[Functional scintigraphic studies of perfusion and ventilation during high frequency jet ventilation (HFJV)]

Abstract

In a controlled study, functional-scintigraphic investigations into perfusion and ventilation were performed on 10 dogs with non-damaged and extremely severely damaged lungs. The pulmonary damage was produced by injecting oleic acid (OA) into the right atrium of the heart under controlled ventilation (IPPV). The scintigraphic examinations were carried out using 133Xenon. The study compared HFJV (HFJV100, HFJV300) with IPPV in the non-damaged lung as well as HFJV300 with IPPV and CPPV (PEEP 1 kPa) after damage by OA. With the aid of the present radionuclide investigations, new insights can be gained into the largely unclear regional conditions of the gas exchange under HFJV in both the healthy and the damaged lung. Results from controlled studies on the distribution of ventilation and perfusion under HFJV have not been reported to date. The functional-scintigraphic examination with 133Xe on dogs shows, based on specific conditions of the gas exchange and special anatomic conditions of the lungs, a ventilation distribution that differs fundamentally from all other forms of ventilation, including HFOV, preference being given to apical pulmonary segments. This refers to the normal and the damaged lungs alike. However, ventilation-specific changes in pulmonary perfusion do not occur. The resulting deviating regional VA/Q relationship are obviously not of crucial influence upon the gas exchange. Rather, it is influenced and determined by damage-induced intraregional functional-structural alterations in the lung.