High-Flow Therapy Lecture Notes

Definition of High-Flow Therapy

• High-flow therapy delivers oxygen at a flow rate that meets or exceeds the patient's inspiratory flow demand.
• Typical adult inspiratory flow rate at rest is 20-30 liters per minute.
• High-flow devices need to deliver at least 20-30 liters per minute.

Characteristics of High-Flow Therapy

• Heated and Humidified: Oxygen should be heated and humidified for patient comfort.
• Terminology:
  • Often called Heated and Humidified High Flow Oxygen Therapy (HHFNC or HFNC).
  • Other variations include HFOT, HFT, or HHFOT.
  • Vapotherm calls their version HHVNI (mask-free NIV).

Device Capabilities

• Devices like Vapotherm's Precision Flow deliver up to 40 liters/min.
• F&P's Airvo can deliver up to 60 liters/min.
• Some devices exceed 60 liters/min to meet high inspiratory demands (up to 100 liters/min in respiratory distress).

High-Flow vs. Non-Invasive Ventilation (NIV)

• Complementary Use: High-flow is not a replacement for NIV; they are often used together.
• NIV addresses both oxygenation and CO2 ventilation issues, while high-flow primarily targets oxygenation.
• High-flow allows for breaks in NIV, enabling patients to perform activities like eating and communicating.

Clinical Studies and Findings

• Vapotherm Study:
  • 104 patients in respiratory distress were placed on high-flow oxygen.
  • 27 failed, 4 intubated immediately, 23 switched to NIV.
  • Of those 23, 20 improved and avoided intubation.
• Post-Extubation Study:
  • Patients at high risk of failure assigned to high-flow only or both NIV and HFT.
  • Lower reintubation rates observed in the group with both NIV and HFT.

Summary Points

• High-flow oxygen therapy delivers oxygen at a flow rate equal to or greater than the patient's inspiratory flow rate.
• It is heated and humidified for comfort and may create a CPAP effect.
• It may help wash out CO2, known as CO2 dead space washout, though the extent is unclear.
• High-flow therapy is an effective tool for treating patients with oxygenation issues and those in respiratory distress.