Amelioration of hemodynamics and oxygen metabolism by continuous venovenous hemofiltration in experimental porcine pancreatitis

AIM: To investigate the potential role of continuous venovenous hemofiltration (CVVH) in hemodynamics and oxygen metabolism in pigs with severe acute pancreatitis (SAP). METHODS: SAP model was produced by intraductal injection of sodium taurocholate [4%, 1 mL/kg body weight (BW)] and trypsin (2 U/kg BW). Animals were allocated either to untreated controls as group 1 or to one of two treatment groups as group 2 receiving a low-volume CVVH [20 mL/(kg·h)], and group 3 receiving a high-volume CVVH [100 (mL/kg·h)]. Swan-Ganz catheter was inserted during the operation. Heart rate, arterial blood pressure, cardiac output, mean pulmonary arterial pressure, pulmonary arterial wedge pressure, central venous pressure, systemic vascular resistance, oxygen delivery, oxygen consumption, oxygen extraction ratio, as well as survival of pigs were evaluated in the study. RESULTS: Survival time was significantly prolonged by low-volume and high-volume CVVHs, which was more pronounced in the latter. High-volume CVVH was significantly superior compared with less intensive treatment modalities (low-volume CVVH) in systemic inflammatory reaction protection. The major hemodynamic finding was that pancreatitis-induced hypotension was significantly attenuated by intensive CVVH (87.4±12.5 kPa vs116.3±7.8 kPa,P＜0.01). The development of hyperdynamic circulatory failure was simultaneously attenuated, as reflected by a limited increase in cardiac output, an attenuated decrease in systemic vascular resistance and an elevation in oxygen extraction ratio. CONCLUSION: CVVH blunts the pancreatitis-induced cardiovascular response and increases tissue oxygen extraction. The high-volume CVVH is distinctly superior in preventing sepsis-related hemodynamic impairment.

Influence of continuous veno-venous hemofiltration on the course of acute pancreatitis

AIM： To investigate whether continuous veno-venous hemofiltration （CVVH） in different filtration rate to eliminate cytokines would result in different efficiency in acute pancreatitis, whether the saturation time of filter membrane was related to different filtration rate, and whether the onset time of CWH could influence the survival of acute pancreatitis. METHODS： Thirty-seven patients were classified into four groups randomly. Group 1 underwent low-volume CVVH within 48 h of the onset of abdominal pain （early CVVH, n = 9）. Group 2 received low-volume CVVH after 96 h of the onset of abdominal pain （late CVVH, n= 10）. Group 3 underwent high-volume CVVH within 48 h of the onset of abdominal pain （early CVVH, n = 9）. Group 4 received high-volume CVVH after 96 h of theonset of abdominal pain （late CVVH, n = 9）. CVVH was sustained for at least 72 h. Blood was taken before hemofiltration, and ultrafiltrate was collected at the start of CVVH and every 12 h during CVVH period for the purpose of measuring the concentrations of TNF-α, IL-1β and IL-6. The concentrations of TNF-α, IL-1β and IL-6 were measured by swine-specific ELISA. The Solartron 1 255 B frequency response analyzer （British） was used to observe the resistance of filter membrane. RESULTS： The survival rate had a significant difference （94.44% vs68.42%, P〈0.01） high-volume and low-volume CVVH patients. The survival rate had also a significant difference （88.89% vs 73.68%, P〈0.05） between early and late CVVH patients. The hemodynamic deterioration （MAP, HR, CVP） was less severe in groups 4 and 1 bhan that in group 2, and in group 3 than in group 4. The adsorptive saturation time of filters membranes was 120-180 min if the filtration rate was 1 000-4 000 mL/h. After the first, second and third new hemofilters were changed, serum TNF-α concentrations had a negative correlationwith resistance （r： -0.91, -0.89, and -0.86, respectively in group 1; -0.89, -0.85, and -0.76, respectively in group 2; -0.88, -0.92, and -0.82, respectively in group 3; -0.84, -0.87, and -0.79, respectively in group 4）. The decreasing extent of TNF-α, IL-1β and IL-6 was significantly different between group 3 and group I （TNF-α P〈0.05, IL-1β P〈0.05, IL-6 P〈0.01）, between group 4 and group 2 （TNF-α P〈0.05, IL-1β P〈0.05, IL-6 P〈0.01）, between group 1 and group 2 （TNF-α P〈0.05, IL-1β P〈0.05, IL-6 P〈0.05）, and between group 3 and group 4 （TNF-α P〈0.01, IL-1β P〈0.01, IL-6 P〈0.05）, respectively during CVVH period. The decreasing extent of TNF-α and IL-1β was also significantly different between survival patients and dead patients （TNF-α P〈0.05, IL-1β P〈0.05）. In survival patients, serum concentration of TNF-α and IL-1β decreased more significantly than that in dead patients. CONCLUSION： High-volume and early CWH improve hemodynamic deterioration and survival in acute pancreatitis patients. High-volume CVVH can eliminate cytokines more effidently than low-volume CVVH. The survival rate is related to the decrease extent of TNF-α and IL-1β. The adsorptive saturation time of filter membranes are different under different filtration rate condition. The filter should be changed timely once filter membrane adsorption is saturated.