Indications for Intubation

simplified_airway_algorithm
Simplified Airway Algorithm

There are three main indications for intubation:

  1. Failure to maintain or protect airway
  2. Failure to ventilate or oxygenate
  3. Predicted decompensation

If the patient does not have a quickly reversible condition, then you need to place a endotracheal tube. Signs of an unprotected airway include:

  • loss of gag reflex,
  • drooling (unable to swallow their own secretions), or
  • the need for requiring a prolonged maneuver to establish airway

A patient who is not ventilating or oxygentating well will demonstrate

  • increasing hypoxia or hypercapnia (perhaps a falling pulse ox),
  • deteriorating mental status (as they become more hypercapnic), and
  • they not responding appropriately to supplemental oxygen.

Arterial blood gases are unnecessary to make the decision to intubate. There is often not enough time to wait for the result and so the decision made clinically.

If you are predicting a decompensation and possible loss of airway, consider this in

  • neck trauma (where an expanding hematoma may compress the airway),
  • a tiring asthmatic (who will not be able maintain the work of breathing),
  • a septic patient (who is becoming more fatigued and unresponsive),
  • whenever a patient leaves the ER (and you can’t watch their airway, i.e. ambulance, CT scan)

The gist of this approach is that unstable patients need to be intubated right away. If you have some time to think, figure out how hard this intubation will be and prepare for it. Use items to make a difficult airway easier. If it’s not hard, go for it using standard rapid sequence intubation.

If you attempt to intubate and fail, and especially if you cannot ventilate via a bag-valve-mask, it’s time to take emergent measures — the cricothyroidotomy. This procedure is not covered in this course, but click the link to watch some videos of it being done.

Rapid Sequence Intubation

RSI is the cornerstone of modern emergency airway management. The goal of rapid sequence intubation is to take a patient from conscious & breathing to unconscious, paralyzed and ventilated. To do this you’ll need to give a potent sedative, a neuromuscular blocker (paralytic) and minimize the risk of aspirating gastric contents. The six steps of RSI are often carried out concurrently. They are:

1. Prepare

Assess for intubation difficulty, get your equipment ready, hook the patient up to monitors, get an IV in.

2. Pre-oxygenate

Pre-oxygenate the patient. Put them on 100% oxygen for at least 5 minutes.

3. Pre-medicate

  • Lidocaine can decrease airway responses.
  • Fentanyl decreases sympathetic tone.
  • Atropine decreases the bradycardia caused by succinylcholine.
  • Vecuronium can lessen the fasiculations caused by succinylcholine, though few use this.
  • Benzodiazepines can prevent the emergence nightmares from ketamine.

4. Paralysis after sedation

Sedate the patient first, then paralyze. It would not be a pleasant experience to be aware of being paralyzed. So a sedative with rapid onset is important.

Typical Sedatives
Drug Notes
Propofol 2-2.5 mg/kg IV – Decreases BP
– Bradycardia
Etomidate 0.3 mg/kg – Decreases BP
– Maintains BP
– Most commonly used
Ketamine 3 mg/kg – Increases BP
– Good for Trauma
– Increases secretions
– Maintains airway reflexes
Typical Paralytics
Drug Notes
Succinylcholine 1.5 mg/kg – Most rapid paralysis
– Defasciulations can cause high K+
– Avoid in chronic, burn victims,
– Avoid in neuromuscular diseases
– Avoid in renal failure
– This is a theoretical risk
Rocuronium 1.2 mg/kg – Not as fast as succinylcholine
– Use if worried about hyperkalemia

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