dialysis and replacement solutions for crrt jordan m. symons, md university of washington school of...
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Dialysis and Replacement Solutions for CRRT
Jordan M. Symons, MD
University of Washington School of Medicine
Children’s Hospital & Regional Medical Center
Seattle, [email protected]
CRRT Solutions:Outline of the Talk
• Purpose of solutions in CRRT
• Goals for a CRRT solution
• Description of solutions currently available for CRRT
• Considerations in choosing a solution for CRRT
Kramer, P, et al. Arteriovenous haemofiltration: A new and simple method for treatment of over-hydrated patients resistant to diuretics. Klin Wochenschr 55:1121-2, 1977.
First CAVH Circuit
CRRT Machines: Current Generation
Convective Clearance
To increase clearance by convection, increase ultrafiltration rate (will require more replacement fluids)
D
Diffusive Clearance
To increase clearance by diffusion, increase dialysate flow rate
Characteristics of the Ideal CRRT Solution
• Physiological• Reliable• Inexpensive• Easy to prepare• Simple to store• Quick to the bedside• Widely available• Fully compatible
Base in CRRT Solutions
• Hemodialysis: first acetate, then bicarbonate
• Peritoneal dialysis: lactate in North America; bicarbonate in Europe
• CRRT: lactate or bicarbonate?
Bicarbonate vs. Lactate in CRRT
• Both can be used for base
• Bicarbonate superior to acetate in HD
• PD uses lactate due to technical issues
Is bicarbonate preferable to lactate?
Zimmerman et al, Neph, Dial & Transpl 1999 14:2387-2391
Bicarbonate vs. Lactate in CRRT:Blood Lactate Levels
Group 1 (Lactate first)
Group 2 (Bicarb first)
Baseline
Bicarbonate
Lactate
16.3 + 1.5
2.4 + 0.8
18.9 + 2.0
1.4 + 0.2
0 – 48 hours
Bicarbonate
Lactate
Receiving Lactate
22.2 + 1.4
2.6 + 0.4
Receiving Bicarb
22.2 + 1.1
1.5 + 0.1
48 – 96 hours
Bicarbonate
Lactate
Receiving Bicarb
24.2 + 2.3
1.8 + 0.6
Receiving Lactate
24.8 + 0.6
3.1 + 0.7
Bicarbonate vs. Lactate in CRRT:Blood Lactate Levels in Children
0
0.5
1
1.5
2
2.5
3
3.5
4
Baseline 8 hrs 16 hrs 24 hrs
Lac
tate
Lev
el
HCO3 soln LR soln
Maxvold et al, Blood Purif 17:#27, 1999 [abstract]
Bicarbonate vs. Lactate in CRRT: Cardiovascular Events
Bicarbonate Lactate
Barenbrock M et al, Kid Int 58:1751-1757, 2000
Options for CRRT Solutions
• Peritoneal dialysate
• Adapted pre-made solutions– Saline, Lactated Ringers
• Multi-bag systems
• Custom-made solutions– Local pharmacy; outsource
• On-line dialysate
• Commercially available CRRT solutions
Baxter Hemofiltration Solution
• Lactate buffered
• 5 liter bag
• Small amount of potassium
• Contains calcium
Chemical Content of Baxter Hemofiltration Solution
Ion Concentration (mEq/L)
Sodium 140
Calcium 3.5
Magnesium 1.5
Potassium 2
Chloride 117
Lactate 30
Glucose (mg/dL) 100
Hemosol (Hospal)
• 5 liter bag
• “L” series (lactate) with variable K+, glucose
• “B0” (bicarbonate) needs to be mixed
• Not available in US
Chemical Content of Hemosol
Ion (mmol/L) L0, LG2, LG4 B0
Sodium 140 – 142 140
Calcium 1.75 1.75
Magnesium 0.75 0.5
Potassium 0 / 2 / 4 0
Chloride 105 – 109.5 109.5
Lactate 40 3
Bicarbonate 0 32
Glucose +/- 0
Normocarb (DSI)
• Bicarbonate buffered
• Concentrate must be compounded
• Final volume 3.24 liters (240ml concentrate added to 3 L bag)
Chemical Content of Normocarb
IonConcentration After
Mixing (mEq/L)
Sodium 140
Calcium 0
Magnesium 1.5
Potassium 0
Chloride 107
Bicarbonate 35
PrismaSate (Gambro)
• Bicarbonate buffered
• Small amount of lactate
• 5 liter bag
• 2 compartments to prevent precipitation
• Two ionic formulations
Chemical Content of PrismaSate
Ion (mEq/L) BK0/3.5 BGK2/0
Sodium 140 140
Calcium 3.5 0
Magnesium 1 1
Potassium 0 2
Chloride 109.5 108
Lactate 3 3
Bicarbonate 32 32
Glucose (mg/dL) 0 110
Choosing a Solution: Issues to Consider
• Anticoagulation
• Cost
• CRRT modality– Diffusion (CVVHD)– Convection (CVVH)– Both (CVVHDF)
• Patient safety
Anticoagulation and Solutions
Solution Calcium?
Baxter Hemofiltration Solution
Yes
Hemosol Yes
Normocarb No
PrismaSateBK0/3.5 – Yes
BGK2/0 – No
Pharmacy Custom Made
User Choice
May need to consider Ca++ content if using citrate for anticoagulation
CRRT Solutions: Costs
BaseCost/bag
($US)Preparation
TimeIndustry Standard
Normocarb Bicarbonate 27.06 5 min Yes
Baxter Hemofiltration Solution
Lactate 30.45 3 min Yes
Pharmacy Custom Made
User choice 29.38 45 min No
Bunchman et al, Blood Purif 20: 2002 [abstract]
Modality May Have an Impact on Choice of Solutions
• Diffusion requires the use of a dialysate
• Convection requires the use of replacement fluids
D
R
R
What’s the Difference BetweenDialysate and Replacement Fluid?
Dialysate is a Device
Replacement Fluid is a Drug
FDA Approval Status of CRRT Solutions
SolutionApproved as Dialysate?
Approved as Replacement?
Baxter Hemofiltration Solution
Yes No
HemosolYes in Europe/ No in the US
Yes in Europe/ No in the US
PrismaSate Yes No
Pharmacy Custom Made
? ?
Normocarb Yes No*
Normocarb as Replacement Fluid
FDA Modernization Act of 1997:
“The Act creates a special exemption to ensure continued availability of compounded drug products prepared by pharmacists to provide patients with individualized therapies not available commercially”.
Bunchman et al, AJKD 42(6):1248-52, 2000
Evaluation of Errors in Preparation of CRRT Solutions
• Survey of 3 Pediatric Listserves:– Pediatric Critical Care– Pediatric Nephrology– Pediatric CRRT
• 31 programs responded to query
Bunchman et al, Blood Purif 22: 2004 [abstract]
Prevalence and Consequences of Errors in Solution Preparation
• 16/31 programs reported errors: – 7 errors in replacement solutions– 9 errors in dialysate solutions
• Consequences of improper solutions– 2 deaths– 1 non lethal cardiac arrest– 6 seizures (hypo/hypernatremia)– 7 without complications
Bunchman et al, Blood Purif 22: 2004 [abstract]
Policy Changes Resulting from Errors in Solutions
• Changed to Normocarb for either replacement or dialysate (11)
• Changed to PrismaSate for dialysate (2)
• Purchased TPN mixer for solutions (2)
• Chemistry lab check of every bag (3)
• Bag label check by at least 2 staff (10)
Bunchman et al, Blood Purif 22: 2004 [abstract]
CRRT Solutions: Summary
• Solutions needed to maximize clearance
• Bicarbonate seems superior to lactate
• Pharmacy made solutions give greatest flexibility but have increased risks/costs
• Several industry-made solutions; none currently approved for replacement
• Still no perfect “solution” for this problem
Thanks!