What is a laryngeal tube (lary tube) in medicine?

What is a Laryngeal Tube?

The laryngeal tube (also called King LT) is a supraglottic airway device—a compact, single-lumen tube with inflatable cuffs that sits above the vocal cords in the esophagus to provide ventilation during emergencies or anesthesia. 1

Device Design and Mechanism

• The laryngeal tube is more compact and simpler to insert than the esophageal-tracheal tube (Combitube) because it can only be placed in the esophagus, eliminating confusion about tube position 1
• It features two inflatable cuffs—one positioned in the hypopharynx and one in the esophagus—that create a seal to direct ventilation into the trachea 2
• Four versions exist: standard laryngeal tube, disposable tube (LT-D), dual-lumen tube with suction capability (LTS II), and disposable LTS-D 3, 2

Clinical Applications

Emergency Airway Management

• The American Heart Association considers the laryngeal tube an acceptable alternative to bag-mask ventilation (Class IIb, LOE C) or endotracheal intubation (Class IIb, LOE C) for cardiac arrest airway management in trained providers 1
• Success rates of 85-97% have been demonstrated in out-of-hospital cardiac arrest patients when inserted by trained paramedics 1
• The device proved effective in "cannot intubate-cannot ventilate" scenarios, including cases with lingual tonsillar hyperplasia and morbid obesity 4

Routine Anesthesia Use

• 96.6% of patients maintained adequate oxygenation and ventilation during mechanical ventilation for elective surgery 5
• The device is effective for positive pressure ventilation during general anesthesia 5, 6
• It can be used in patients with pharyngeal and laryngeal tumors where conventional intubation may be difficult 6

Insertion Technique and Success

• Insertion is as easy as the laryngeal mask airway and does not require laryngoscopy or visualization of vocal cords 1, 2
• The device provides a better airway seal than standard laryngeal mask airways 3, 2
• Training requirements are simpler than for endotracheal intubation 1

Limitations and Complications

Known Failure Modes

• Cuff rupture can cause ventilation failure (occurred in 3 of 40 cardiac arrest patients in one series) 1
• Massive regurgitation and aspiration before placement can prevent effective ventilation 1
• The device may require more position adjustments than the laryngeal mask airway to maintain a clear airway 3, 2

Comparative Effectiveness

• The standard laryngeal tube may be less effective than the ProSeal laryngeal mask 3, 2
• Efficacy in spontaneously breathing patients and children remains unclear based on limited evidence 2

Critical Practice Points

• Always have an alternative airway strategy ready, as a small proportion of patients cannot be ventilated with any supraglottic device 1
• Providers must receive adequate initial training and regular practice to maintain insertion skills 1
• Monitor success rates and complications closely in any system using the laryngeal tube 1
• The device does not provide absolute protection against aspiration, though it offers more protection than bag-mask ventilation 7