The Decision to Intubate

The I.C. Cordes College of Airway Knowledge, written by Dr. Steven Carleton, is known to many who have passed through our doors.  Today, however, we begin to set them free to the #FOAMed world starting off with I.C. Cordes #1 - The Decision to Intubate.  I felt like I had found a mint copy of the Amazing Fantasy Introducing Spiderman comic book or a Honus Wagner baseball card receiving these collected cases by email from Dr. Carleton earlier today. - Jeffery Hill, MD

I.C. Cordes College of Airway Knowledge #1: The Decision to Intubate

A 43 year-old woman presents by squad after taking a suicidal ingestion.  An empty bottle of amitriptyline was found at the scene, along with an empty liquor bottle.  The squad reports that the patient was somnolent but arousable at the scene, and had no improvement with Narcan.  FSBS was 116

Her vital signs are:  p 136, r 12 and shallow, bp 116/68, T 99.6, O2 sat. 94% RA.  Her GCS is 10.

Her exam shows dilated pupils, dry mucous membranes, an odor of alcohol on the breath, shallow respirations, flushed skin, and a rapid pulse.  She mumbles obscenities, and is observed to swallow secretions.

Does this patient need to be intubated?

Indications for Intubation

The indications for intubation include:

1)      Failure to oxygenate.  This is easy to assess with pulse oximetry, as long as the patient has adequate pulses and is not overly vasoconstricted or cold.  The clinical assessment of oxygen saturation is totally unreliable.

2)      Failure to ventilate.  This is easy to assess with capnographic ETCO2 monitoring, but this is too expensive for routine use.  Shallow respirations and bradypnea can give an indication of hypoventilation, but the clinical assessment of this parameter is unreliable.  If a VBG is available, the pvCO2 is useful – if it is normal or nearly normal you can count on the value being nearly identical, or only slightly higher, than the paCO2.

3)      Inability to protect or maintain the airway.  This one can be subtle.  All obtunded ED patients must be assumed to have a full stomach.  Whether the obtundation results from alcohol, drugs, metabolic derangement or trauma, the potential for vomiting is high.  The potential for vomiting is higher still if you attempt to assess airway protection by gagging the patient.  NEVER DO THIS!Do not push on the posterior portion of a somnolent patient’s tongue.  It cannot improve the situation.  Instead, observe the patient.  If they can phonate sensibly, they can protect their airway.  If they can swallow, they have the functioning afferent innervation to sense secretions in the pharynx, and they have the functioning efferent innervation to coordinate the complex muscular contractions that constitute swallowing.  They can likely protect their airway against anything other than a high-volume emesis, unless they are strapped to a stretcher on their backs.

4)      The subsequent clinical course will be improved by early intubation.  This indication is broad and often requires considerable clinical judgment.  Patients who go to the CT scanner will have relatively lax monitoring and observation compared to the SRU.  They will be strapped down, supine.  Decompensation in respiratory status, or ability to protect the airway, may not be noticed until it is too late, and the patient’s position will not facilitate clearing the airway.  This is true also of the angio suite, in nuclear medicine, and in the Pods.  Patients whose condition is dynamic and progressive will benefit from early intubation.  The woman in the case is going to get worse before she gets better.  However, the time-cost of intubation must be considered, particularly when the patient is awaiting a time-dependent, critical intervention.  This is particularly true in helicopter transports.  Unfortunately, the only thing that justifies, or condemns, your judgment is the result – if you intubate and the patient suffers a complication from the procedure, or deteriorates from a progressive condition, your judgment is subject to question.  If you don’t intubate and the patient aspirates in the scanner or in the aircraft, you are similarly subject to question about your decision.

For this case, the patient is not suspected to have failure to oxygenate or ventilate now, but what about 15 minutes from now?  She is protecting her airway now, but will she protect it in the near future?  She is hemodynamically stable now, but may not be soon.  She needs to be intubated, but you have time to optimize the process.

Always articulate the indication for intubation, at least to yourself.  It is a thought clarifying process.  The first two indications necessitate very fast action.  The second two indications may mandate emergent intubation within a few minutes, or may permit ample time for preparation and optimization of your subsequent plan.