ObjectiveTo investigate the effect of high volume hemofiltration (HVHF) combined with mechanical ventilation (MV) on seawater respiratory distress syndrome (SW-RDS) canine models.MethodsTen nomal hybrid dogs were randomly assigned into two groups:MV group(MV group,n=5),all the animals only received MV after establishing model successfully; HVHF combined with MV group (HVHF+MV group,n=5),all were received HVHF plus MV after establishing model successfully.Both groups were observed for 4 hours.Mean arterial pressure (MAP),heart rate (HR),central venous pressure(CVP),arterial blood gas and venous plasma osmotic pressure were detected at baseline,0 min(model establishment),60 min,120 min,180 min,240min after treatment.Venous blood was collected to detect inflammatory mediators (IL-8,IL-6,TNF-α)at baseline,0 min,120 min,240 min after treatment.The lung pathology was examined at the end of the experiment.Results(1)All the animals were suvival after four hous of treatment in both groups. (2)Pattial pressure ofoxygen(PaO2) and O2 saturation(SaO2) rised after four hours of treatment in both groups(P＜0.05), and HVHF+MV group was better than MV group.After 4 hours of treatment,pH,actual bicarbonate (AB),bases excess(BE) in HVHF+MV group were significantly better than those in MV group(P＜0.05),recovering to the baseline values.(3)MAP,HR,CVP were stable during the four hours of treatment,and compared with 0 min,there was no significant differences after 4 hours of treatment in bothgroups. There were no significant differemces at the same time of treatment in both groups. (4)Plasma osmotic pressure were stable during the four hours of treatment,and compared with 0 min,there was no significant difference in MV group.But in HVHF+MV group,osmotic pressure was significantly higher after 4 hours of treatment than that at the same time in MV group(P＜0.05),and compared with 0 min and 180 min,those were higher too(P＜0.01). (5)Compared with those at the same time in MV group,plasma inflammatory mediators (IL-8,IL-6,TNF-α) were significantly decreased after 4 hours of treatment in HVHF+MV group(P＜0.01).After 4 hours of treatment IL-8,TNF-α in MV group were higher than those at the same time in 0 min (P＜0.05).(6)Compared with those in MV group,there were less infiltration of neutrophils,edema and injury of alveolar epithelium from pulmonary pathology.ConclusionsHVHF combined with MV can significantly improve hypoxemia and correct acidosis of SW-RDS model in canines.HVHF can effectively clear plasma inflammatory mediators and redundant water,improve pulmonary pathology changes.HVHF has no impact on MAP,HR and CVP of SW-RDS.