High Frequency Ventilation

OVERVIEW

High Frequency Ventilation  ventilation with small tidal volumes at high frequencies

TYPES

  • high-frequency positive-pressure ventilation
  • high-frequency percussive ventilation
  • high-frequency jet ventilation
  • high-frequency oscillatory ventilation

HIGH FREQUENCY POSITIVE-PRESSURE VENTILATION

  • TV 3-4mL/kg at 60-100/min
  • conventional mechanical ventilator
  • often used with high PEEP
  • expiration is passive and relies on elastic recoil
    • -> risks: gas trapping, hyperinflation and overdistension injury

HIGH-FREQUENCY PERCUSSIVE VENTILATION

  • aims to combine high frequency and conventional ventilation
  • conventional ventilator used + a gas driven piston at the end of the ETT
  • piston generates oscillation at 3-15Hz with short expiratory times which are superimposed on conventional inspiratory-expiratory pressure waves.
  • high frequency bursts generate auto-PEEP through breath stacking -> then are stopped and allow alveolar pressure to fall back to baseline.
  • improves alveolar recruitment with exposing them to high peak airway pressures

HIGH FREQUENCY JET VENTILATION

  • jet drive pressure augments TV
  • expiration is passive and gas trapping with intrinsic PEEP can develop
  • risks: trauma to upper airway, humidification and warming a problems, lung injury through shear forces

HIGH-FREQUENCY OSCILLATORY VENTILATION

  • oscillating diaphragm creates pressure waves in the ventilator circuit.
  • diaphragm is active in both directions -> creates inspiratory and expiratory pressure waves -> expiration is active.
  • clinicians set: flow rate, mean airway pressure, frequency, inspiratory-expiratory ratio, energy applied to the oscillating diaphragm.
  • see HFOV page for more details

Advantages

  • decreased risk of overdistention injury
  • increases mean airway pressure -> improved oxygenation and prevention of atelectrauma
  • good evidence base in paediatrics and neonates

CCC Ventilation Series

Journal articles

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the  Clinician Educator Incubator programme, and a CICM First Part Examiner.

He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.

His one great achievement is being the father of three amazing children.

On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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