Manual CVVH Automatic machine

Transcription

1 Blood pump & infusion pumps Manual CVVH Automatic machine

2 Anticoagulant Predisposing factors : blood flow, hemofilter type, coagulation pathway activation, convective mass transfer Site of thrombus formation hemofilter bubble trap catheter Areas of turbulence resistance

3 Anticoagulant(2) No anticoagulation Technical aspects circuit Blood flow rate FF / predilution Saline flush Hemodilution Heparin Unfractionated LMWH Citrate Others Prostacyclin Danaparoid Hirudin

4 Heparin Heparin infusion prior to filter and adjustment based upon parameters Bolus with 1020 units/kg Infuse at 1020 units/kg/hr Adjust post filter aptt time Interval of checking is local standard and varies from hr increments

5 LMWH Anticoagulant effect predominantly through Antifactor Xa Less bleeding complication Longer half life and cleared by the kidneys

6 Citrate Clotting is a Ca dependent mechanism, removal of Ca from the blood will inhibit clotting Adding citrate to blood will bind the ionized Ca in the blood thus inhibiting clotting Citrate is infused at prefilter site and calcium is infused via independent line

7 Replacement fluid/dialysate Electrolyte composition Glucose composition Buffer selection Lactate Acetate Bicarbonate Citrate

8 Na K Cl HCO3 Lactate Acetate Ca P Mg Dextrose (mg/dl) Replacement fluid/dialysate RL RA %PD Normocarb Accusol 140 0/2/ Costume made Costume made : 0.45% NaCl 1000 ml + 7.5%NaCO3 30 ml + 15%KCl 2 ml + 20% NaCl 7.5 ml + 50% MgSO4 0.4 ml + 50% glucose 3 ml

9 Pre vs. Post dilution Predilution Decrease filtration fraction Diminished solute clearance by diluting blood reaching hemofilter Postdilution No effect on filtration fraction Solute conc. within hemofilter unchange from systemic conc.

10 Comparison of CRRT SCUF CHF CHD CHDF BFR (ml/min) DF (ml/min) Urea clearance (L/day) ± UF rate (ml/min) Diffusive clearance Convective clearance ± +++ ± ++ Replacement fluid Pre or postdilution Pre or postdilution Efficiency : remove water middle/ large molecule small molecule small to large molecule

11 CRRT Prescription BFR: 4 10 ml/kg/min or lower Replacement fluid: L/1.73 m 2 /hr Dialysate L/1.73 m 2 /hr (for CHD, CHDF): Net UF rate: 122 ml/kg/hour or higher Heparin: ACT times Total UF rate: RF + Dialysate + Net UFR + Heparin UF rate should not > 20% BFR

12 Monitoring Clinical Laboratories Na, K, Cl,, HCO 3, Ca, BS q 6126 hrs BUN, Cr, Mg, PO4, CBC, PT,PTT q 24 hrs Venous pressure : keep < 200 mmhg

13 Sign of hemofilter clotting Darkening of blood in extracorporeal circuit Separation of rbc and plasma in circuit Sustained reduction in volume of UF Screening : filtrate urea nitrogen : BUN ratio if < 0.6 > > clotting is imminent

14 Sepsis and MODS CRRT (high volume)

15 Sepsis and MODS CHF, CHDF C : ability to remove septic mediators from circulation by adsorption and convection Use high volume hemofiltration clearance dose 35 ml/kg/hr (sepsis dose)

16 BUN IHD CRRT

17 Complications of CRRT Heparin associated : bleeding, HIT Catheter related : sepsis, thrombosis, pain, arrhythmia, pneumothorax,, line disconnection Hypothermia Anemia Hypovolemia Hypotension Membrane reaction (bradykinin( release, anaphylaxis) Electrolyte abnormalities (hypopo 4, hypo K + ) Metabolic acidosis or alkalosis Air embolism

18 Case Start CVVH UF ml/day BUN/CR 69/5.1 42/3.1 (day 3) Problem clotted changed

19 Case 2nd CVVH (start day 3) Day 5 BUN/Cr 50/3 Na 132, K 3.4, Cl 87, HCO 3 17 Ca 9.7 PO 4 3.0

20 Case Continue CRRT นาน 15 ว น ช วง 10 ว นแรก BUN/Cr ลดลงด (last 40/2) D13 เร มม ป ญหาบร เวณแผลผ าต ด ต องเข า OR ใหม กล บจาก OR try off CVVH แต ม ป ญหา pulmonary edema และ hyper K

21 CVVH ท าได นานแค ไหน อะไรท ม กเป นสาเหต ให ต องหย ดท า เม อไหร ต องพ จารณาเปล ยนเป นว ธ อ น รายน ม indication อะไรท ต องเปล ยนเป น hemodialysis Hemodialysis ต องระว งอะไร ท าต างจ งหว ดได ไหม เคร องม อ ในผ ใหญ ต างก นไหม

22 Hemodialysis Individual prescription is required. Assessment and adjustment is needed regularly esp. in small children. Machine : adjustable blood pump, bicarbonate buffer system, temperature controlled, volume accuracy The 1 st dialysis session is the most critical, therefore appropriate preparation is needed.

23 Hemodialysis prescription Dialyzer and blood line Blood flow rate (Q B ) Dialysate flow rate Anticoagulant Ultrafiltrate rate Duration and frequency

24 Dialyzer and blood line Total extracorporeal blood volume should be less than 10% of blood volume Dialyzer should have low internal blood volume Membrane surface area should approximately match the body surface area

25 Dialyzer and blood line(2) Dialyzer F3 F4 Priming vol Surface area K UF F5 F6 Surflux Surflux

26 Dialyzer and blood line(3) Blood line (Kawasumi( R ) Patient size Type Internal volume(ml) Internal diameter (mm) < 30 kg pediatric 48 6 > 30 kg adult 88 8

27 Blood flow rate (Q B ) Target BFR ml/min/m 2 or 5 7 ml/kg/min In small children can determine by = (BW+10) x 2.5 ml/min Determine by urea clearance First session 2 ml/kg/min Target 5 ml/kg/min

28 Example A child 10 year old, BW 29 kg, Ht 130 cm blood volume 80 ml/kg x 29 kg = 2320 ml BSA = 130 cm x 29 kg = 1.02 m Use F5 surface area 1 m 2 priming vol.63 ml pediatric blood line priming vol. 48 ml

29 Example Blood flow rate urea clearance 2 ml/kg/min Desired Q B = 200 ml/min Desired Cl Urea 170 ml/min Desired Q B = 200 ml/min 2 ml/kg/min x 29 kg 170 ml/min Desired Q B = 68.2 ml/min

30 Dialysate flow rate Bicarbonate buffer Not less than 1.5 of BFR In general practice : 500 ml/min In children < 10 kg risk to hypothermia should be adjusted dialysate temperature to 39 C

31 Anticoagulant Minimize risk of clotting formation Risk factor : Small lumen diameter and large contact surface area Low blood flow rate

32 Anticoagulant(2) Heparin remains standard anticoagulant Loading dose : 2540 U/kg Maintenance dose : 1530 U/kg/hr should be stopped some 30 min or so prior to the end of dialysis Monitoring : activated clotting time times aptt sec

33 Anticoagulant(3) Low molecular weight heparin More effective in reducing fibrin deposit in dialyzer membrane and extracorporeal clotting Fewer hemorrhagic complications Enoxaparin 1 mg/kg

34 Amount and rate of UF Adjust to tolerance Total amount should no more than 5 10% BW per session Rate should not exceed 1.5 2% BW per hour Use sequential UF or sodium modeling if large amount of fluid must be removed

35 Duration and frequency 1 st session 11 2 hours Ideal : daily hemodialysis Usually 3 times/week, duration 4 6 hours In small children : 4 5 times/ week

36 Pediatric HD Prescription Priming: NSS, 5% albumin, plasma, blood Extracorporeal volume: < 10 % blood volume Fluid removal: < 5 10 % body weight/treatment Blood Flow Rate: per urea clearance needed Dialysate Flow Rate: 1.5 to 2 times BFR Heparinization: : ACT times Osmotic agent: 20% mannitol g/kg continuous IV drip Indication : 1 st st treatment, BUN > 100 mg/dl

37 Hemodialysis adequacy Urea kinetic modeling has been accepted as a method for assessment Urea dialytic clearance in children is usually low in comparison with high K ie Kt / V K = dialyzer urea clearance t = duration V = patient s s urea distribution volume or total body water

38 Volume of distribution of urea in Boy children Ht < cm V = /BW /Ht Ht > cm V = /BW /Ht Girl Ht < cm V = /BW /Ht Ht > cm V = /BW /Ht

39 Hemodialysis adequacy Kt / V = ln(c 1 /C o 0.008* t)+(43.5*c 1 /C o )* UF/BW Minimum Kt / V level of is desirable

40 Complications Intradialytic hypotension Muscle cramp Air embolism Dialysis disequilibrium Catheterrelated related blood stream infection Sudden death

41 Nutrition Catabolic state : Negative nitrogen balance Insulin resistance Acidosis Excessive secretion of catecholamines, glucocorticoids, glucagon Inflammatory mediators and protease from activated leukocytes

42 Nutrition Energy intake 35 kcal/kg (60% from CHO, 40% from lipids) Protein g/kg/day depend on catabolic state and RRT modality Enteral feeding is preferable Supplement of water soluble vitamin is recommended, esp. in RRT Fortification of feeds with glutamine, arginine, nucleotides, and Omega 3 fatty acids is used for immune enhancement

43 Understand natural history of AKI Identify children at high risk of AKI Underlying CKD Undergoing CVS surgery Those requiring contrast for imaging Understand ass. AKI and poor outcome Improve severity of illness scoring in PICU Identify risk factors for poor outcome Identify factors influence renal recovery Strategies to improve pediatric AKI outcome Prevent AKI in those at risk NaHCO3, Fluid resuscitation, Pharmacy, Avoid nephrotoxic drugs Alter natural course of AKI Early identification of AKI : IL18, NGAL, KIM1 Blood pressure support : drugs to provide adequate renal perfusion, assess intravascular volume Goaloriented strategies to support children with AKI Fluid management strategies Blood pressure support Ventilation support Renal replacement therapy Kidney Int 2007

44 Outcome Overall mortality : vary (2489%) Factor associated with mortality in ARF ARF (with minor problem) mortality < 48% 4 + oliguria + younger age (preterm) increased up to 89% + assisted ventilator + Multiorgan failure + surgery for congenital heart disease + sepsis/cvs failure and hypoalbuminemia(< 3g/dl)

45 Outcome N=245 Non survivors N=71 Survivors N= died after discharge 16 ESRD 3 died 13 alive 126 potential subjects 69 unable to locate 28 refused 29 subject Microalbuminuria Hyperfiltration HTN Microscopic hematuria CKD stage 1 N = 9 CKD stage 2 N = 4 Askenazi,, et al. Kidney Int 2006