Clinical Comparison of the Disposable Laryngeal Tube Suction, Esophageal Tracheal Combitube and Proseal Laryngeal Mask Airway

• Duration of Intubation [ Time Frame: duration of intubation ] [ Designated as safety issue: No ]
  The time taken to successfully place the device in seconds.
• Number of Participants With a Successful First Attempt Placement [ Time Frame: Time taken for successful placement ] [ Designated as safety issue: No ]
  The number of patients in whom the assigned device was successfully placed in the first attempt as per protocol.
• Number of Patients Who Required Multiple Attempts. [ Time Frame: Time taken for intubation ] [ Designated as safety issue: No ]
  The number of repeated attempts required for successfully placing the device. Each device was given a chance of 3 attempts if still unsuccessful after 3 attempts another device was placed.
• Leak Pressures [ Time Frame: Duration of surgery ] [ Designated as safety issue: No ]
  The maximum leak pressure attained for each device.
• Post Operative Morbidity [ Time Frame: 2 hrs and 24 hrs after surgery ] [ Designated as safety issue: No ]
  We followed the patients 2 and 24 hours after the surgery for sore throat, hoarseness and dysphagia.The numbers represented here are the number of patients who reported sore throat at 2 hrs and after 24 hrs as per the protocol.
• Number of Failed Cases [ Time Frame: Time taken for successful intubation ] [ Designated as safety issue: No ]
  We calculated the number of failed cases. As per protocol, that is number of patients in whom successful intubation was not achieved with the assigned device after 3 attempts.

• Level of difficulty for intubation [ Time Frame: duration of intubation ] [ Designated as safety issue: No ]
• Time and number of attempts required; [ Time Frame: duration of intubation ] [ Designated as safety issue: No ]
• Degree of irritation of the pharynx, epiglottis, and arytenoids [ Time Frame: post operative, immediately and 24 hours later ] [ Designated as safety issue: Yes ]

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).

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.

• Intubation
• Endotracheal

• Device: LTS-D
  supra-glottic airway device
  Other Name: LTS-D King Systems, Noblesville, IN
• Device: ProSeal Laryngeal Mask Airway
  pre-existing double-lumen supra-glottic device
  Other Name: Laryngeal Mask Airway (PLMA, LMA North America Inc.)
• Device: Esophageal Tracheal Combitube (ETC)
  disposable double-lumen tube
  Other Name: ETC(Tyco-Healthcare/Mallinckrodt Nellcor Puritan Bennett,St.Louis,MO)

• Experimental: LTS-D
  All the cases were divided into one of the group LTS-D, PLMA, and ETC
  Intervention: Device: LTS-D
• Experimental: PLMA
  All patients were divided into either LTS-D, PLMA, or the ETC group.
  Intervention: Device: ProSeal Laryngeal Mask Airway
• Experimental: ETC
  All patients are divided into one of the group, LTS-D, PLMA, or the ETC.
  Intervention: Device: Esophageal Tracheal Combitube (ETC)

Inclusion Criteria:

1. The subjects will be adult surgical candidates aged 18-80, ASA I-III, Mallampati I or II, presenting for elective surgery who require general anesthesia in whom tracheal intubation is not necessary.
2. Both male and female patients will be included.

Exclusion Criteria:

• Patients will be excluded from the study if they present as Mallampati III or IV, ASA IV-V or emergency status. Additionally, they will be excluded if they meet one of the contraindication criteria of the LMA ProSeal including:

  1. Obesity
  2. Pregnancy
  3. History of gastric regurgitation, heart burn, ileus or "full stomach"
  4. History of low pulmonary compliance or high pulmonary resistance
  5. Known history of difficult endotracheal intubation or signs suggesting the possibility of difficult intubation
  6. Pharyngeal pathology or
  7. Upper airway obstruction due to laryngeal pathology.

• Additionally, they will be excluded if they meet one of the contraindication criteria for the Combitube including:

  1. Intact gag reflexes
  2. Height <4 feet
  3. Central airway obstruction
  4. Recent ingestion of caustic substances
  5. Known esophageal pathology, or
  6. Known latex allergy.
• They will also be excluded if any tracheal disease is present such as tracheal tumors, stenosis or previous tracheal surgery.