One of my favourite parts about having medical students in the ICU is that they remind us of some of the core questions in critical care. Today @mlipkus asked what clinical factors would push me to intubate a patient. Let’s review some of the indications for intubation..
1) Neurological status
– Airway protection is a commonly referred to indication for intubation. “GCS less than 8? Intubate!”
– The rational for this is that a patient who is not awake is a patient who is at risk for aspiration and subsequent worsening respiratory status
– When intubating for this indication, have a close look at the patient and how vulnerable their airway really is. Do they have a cough? A gag? Ever extubated a patient with GCS of 8 or below? (I have..)
– My general threshold for hypoxia before I start considering intubation is ~ SaO2<90% on FiO2>60%
– It’s more than numbers – how hard are they working to breathe? How reversible is the underlying cause?
– Many patients are hypercapnic at baseline so important to look at pH as well
– Generally consider ventilation if pCO2>60 and pH<7.25
– Similar to hypoxia – think about the cause of the problem and how reversible it is.
Those are your basic 3 indications for intubation, but I’d like to offer two more indications that would push me to intubate..
4) Impending airway loss
– Think about this in your patient with facial/neck trauma, anaphylaxis, angioedema
– You may be better off protecting the airway early instead of dealing with an airway emergency later
– In normal conditions, about 10-15% of cardiac output is directed at respiratory muscles. In settings of shock and increased work of breathing, up to ~50% of cardiac output may be consumed by respiratory effort
– In this scenario, intubation and ventilation may help deliver precious oxygenated blood to the brain, kidney, liver, and gut instead of to the diaphragm
**Also remember scenarios where non-invasive ventilation may be indicated
– COPD exacerbation
– Decompensated CHF
– The immunocompromised patient with a reversible cause