What is high frequency ventilation (HFV) stuttering?

From the Guidelines

High frequency ventilation (HFV) stuttering is not directly defined in the provided evidence, but based on the context of HFV, it can be inferred that stuttering refers to the rapid, repetitive breaths delivered by the ventilator, which can be adjusted to optimize gas exchange and minimize lung injury 1.

Key Considerations for HFV

• HFV is typically used as a rescue therapy for infants failing conventional ventilation, particularly in cases of severe congenital diaphragmatic hernia (CDH) or persistent pulmonary hypertension of the newborn (PPHN) 1.
• The initial target for delivered tidal volumes in HFV is roughly 3.5 to 5 mL/kg, recognizing that functional residual capacity and total lung volume are reduced in infants with CDH 1.
• High-frequency oscillatory ventilation is a reasonable alternative mode of ventilation for subjects with CDH when poor lung compliance, low volumes, and poor gas exchange complicate the clinical course (Class IIa; Level of Evidence A) 1.

Adjusting HFV Settings

• The frequency of HFV can be set between 3-12 Hz (180-720 breaths/minute) depending on the specific device and patient condition, with lower frequencies for CO2 elimination and higher frequencies for oxygenation.
• The amplitude (delta P) of HFV can be adjusted based on chest wall vibration and blood gas results, with a typical starting value of 60-90 cmH2O.
• Regular blood gas monitoring is essential to guide adjustments, with mean airway pressure (MAP) primarily controlling oxygenation and amplitude/frequency controlling ventilation 1.

From the Research

Definition of High Frequency Ventilation (HFV)

• High-frequency ventilation is the application of mechanical ventilation with a respiratory rate > 100 breaths/min 2
• High-frequency oscillatory ventilation (HFOV) is the form of high-frequency ventilation most widely used in adult critical care 2

Principles of HFV

• The principles of lung-protective ventilation have matured in parallel with the technology for HFOV 2
• The 2 basic principles of lung-protective ventilation are the use of small tidal volume and maintenance of adequate alveolar recruitment 2
• HFOV uses low tidal volumes and constant mean airway pressures in conjunction with high respiratory rates to provide beneficial effects on oxygenation and ventilation 3

Clinical Applications of HFV

• HFOV is often utilized as a rescue strategy when conventional mechanical ventilation (CV) has failed 3
• HFOV seems to be safe and effective for adults with severe acute respiratory distress syndrome who have failed conventional ventilation 4
• All patients who have ventilator-induced lung injury (VILI) or are at risk of developing VILI or ARDS would be suitable candidates for HFOV, especially those who have failed conventional mechanical ventilation 3

Comparison with Conventional Ventilation

• Available evidence does not support that survival in adults with acute respiratory distress syndrome is improved by HFOV 2
• The findings of a systematic review suggest that HFOV does not reduce hospital and 30-day mortality due to ARDS; the quality of evidence was very low 5
• HFOV may improve oxygenation in some patients, but this improvement is often transitory 2

Stuttering in HFV

• There is no direct mention of "stuttering" in the context of high frequency ventilation in the provided studies 3, 4, 2, 5, 6
• The term "stuttering" is not defined or discussed in relation to HFV in the available evidence.