Background for Fast Fact #503: High flow nasal cannula (HFNC) is a system for delivering heated humidified oxygen to patients experiencing acute hypoxic respiratory failure (see Fast Facts #330). It can deliver up to 100% oxygen at a flow rate of up to 60 L/min and is generally only available in the inpatient setting (1,2). This Fast Facts will discuss a guideline for the withdrawal of HFNC in patients who are dependent on this modality and wish to transition to comfort-focused care (3). In contrast to mechanical ventilation, patients on HFNC more often are awake and decisional, so the process of weaning may be more emotionally distressing for patients, families, and clinicians. There is little published evidence to guide best practice; this Fast Fact assimilates expert opinion and anecdotal evidence to offer recommendations.

HFNC and ventilator withdrawal: In general, the withdrawal process for HFNC is very similar to the ventilator withdrawal process. Preparation, communication, pre-medication and post-withdrawal symptom assessment and management are essential. See Fast Fact #34, Fast Fact #126, and Fast Fact #453 for more information on best recommended practices for compassionate ventilator withdrawals. What distinguishes the HFNC withdrawal process from ventilator withdrawals are: A) patients are more likely to be awake and decisional; B) removal of HFNC (as opposed to an endotracheal tube) often occurs in a slower and more stepwise fashion; C) HFNC more frequently occur outside of intensive care settings (e.g., on general medical wards) and may not require the assistance of a respiratory therapist; D) clinicians may be more apt to reinstitute HFNC once withdrawn in cases of post-withdrawal symptom distress.

HFNC withdrawal in patients who are awake and decisional: Anxiety and apprehension surrounding withdrawal of HFNC is especially common among an awake patient. It is important that clinicians attend to the psych-, socio-, spiritual- needs of the patient and family, not just the patient’s physical needs.    

• Provide an opportunity for patients and family members to participate in a goals of care conversation prior to the withdrawal process. Many patients vocalize concerns about suffering during or after the withdrawal procedure. Patient-centered education on pre-medication, withdrawal procedure and aggressive symptom management after withdrawal often ease anxieties. If the clinical scenario allows, allow the patient and family to determine the timing of the withdrawal process.
• For an awake patient, the decision of how much to pre-medicate prior to withdrawal is based on patient symptom burden, patient preference, and clinical judgment. In many scenarios, it may be prudent to pre-medicate with a short acting parenteral opioid (e.g., morphine 1-2 mg IV) and/or a benzodiazepine (lorazepam 0.5-1 mg IV) about 15-20 minutes prior to the planned withdrawal and ensure the patient shows no signs of respiratory distress or pain before proceeding.
• Lower doses of opioids and benzodiazepines (e.g., morphine 1-2 mg IV prn vs 2-4 mg) may be sufficient since secretion burden can be easier to predict in comparison to a ventilator withdrawal.
• Some experts suggest utilizing a concise clinical tool to guide the need for additional bolus dosing such as the Respiratory Distress Observation Scale (RDOS), PAINAD, or the Richmond Agitation Sedation Scale (RASS) (4-6). Below are some clinically relevant scores:
  • RDOS < 3, indicates no respiratory distress.
  • PAINAD < 4, indicates mild to no pain.
  • RASS score of -1 (lightly sedated) or less, depending on patient’s preference.

Withdrawal of HFNC:  Once symptoms are well controlled (e.g., RDOS <3), proceed with the withdrawal procedure. One study suggests the following protocol for decreasing the FiO2 and liter flow:  

• Decrease FiO2 and liter flow by 25% at 10 minute-intervals with boluses of opioids and/or benzodiazepines every 10 minutes as needed for symptom control (3).
  If the patient becomes dyspneic or uncomfortable, pause further weaning and bolus with appropriate medications until the patient is comfortable. Consider up-titration of oxygen/flow while waiting for medication to achieve desired comfort.

Post-withdrawal care must be individualized based on respiratory needs and patient care preferences. For example, some patients may not want their dying to be prolonged medically once HFNC is withdrawn and can be left on room air as long as they have access to prompt and effective as needed opioids and benzodiazepines; other patients hoping to survive the hospitalization so they could die at a preferred location, may benefit from being placed on supplemental oxygen.  What is uniform is the need for frequent assessment of the patient’s comfort and the family’s communication needs.  

• Nurse presence at bedside for first 15 minutes, followed by every 15-minute assessment x3, followed by q1 hour is a common monitoring protocol. Provide bolus doses of opioids or benzodiazepines for any signs of nonverbal distress and titrate doses to effect.
• Unfortunately, there is no published evidence regarding prognosis after HFNC and how it compares with patients who undergo a ventilator withdrawal at the end of life. Physiologically, patients who undergo HFNC withdrawals may have a greater chance of living > 1 day and being able to be discharged to their desired end-of-life location (e.g., home or a free-standing hospice facility).
• Considering the relative prognostic uncertainty after HFNC withdrawals, clinicians must be diligent in providing iterative emotional support and anticipatory guidance on the variable prognosis.

References 

1. Hyzy, R. (2020). Heated and humidified high-flow nasal oxygen in adults: Practical considerations and potential applications. Waltham, MA: UpToDate.
2. Bramati, P. S., Azhar, A., Khan, R., Tovbin, M., Cooper, A., Pangemanan, I., … & Bruera, E. (2023). High flow nasal cannula in patients with cancer at the end of life. Journal of pain and symptom management, 65(4), e369-e373.
3. Brackett, H., Forman, A., Foster, L. A., & Fischer, S. M. (2021). Compassionate removal of heated high-flow nasal cannula for end of life: case series and protocol development. Journal of Hospice & Palliative Nursing, 23(4), 360-366.
4. Zhuang, Q., Yang, G. M., Neo, S. H. S., & Cheung, Y. B. (2019). Validity, reliability, and diagnostic accuracy of the Respiratory Distress Observation Scale for assessment of dyspnea in adult palliative care patients. Journal of Pain and Symptom Management, 57(2), 304-310.
5. Warden, V., Hurley, A. C., & Volicer, L. (2003). Development and psychometric evaluation of the Pain Assessment in Advanced Dementia (PAINAD) scale. Journal of the American Medical Directors Association, 4(1), 9-15.
6. Ely, E. W., Truman, B., Shintani, A., Thomason, J. W., Wheeler, A. P., Gordon, S., … & Bernard, G. R. (2003). Monitoring sedation status over time in ICU patients: reliability and validity of the Richmond Agitation-Sedation Scale (RASS). Jama, 289(22), 2983-2991.

Authors’ Affiliations: University of Utah, Salt Lake City, Utah.
Conflicts of Interest:  None.
Version History: Originally edited by Sean Marks MD; first electronically published in February 2025.