High Flow


    High Flow

    Clinical Question – Why use High Flow Nasal Cannula? When should you use it over BIPAP?

    HFNC offers several advantages compared to conventional oxygen therapy, including:

    1. Ability to deliver O2 at up to 60 LPMs at nearly 100% FiO2. This is huge compared to regular Nasal Cannula (1-6 LPMs, maxing out at 45% FiO2) and NRB (10-15 LPMs, ~ 95% FiO2).
    2. The oxygen is humidified. It’s comfortable to use. Unlike having a big honking mask blowing into your face, you get a smooth flow of Os up the nose.
    3. Provides a small amount of CPAP (2-6 cm H2O). This mechanically splints open the nasopharynx, preventing supraglottic collapse and decreasing nasopharyngeal resistance.
    4. Reduces work of breathing by assisting in dead-space washout.

    When should you call RT to set-up HFNC?

    1. Type 1 (Hypoxemic) Respiratory Failure – This is the type of respiratory failure where oxygenation is the primary issue. Has great application in: Pneumonia, PE, Carbon Monoxide Poisonings.
    2. Respiratory Failure Patients where BIPAP is contraindicated – e.g. aspiration risk, actively vomiting, facial trauma, hyperactive delirium. If the patient fails HFNC, it can be used as a bridge to preoxygenate.
    3. Patients with copious respiratory secretions – Positive Pressure/BIPAP will impair expectoration.
    4. When the Diagnosis is Unclear – it’s much easier to speak to a patient on HFNC compared to BIPAP.
    5. Apneic Oxygenation – Preoxygenate with a NRB or BIPAP as normal. Push your meds and watch the SpO2 remain steady.
    6. Palliative Care Patients

    Here’s a video of how to set-up HFNC. Picture credit goes to Reuben Strayer and SinaiEM alum Nelson Wong.


    1. PulmCrit – Mastering the Dark Arts of BiPAP and HFNC
    2. LIFTL – HFNC
    3. Deranged Physiology – High Flow Nasal Prongs
    4. EMUpdates – High Flow Nasal Cannula in the ED
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