Continuous Renal Replacement Therapies - Solomon R. Dawson, MD.pdf

hd

1. Continuous Kidney
Replacement Therapy
Solomon Dawson, MD
Assistant Professor of Medicine
Cooper University Hospital
7-02-2024

2. What you will get called about in 3 days
●55yo
●PMHx diabetes, COPD, CAD s/p CABG 10 years ago, 90kg
●Presented with Fevers and fatigue for 3 days and found to have a large
pleural effusion and pneumonia
●Treated for pneumonia and fluid resuscitated w/ 3L of IVFs but started on
levophed in ED and intubated
●Baseline creatinine is 0.9
●Day 2 of hospitalization Nephrology is consulted
○Still on levophed, HR 100, BP 95/60, still intubated, 80% FiO2
○Creatinine up to 2.5, K is 5.6, HCO3 is 13
○UOP is about 10cc/hr, 4.5L positive over past 48 hours
○CXR shows a LLL infiltrate, Right sided pleural effusion, and some vascular congestion
throughout
What Do you Do?
KRT?
If so, what type?

3. Outline
●Types of Continuous Dialysis Modalities
●Indications
●How to Order
●Common issues you will encounter and be called about

4. Nomenclature
●Continuous Renal Replacement Therapy -> Continuous Kidney Replacement
○CRRT -> CKRT
○RRT -> KRT
●Older articles and books will use RRT
○All the same

5. CKRT Modalities
●SCUF -Slow Continuous Ultrafiltration
●CVVHD -Continuous Veno-Venous Hemodialysis (diffusion)
●CVVH -Continuous Veno-Venous Hemofiltration (Convection)
●CVVHDF -Continuous Veno-Venous Hemodiafiltration (both)
●SLED -Slow Low-efficiency dialysis (diffusion)
●PIRRT -Prolonged Intermittent Renal Replacement Therapy (Diffusion)

6. Convection
1L of
Fluid
4meq/
L of K
Blood
Dialyzer
1L of
Fluid
4meq/
L of K
●Solute removed
by traveling with
the fluid it is
contained in
●Example: Orders
written for 1L of
ultrafiltration over
24 hours
●At end of 24
hours, 4meq of K
would have been
removed with the
1L of fluid

7. Diffusion
●Molecules travel
down their
diffusion gradient
to areas with
lower
concentrations
●Also affected by
filter surface
area, pore size
Blood
Dialyzer
K K
KK
K
K K K
K
K

8. CKRT Orders -Prescription
●BFR
○cc/min
●CVVHD
○Dialysate flow rate
■L/hr
●CVVH
○Effluent Flow Rate
■L/hr
●SCUF & All other modalities
○Ultrafiltration Rate
○cc/hr or net I&O goals/unit time
●Intermittent Hemodialysis
○BFR 400-500 cc/min
○DFR 600-800 cc/min
■36L/hr
○Outpatient UF restricted to 13cc/kg/hr
■1300cc/hr max generally
Solute
Removal
Fluid
Removal

9. CKRT vs iHD -Indications
●Think about the rates
○UF rates/hr
■CKRT -0-300cc/hr
■iHD -0-1300cc/hr
○DFR
■iHD -36L/hr
■CKRT -2L/hr
Indications
●Increased ICP
●Hemodynamically unstable patients
●Profound fluid overload
●Severe Hyperkalemia
Practical Considerations
●Procedures
●Scans
●Physical Therapy
●Access
○No Fistulas for CKRT
Intermittent

10. CKRT Orders -Dialysate Composition
●Much less flexibility with CKRT
○K 0, 2, 4k bags
○Na 142 (135-150)
○HCO3 35 (30-50)
○Phosphate +/-
○Calcium 2-3meq/L
○Magnesium 0.5 -1.5 meq/L
○Glucose 100-200mg/dL
●Can be altered by pharmacy at some institutions
***Special Consideration***
Hyponatremic Patient -Fixed Na -at risk
for overcorrection

11. What you will get called about in 3 days
●COPD & CAD s/p CABG presents with pneumonia
and septic shock
●Creatinine is 2.5, K is 5.6, minimal UOP and 4.5L
positive over 2 Days
●Still intubated and on levophed with a CXR showing
some vascular congestion
●Getting 1.8L of IVFs a day with levophed and ABx
What Do you Do?
KRT?
-Still hypotensive, declining
urine output, unlikely to
improve and is already
hyperkalemic
-Needs potassium removal
which might be better with
iHD, but is also fluid positive
and hypotensive, so fluid
removal would be better
achieved with CKRT
-BFR 300, 2K bath, UF
50cc/hr (1.2L a day)

12. How much dialysis to prescribe?
●VA ATN Trial
●Critically ill patients with
AKI
●Randomized to High
intensity or low intensity
groups
6/wk SLED or iHD and
35ml/kg/hr of DFR
3/wk SLED or iHD and
20ml/kg/hr of DFR
Palevsky et Al, 2008

13. How much dialysis to prescribe?
Palevsky et Al, 2008

14. Common Issues -Antibiotic Clearance
●Dosing of antibiotics needs to be adjusted based on dialysate flow rate
●Underdosing of antibiotics
●Discuss DFR with ICU team and Pharmacy
●Avoid excess changes in dialysate flow rate
***Consideration***
-Remember to discuss with pharmacy
when patient going to intermittent
hemodialysis

15. Common Issues -Clotted Access
●Ensure getting appropriate blood flow
●Heparin Pre-filter
●Citrate
●Line positioning
○Adequate length and caliber
○Tip ends in RA
***FYI***
-Non tunneled or tunneled dialysis
catheter is required for CVVHD

16. What you will get called about in 3 days
●COPD & CAD s/p CABG presents with pneumonia
and septic shock
●Creatinine is 2.5, K is 5.6, minimal UOP and 4.5L
positive over 2 Days
●Still intubated and on levophed with a CXR showing
some vascular congestion
●Getting 1.8L of IVFs a day with levophed and ABx
●Decided to start on CKRT -300BFR, 2K bath,
50cc/hr
-Dialysate flow rate =
25cc/kg/hr = 2.2L/hr
-Pharmacy is notified to
redose antibiotics
-Right sided non tunneled
dialysis catheter placed
-CXR confirms tip in
RA

17. Common Issues -ECMO
●VV & VA ECMO
●32% of patients get AKI
○Of those 50% get KRT
●Indications for KRT
○#1 is fluid overload

18. Common Issues -ECMO -How to Connect?
●Independent access?
○No risk for air embolism
○No alarms on machine
○Increased risk for infection
○Real estate for Access
●In-Line access (VV ECMO)
○Many configurations require the
alarms on the CKRT machine to
be disabled
○Risk for Air embolism if return line
is after oxygenator
We use this configuration

19. Transition to iHD
●No standard of care
●Generally
○Off pressors
○<2L of obligate inputs each day
■Equals 4L of UF every other day
Another way to Approach It -what is
your goal of KRT?
-Fluid removal?
-Purely clearance?
-Will the chosen modality achieve
the goal

20. Transition to iHD -example
●Fluid overloaded, hypertensive, off pressors, goal to be net negative 1L by
end of day
●Gets 3.0L in each day (Tube feeds, IV Vancomycin), looses 500cc stool, and
500cc NGT output
●3.0L -1L = +2L by end of day, so 3L UF/24hr needed to get negative 1L
●If QoD (Intermittent HD) would need 6L UF
○6L/4hr = 1.5L/hr - very unlikely to tolerate

21. What you will get called about in 3 days
●COPD & CAD s/p CABG presents with pneumonia
and septic shock
●Creatinine is 2.5, K is 5.6, minimal UOP and 4.5L
positive over 2 Days
●Still intubated and on levophed with a CXR showing
some vascular congestion
●Getting 1.8L of IVFs a day with levophed and ABx
●Decided to start on CKRT -300BFR, 2K bath,
50cc/hr with DFR of 2.2L/hr
-3 Days later he is off of
pressors and extubated
-Only getting 250cc/day in of
IVFs and now oral intake on
top of that
-Making 500cc/urine a day
-Transitioned to intermittent
HD

22. Take Homes
●Continuous Hemodialysis is indicated for increased ICP and is useful in
patients who are hemodynamically unstable or need large amounts of fluid
removed
●Order includes blood flow rate, dialysate flow rate, ultrafiltration rate, and
dialysate potassium
●Catheter issues are common
○Ensure catheter is in correct place and correct size
○Use heparin or citrate if able
●Transition to intermittent hemodialysis when hemodynamically stable and
able to accomplish goals of dialysis i.e. negative or even fluid balance
●Communication with ICU & Dialysis unit is key for care of these patients