The recently reported differences between pulmonary and extrapulmonary acute respiratory distress syndromes (ARDSp, ARDSexp) are the main reasons of scientific discussion on potential differences in the effects of current ventilatory strategies. The aim of this study is to assess whether the presence of ARDSp or ARDSexp can differently affect the beneficial effects of high-frequency oscillatory ventilation (HFOV) upon physiological and clinical parameters. Thirty adults fulfilling the ARDS criteria were indicated for HFOV in case of failure of conventional
ventilation strategy. According to the ARDS type, each patient was included either in the group of patients with ARDSpor ARDSexp. Six hours after normocapnic HFOV introduction, there was no significant increase in PaO
2/FIO2 in ARDSpgroup (from 129±47 to 133±50 Torr), but a significant improvement was found in ARDSexp (from 114±54 to 200±65 Torr, p<0.01). Despite the insignificant difference in the latest mean airway pressure (MAP) on conventional mechanical ventilation (CMV) between both groups, initial optimal continuous distension pressure (CDP) for the best
PaO2/FIO2 during HFOV was 2.0±0.6 kPa in ARDSp and 2.8±0.6 kPa in ARDS
exp (p<0.01). HFOV recruits and thus it is more effective in ARDSexp. ARDS
exp patients require higher CDP levels than ARDSp patients. The testing period for positive effect of HFOV is recommended not to be longer than 24 hours.