(See also Airway Establishment and Control and Airway and Respiratory Devices.)
The esophageal-tracheal double lumen tube (Combitube®) and the King laryngeal tube are twin-lumen tubes that have fundamental similarities:
Supraglottic airways are useful for providing rescue ventilation to unconscious patients or patients without a gag reflex and are also used in some elective settings.
The esophageal-tracheal double lumen tube and King laryngeal tube have some advantages over other methods of ventilation:
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Unlike endotracheal tubes, they can be successfully inserted blindly and by inexperienced operators.
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Unlike bag-valve-mask (BVM) ventilation, they avoid the difficulties of attaining and maintaining an adequate face-mask seal.
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They cause less gastric insufflation or aspiration than BVM or laryngeal mask (LMA) ventilation because they better isolate the esophagus from the trachea and because the distal lumen permits gastric tube insertion
Like the other supraglottic airways, the Combitube® and King laryngeal tube are temporary airways that must be removed or replaced by a definitive airway, such as an endotracheal tube or surgical airway (cricothyrotomy or tracheostomy).
Indications
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Apnea, severe respiratory failure, or impending respiratory arrest in which endotracheal intubation cannot be accomplished
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Certain elective anesthesia cases
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Situations where BVM ventilation is difficult or impossible (eg, in patients with severe facial deformity [traumatic or natural], thick beard, or other factors that interfere with the face mask seal, and in patients with upper airway blockage due to obstructing soft tissues
Contraindications
Absolute contraindications
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There is no medical contraindication to providing ventilatory support to a patient; however, a legal contraindication (do-not-resuscitate order or specific advance directive) may be in force
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Restricted mouth opening that blocks tube insertion (nasotracheal intubation or a surgical airway would be indicated in this case)
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Impassable upper airway obstruction (surgical airway would be indicated in this case)
Relative contraindications
Complications
Equipment
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Gloves, mask, gown, and eye protection (ie, universal precautions)
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Syringes for balloon cuff inflation
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Sterile water-soluble lubricant or anesthetic jelly
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Combitube® or King laryngeal tube, appropriately sized to patient
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Oxygen source (100 % oxygen, 15 L/minute)
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Suctioning apparatus to clear the pharynx as needed
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Pulse oximeter, capnometer (end-tidal carbon dioxide monitor), and appropriate sensors
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Equipment for alternate methods of airway control should insertion fail (eg, laryngeal mask airway, bag-valve mask ventilation, endotracheal intubation, cricothyrotomy)
Additional Considerations
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The balloon cuffs of the Combitube® are inflated individually. The balloon cuffs of the King laryngeal tube share a single pilot tube and inflate simultaneously.
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An estimated 1 to 5% of Combitube® insertions enter the trachea; in these cases, if the misplacement is recognized, the cuffed distal lumen can be used to function as an endotracheal tube. Probably at least 10% of insertions done with newer King laryngeal tubes enter the trachea; ventilation may be possible through the distal lumen in these cases. Older King tubes are contoured such that virtually all insertions enter the esophagus.
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The ventilating lumen of the King tube is suitable for stylet insertion to facilitate conversion of the King tube to an endotracheal tube. However, visualization of the glottis through this lumen is often impossible.
Relevant Anatomy
Positioning
The sniffing position is used only in the absence of cervical spine injury:
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Position the patient supine on the stretcher.
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Place folded towels or other materials under the head, neck, and shoulders, flexing the neck so as to elevate the head until the external auditory meatus lies in the same horizontal plane as the sternal notch. Then, tilt the head so that the face aligns on a parallel horizontal plane; this second plane will be above the first. In obese patients, many folded towels or a commercial ramp device may be needed to sufficiently elevate the shoulders and neck (see figure head and neck positioning to open the airway).
Head and neck positioning to open the airway
If cervical spine injury is a possibility:
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Position the patient supine or at a slight incline on the stretcher. Avoid moving the neck and use only the jaw thrust maneuver or chin lift without head tilt to manually facilitate opening of the upper airway.
Step-by-Step Description of Procedure
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Clear the oropharynx, as necessary, of obstructing secretions, vomitus, or foreign material.
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Pre-oxygenate the patient with bag-valve-mask ventilation, if possible.
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Select the appropriately sized Combitube® or King laryngeal tube and note the appropriate cuff inflation volume for King tubes. This information is on the tube packaging and the cuff of the tube itself.
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Inflate and deflate the cuffs to check that there are no leaks.
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Apply a small amount of sterile, water-soluble lubricant to the deflated cuffs.
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Lift the chin and tongue with your non-dominant hand. Grasp the tongue and chin between your thumb inside the mouth and your fingers on the underside of the chin, and lift up.
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Insert the Combitube® or King tube into the mouth. Insert the Combitube® with a midline orientation. Insert the King tube initially at the corner of the mouth 45 to 90 degrees of rotation off-center, and then rotate it to midline position when the tip of the tube is past the tongue. Do not force either tube; you may cause soft tissue damage. If resistance is encountered, pull back somewhat and re-advance the tube, trying to follow the posterior pharyngeal wall. You may need to remove the tube, alter its curvature, and then reinsert it. At the proper distance of insertion (as confirmed by markings on the tube), the proximal (ventilating) lumen will open over the laryngeal opening, and the distal lumen will have entered the esophagus (in most cases).
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Release your hand from the tube before inflating the cuffs.
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Inflate the cuffs. When using a King laryngeal tube, use the manufacturer’s recommended volume. When using a Combitube®, inflate the distal balloon first using 10 to 15 mL, then inflate the proximal (pharyngeal, blue) balloon using 50 to 85 mL.
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Connect a bag-valve apparatus to the ventilating lumen (on the Combitube®, the blue [pharyngeal] lumen).
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Begin ventilation (8 to 10 breaths/minute, each about 500 mL and lasting about 1 second).
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Assess lung ventilation by auscultation and chest rise. Check end-tidal carbon dioxide to confirm tube placement. Auscultation for Combitube® placement is often difficult and unreliable, so rely more on capnometry. However, during cardiac arrest, capnometry may not reliably indicate proper tube placement.
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If assessment suggests inadvertent tracheal placement of a Combitube®, try ventilating through the distal cuff.
Aftercare
Warnings and Common Errors
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In about 5% of Combitube® insertions, the distal tube will enter the trachea; in this case, ventilation can be done through the distal tube. In up to 10% of insertions of newer King tubes, the distal tube will enter the trachea; adequate ventilation may be possible through the distal tube.
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Generally, supraglottic airways should be inserted only in patients who are unresponsive; otherwise, aspiration is a risk. Do not allow a patient to awaken during insertion or ventilation with a supraglottic airway. If necessary, prevent the patient from waking up or gagging (using paralytics, adequate analgesia, and sedation), or remove the airway as clinically indicated.
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Placing the dual lumen tubes too deeply may cause the balloon to obstruct the tracheal opening and inhibit ventilation. Obstruction can be remedied by pulling the airway back a few centimeters.
