Clinical Comparison of the Airway Devices
Condition: Endotracheal Intubation; Supraglottic Airway
Study type: Interventional

Summary: 
      The purpose of this study is to evaluate a new supra-glottic airway device, the "Disposable
      Laryngeal Tube Suction" (LTS-D; King Systems, Noblesville, IN). We propose to test its ease
      of insertion, position within the airway, patency of drain tube and anatomic sealing
      properties during spontaneous ventilation in anesthetized patients. The study device will be
      compared to the ProSeal Laryngeal Mask Airway (PLMA, LMA North America Inc.) and the
      Esophageal Tracheal Combitube (ETC; Tyco Healthcare/Mallinckrodt Nellcor, Pleasanton, Calif).
    

Detailed description: 
      During the past decade, several pharyngeal airways have been introduced into clinical
      practice for airway management, such as the Laryngeal Mask Airway (LMA), the Cuffed
      Oropharyngeal Airway (COPA), the Esophageal Tracheal Combitube (ETC), and most recently, the
      Laryngeal Tube (LT). These airway devices have become very popular because of their ability
      to maintain an airway without perturbing the trachea, and can be used in patients without
      muscle relaxation and who are only lightly anesthetized.

      The LMA generally provides an adequate airway, but certain problems remain. (1) In 8-33% of
      LMA placements, more than one attempt is required. (2) It is sometimes difficult to advance
      the LMA without extending the neck (which is contraindicated in some patients). (3) The
      device does not protect the airway from aspiration of gastric contents. (4) It does not
      provide an airtight seal around the larynx (the usual pressures causing leakage of gas being
      15-20 cm H20). Consequently, the device functions poorly during positive-pressure
      ventilation. (5) The esophagus is included within the rim of the LMA in 10-15% of patients,
      directly exposing the esophagus to positive airway pressures. This often results in
      insufflation of the stomach and postoperative discomfort.

      The ETC is a disposable double-lumen tube that combines the features of a conventional
      endotracheal tube with those of an esophageal obturator airway. It is appropriate for
      prehospital, intraoperative, and emergency use and is especially useful for patients in whom
      direct visualization of the vocal cords is not possible, patients with massive airway
      bleeding or regurgitation, limited access to the airway, and patients in whom neck movement
      is contraindicated. Ventilation with the ETC is possible with either tracheal or esophageal
      intubation, as its distal cuff seals off the esophagus to prevent aspiration of gastric
      contents. The ETC has a 6.9% incidence of placement failure and a failed ventilation rate of
      21.1%.

      The Laryngeal Tube Suction (LTS; VBM Medizintechnik; King Systems, Noblesville, IN) is a
      supra-glottic airway device designed to provide a more effective seal than the LMA, thus
      eliminating problems 3-5 described above. The insertion of the standard laryngeal tube is
      generally easy. The reported success rate of insertion of, and ventilation through, the
      laryngeal tube ranges from 92-100% for the earlier prototype and 97-100% for the newest
      version. It is a flexible, curved tube that passes through the mouth, advances posterior to
      the epiglottis, and terminates in the upper esophagus. The multi-use, double-lumen, silicon
      LTS is designed with ventilation outlets located between an oropharyngeal and an esophageal,
      low-pressure cuff. The second lumen allows for an orogastric tube to be passed through for
      gastric drainage and pressure release. Patients at risk of regurgitation now have an
      alternative to tracheal intubation. This device has been used in a number of patients by
      anesthesiologists in Europe. There are many published scientific abstracts in the use of the
      LTS. A disposable version of the LTS is now available, the LTS-D. The LTS-D offers the same
      benefits as the LTS, but being disposable, it also eliminates the risk of cross-infection.

      The ProSeal Laryngeal Mask Airway (PLMA, LMA North America Inc.) is the pre-existing
      double-lumen supra-glottic device that allows gastric drainage and pressure release. Its
      design is based on the LMA with an added lumen. It is reusable. The ProSeal exhibits an
      unsuccessful ventilation rate of 9%, and a first time insertion failure of 12.7%. Currently,
      the ProSeal exhibits a 3% incidence of foldover during insertion that prevents it from
      functioning properly. Due to differences in design, we postulate that the LTS-D will have a
      lower incidence of foldover than the PLMA.

      This clinical study has been designed to compare the ProSeal, ETC and LTS-D as to the ease of
      placement and ventilation during controlled ventilation, proper positioning, the seal
      pressure with each placement, the patency of the drain tube by suctioning and measuring
      stomach contents, and finally, any complications with their use. Fiberoptic observations
      through each device will provide information in relation to the epiglottis and the distal
      opening of the device.
    

Intervention name(s): LTS-D; ProSeal Laryngeal Mask Airway; Esophageal Tracheal Combitube (ETC)
Intervention type(s): Device; Device; Device
Intervention description(s): supra-glottic airway device; pre-existing double-lumen supra-glottic device; disposable double-lumen tube
Other intervention name(s): LTS-D King Systems, Noblesville, IN; Laryngeal Mask Airway (PLMA, LMA North America Inc.); ETC
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: Endotracheal Intubation; Supraglottic Airway