[High-frequency ventilation. Development of new ventilation systems--experimental and clinical results].
Based on the well known High Frequency Jet Ventilation (HFJV) two modified types of High Frequency Ventilation, Forced Diffusion Ventilation (FDV) and High Frequency Pulsation (HFP) have been developed. Both systems are designed to allow ventilation with very small volume portions in the upper range of HFV frequencies. In dog experiments sufficient gas exchange could be maintained during FDV up to frequencies 3000 per minute and even with an uninterrupted "continuous" jet entering the lungs on carina level. With this mode of ventilation lung could be kept in a resting position. Due to particular configuration of a pair of nozzles at the tip of a modified endotracheal catheter fresh gas is forced down the airways along the inner edges of bifurcations towards the lung periphery. At the same time stale gas leaves the lung via the remaining cross section of the airways. Thus a continuous scavanging process can be established without significant lung inflation. This mechanisms are not met during HFP. Therefore the range of frequencies achievable with this type of ventilation is significantly lower (250 to 500/min.) and "tidal volumes" are much higher. However, they are still beyond the anatomical dead space which suggest again a contribution of alternative mechanisms to gas transport. The impact of both types of HFV on gas exchange and pressure-flow conditions were studied in lung models as well as in animal experiments. FDV and HFP were also applied successfully to a group of 23 patients undergoing major lung surgery. In all patients it was possible to maintain excellent gas exchange throughout the whole surgical procedure. The exposure of the surgical field was much more quiet as compared to IPPV. Due to the small tidal volumes lung pressures can be kept much lower and gas losses via the open bronchi and lung surface are reduced dramatically.
D000818:Animals; D001794:Blood Pressure; D004285:Dogs; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008448:Maximal Expiratory Flow Rate; D008451:Maximal Voluntary Ventilation; D008875:Middle Aged; D010313:Partial Pressure; D011175:Positive-Pressure Respiration / Q000295:instrumentation / Q000379:methods*; D013903:Thoracic Surgery
Hochfrequenzbeatmung. Entwicklung neuer Beatmungssysteme--experimentelle und klinische Ergebnisse.