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May 23, 2012

Basic airway management techniques

Skillful airway management is often the first step in the successful resuscitation of a compromised patient. Neurologic damage caused by hypoxia occurs within minutes. Non-definitive methods (basic airway management) are very important and will, if performed correctly, provide good oxygenation. Remember, people die from lack of oxygenation, not from lack of intubation.

Basic airway management will not protect against aspiration of gastric contents should vomiting occur. Always have suction equipment on and ready during airway procedures. The gold standard for securing the airway is still endotracheal intubation.

Some EMS systems may authorize use of extraglottic devices by basic level providers; however, this article is intended to stress simple, basic techniques.

It is not uncommon for me to find a compromised patient with a poorly managed airway during the wait for medication-assisted intubation/rapid sequence intubation (RSI). I am easily guilty of the same poor technique during the setup for RSI unless I frequently review the process.

Good oxygenation is a must prior to starting RSI.

Basic airway management starts with assessment of the airway. Is the airway free of obstructions? Is the respiratory rate and volume adequate? It's a common belief that airway obstruction is usually caused by the tongue, yet studies have shown that the epiglottis and other soft structures in the hypopharynx are more likely responsible for these obstructions1.

Suctioning and anatomical positioning such as the head tilt, chin lift or jaw thrust will in most circumstances relieve these obstructions regardless of the anatomy responsible for causing them.

We are taught these airway techniques in various classes (first responder, EMT, nursing, ACLS, PHTLS, ATLS, etc.), but in practice, it is easy and common to rush and fail to use good-quality basic airway management skills.

This is typically all the patient with spontaneous sonorous respirations requires for an open airway. Adjuncts to help in maintaining the open airway are also helpful.

Oral airway devices: Oropharyngeal airways will relieve soft tissue obstruction of the posterior airway by displacement of the tongue and soft tissue anteriorly. They should only be used in the unconscious patient as vomiting, aspiration and laryngospasm may otherwise occur.

There are two primary insertion techniques:

  1. The airway device may be inserted sideways or upside-down and, once it is well into the mouth, rotated and advanced in to the full position
  2. A tongue blade can hold the tongue in a down and forward position until the airway is in place

Choose the method that works best for you so long as the end result is correct2.

The desirable results: The patient is not responding with a gag reflex or snoring, and air is going in and out. Be vigilant in observing for vomiting.

Nasal airway: The nasopharyngeal airway is another option. These are placed in either nasal passage and allow unobstructed routes for ventilation through the nose to the hypopharyngeal area. They tend to be less stimulating than the oral airway but can cause epistaxis.

The base of the nasal passage is relatively flat and parallel to the roof of the mouth. When inserting the airway, lift slightly on the tip of the nose with the free hand, and place the lubricated airway straight into the passage with the bevel against the nasal septum, not upward as is the natural tendency. This limits contact with the turbinates and hopefully avoids the resultant nosebleed.

The airway should be constructed of a soft, flexible material, and apply a water-based lubricant such as KY jelly prior to insertion2.

Ventilation: Ventilating the patient after a clear airway has been established is the next technique to master. The American Heart Association's opinion on bag-mask ventilation is that when possible, it should be a two-person job. One provider should hold the mask with both hands and maintain proper position of the head while maintaining a good mask seal; the second provider should squeeze the bag.

Because assigning two people for this task is not always practical, we should use good technique and do the best possible job for the given situation3.

The bag-valve mask unit (BVM) should consist of a self-inflating bag, oxygen reservoir and non-rebreathing exhalation valve (NRV). The mask and NRV should be constructed of a clear see-through material to allow observation for emesis.

The bag should have the ability to deliver 800 ml while squeezing with one hand. It should not require oxygen flow or volume in the reservoir to inflate, and it must be constructed of a non-slip material for easy grasp and be able to deliver an FiO2 of 0.85 to 1.04.

First, choose the proper size mask for an optimal fit. The best fit is the smallest mask that will provide a good seal around the mouth and nose. This will cause the least amount of dead space and be easier to hold. For patients with thick beards, the edentulous or anyone with facial deformity from trauma, it will be difficult to maintain a good seal.

Second, the mask should not be pressed down onto the face. This pressure will cause airway misalignment. The provider should for a "C" shape on the mask with the thumb and index finger and grasp the mandible with the remaining three fingers, pulling the face into the mask. This works best when using two hands but with practice can be accomplished with one. It will be easier for the provider to maintain correct positioning of the airway without the misaligning forces caused by pushing the mask down on the unsupported head and face.

Third, ventilations should be delivered with emphasis on a slow inspiratory phase (1.5 to 2.0 seconds) in the non-intubated patient. This should keep airway pressures low and minimize gastric inflation. The target is a high volume-low pressure ventilation5.

Advanced airway management will provide the best protection from aspiration. It is the most precise method for of control of the gases of respiration and supplies a medication route. However, the best advanced skills are of little value if the patient suffers a hypoxic insult during the basic airway management phase. Practice of high-quality basic skills is the foundation of good medical care.

References

  1. Nandi PR, Charlesworth CH, Taylor SJ, et al: Effects of general anesthesia on the pharynx. Br J Anesth. 66:157, 1990.
  2. Roberts JR, Hedges JR, Vrocher D, et al: Clinical procedures in emergency medicine. 4th Ed., 2004, WB Saunders pg. 58.
  3. Cummins R.O., Field J.M., et al. ECC/AHA, ACLS: Principals and Practice. Pg. 139-164.
  4. Hess DR: Manual of gas powered resuscitators. Respiratory Care Equipment. Philadelphia: 1999, Lippincott Williams and Wilkins, pg. 187-202.
  5. Miller R.D., Cucchiara R.F., et al. Miller: Anesthesia, 5th ed., 2000, Churchill Livingstone, Inc. Pg. 2533.
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