Gas exchange and facilitation of high-frequency ventilation in intrathoracic surgery

High-frequency ventilation (HFV) of the jet type was evaluated for facilitation of intrathoracic operations because HFV does not necessitate ventilatory movement of the lung and reduces the volume of the lung. The feasibility of HFV as a substitute for the current respiratory management of intermittent positive-pressure ventilation (IPPV) was determined in 12 patients with cancer of the lung by employing two types of HFV-HFV alone (Group 1) and HFV on physiological dead-space volume (VD) (Group 2). For the 6 patients in Group 1, HFV was set at a frequency of 3 Hz and a driving pressure of 0.5 kg/cm2. For the 6 patients in Group 2, HFV was set at 6 Hz with the same driving pressure but was superimposed on a small tidal volume equal to a dead space. High-frequency ventilation facilitated intrathoracic operations because of the disappearance of ventilatory movement and the reduced volume. No significant difference between the groups was found for arterial oxygen tension. Arterial carbon dioxide tension (PaCO2) in patients in Group 1 remained in the normal range, although it was slightly acidotic. The PaCO2 in Group 2 was acidotic. Therefore, it was concluded that HFV alone can be substituted for IPPV in gas exchange and provides good accessibility to the operative field.