Anest. intenziv. Med. 2009;20(1):18-24

The importance of tidal volume and its monitoring during high-frequency ventilationIntesive Care Medicine - Review Article

Roubík Karel^1,*, Pachl Jan²

¹ České vysoké učení technické v Praze, Fakulta biomedicínského inženýrství

² Klinika anesteziologie a resuscitace 3. LF UK a FNKV, Praha

Even though High-Frequency Ventilation (HFV) meets criteria defining so called protective ventilatory strategy, HFV is not widely used in the clinical practice. Rational initiation of HFV and consequent maintenance of a constant ventilation belong to the limiting factors. Tidal volume is a parameter playing a crucial role in HFV. In the initial phase of HFV, monitoring of tidal volume allows reaching normocapnia promptly. As tidal volume generated by the ventilator depends on the relationship between the output impedance of the ventilator and the connected impedance of the respiratory system, stability of the adjusted ventilatory regimen also depends on this relationship. Furthermore, the effect of the connected impedance changes upon the delivered tidal volume differs in conventional and in high-frequency ventilation. Tidal volume plays also other important roles during high-frequency ventilation; tidal volume affects oxygenation much strongly during HFV than during conventional ventilation. Considering the differences between conventional and high-frequency ventilation and considering the effects of tidal volume changes during HFV, continuous monitoring of tidal volume seems to be essential for the rational and efficient application and control of high-frequency ventilation.

Keywords: high-frequency ventilation; tidal volume; impedance; ventilator; oxygenation; monitoring

Received: September 6, 2008; Accepted: December 7, 2008; Published: February 1, 2009  Show citation