Acute Renal Replacement Therapy for the Infant
Jordan M. Symons, MDUniversity of Washington School of Medicine
Children’s Hospital & Regional Medical CenterSeattle, WA
Objectives
• Indications and goals for acute renal replacement therapy
• Modalities for renal replacement therapy– Peritoneal dialysis– Intermittent hemodialysis– Continuous renal replacement therapy
(CRRT)
• Special issues related to the infant
Indications for Renal Replacement
• Volume overload
• Metabolic imbalance
• Toxins (endogenous or exogenous)
• Inability to provide needed daily fluids due to insufficient urinary excretion
Goals of Renal Replacement
• Restore fluid, electrolyte and metabolic balance
• Remove endogenous or exogenous toxins as rapidly as possible
• Permit needed therapy and nutrition
• Limit complications
Renal Replacement for the Infant: A Set of Special Challenges
• Small size of the patient
• Equipment designed for larger people
• Small blood volume will magnify effects of any errors
• Achieving access may be difficult
• Staff may have infrequent experience
Modalities for Renal Replacement
• Peritoneal dialysis
• Intermittent hemodialysis
• Continuous renal replacement therapy (CRRT)
Modalities for Renal Replacement
• Peritoneal dialysis
• Intermittent hemodialysis
• Continuous renal replacement therapy (CRRT)
PD: Considerations for Infants
ADVANTAGES• Experience in the
chronic setting• No vascular access• No extracorporeal
perfusion• Simplicity• ? Preferred modality
for cardiac patients?
DISADVANTAGES• Infectious risk• Leak• ? Respiratory
compromise?• Sodium sieving• Dead space in tubing
H2O
H2OH2O
H2O
H2O
H2O
H2O
H2O
H2O H2O
Sodium Sieving: A Problem of Short Dwell PD
Na+
Na+ Na+
Na+
H2O
Na+
Na+
Na+
Na+
Result: Hypernatremia
Modalities for Renal Replacement
• Peritoneal dialysis
• Intermittent hemodialysis
• Continuous renal replacement therapy (CRRT)
IHD: Considerations for Infants
ADVANTAGES• Rapid particle and fluid
removal; most efficient modality
• Does not require anticoagulation 24h/d
DISADVANTAGES• Vascular access• Complicated• Large extracorporeal
volume• Adapted equipment• ? Poorly tolerated
Modalities for Renal Replacement
• Peritoneal dialysis
• Intermittent hemodialysis
• Continuous renal replacement therapy (CRRT)
CRRT for Infants: A Series of Challenges
• Small patient with small blood volume
• Equipment designed for bigger people
• No specific protocols
• Complications may be magnified
• No clear guidelines
• Limited outcome data
Potential Complications of Infant CRRT
• Volume related problems
• Biochemical and nutritional problems
• Hemorrhage, infection
• Thermic loss
• Technical problems
• Logistical problems
CRRT in Infants <10Kg: Outcome
85
69
16
32 28
4
N
Survivors
Patients <10kg Patients 3-10kg Patients <3kg
38% Survival 41%
Survival
25% Survival
Am J Kid Dis, 18:833-837, 2003
ppCRRT Data of Infants <10Kg: Demographic Information
Number of Subjects 84(51 boys (61%))(33 girls (39%))
Age Median 69 days(1 d - 2.9 y)
ICU Admit weight Median 4.4 kg(1.3 - 10 kg)
ppCRRT Data of Infants <10Kg: Primary Diagnoses
19%
10%
21%
15%35%
Sepsis GI/Hepatic Cardiac Inborn Error of MetabolismPulmonary
ppCRRT Data of Infants <10Kg: Indications for CRRT
Fluid Overload and Electrolyte Imbalance 84%
Other (Endogenous Toxin Removal) 16%
N=84
ppCRRT Data of Infants <10Kg: Clinical Data
Parameter Median Range
Days in ICU prior to CRRT 2 0 - 135
PRISM score — ICU admit 17.5 0 - 48
PRISM score — CRRT start 20 0 - 48
Inotrope number — CRRT start 1 0 - 4
Urine output — CRRT start(ml/kg/hr over prior 24hrs)
0.7 0 - 12
% Fluid overload from ICU admission to CRRT start
13.7 -28 - 220
ppCRRT Data of Infants <10Kg: Technical Characteristics of CRRT
Catheter Site Femoral 60%
Internal Jugular 28%
Subclavian 12%
Modality CVVHD 59%
CVVH 18%
CVVHDF 23%
Anticoagulation Citrate 55%
Heparin 45%
Prime Blood 87%
Saline 8%
Albumin 5%N=84
ppCRRT Data of Infants <10Kg: CRRT Treatment Data
N=84
Parameter Median Range
Blood Flow (ml/kg/min) 8 1.7-46
Fluid Flow (ml/kg/hour) 67 7-571
Average CRRT Clearance (ml/hr/1.73M2) 2582 135-19319
Aggregate CRRT Clearance (ml/hr/1.73M2) 3540 135-12713
CRRT duration (days) 5 0-83
ppCRRT Data of Infants <10Kg: Survival by Weight
0%
10%
20%
30%
40%
50%
60%
70%
<5 kg 5-10 kg <10 kg >10 kg
44% 42% 43% 64%
p=0.001
p=1.0
ppCRRT Data of Infants <10Kg: Factors Effecting Survival
Clinical Variable Survivors Non-Survivors P
Admission PRISM score 16 21 <0.05
GI/Hepatic disease 8% 31% 0.01
Multiorgan dysfunction 68% 91% 0.04
Pressor Dependency 36% 69% <0.01
Mean Airway Pressure 11 20 <0.001
Initial urine output (ml/kg/hr) 2.4 1.0 0.02
%Fluid Overload at Start 15% 34% 0.02
>10% Overload at Start 43% 71% 0.02
ppCRRT Data of Infants <10Kg: Survival by Return to Dry Weight
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
Survivors Non-survivors
Dry Weight Achieved
Dry Weight Not Achieved
78%
35%
22%
65%
Infant CRRT in Seattle: Overview
• Coordinated by nephrology
• Performed in infant/pediatric ICU
• Set up by dialysis nurses
• Run at the bedside by neonatology or critical care nurses
• Dedicated CRRT device– BM-25: 1999 – 2005– Prisma: 2005 - present
CRRT Access in the Neonate:What Works?
• Hemodialysis Line: 7 Fr double lumen
• Two single lumen lines:– 5 Fr catheters or introducers
• Umbilical lines:– 5 Fr UAC; 7 Fr UVC
• Leg position - be creative
• Tape on the skin - may need to get creative
CRRT Filter Sets for PrismaSurface
AreaPriming Volume
Membrane
M-10* 0.042m2 50ml AN-69
M-60 0.6m2 90ml AN-69
M-100 0.9m2 107ml AN-69
HF-1000 1.15m2 128mlPolyarylethersulfone
(PAES)
* Not available in US
Bradykinin Release Syndrome
• Mucosal congestion, bronchospasm, hypotension at start of CRRT
• Resolves with discontinuation of CRRT
• Thought to be related to bradykinin release when patient’s blood contacts hemofilter
• Exquisitely pH sensitive
Bypass System to Prevent Bradykinin Release Syndrome
PRBC Waste
Modified from Brophy, et al. AJKD, 2001.
Recirculation System to Prevent Bradykinin Release Syndrome
D
Waste
Recirculation Plan:
Qb 200ml/min
Qd ~40ml/min
Time 7.5 min
Based on Pasko, et al. Ped Neph 18:1177-83, 2003
Normalize pH
Normalize K+
Simple Systems to Limit Likelihood of Bradykinin Release Syndrome
• Don’t prime on with blood
• Don’t use the AN-69 membrane
Thermal Regulation
• Hotline® blood warming tubing
• Place at venous return to patient
• Leave on at set temperature of 39 C
• Treat temp elevations if they occur
Infant CRRT in Seattle: CRRT Staffing
• Dialysis RN sets-up & initiates therapy
• PICU/IICU RN manages patient
• Nephrology/Dialysis RN on call 24/7
• Acuity assigned to pump as if a separate patient
• Staffing determined by acuity
Infant CRRT in Seattle: How to Handle a Rare Procedure
• Developed an Acute Initiation Checklist defining specific roles/actions for:– Infant ICU MD– Nephrology MD– Infant ICU RN– Dialysis RN– IV access MD
Acute Initiation Checklist: Example
Infant ICU Nurse• Time Zero:
– Move pt to room with dialysis water
– Get orders from resident for IV fluids to keep access open
• 20 – 40 min:– Meet MD; discuss RRT plan
• 60 – 120 min:– Meet ICU team
Dialysis Nurse• 10 – 60 min:
– Arrive and begin setup
• 20 – 40 min:– Meet MD; discuss RRT plan
• 60 – 120 min:– Complete prime; ready for
access– Begin RRT– Meet ICU team
Acute Initiation Checklist: Example
Nephrology MD• Time Zero:
– Contact dialysis nurse to start RRT urgently
• 10 – 20 min:– Bring catheters to ICU– Enter orders for RRT
• 20 – 40 min:– Meet ICU MDs & RNs,
discuss plan
• 60 – 120 min:– Present in ICU for initiation– Meet ICU team
IV Access MD• 10 – 30 min:
– Arrive and begin insertion of dialysis access
• 60 min (or when circuit is ready for Rx)– Complete insertion of access– Connect ports to heparin IV
solutions
Infant RRT: Summary
• All modalities of RRT possible for infants
• No modality is perfect
• Technical challenges can be met
• Careful planning with institution, program, and individuals improves care
• Cooperation, communication, and collaboration will increase our success