Background and Aims High frequency oscillation (HFO) and prone position ventilation have their places in the treatment of an inhomogeneous pulmonary pathology of ARDS. Possible benefits of early used HFO include improved ventilation and oxygenation, reduced risk of ventilator induced lung injury development, lower plasmatic levels of pro-inflammatory cytokines, and therefore reduced mortality of ARDS patients. Prone position ventilation improves oxygenation, but without an impact on mortality or length of hospitalization. Aim of this study was to compare the pressure hemodynamic parameters in experimental models of ARDS ventilated in prone position or by HFO.

Methods Total of 16 experimental piglets were randomised into 2 groups of 8 piglets: PP group ventilated conventionally in prone (18 hours) and supine (6 hours) position, HFO group ventilated 24 hours in supine position with HFO. Mean arterial pressure (MAP), central venous pressure (CVP), mean pulmonary artery pressure (mPAP) and pulmonary capillary wedged pressure (PCWP) were measured invasively, indexed systemic (SVRI) and pulmonary (PVRI) vascular resistances were calculated.

Results MAP is lower in HFO group than in PP (3 hours: p=0,001; 6 hours: p=0,016; 9 hours: 0,007; 12 hours: 0,041). mPAP is higher in PP group (3 hours: p=0,001), as well as PVRI (1 hour: p=0,003) and SVRI (9 hours: 0,027). CVP and PCWP values show no differences between groups.

Conclusions Early used HFO lowers PVRI in first hours of ARDS, PP has milder impact on systemic pressures - combination of both procedures can be beneficial.

Grant Acknowledgment IGA MZčR NS 11100–4