Objective: The feasibility of prototypes of the LTS, a laryngeal tube with an additional oesophageal drain tube for pressure relief, was tested for ventilation during surgery.
Methods: After approval of the ethics committee, a LTS was placed in 30 orthopaedic patients, ASA I and II, induction of general anaesthesia with fentanyl and propofol. Position of the LTS was verified by auscultation and end tidal CO(2)-measurement. Oxygen saturation, number of placement attempts, cuff pressure, time until first tidal volume, tidal volume and airway pressures were registered intraoperatively. Patients were questioned about hoarseness and soar throat 1 h, 6 h and 24 hours after surgery, graded on a visual analogue scale (VAS).
Results: 16 women and 14 men were investigated. In 29 patients (96.7%), the LTS was placed successfully (second attempt in three patients). In one patient, sufficient ventilation was not possible. In this case and in another patient with sufficient ventilation but estimated duration of surgery >3 h, endotracheal intubation was performed. Average time until first tidal volume was 17.3 seconds, ventilation was performed for 74 minutes. Pulse oximetric oxygen saturation was > or =97% at all times. Auscultation over the stomach was negative in all patients with an average cuff pressure of 73.7 cm H(2)O. During controlled ventilation aiming at an end tidal CO(2) of 35 mmHg (average 36.3 mmHg), an average tidal volume of 579 ml was reached, resulting in an inspiratory peak pressure of 20.2 cm H(2)O. Minimal traces of blood on the LTS were found in 5 patients, hoarseness was present in one patient after 6 hours, soar throat was stated after 1 hour by one patient (VAS 3), after 6 hours by 6 (average VAS 2.7) and after 24 hours by 3 patients (VAS 1.3).
Conclusions: The LTS can be used for ventilation during elective surgery and can be placed with a high success rate. Postoperative complaints are infrequent and mild.