Continuous venovenous hemofiltration decreases mortality and ameliorates acute lung injury in canine model of severe salt water drowning

Background: Pulmonary edema is an important cause of complications and death in severe drowning. Continuous veno-venous hemofiltration (CWH) may reduce pulmonary edema and thus may be a treatment modality for severe sea water drowning resuscitation. Methos: 20 dogs were anesthetized and tracheally intubated. 10 ml/kg of sea water was infused into trachea in a minute. All animals developed signs of respiratory distress and severe hypoxia (PaO2 < 40 mmHg) within 15 minutes after infusion. They were then mechanical ventilated and randomized to receive either CWH (n = 10) or no additional treatment (control, n = 10) and followed over 4 hours. Arterial gas, hemodynamic parameters, and the levels of circulating inflammatory cytokines including interleukin 6 (IL-6), interleukin 8 (IL-8), and tumor necrosis factor a (TNF alpha) were determined. Additionally, blood endothelin and the levels of oxidative stress in lung were measured at sacrifice. Results: 5 animals in the control group (50 %) died within 4 hours after sea water aspiration, while 10 animals received CWH all survived (p < 0.05). Importantly, CWH significantly improved blood gas exchange as evidenced by higher PaO2, normal oxygen saturation, and no carbon dioxide retention after 3 hour of CWH, while also correcting against acidosis. Levels of circulating IL-6, IL-8, and TNFa were elevated in control but not in CWH group (p < 0.01). CWH also reduced plasma endothelin and alleviated oxidative stress. Histology examination further revealed reductions in pulmonary alveolar injury, blood congestion, and inflammation by CWH. Discussion and conclusions: CWH decreased mortality and pulmonary injury and largely maintained hemodynamic and acid-base balance in animals with severe sea water drowning and thus, may be added as a new measure to aid in resuscitation from severe sea water drowning.