What is high flow nasal cannula (HFNC)
The use of humidified and heated high flow nasal cannula (HFNC) oxygen (O2) therapy is an innovative respiratory support system that has become increasingly popular and discussed in treating critically ill patients with acute hypoxemic respiratory failure with nasal high flow oxygen therapy. Moreover, HFNC has been proven effective in hypercapnic patients with a stable status which suggested by numerous recent studies. High flow nasal cannula system comprises an air-oxygen blender, a heated wire breathing circuit, a respiratory humidifier, and a nasal cannula. To reach the requirement of HFNC, it is not just a standard nasal cannula rotated to a very high flow rate. The gas must be heated to 37oC, 100% relative humidity, and 21%-100% FiO2 at flow rates up to 60LPM. Although HFNC is not a mechanical ventilation system, it is considered more and more as a respiratory support system.
Improve clinical efficiency
High flow nasal cannula (HFNC) oxygen therapy can improve lung volume, oxygenation post-extubation, and patient comfort compared with traditional standard masks or non-rebreather masks. In general studies, HFNC oxygen therapy reduced the need for non-invasive ventilation by 80%, reduced episodes of oxygen desaturation by 66 percent, reduced the need for reintubation by 80 percent, and reduced length of stay in the intensive care unit (ICU) by an average of 1.3 days. HFNC also can reduce the claustrophobia of some patients wearing face masks attributed to being able to eat, drink, and speak more easily.
In addition, HFNC provides many respiratory benefits in addition to improved oxygenation. It decreases breathing workload and cardiac, directly reduces carbon dioxide production and dead space in the lungs by increasing surface area available for gas diffusion and providing continuous positive airway pressure.
High flow nasal cannula (HFNC) oxygen therapy offers an alternative to conventional oxygen therapy in terms of workflow efficiency and equipment cost. Comparing to a ventilator, the HFNC device reduces the expanse of biomedical requirements, maintaining and consumables by using nasal cannula instead of an aerosol oxygen mask.
HFNC in neonates
The concept of high flow nasal cannula (HFNC) oxygen therapy started in the neonatal intensive care unit (NICU) as an alternative to Nasal Continuous Positive Airway Pressure(NCPAP). Generally, flow high than 1LPM is considered as a high flow for neonates and gas flows up to 2LPM through nasal cannula were able to generate up to 9.8 cmH2O of end-expiratory distending pressure as a useful respiratory modality to help reduce the need for intubation in premature infants with early respiratory distress.
HFNC in adults
The basic components for adults high flow nasal cannula (HFNC) oxygen therapy include a flow generator providing gas flow up to 60LPM, an oxygen mixer that achieves escalation of FiO2 21%-100%, a respiratory humidifier that heating temperature to 37oC, and a heated wire circuit to minimize heat loss and condensation.
Choose proper equipment and consumables, including the correct size and length of a nasal cannula. Choose between small, medium, or large adult size according to the patient.
Connecting the air and oxygen supply while ensuring humidification liquid is in place, the heated wire circuit and humidifier are plugged in with power and functioning normally.
Adjust the flow rate and FiO2 to the appropriate level.
Insert the cannula into the patient's nostrils and secure it to the patient’s head with an elastic strap to prevent air loss.
Adjust the head strap to the patient's head, carefully avoiding the ears; do not over-tighten.
Adjust the head strap clip to the nasal cannula and clip HFNC tubing to the patient's gown to relieve tension.
Maintain the patient in semi-Fowler's position and consider periodic prone positioning to promote lung expansion.
Monitor the patient for comfort and tolerance.