Anticipated Difficult Intubation: Should I Intubate The Patient Awake?

When I was training, awake intubation for anticipated difficult airway was routine. Blind nasal intubation and fiberoptic intubation were common events. The advent of video laryngospcopy  has made the need for awake intubation much less common. Instruments like the Glidescope and the McGrath video laryngoscope have revolutionized intubation, and made the difficult intubation scenario fortunately much more uncommon.

However, awake intubation with the patient breathing spontaneously is still sometimes optimal for patient safety.  Awake intubation can be performed using standard laryngoscopy techniques, but it is more commonly done using specialty intubation techniques such as blind nasal or fiberoptic intubation.

Many providers are uncomfortable with performing awake intubations and leave it as a last resort. There are a variety of reasons for this discomfort, including lack of experience and/or the fear that the patient will remember the intubation and think poorly of their care. However, awake intubation can be a safe and comfortable strategy in many clinical situations and all providers should develop expertise with one or more techniques of choice — before an emergency forces them to use one.

This article will discuss how to decide when to do an awake intubation. Future articles will discuss how to do them.

Awake or Not Awake? — That is the Question

When should we think about awake intubation? Making that decision is a judgment call. Many of the signs for evaluating an airway prior to intubation are highly predictive of success if they are negative, but have a significant number of false positives. In others words, the signs may predict the patient will be difficult to intubate when, in fact, they are not difficult. The reverse is unfortunately also true. The patient may look easy to intubate, but they’re not. We always have to be prepared for the unexpected.

There are some key questions I ask myself when deciding whether to intubate a patient awake.

Will The Patient Be Difficult To Ventilate?

When you induce unconsciousness and paralyze a patient, you are betting the patient’s life that you will be able to ventilate him or her if you can’t intubate. Ability to ventilate is always more important than ability intubate. Try to imagine what might get in the way of a good mask seal. Conditions that may make the patient a challenge to ventilate, especially if occurring together, include:

  • BMI greater than 40: especially if the neck is short with a large neck circumference
  • Full beard
  • Mallampati Class  4
  • Edentulous
  • Sleep apnea or snoring
  • Abnormal facial anatomy or trauma

Usually, patients who are difficult to ventilate have more than one of these factors. The ability to ventilate a patient with complicating airway factors is dependent on skill and experience. It may also depend on whether you will have help available if you get into difficulty. Be honest with yourself. If you are questioning whether or not you will be able to ventilate a patient then seriously consider awake intubation.

Will The Patient Tolerate Induction Medications?

Administration of induction agents for intubation can cause hypotension from such things as vasodilation in the face of hypovolemia and myocardial depression in the face of poor cardiac reserve or sepsis. We typically use our best judgment on choice of induction agent and dose to minimize this risk, and are prepared to treat hypertension if it occurs. However,  there are some patients who are so sick that we we may be concerned that giving any induction agent would cause severe decompensation.

If the patient is in that type of severe shock or respiratory failure, awake intubation may be less stressful and more likely to maintain hemodynamic stability.

Can Your Patient Tolerate Apnea?

If your patient is suffering severe hypoxia which is refractory to oxygen administration, the risk of decompensation if the intubation attempt is prolonged is very high. Risking the period of apnea then depends on the circumstances.

If hypoxia is due to hypoventilation in patient in respiratory failure, the airway looks easy to ventilate, and you believe that if intubation is prolonged your manual ventilation would actually improve oxygenation, then the risk of proceeding with sleep intubation is low.

If the patient is hypoxic because they have severe upper airway obstruction from an airway tumor, you suspect intubation will be difficult, and that ventilation might be difficult as well, stop and think. In this case  the risk of precipitating worsening hypoxia and a can’t intubate can’t ventilate scenario  is high. Seriously consider awake intubation.

Is There a History of Difficult Intubation?

Most patients don’t come with this history, but you won’t know unless you ask or look at available records. If there is a history of difficulty try to find out as much as you can about the circumstances. Today, with video laryngoscopy, most subsequent intubations are often easy. But likelihood of success with video laryngoscopy depends on the cause of the difficulty.

  • Does the patient have a congenital facial anomaly like  Pierre Robbin?
  • Have they had radical airway surgery and neck irradiation that would limit manipulation of larynx and neck angles?
  • Is there an obvious abnormality predisposing to difficult intubation or difficult ventilation?
  • Can the patient open their mouth widely enough to accept the laryngoscope?
  • Is their thyromental distance extremely short?
  • Is there a large tumor or swelling filling their mouth or submandibular space?

If so, consider awake intubation.

Is the Patient at Risk of Vomiting and Aspiration?

We certainly intubate patients with full stomachs and at risk for aspiration all the time using rapid sequence induction. However, if you have a patient who you are worried may be difficult to intubate, and the patient is actively vomiting or at very high risk of aspiration, then awake intubation may be safer.

Is It Dangerous to Move This Patient’s Neck?

Sometimes a patient will present with cervical spine compression symptoms from spinal stenosis, or will have an unstable cervical spine fracture. Careful awake intubation with neck stabilization and monitoring of neurologic signs may be the safest choice. In this case, awake intubation also has the advantage of allowing a neurologic exam after the intubation is completed to document that no injury has been sustained.

Contraindications to Awake Intubation

Are there patients who should not be intubated awake? Yes there are.

Patient Refusal

A patient who is awake, alert and oriented and therefore competent to refuse treatment after being told the risks and alternatives can refuse awake intubation. However, most patients are initially hesitant out of fear. Approach them with empathy, explain the facts regarding risks, and a plan outlining their safety and comfort and they will rarely refuse.

Inability to Cooperate

Awake intubation absolutely requires cooperation between patient and provider. If the patient can’t cooperate, the risks of injuring the patient (or the provider) can be significant. Uncooperative patients include most younger children, most developmentally delayed patients, and the intoxicated or combative patient.

Local Anesthetic Allergy

Awake intubation with a well-anesthetized airway is not that uncomfortable, even with light or no sedation. If you can’t numb the airway safely, then awake intubation would be difficult and painful to perform, leading to loss of cooperation and potentially patient refusal.

What Options Do I Have?

What do you do if you have a patient who is poor candidate for awake intubation, who you think will be difficult to intubate or perhaps difficult to ventilate. In this case, local anesthetic topicalization (assuming no allergy) and allowing spontaneous ventilation under general anesthesia is a reasonable alternative. If you allow the patient to continue to breathe on their own, you have an additional margin of safety.

Children, for example, are often anesthetized with either inhalation agent or a total intravenous technique with propofol and then  intubated with a fiberoptic scope while asleep and breathing spontaneously.

Deciding to intubate a patient awake is a judgment call. It all comes down to your assessment of risk vs. benefit for patient safety taking into account the patient’s condition, the location of care, the equipment available, the experience you have, and the help that is present. Err on the side of safety if you have concerns. And regardless of which path you choose, always have plan B.

May The Force Be with You

Christine Whitten MD
Author: Anyone Can Intubate, 5th Edition

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