Providing ongoing oxygenation and CO 2 removal for patients during intubation.In addition, the preoxygenation with HFNO can be continued into the peri-intubation period of oxygenation. 5,6 HFNO is well-tolerated by awake patients at flow rates of 30–40 liters per minute, provides effective preoxygenation without the use of a facemask, and provides ongoing CPAP, which reduces pulmonary shunting. Preoxygenation using HFNO can be a good alternative to standard preoxygenation, which is usually performed with an FiO 2 of 1.0 delivered via a closed anesthesia breathing circuit and an appropriately fitted face mask. Improving preoxygenation before induction of general anesthesia (GA).Several applications of HFNO are described below, each with its potential benefits and risks.Ĭlinical applications of HFNO with specific benefits and risks: Depending on the physiology of the patient, HFNO may have benefits for clinical anesthetic management, but it is important to recognize that use of HFNO has its own inherent risks. HFNO is capable of delivering very high gas flows with high FiO 2 or oxygen/air blends to anesthetized, sedated, or awake patients. 1-3 In addition, it can reduce the work of breathing and reduce airway resistance. At high flow rates, it can provide continuous positive airway pressure (CPAP), washes out CO 2 from the respiratory dead space, and assists the process of oxygen diffusion into the alveoli (replacing oxygen which has been absorbed). HFNO has a number of beneficial effects not provided by standard nasal cannula. Specialized wide bore nasal cannulae, which convey the oxygen/air blend from the gas tubing to the patient’s nose.Wide bore tubing to deliver gas from the gas supply to the nasal cannulae.
A humidifier capable of fully humidifying the inspired oxygen/air mixture.A flowmeter capable of flows of up to 100 liters per minute.An electrically powered high-pressure oxygen/air supply (ideally with a blender to blend air into the gas flow to reduce the FiO 2 if needed).Therefore, there is little entrainment of room air which allows the delivery of a high FiO 2 (95–100%). With this technique, the high flows delivered via the specially designed nasal cannulae now exceed the patient’s IFR. In contrast, HFNO uses oxygen flows of 50–100 L/M. The effective delivered oxygen concentration (which reaches the lungs) is usually 25–30%, if a patient is receiving 2–4 L/M of nasal O 2. Once the IFR exceeds the flow of O 2 coming from the nasal cannulae, room air will be entrained which dilutes the FiO 2. Spontaneously breathing patients typically have an inspiratory flow rate (IFR) of 20–40 L/M. When patients are administered low flow nasal O 2, the oxygen flow rates are typically between 2–10 liters/minute (L/M). There is a marked difference between oxygen administration with standard low flow nasal cannulae and HFNO.