediately. The immediate use of the CT may offer the possibility of prompt ventilation after blind intubation. This is the major advantage of the CT, but for safe use, frequent training is essential.