CVVH时治疗剂量的计算

CVVH时治疗剂量的计算,北京协和医院杜斌,内容,肾脏的生理功能,肾脏替代治疗 vs. 肾脏,heparin,V,V,PV,PA,high-flux,肾小球,原尿,肾小管,滤器剖面图,滤器清除物质的原理,超滤(ultrafiltration)对流(convection)弥散(diffusion)吸附(adsorption),超滤作用的原理: 跨膜压,跨膜压(TMP): 半透膜两侧的压力差溶剂的移动从压力高的一侧向压力低的一侧增加压力差可以增加溶剂的超滤,超滤作用的原理: 跨膜压,跨膜压(TMP): 半透膜两侧的压力差溶剂的移动从压力高的一侧向压力低的一侧增加压力差可以增加溶剂的超滤压力差消失时超滤作用终止,UFR = BFRin BFRout,超滤作用的原理: 超滤率,通过超滤作用清除的溶剂量(UFR),BFRin,BFRout= BFRin UFR,UFR = Lp.A.P = Kuf.P,超滤率的影响因素,Lp: 膜超滤系数ml/(hr.mmHg.m2)Kuf: 滤器超滤系数ml/(hr.mmHg),P: TMP,高通量滤器,低通量滤器,超滤率的影响因素: 膜超滤系数,Lp (ml/(hr.mmHg.m2),10,20,膜对溶剂(水)的通透性,超滤率的影响因素: 跨膜压,超滤率的影响因素: 滤过分数,BFR血细胞 BFR x Hct血浆 BFR x (1 Hct),BFR血细胞 BFR x Hct血浆 BFR x (1 Hct) - UFR,UFR,超滤率的影响因素: 滤过分数,FF% = UFR x 100 / QpQp = BFR x (1 Hct),FF% 30%以防止血液滤器凝血,超滤率的影响因素: 滤过分数,BFR血细胞 BFR x Hct血浆 BFR x (1 Hct),BFR血细胞 BFR x Hct血浆 BFR x (1 Hct) - UFR,UFR,100 ml/minHct 30%血细胞 30 ml/min血浆 70 ml/min,BFR血细胞 30 ml/min血浆 70 - UFR,UFR,超滤率的影响因素: 滤过分数,BFR = 100 ml/min, Hct = 0.30Qp = BFR x (1 Hct) = 70 ml/minFF 30%,UFR FF x Qp = 21 ml/min,血流量是影响超滤率的最主要因素*后稀释,对流作用的原理,跨膜压(TMP): 半透膜两侧的压力差溶质的移动随溶剂移动从压力高的一侧向压力低的一侧,对流作用的原理,对流清除溶质的效率,肾脏CrCl = Ucr x UO / Scr,CVVHC = Ufcr x UFR / Scr,BFR,BFR,UFR,对流作用的原理: 筛选系数,筛选系数(S, sieving coefficient)S = UF / plasma,plasma,UF,对流作用的原理: 对流清除率,C = S.UFR,Kuf.P = Lp.A.P,筛选系数: UF / plasma,对流作用的原理: 筛选系数,对流作用的应用: 持续血液滤过(CVVH),heparin,V,V,PV,PA,high-flux,内容,肾脏替代治疗的剂量: Ronco,筛选患者(n = 492),随机分组(n = 425),排除患者(n = 67),UFR 35 ml/kg/hr(n = 139),UFR 20 ml/kg/hr(n = 146),UFR 45 ml/kg/hr(n = 140),Ronco C, Bellomo R, Homel P, et al. Effects of different doses in continuous veno-venous haemofiltration on outcomes of acute renal failure: A prospective randomised trial. Lancet 2000; 356: 26-30,肾脏替代治疗的剂量: Ronco,Ronco C, Bellomo R, Homel P, et al. Effects of different doses in continuous veno-venous haemofiltration on outcomes of acute renal failure: A prospective randomised trial. Lancet 2000; 356: 26-30,肾脏替代治疗的剂量: Ronco,Ronco C, Bellomo R, Homel P, et al. Effects of different doses in continuous veno-venous haemofiltration on outcomes of acute renal failure: A prospective randomised trial. Lancet 2000; 356: 26-30,肾脏替代治疗的剂量: Ronco,Ronco C, Bellomo R, Homel P, et al. Effects of different doses in continuous veno-venous haemofiltration on outcomes of acute renal failure: A prospective randomised trial. Lancet 2000; 356: 26-30,ARF的治疗剂量: Kellum,“Patients with ARF should be treated with at least 35 mL/kg/h of hemofiltration/ hemodiafiltration or daily hemodialysis until or unless ongoing multi-center clinical trials show otherwise.”,CVVH的参数设置,R,heater,heparin,V,V,PV,PA,UF,BLD,SAD,BWt 60 kgHct 30%后稀释BFR = 150 ml/minRFR = 2000 ml/hr平衡 = -100 ml/hr,流出液 = 2100 ml/hr交换量 35 ml/kg/hr但是FF% = 35 / (150 x 70%) = 33%,CVVH的参数设置,R,heater,heparin,V,V,PV,PA,UF,BLD,SAD,BWt 60 kg后稀释交换量 35 ml/kg/hrBFR应当设置为多少?,FF% 30%以防止血液浓缩,流出液 35 x 60 = 2100 ml/hr流出液 35 ml/min血浆流量(Qp) 35 / 30% = 117 ml/minBFR = 117 / 70% = 167 ml/min,CVVH的参数设置,如果BFR只能维持150 ml/min如何达到35 ml/kg/hr的交换量?,内容,增加对流清除溶质能力的方法,增加UFR提高跨膜压(TMP)超滤液一侧的负压血液一侧的正压增加膜超滤系数(Lp)增加滤器膜面积(A)提高血流量(BFR)采用前稀释方式增加弥散清除,C = S.UFR = S.Lp.A.P,C = S.UFR.BFR / (BFR + RFR),KT = KD + UFR.S.(1 KD/BFR),对流清除能力的影响因素: 滤过分数,R,heater,heparin,V,V,PV,PA,UF,BLD,SAD,FF% = UFR x 100 / QpQp = BFR x (1 Hct),FF% 30%以防止血液浓缩,后稀释时, BFR是影响UFR的主要因素,增加对流清除能力: 前稀释 vs. 后稀释,R,heater,heparin,V,V,PV,PA,UF,BLD,SAD,前稀释的优点与缺点,BFR,BFR,UFR,BFR,BFR,UFR,RFR,RFR,后稀释,前稀释,有血液浓缩过程UFR受到滤过分数的限制,没有血液浓缩过程UFR不受滤过分数的限制,前稀释的优点与缺点,BFR,BFR,UFR,BFR,BFR,UFR,RFR,RFR,后稀释,前稀释,血液没有被稀释UF中溶质浓度与血浆浓度相似SC = 1,血液被稀释UF中溶质浓度低于血浆浓度SC 1,前稀释CVVH时交换量的计算,BWt 60 kgHct 30%BFR 150 ml/min全部前稀释RFR 2000 ml/hr平衡-100 ml/hr,R,heater,heparin,V,V,PV,PA,UF,BLD,SAD,BFR 150 ml/min,RFR 2000 ml/hr,UFR2100 ml/hr,前稀释CVVH时交换量的计算,首先按照完全后稀释方式计算交换量UFR 2100 ml/hr = 35 ml/kg/hrC = SC x UFR = 35 ml/kg/hr其次计算稀释比例BFR = 150 ml/min, Hct = 30%Qp = 150 x (1 30%) = 105 ml/min前稀释RFR = 2000 ml/hr = 33 ml/min稀释比例 = Qp / (Qp + RFR) = 105 / (105 + 33) = 76%最后计算校正后交换量C = 35 x 76% = 26.6 ml/kg/hr,流出液量相同的情况下溶质清除效率前稀释 后稀释,前稀释CVVH时交换量的计算,BWt 60 kgHct 30%BFR 150 ml/min全部前稀释平衡-100 ml/hrRFR x ml/hr才能保证交换量35 ml/kg/hr,R,heater,heparin,V,V,PV,PA,UF,BLD,SAD,BFR 150 ml/min,RFR x ml/hr,UFRX+100 ml/hr,前稀释CVVH时交换量的计算,首先按照完全后稀释方式计算交换量UFR x + 100 ml/hr = (x + 100) / 60 ml/kg/hrC = SC x UFR = (x + 100) / 60 ml/kg/hr其次计算稀释比例BFR = 150 ml/min, Hct = 30%Qp = 150 x (1 30%) = 105 ml/min前稀释RFR = x ml/hr = x / 60 ml/min稀释比例 = Qp / (Qp + x / 60) = 105 / (105 + x / 60)最后计算校正后交换量C = (x + 100) / 60 . 105 / (105 + x / 60) = 35 ml/kg/hr,RFR = x = 3000 ml/hr,CVVH时交换量的计算,BWt 60 kgHct 30%BFR 150 ml/min平衡-100 ml/hrRFR 3000 ml/hr如何保证交换量40 ml/kg/hr,R,heater,heparin,V,V,PV,PA,UF,BLD,SAD,CVVH时交换量的计算,全部前稀释RFR 3000 ml/hrUFR 3100 ml/hrC 35 ml/kg/hr,全部后稀释RFR 3000 ml/hrUFR 3100 ml/hrC 51.7 ml/kg/hrFF% 50%,满足C 40 ml/kg/hr部分前稀释+部分后稀释?,CVVH时交换量的计算,BWt 60 kgHct 30%BFR 150 ml/min平衡-100 ml/hrRFR 3000 ml/hr如何保证交换量40 ml/kg/hr,R,heater,heparin,V,V,PV,PA,UF,BLD,SAD,preRFR 3000 x pre% ml/hr,postRFR 3000 x (1 - pre%) ml/hr,BFR 150 ml/min,UFR3100 ml/hr,前稀释+后稀释交换量的计算,首先按照完全后稀释方式计算交换量UFR 3100 ml/hr = 51.7 ml/kg/hrC = SC x UFR = 51.7 ml/kg/hr其次计算稀释比例BFR = 150 ml/min, Hct = 30%Qp = 150 x (1 30%) = 105 ml/min前稀释RFR = 3000 x pre% ml/hr = 50 x pre% ml/min稀释比例 = Qp / (Qp +