Cánula Nasal De Alto Flujo

WHAT IS A HIGH FLOW NASAL CANNULA (HFNC)?

A high-flow nasal cannula (HFNC) is a heated and humidified system that delivers the prescribed fraction of inspired oxygen (FiO2) at very high flow rates. The primary intended use of HFNCs is to provide precise oxygen delivery, improve gas exchange, significantly reduce the work of breathing , and create a high FiO2 reservoir in the nasal cavity.

Let’s now consider how HFNC can help patients improve their respiratory disease.

HOW DOES A HIGH-FLOW NASAL CANNULA WORK?

HFNC is performed using an air/oxygen mixer, an active humidifier, a single heated tube, and a nasal cannula. It can heat (to 98.6°F or 37°C) and humidify the gas, which can decrease airway inflammation, maintain mucociliary function, improve mucus clearance, and reduce caloric expenditure in acute respiratory failure.

Furthermore, an HFNC can deliver appropriately heated and humidified medical gas at flows up to 60 L/min. HFNCs such as the Fisher and Paykel Airvo 2 are considered to have several physiological advantages compared to other standard oxygen therapies.

PRECISE OXYGEN DELIVERY

Traditional nasal cannula delivers flow rates of 2 to 6 L/min. However, patients with respiratory distress may have much higher peak inspiratory flow rates, which can cause the patient to draw ambient air into the lungs. This can result in oxygen dilution, and the patient may not receive the precise amount of oxygen required.

When a high-flow nasal cannula is used to deliver oxygen, flow rates are much higher than those achievable with a traditional nasal cannula. This results in a greater delivery of prescribed oxygen to the lungs and less entrainment of ambient air.

WASHING OF THE ANATOMICAL DEAD SPACE

Finally, when HFNC is applied, the constant high flow of oxygen provides a washout of the anatomical dead space of the oropharynx and proximal tracheobronchial tree , resulting in more efficient breathing.

PUTTING THE HIGH-FLOW NASAL CANNULA (HFNC) INTO USE

The main indications in adults include hypoxemic respiratory failure due to pneumonia, post-extubation, pre- intubation oxygenation , acute pulmonary edema, and use in «do not resuscitate/intubate» patients. The main pediatric indication in infants is bronchiolitis, but other indications are being studied, such as its use in asthma, croup, pneumonia, transport of a critically ill child, and post-extubation.

INTRODUCTION TO THE FISHER AND PAYKEL AIRVO 2

A perfect example of a HFNC is the Fisher & Paykel Airvo 2. This humidifier has an integrated flow generator that delivers high-flow, heated, humidified respiratory gases to spontaneously breathing patients through a variety of patient interfaces. The Airvo 2 is suitable for hospitals and long-term care facilities.

• Double coil heated breathing tube with integrated temperature sensor.
• Use with Optiflow nasal cannula interfaces, direct-connect tracheostomy, and mask interfaces.
• Optionally, oxygen from a concentrator or cylinder is added.
• The built-in ultrasonic analyzer requires no calibration, service, or replacement.
• Adjustable temperature and flow settings.
• Designed for easy installation, use and cleaning.

FISHER AND PAYKEL AIRVO 2 SPECIFICATIONS

Dimensions

• Height: 11.6″ (29.5 cm)
• Width: 6.7″ (17 cm)
• Depth: 6.9″ (17.5 cm)
• Weight: 4.8 pounds (2.2 kg)

General

• Supply frequency: 50-60 Hz
• Supply voltage/current: 100-115 V 2.2 A (2.4 A max. †); 220-240 V 1.8 A (2.0 A max.)
• Sound pressure level: alarms exceed 45 dBA at 1 m
• Audible alarm pause: 115 seconds
• Expected lifespan: 5 years
• Serial port: The serial port is used to download product data using F&P Infosmart software.
• Heating time: 10 minutes at 31°C (88°F), 30 minutes at 37°C (98.6°F)
• MR290 chamber with a flow rate of 35 L/min and an initial temperature of 23 ± 2 °C (73 ± 3 °F)
• Target temperature settings: 37, 34, 31 °C

Performance

• Humidity performance
• 33 mg/L at 37°C target
• 12 mg/L at 34°C target
• 12 mg/L at 31°C target
• Maximum temperature of supplied gas: 43 °C (109 °F) (according to ISO 80601-2-74)
• Maximum surface temperature of applied parts: 44 °C (111 °F) (according to ISO 80601-2-74)
• Flow range (default): 10-60 L/min
• Flow range (Junior mode): 2-25 L/min
• Maximum oxygen inlet: 60 L/min
• Oxygen analyzer accuracy: <± 4% (within the 25-95% O2 range)
• Operating conditions: 18-28°C (64-82°F), 30-70% RH

FINAL THOUGHT

Physicians have been using it for a wide variety of diseases and underlying conditions. High-flow nasal cannula (HFNC) oxygen delivery has already proven its value as an effective mode of non-invasive ventilatory support and has been gaining attention as a simple and well-tolerated alternative means of respiratory support for critically ill patients.