Airway Algorithm


  • List the three main indications to intubate a patient (though there are way more than three).
  • Outline an algorithm for approaching the patient who requires intubation.

As said before, your first priority with your patient is to ensure a secured airway. But how do you decide who to intubate?

Who gets the tube?

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-masktime to take emergent measures — the cricothyroidotomy.

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:

The 6 P’s of Rapid Sequence Intubation
Prepare Assess for intubation difficulty, get your equipment ready, hook the patient up to monitors, get an IV in.
Pre-oxygenate Pre-oxygenate the patient. Put them on 100% oxygen for at least 5 minutes.
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. Benzodiazepines can prevent the emergence nightmares from ketamine.
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.

Placement of the tube Placement of tube after sedation and paralysis.
Post-intubation Management Confirmation you didn’t accidentally intubate the esophagus:

  • listen for bilateral breath sounds,
  • listen for a lack of air in the stomach,
  • look for symmetric chest rise,
  • use an end-tidal CO2 detector to look for color change (after at least 6 breaths)
  • get a chest x-ray to assess for depth of intubation.


Alright, so which drugs would you use? Remember first you sedate, then you paralyze. Imagine how horrible it would be to paralyzed and not sedated?! A nightmare. It’s happened. Don’t ever do that.

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+
  • Watch out in chronic, burn victims, kids (undiagnosed muscular dystrophies), neuromuscular diseases
  • This is a theoretical risk
Rocuronium 1.2 mg/kg
  • Not as fast as succinylcholine
  • Use if worried about hyperkalemia


  1. Amanda says:

    As an inexperienced student, I am still a bit uncertain about blade choice, what size tubes to use, and indications for glidescope use. I’m guessing this probably comes with experience and further training…

    1. Rahul Patwari says:

      Here’s the rule of thumb I use: men use a MacIntosh 4 and an 8.0 tube, women use a MacIntosh 3 and a 7.5 tube. However I always have the other sizes of blades and tubes handy and make sure they work beforehand. One adage I’ve heard is: you can always intubate someone with a blade that’s too big and a tube that’s too small.

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