Effects And Safety Of Hemofiltration At Early Stage Of Septic Shock With Different Ultrafiltration Doses In Piglet Models

BackgroundSevere sepsis and septic shock are noted problems globally in the healthcare of children. Studies have suggested that an imbalance between the pro-inflammatory and anti-inflammatory mechanisms plays an important role in the developing from sepsis to multiple organ dysfunction syndromes (MODS). Continuous blood purification therapy (CBP) enables stable internal environment of the body and may relieve over-inflammatory responses. High volume hemofiltration (HVHF), extended from standard continuous renal-replacement therapy (CRRT), may enhance non-selective removal of inflammatory mediators in sepsis and MODS by increasing the amount of replacement fluid. Animal and clinical studies in the last10years show that HVHF has some advantages in the treatment of sepsis and MODS by significantly improving hemodynamics and survival rate.Up to now, few reports have been found in HVHF treatment in children with sepsis. Therefore, it is necessary to evaluate the dose, efficacy and safety of HVHF in children with severe sepsis. This experiment was designed to perform HVHF on piglets with endotoxin-induced septic shock, observe the effect on vital signs, hemodynamics, oxygenation levels, inflammatory mediators and internal environment, and approach the mechanism of HVHF, The results may be useful for the clinical HVHF application for children as well as infant with severe sepsis.ObjectivesTo observe the effects of hemofiltration at early stage of septic shock with different ultrafiltration doses (30ml/kg/h Vs50ml/kg/h), including hemodynamics, oxygenation, inflammatory mediators in plasma and tissue, and internal environment in piglet models, evaluate the therapeutic effects and safety of HVHF.Methods1. The18healthy young piglets (Shanghai species) were divided randomly into three groups:control group (n=6), CVVH group (n=6, ultrafiltration volume=30ml/kg/h) and HVHF group (n=6, ultrafiltration volume=50ml/kg/h);2. Anesthesia was given with ketamine and fentanyl; tracheotomy and mechanical ventilation were performed; placing PiCCO arterial and venous lines. Double-lumen catheters were used for CRRT. Base state (B0h) parameters were recorded30minutes after catheters were placed.3. Establish animal model of septic shock by injection LPS (150μg/kg) O111:B4. Models were established (0h) when MABP reduced by>20%vs. base value.4. CVVH group and HVHF group received hemofiltration at different doses respectively, whereas control group were not given CRRT. All groups were supplied with hydroxyethyl starch to maintain volume load during experiment.5. During the experiment, the following observations were carried out:1) All Groups:Changes of hemodynamic and oxygenation at the time of BOh, Oh,2h,4h and6h;2) All Groups:changes of TNF-α、IL-6、IL-10in plasma at different time points(B0h、0h、2h、4h、6h);3) All Groups:recorded internal environment at different time points(B0h, Oh,2h,4h, and6h) and hemodialysis machine pressure at different time points (0h、2h、4h and6h).6. Animal models were killed after experiment and their hearts and lungs were analyzed histopathologically. Lung tissues homogenates were used to evaluated TNF-α、IL-6、IL-10levels.Results1. Changes of hemodynamics and oxygenation after modeling:1) Hemodynamics (MABP, CO, SVRI):a. The MABP in all groups showed a downward trend over time after model established. The decrease values of Control Group were larger than that of CVVH group and HVHF group. At4h, the MABP level in HVHF was higher than that in other two groups (P<0.05), whereas levels of both CVVH group and HVHF group were higher than that of Control group at6h (P<0.05).b. The CO in control group showed downward trend over time after model established and CO at6h was lower than that at BOh (P<0.05). However, the CO in CVVH group and HVHF group kept at a high level at6h than that at BOh (P<0.05). And CO at6h in HVHF group was higher than that in CVVH group (P<0.05).c. The SVRI in control group was lower at Oh,2h and4h compared with BOh (P<0.05), but was higher at6h compared with BO h(P<0.05). However, the SVRI in CVVH group and HVHF group was lower at0h,2h,4h and6h than that at BOh (P<0.05). Furthermore, at6h, SVRI in control group was higher than that in other two groups (P<0.05) and SVRI in HVHF group was higher than that in CVVH group (P<0.05).2) Oxygenation(P/F, EVLWI):a. P/F in all groups showed a downward trend over time after model established and P/F at2h,4h and6h were lower than that at BOh (P<0.05). And the P/F was higher in HVHF at6h than that in other two groups (P<0.05);b. The EVLWI in all groups showed a significant increase after model established and EVLWI at0h,2h,4h and6h were higher than that at BOh (P<0.05). However, the EVLWI in CVVH group and VHVF group was lower than that in control group at4h and6h(P<0.05).2. Changes of inflammatory mediators in plasma(IL-6, TNF-α; IL-10):1) The IL-6level was higher at Oh in all groups than that at B0h (P<0.05). The levels of IL-6in two treatment groups were lower than that in control group at4h and6h after model established (P<0.05) and the level of IL-6in HVHF group was lower than that in CVVH group (P<0.05).2) The TNF-α level was higher at Oh in all groups than that at B0h (P<0.05). However, the levels of TNF-a in two treatment groups were lower than that in control group at4h and6h after model established (P<0.05), and the TNF-a level in HVHF group was lower than that in CVVH group at6h (P<0.05).3) The IL-10level was higher at Oh in all groups than that at B0h (P<0.05), the IL-10level in control group increased at2h,4h and6h as compared with B0h (P<0.05). However, the increase rate of IL-10in two treatment groups were lower than that in control group and the IL-10level in HVHF group was lower than that in CVVH group at2h,4h (P<0.05).3. Internal environment and hemodialysis circulation pressures:1) Blood PH value in control group was lower at2h,4h and6h than at BOh (P<0.05). However, there were no significant differences at all time points in two treatment groups and PH value in two treatment groups was higher than that in control group at6h (P<0.05);2) Serum electrolytes (sodium, potassium, calcium, and magnesium) showed no significant differences between CVVH group and HVHF group at6h; 3) Blood glucose in two treatment groups was higher than that in control group at2h,4h and6h(P<0.05). However, there were no significant differences between CVVH group and HVHF group at all time points;4) Body temperature in all groups increased after model established. At4h and6h, the temperature was lower in two treatment groups than that in control group (P<0.05). At4h, the temperature in HVHF group was lower than that in CVVH group (P<0.05);5) Blood lactate in all groups increased after model established and was lower in two treatment groups than that in control group (P<0.05). At6h, lactate in HVHF group was lower than that in CVVH group (P<0.05);6) The hemodialysis machine and transmembrane pressure showed no significant differences between CVVH group and HVHF group.4. Pulmonary inflammatory mediators content:CVVH group and HVHF group has less inflammatory mediators level than control group (P<0.05). The levels of IL-6and TNF-a in HVHF group showed a downward trend against CVVH group whereas there was no significant difference (P>0.05).5. Pathomorphology:1) Pulmonary pathomorphology:In lung injury scores, CVVH group(8.62±2.56) and HVHF group(7.35±2.32) were lower than control group(12.85±3.21)(P<0.05). HVHF group showed a downward trend against CVVH group whereas there was no significant difference.2) Cardiac pathomorphology:piglets in control group were observed of myocardial cells derangement and myocardial interstitial edema. However, there were no significant lesions in both CVVH group and HVHF group.Conclusions1. High volume hemofiltration (HVHF) at early stage of septic shock piglet models is more effective in improving hemodynamics, oxygenation than conventional CVVH.2. HVHF eliminate blood inflammatory mediators more effectively than conventional CVVH, but there were no significant differences on inflammatory mediator levels in lung tissue between the two groups.3. HVHF is more effective in stabling internal environment than conventional CVVH. There is no significant difference on the hemodialysis machine pressure between HVHF treatment and conventional CVVH.