High Flow Nasal Cannula Therapy in Bronchiolitis

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The Pre-brief

Bronchiolitis is the narrowing of the bronchioles as a result of an infection caused by a virus. The lungs natural line of defense against organisms or particles is to create mucus. When mucus collects in these narrow, smaller airways, the flow of air becomes obstructed making it hard for children to exhale. Oxygen is then unable to flow freely in and out of the lungs.

Bronchiolitis often occurs during the winter months.  It is most commonly caused by a virus such as RSV (respiratory syncytial virus), parainfluenza, rhinovirus, and other viruses that cause the common cold.  The viruses that cause bronchiolitis are easily spread.  You can contract the virus in the air (airborne droplet form) from an infected person when they sneeze or cough. Another way is from saliva, which can come from sharing a toy, a drink, or by kissing a person who is sick. Lastly, skin-to-skin can also spread the droplets of the virus, so think about hugging and handshakes. Oftentimes, children can be re-infected, as studies have shown a previous infection doesn’t guarantee lasting immunity. Bronchiolitis usually lasts from as little as seven days up to one month.


Bronchiolitis begins like the common cold with a runny nose, coughing, sneezing, and fever, but can progress into congestion, wheezing, trouble breathing, and ear infections.

Treatment in the Home Care Setting

Treatment is usually supportive in the home care setting. Bronchiolitis can be self-healing and usually improves over time without any treatment. Mucus removal from the nose is key when caring for a child with bronchiolitis. At home, a simple bulb syringe (nasal aspirator) and normal saline drops can effectively clear secretions from the nose.  If the nose is not cleared of mucus, the child will have difficulty sleeping and eating and may begin to show signs of respiratory distress, especially in small babies and infants since they are obligate nose breathers. It is recommended to clear nasal congestion prior to eating and sleeping routines.

Cool mist humidifiers can be utilized in the room. Keeping the air moist will act as an additional tool to keep mucus loose and relieve cough and congestion. If using a humidifier it is important to follow manufacturer guidelines for recommended cleaning to prevent a buildup of bacteria and mold.  In conjunction with offering a moist environment, elevating the child’s head during sleep will also help to aid in mucus clearance and promote ease of breathing.

Since the treatment of bronchiolitis is supportive, for babies and children who are old enough, medications such as Tylenol or Motrin may be given to help alleviate a fever or irritability.  It is not recommended to give medications to the pediatric population for cough and congestion. It is important to consult a health care provider prior to administering these medications. 

Hydration is very important. Babies who have bronchiolitis often breathe very fast and can become dehydrated and tired. While at home, caregivers should offer clear, low sugar fluids as often as possible and should monitor wet diapers.

When it’s time to see the Doc

 If the child has fewer wet diapers than normal, has poor fluid intake, seems dehydrated or overly tired, a physician should be notified. More importantly, if the child shows any signs or symptoms of respiratory distress such as rapid shallow respirations, wheezing, nasal flaring, or retractions, a visit to the hospital may be necessary.

Treatment of the In-Patient 

Most of the time bronchiolitis presents as a mild respiratory illness; therefore a small percent requires a hospital stay.  When symptoms are more severe, kids need to be admitted to the hospital for observation and care. Much like the supportive treatment at home, an in hospital admission consists of clearing nasal mucus, keeping the head elevated, and keeping the baby hydrated, but also starting oxygen or high flow therapies.

As mentioned previously it is crucial to keep mucus cleared from the nose. Healthcare workers may provide nasopharyngeal suction to clear the nasal passages. In the hospital setting clearing the airway will be monitored and maintained as often as every two hours if needed.

The encouragement of fluid intake during hospital admission is just as important as if the child were at home. If the child isn’t taking in sufficient fluid with simple encouragement, an IV would be placed and fluid hydration would be maintained intravenously. Additionally, if the child has poor oral intake a feeding tube may be inserted to promote optimal nutrition.  

Bronchodilators have not been helpful on a routine basis, however, in severe cases Albuterol can be administered on a trial basis only to help open the airway, with the exception of children who have a known history of reactive airway disease who may be ordered more frequently.

High Flow Nasal Cannula (HFNC)

High flow nasal cannula can be an additional supportive measure of defense for clinicians in children who have low oxygen levels, labored breathing, and/or retractions. HFNC works by washing out CO2 dead space. It can provide low levels of PEEP helping to stent the airway open and allowing oxygen to move freely in and out of the lungs. Unlike the traditional nasal cannula, HFNC provides warmth and humidity and can aid in thinning secretions and helping to facilitate mucociliary clearance. Another added benefit, especially in smaller babies, HFNC can help to reduce the energy exerted trying to warm and humidity inhaled air.  HFNC in the pediatric population lowers intubation rates, which in turn lowers hospital length of stay.

Knowing appropriate settings is key when starting high flow therapy. The cannula should not occlude more than 50% of the internal diameter of the nares. This ensures the child can exhale around the prongs. Select the appropriate size cannula based on the sizing chart included in the manufacturer package. Be sure to check how much flow the prong selection can accommodate. Once prong size is selected, the cannula can be secured in place.

To get started, use a flow of 5-8L/min for children up to one-month-old.  Children one month to one year start at 8-12L/min. Be sure to check your institution’s guidelines and physician’s orders. Inspiratory demand increases with respiratory distress. Adjust the flow rate accordingly to meet the child’s demands but being careful to not use more than necessary. Titrate FiO2 to maintain appropriate SpO2.


While children are susceptible to many illnesses, one to especially look out for in the winter months is bronchiolitis. This respiratory illness initially appears similar to the common cold but could progress further. While treatments often are able to be done at home, at times the child may require hospital admission. One of the leading treatments in the hospital setting would be the initiation of high flow nasal cannula therapy which often leads to better outcomes.

The Debrief

  • HFNC can help support increase respiratory demand thus decreasing retractions
  • HFNC hydrates mucus helping to facilitate mucociliary clearance allowing for easier suctioning 
  • Be sure to set appropriate settings and use the appropriate cannula


  1. Moreel L, Proesmans M. High flow nasal cannula as respiratory support in treating infant bronchiolitis: a systematic review. Eur J Pediatr. 2020 May;179(5):711-718. doi: 10.1007/s00431-020-03637-0. Epub 2020 Mar 31. PMID: 32232547.


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