High Frequency Ventilation

ho w to increase CO2 clearance

1.Increased "delta P” (peak pressure - PEEP)
This is also known as Amplitude
2. Decreased frequency
3. Deflate the ET tube -adult

indications of HFV

A. Bronchopleural fistula (and other air leak
syndromes eg. Pneumomediastinum, pneumopericardium
B. ARDS (and other low compliance lung diseases)
C. IRDS, PIE, prophylactic treatment of BPD

Physiologic Effects/Goals of High frequency ventilation (HFPPV, HFJV, HFOV)

1. Lower incidence of barotrauma
 2. *MAP is set
 3. Less depression of cardiac output
 4. Less fluctuation of intracranial pressure
 5. improved oxygenation through increased MAP

explain pendulluff effect

The pendelluft effect refers to the inter-compartmental gas exchange between regions of the lungs with differing compliance, allowing for better ventilation distribution during mechanical ventilation. It can enhance gas exchange by transferring air to areas of the lung that are better perfused.

explain spike theory

Double helix structure in which there is
asymmetric velocity profiles, inspiration occurring constantly in the center of the structure and expiration happening constantly around the outside of structure
(much like a DNA strand) also called “spike theory”

theory of action

bulk convention

pendelluff effect

spike theory

cardiogenic mixing and molecular diffusion

Initial control settings (Jet Ventilator )

A. Rate 100 - 150/minute
B. %I time 25 -35% on jet ventilator
C. FIO2 same as before HFJV
D. Driving pressure: Set to yield Delta P = 1/3 of Delta P during conventional ventilation
E. PEEP 3 cm H2O or same as that used before HFJV