Complications of Pediatric CRRT Theresa A. Mottes RN Pediatric Dialysis/Research Nurse C.S. Mott Children’s Hospital University of Michigan

Complications of Pediatric CRRT b Temperature instability b Hemodynamic instability b Anticoagulation Risk b Circuit/Access Complications

Factors effecting hemodynamics b Patient Volume Status Ultrafiltration RateUltrafiltration Rate –patients hemodynamic –typically vasopressor dependent –patients intravascular volume Ultrafiltration RateUltrafiltration Rate –1-2ml/kg/hour net ultrafiltration –absolute necessity to control ultrafiltration –error of accurate ultrafiltration monitoring

RESULTS (Smoyer et al, CRRT 1997) IV Pump Flow Rate (ml/hr) % Error Trilogy Pump: Accuracy over Range of Flow Rates

Ultrafiltration accuracy 2.8 kg infant on PRISMA Ccs/hr Hour of Therapy Prescription BFR 30 mls/min Dx FR 300 mls/hr

Factors effecting hemodynamics b What now? Hourly assessment of Intake and OutputHourly assessment of Intake and Output Hourly Ultrafiltration calculationsHourly Ultrafiltration calculations – adjusting for pump error Accurate measuring of UltrafiltrationAccurate measuring of Ultrafiltration Close monitoring of hemodynamicsClose monitoring of hemodynamics Accurate daily weightAccurate daily weight

Factors effecting hemodynamics b Calculation for Pump Error

Factors effecting hemodynamics b Vasopressor clearance Vasopressor agents all have in common a small molecular weight and minimal protein bindingVasopressor agents all have in common a small molecular weight and minimal protein binding –Epinephrine –Norepinephrine –Dopamine –Dobutamine

Factors effecting hemodynamics b Vasopressors Due to proximity of infusionDue to proximity of infusion –be aware of infusing vasopressor agents in immediate proximity to the “arterial” port of the hemofiltration machine –potential for recirculation – effects delivery and clearance

Intravascular Blood Volume b < 10 kg 80 ml/kg e.g. 8 kg infant = 640 ml intravascular volumee.g. 8 kg infant = 640 ml intravascular volume b > 10 kg 70 ml/kg e.g. 20 kg child has 1.4 liter intravascular volumeBloode.g. 20 kg child has 1.4 liter intravascular volumeBlood b Priming Hemofiltration Circuit Recommended when circuit volume > 10 % of patients intravascular blood volumeRecommended when circuit volume > 10 % of patients intravascular blood volume

Anticoagulation b Heparin b Citrate b None

Circuit Complications Circuit Complications b Circuit Clotting Inability to ultrafiltrate desired amountInability to ultrafiltrate desired amount Increasing Access/Return PressureIncreasing Access/Return Pressure Inadequate clearancesInadequate clearances Observe clotting in filter/ tubingObserve clotting in filter/ tubing

Clotting with CVVH vs CVVHD (Mottes et al, CRRT 1999)

Flow Rates b Blood 5-10 ml/kg/min keeping venous pressure under 200 mm Hg5-10 ml/kg/min keeping venous pressure under 200 mm Hg b Dialysate/Replacement fluid 2 liters/1.73 m 2 /hr2 liters/1.73 m 2 /hr –(extrapolation of adult data)

Access Complications b What is the correct access? One that worksOne that works

In Flow Difficulties b Obstruction or clot on the return line high intrathoracic pressure with HIFIhigh intrathoracic pressure with HIFI up against the vessel wallup against the vessel wall b Clamp on inflow b Access kinked at skin site b Consider reversing or changing access

Out Flow Difficulties b Clamp on access/”arterial” line b Inflow port up against vessel wall b Patient “dry” eg with femoral site b High of blood flow requirements based upon flow ability of access b Consider reverse flow, change access, decrease blood flow ratesreverse flow, change access, decrease blood flow rates