How dead space clearance improves oxygenation with just room air.

Watch this effect in action
 

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This video depicts the clearance of a radioactive tracer from an upper airway model using Gamma camera imaging superimposed on a CT scan.

Flow rates were 15, 30, and 45 L/min.

In this experiment, as the flow rate increases, so does clearance.¹

How pressure creates slower, deeper, more regular breathing.
 

• Breath and flow-dependent airway pressure^,2,3 ...
• ...promotes slower, deeper breathing by prolonging expiration time³ resulting in...
• ...an increase in alveolar ventilation³ and reduced work of breathing.

Watch this effect in action
 

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Corley et al. 2011⁴ demonstrated a significant increase in lung aeration once therapy starts.

This change reflects enhanced lung volume and tidal volume.

This effect is flow-dependent
 

Increases approximately 0.5 - 1 cmH₂O per 10 L/min^3,5-6

Mean airway pressure (for illustrative purposes only)

It's different from CPAP pressure!
 

• NHF pressure is dynamic, not set, and not constant.
• With NHF, the level of pressure changes throughout the breath cycle and is dependent on the size of cannula prongs, breathing rate, mouth opened or closed, i.e., pressure fluctuates.
• Is the Airvo 2 a continuous positive airway pressure (CPAP) device?

Humidity... 
 

• ...prevents desiccation of the airway epithelium⁷and...
• ...maintains⁹ and improves mucociliary clearance / transport^7,8 as illustrated in the animation.
• Image: healthy cilia beating to remove debris (e.g., bacteria) from the airway.

Watch this effect in action.
 

Watch the effect of low humidity under a microscope (1 min - turn audio on)

As the clip starts, you can see cilia beating. The dark spots moving across the left panel are debris (possibly bacteria) removed by effective mucociliary transport.

Conversely, debris in the right low-humidity panel stops as cilia slow, the effect of low humidity. After just an hour at 90% RH, the mucosa has dried out.

Do you need a refresher on how MCT works - watch this cool animation!

Patient comfort
 

Clinical evidence suggests that Optiflow NHF therapy provides better comfort than conventional oxygen delivery devices.^10,11

Patients can eat, drink and sleep with the Optiflow interface and can more easily communicate with clinicians and families than with a mask.

Additionally, a study in JAMA¹² found significantly reduced skin breakdown and noted a lower nurse workload with Optiflow NHF therapy compared with Bi-level ventilation.

The advantage of NHF for oxygen delivery - is reducing oxygen dilution.
 

In the example illustrated, the maximum oxygen flow from the face mask (in the left panel) is limited to 10 L/min, which is insufficient to meet the patient’s peak inspiratory demand of 50 L/min.
The patient will draw in/entrain 40 L/min of room air to compensate, diluting the 100% oxygen delivered via the face mask.

Conversely, in the right panel, NHF therapy can meet the patient’s total inspiratory demand of 50 L/min without the need for dilution of oxygen - this gives confidence in the delivery of a specified FiO₂.

Why using NHF gives you confidence in the oxygen fraction you are delivering. 
 

With conventional oxygen, inspiratory flow is variable, so the oxygen fraction delivered is variable.

In contrast with NHF, you may be able to meet or exceed peak inspiratory flow, reducing or eliminating dilution from room air.