Blind Insertion Airway Devices (BIAD's)

With the importance of maintaining the airway and the sheer number of patients who experience airway compromise, several companies have created devices to ease the process of obtaining a "definitive airway." A definitive airway is one that cannot be easily compromised by vomit, secretions, or swelling. (e.g., a tube of plastic that maintains a path for air at all costs).

In the past, this role was traditionally played by intubation and placement of an endotracheal tube. However, the complexity of this procedure leads to frequent failures in the uncontrolled EMS environment. BIADs are tools that simplify this process. Per the name, they can be inserted blindly without visualization of the vocal cords to confirm placement. 

This section will review the indications for BIAD use, the two most common types, and the usage of BIADS in general.

 

Indications, Contraindications, and Complications

INDICATIONS: BIADs are used when a definitive/advanced airway is required, and intubation is either unsuccessful or unrealistic. The indications for an advanced airway are as follows:

• An unresponsive patient who is hypoxic despite adequate BVM ventilation
• Patient with trauma to the face/neck who is experiencing confirmed or suspected swelling.
• Penetrating injury to the head or neck 
• More routine injuries with suspected long transport times

CONTRAINDICATIONS: The contraindications to BIAD are focused on causing vomiting, bleeding, or potentially perforating the larynx/esophagus. They are as follows:

• An intact gag reflex
• known esophageal disease (cancer, varices, stricture)

Cancer tissue is very fragile--you can easily perforate the esophagus (or trachea in laryngeal or tracheal cancer) without feeling the breach of resistance! 

• laryngectomy with a stoma
• Caustic ingestion or airway burns
• stature < 4 feet

COMPLICATIONS: The complications of BIAD use surround the nature of pushing a rigid tube into relatively soft tissue and inflating a balloon within it (trauma/compression), along with the risk of inflating the stomach.

• Inflation of the stomach leads to regurgitation and aspiration of gastric contents
• compression of vascular structures in the neck
• Trauma to the airway/esophagus
• nerve injury to the "laryngeal nerves" that control the vocal cords.
• Hypotension due to positive pressure ventilation and/or vagus nerve stimulation.

 

Supraglottic Airways

The Combitube used to be the most common BIAD in the prehospital setting. However, thanks to advances in technology and better data, the more common ones are now the King LT airway and the i-Gel supraglottic airway device. Both of these airways are dual-lumen devices. One of the key differences between the Combitube versus the King LT is that the King LT only has one inflation cuff, whereas the Combitube has two. The i-Gel has neither and acts similarly to that of an LMA, which we will discuss in the next section of this unit.

The goal of the Combitube is an insertion into the esophagus. Since the esophagus is much easier to access, the lower balloon generally seals it off; the upper balloon will naturally seal off the bottom of the pharynx. This sends air through the secondary lumen, exiting between the two balloons and entering the larynx. This is confirmed by listening for breath sounds and watching for chest rise.

In the rare case that the tube is inserted into the larynx, the primary lumen can be used to ventilate just like a traditional ET tube. This is suspected when ventilation of the secondary lumen does not result in breath sounds or chest rise.

The time usage of this tube becomes complicated if the patient has a bilateral pneumothorax, in which case auscultation is not a reliable method of confirming placement.

 

Laryngeal Masks

The laryngeal mask airway (LMA) is an ET tube that goes over the larynx instead of into it. These devices are less common than the King LT or the Combitube outside the hospital.  

The i-Gel has taken the place of the LMA in the prehospital setting and is also placed blindly. After figuring the patient's weight, it is advanced into the oropharynx until resistance is met. The i-Gel seals as the patient's body temperature warms the gel-type distal end of the device and provides a custom fit to protect the airway during ventilation. Correct placement will position it to sit atop the glottis and protect the airway from vomit/blood/secretions. Auscultation for breath sounds and end-tidal capnography is the preferred method of confirming placement. 

 

 

Usage of BIADS

To place any BIAD:

1. Ensure the patient is pre-oxygenated with 100% O2 for at least 30 seconds.
2. Assemble your equipment: Suctioning, lubricant, oxygen, BVM, and at least two full correctly-sized BIAD devices.
3. Check the equipment to ensure it is in working order.
   (If the BIAD of choice is the King LTD airway or the Combitube, ensure the cuffs will inflate to the proper pressure.)
4. Lubricate the distal tip of the BIAD and open the patient's airway.
5. Remove any adjunct (OPA, NPA) present and suction airway of any secretions.
6. Insert the BIAD at a 90º angle (pointing to the right or left corner of the mouth) with the distal tip sliding back over the patient's tongue.
7. Rotate the BIAD to be in line with the patient's airway.
8. The device is advanced until the phalange rests against the patient's teeth.
9. Inflate the pilot balloon with air from the included syringe to the manufacturer-indicated pressure.
10. To confirm correct placement, connect to capnography or capnometry and then to the BVM, and auscultate over the abdomen as a breath is delivered

• If no breath sounds are heard in the abdomen, move up to auscultate the L lung first, then the R (right main stem placement is rare but possible.)
• If breath sounds are heard in the abdomen, deflate the front (pilot) balloon some and withdraw the BIAD a few centimeters, remembering to re-inflate the balloon when finished. Auscultation over the stomach should produce no breath sounds.
• If no breath sounds are auscultated in the L lung but are present in the R lung, perform the same method described for abdominal breath sounds and reassess until equal sounds are auscultated in the L and R lung.

11. Secure the device with a commercial tube holder or by other protocol-indicated means and monitor SPO2 and ETCO2 for changes.

CAVEATS:

• A pneumothorax could prevent bilateral breath sounds even with correct placement.
• Always use a water-based lubricant when necessary, e.g., KY jelly, Trachjell. Never petroleum-based, e.g., Vaseline.
• Combitubes are contraindicated in children < 16 or under 5' tall.