AKI and CVVH - Pediatric Continuous Renal Replacement Therapy
Download
Report
Transcript AKI and CVVH - Pediatric Continuous Renal Replacement Therapy
CRRT IN ACUTE KIDNEY
INJURY
Dr Umut Selda Bayrakçı
Yıldırım Beyazıt University, Ankara, Turkey
Acute renal failure is not a “cute” renal
failure Druml W, 2004
The epidemiologic importance of AKI as a public health
problem is underscored
because renal function can easily and practically
indefinitely be replaced by modern renal replacement
modalities, AKI presents a rather harmless complication
Despite the advances in the ability to provide dialysis to
children, the out come of AKI remains surprisingly poor
MORTALITY in critically ill patients
53 % in the ATN trial
44.7 % in the RENAL trial
Even a small reduction in the renal function
(0.3 mg/dl SCr increase) is a risk factor for
morbidity and mortality in hospitalized
patients.
It is not a problem restricted to the kidneys
It’s a systemic disease process
AKI exerts a fundamental impact
On the course of disease
The evolution of associated complications
Prognosis
Independently from the underlying disease
Patients with ARF, die not
(only) with but (also) from AKI;
acute renal failure is not a
“cute” renal failure but a
dangerous condition.
Druml W, Intensive Care Med 2004, Bellomo R, et al. Lancet,2012, Hobson CE et al. Circulation
2009, Coca SG et al. Am J Kidney Dis 2009, Murugan R, Kellum JA. Nat Rev Nephrol 2011
Management of AKI
Largely supportive
Aimed preventing of life-threatening fluid or electrolyte
complications
Avoiding or minimizing further renal injury
Providing appropriate nutrition to allow recovery from acute
illness and renal dysfunction
Severe AKI or milder AKI in association with severe fluid
overload or solute imbalance may require renal replacement
therapy (RRT)
When RRT is indicated
What is the OPTIMAL RRT modality
When to start?
Should clinicians wait for
Frank anuria?
Unequivocal signs of uremia?
Fluid overload?
Should treatment be indicated
proactively?
Are there reliable indices helping to choose
RRT timing?
Absolute indications to start RRT
Uremic complications, for example encephalopathy, pericarditis,
bleeding.
Serum urea at least 36 mmol/l (100 mg/dl).
K+ at least 6 mmol/l and/or ECG abnormalities.
Mg at least 4mmol/l and/or anuria/absent deep tendon reflexes.
Serum pH 7.15 or less.
Urine output less than 200 ml/12 h or anuria.
Diuretic-resistant organ edema (i.e. pulmonary edema) in the
presence of AKI.
Acute Dialysis Quality Initiative (ADQI) workgroup,2001
When to start?
Not only the presence of AKI but also its severity
should be assessed: pediatric RIFLE (Risk, Injury,
Failure, Loss, End stage)
Severe AKI and/or rapidly deteriorating kidney
function (towards “F” level) RRT initiation should
be considered.
Particularly if there was failure to respond to initial
therapy.
Critically ill patients with mild to moderate AKI (i.e.
RIFLE category R/I): the most challenging
Decision should be tailored dynamically
Sometimes we should consider RRT in earlier stages of
AKI:
Severe sepsis
Reduced renal reserve
Primary diagnoses associated with high catabolic
rates
(septic shock, major trauma, burn, injury)
Gastrointestinal bleeding, rhabdomyolysis placing
considerable demand on kidney function
A positive fluid balance and overt clinical fluid overload
When RRT is indicated?
30 children
Children with volume excess of 10% or less
improved survival
21 children on CRRT
Mean volume excess 16%
Mean volume excess 33%
survived
did not survived
116 children with AKI, CRRT, 13 different center
Mean volume excess 14%
survived
Mean volume excess 25%
did not survived
Lane PH et al. Bone Marrow Transplant 1994, Goldstein et al Pediatrics 2001
Goldstein et al. Kidney Int 2005
When RRT is indicated?
As soon as fluid overload occurs
unless there is excessive solute load
Reasonable TRESHOLD for initiation of RRT:
fluid overload of 15%
*BUN levels at initiation of RRT was not associated with survival
(increased in nonsurvivors)
Bunchman TE.Nature Clinical Practice 2008
When to start?
1847 ICU patients with AKI requiring RRT
Relationship between biochemical, physiological and comorbid
factors at time of RRT start and ICU mortality
Independent risk factors for ICU mortality
Mechanical ventilation
Oligoanuria
Serum urea
Cardiovascular failure
Failure to correct acidosis and development of more organ
failure within 48 hours of RR
Survivors tended to have higher creatinine and lower urea
levels at the start of RTT
YH Chou et al. Crit Care
2011.
Take home message-1
RRT should be recommended for AKI in critically ill
patients before organ failure and and metabolic
derangements have reached the slippery threshold
of irreversibility!!
Creatinine is not an ideal biomarker for decision on RRT timing
New biomarkers will hopefully improve the performance
of creatinine, urea and RIFLE
The message-2
The decision when to start RRT should be established
case by case and guided by
Associated dysfunction of other organ systems
patients’ AKI severity
Urine output
Serum pH
locally available technics and devices
Stuivenberg Hospital Acute Renal Failure
Project (SHARF)
RRT patients have higher mortality (43 vs
58%)
Longer ICU and hospital stay compared to
patients treated with conservative
approach
Elseviers MM et al. Crit Care 2010
Which is the best dialysis
modality
The two most important factors that
influence choice of dialysis:
The indication for dialysis
Overall clinical status of the patients
*The decision will be based upon
Specific patient characteristics
Patients requirements/limitations
The status of major organ systems
LOCAL EXPERTISE with specific
dialysis techniques
Facility experience
Local resources
Should intermittent RRT or continuous
RRT be used
No suitable powered randomized controlled trials
Results of present studies do not suggest a
difference in patient survival
On the basis of patient survival all seem to be
acceptable
State of the art
Clinical status of the patient
Intermittent HD requires careful use in patients
with impaired hemodynamic status
CVVH
Venovenous forms of CRRT is considered
superior to other forms of CRRT because of
Lover risk of hemorrhage
Less frequent circuit clotting
More predictable driving pressure through
the hemofilter
Advantages of CVVH
1. Continuous solute clearance and ultrafiltration
Gradual removal provided by hemofiltration
**Ideal modality for patients with cardiovascular instability
and hypotension
Continuous removal
Fluid restriction is usually unnecessary
Freedom to provide large volumes of nutritional support,
drugs, blood products etc..
Advantages of CVVH
2. Specific metabolic advantage
Wide variety of metabolic problems can be corrected easily
Severe metabolic acidosis
Lactic acidosis
Electrolyte abnormalities (s.a. hyperkalemia)
Superior control of uremia than intermittent HD
It can also be adopted to gradually correct hyperosmolar
states
3. Less likely to lead to cerebral edema
4. Removal of mediators of inflammation
Cost of dialysis equipment (in U.S. dollars)
Manual Automated İntermittent Continious
Modality
PD
PD
HD
HF
Device
Ultra Set
(Y-set)
Freedom cycler
C3
Prisma
Manufacturer
Baxter
Fresenius
Gambro
Gambro
Cost per unit
$6.95
$12,295.00
$18,000.00
$25,000.00
Cost of
additional
supplies
1.5%
Dianeal
$24.43/2 L
Pediatric tubing
set $32.00 each
Peritoneal
dialysate as at
left
100HG dialyzer
$50.00 each;
pediatric
bloodlines
$11.40 each
M60 hemofilter
set (filter and
bloodlines)
$160.00 each
Normocarb
dialysate
concentrate
$20.00/3.0L
Flynn JT, Pediatr Nephrol 2002
GUIDANCE FROM THE LITERATURE
1995: 42 children (following repair of congenital heart dis):
21 PD
21 HF; 9 CAVH, 12 CVVH
Survival: identical
Fluid removal, urea and creatinine clearance, and caloric
intake superior in HF
Fleming et al, J Thoracic Cardiovasc Surg, 1995
Adults: Because of limitations in clearance and difficulties in fluid
removal PD is rarely used in ARF
Pediatrics: PD used to be the first choice; technical difficulties of HD in
infants and young adults
1997: Comparison of HD and hemofiltration in pediatric ARF
122 children with ARF (retrospective)
58 HD
64 HF
Survival: 83% in HD, 48% in HF group
Higher percentage of children with primary renal dis in HD group
Higher percentage of patients with sepsis in HF group,
greater severity of illness in HF
Maxvold et al; Am J Kid Dis 1997
Comparison of 3 dialysis modality
279 children with ARF and/or inborn errors of
metabolism (retrospective)
59 PD
140 HF
80 HD
Overall survival was 53%
Variation in survival among modalities for certain
diagnoses
Comparison of 3 dialysis modality
ARF following bone
ARF following repair of
marrow transplant
congenital heart disease
%78 intermittent HD
100% intermittent HD
33% PD
33% PD
21% HF
50% HF
Hemodynamic instability
affect patient outcome
predictive of modality choice
patients who were the most hemodynamically unstable were usually
treated with either HF or PD whereas stable patients were usually
treated with intermittent HD.
Bunchman TE, J Am Soc Nephrl, 1999, abstr
Limitations:
Retrospective
Single center study designs
Small patient numbers
Homogenous patient populations: results
couldn’t be generalized
Intermittent HD vs CRRT
Multicentre, prospective,
randomized, controlled trial
Single center, randomized,
controlled trial (CONVINT)
316 adults, AKI patients
252 adult AKI patients
Mortality:
Survival rate: 39.5% IHD
intermittent HD:62.5%
CRRT: 58.1%
Modality of RRT has no
impact on the outcome in
ICU
43.9% CVVH
No significant difference
regarding mortality, renal
outcome measures or
survival
Schefold JC et al. Critical Care 2014
Rins RL et al. Nephrol Dial Transplant 2009
Intermittent HD vs CVVH
Multicenter, randomized and prospective
study (21 center, Hemodiafe Study Group)
Adults with multiorgan dysfunction syndrome
and AKI
Rate of survival did not differ between the
intermittent HD and CVVH
Vinsonneau C et al, The Lancet, 2006
Intermittent HD vs CVVH
ATN and RENAL studies suggest that CVVH might
help with renal recovery
Meta-analysis studies reveals no difference in long
term dialysis dependency
Ghahramani N et al. Nephrology 2008
Suggested modality choice in pediatric ARF
Goal of dialysis
Hemodynamic
status
modality
Ultrafiltration
Normotensive
hypotensive
Intermittent HD (w isolated
UF)
Continuous HF or PD
Urea clearance
Normotensive
hypotensive
Intermittent HD or PD
Continuous HF or PD
Treatment of
hperkalemia
Either normotensive Intermittent HD
or hypotensive
Correction of
metabolic acidosis
Normotensive
hypotensive
Any
Continuous HF or PD
Treatment of
Either normotensive Any; continuous hemofiltration
Hyperphosphatemia or hypotensive
possibly superior
Flynn JT. Pediatr Nephrol 2002
RRT modality: conclusion
Few data available
regarding pediatric patients
Decision: empirical
Consider:
Underlying disease
Severity of illness
Advantages and
disadvantages of the
various modalities
available locally
Cost
Although survival was
somewhat the same/better
in intermittent HD group,
provision of HF most likely
contributed to the survival
of many patients who might
not survived had HF not
available
Maxvold NJ et al. Am J Kid Dis 1997 (abstr)
Conclusion
Combination
CRRT: early correction of hemodynamic
instability as long as multiorgan failure exist
Classic intermittent HD for long lasting-isolated
AKI
Rins RL et al. Nephrol Dial Transplant 2009
Dose of CVVH in AKI
Expression of how much dialysis should be prescribed in
order to achieve a certain level of blood cleansing
Dose relies on
Patient clinical picture (catabolic rate, muscle mass,
presence of pulmonary edema, fever, dysionemia etc.)
Solute to clear (water, urea, electrolytes, cytokines..)
The final desired blood level of the target solute
In CVVH (small solute) clearance is essentially considered
equal to UF rate
Optimal RRT dose in ICU: 2 multicenter clinical trials
Compare normal or less intensive renal support to
intensive therapy
RENAL
VA/NIH ARF trial network
(ATN) study
1124 patients
1500 patients
25 ml/kg/h CVVHDF
20 ml/kg/h CVVHDF/
vs 40 ml/kg/h
N England J Med, 2009
thrice weekly IHD vs
35 ml/kg/h/daily IHD
N England J Med, 2009
No benefit in outcomes by increases in intensity of RRT
dose
Conclusion
Normal dose: 20-30 ml/kg/h for continuous
therapy
Ricci Z, Ronco C. Current Opinion Critical Care, 2011
Overt underdialysis might be harmful in ICU!!
Be careful about the discrepancy between
prescribed and delivered dose!!!
DOse REsponse Multicenter International
Collaborative Initiative (DoReMi)
The difference between prescribed and delivered dose
Relies on therapy downtime (the amount of time the
CRRT does not run in a 24 h period),
clotting of the circuit,
Vascular access problems
Prescription errors
Crit Care 2009
When you prescribe 20-25 ml/kg/h during CRRT significant reduction in
dialysis dose delivery should be considered!
In practice you may need to over-
prescribe RRT with 25% of safety
margin
Recommendation: 30-35 ml/kg/h?
Kellum JA, Ronco C Nat Rev Nephrol 2010
Ricci Z, Ronco C. Curr Opin in Crit Care, 2011
Anticoagulation
Low dose heparin
10-20 IU/kg bolus
10-20 IU/kg/h continuous drip (target activated clotting time:
180-200 s or partial tromboplastin time that is double the
normal value)
Citrate anticoagulation
No anticoagulation
When to stop?
No randomized controlled trials addressing this issue
Observational studies have suggested that urine output
can be used to predict successful cessation of CRRT
Spontaneous urine output >500 ml/day? (adult)
Uchino S et al. Crit Care Med 2009
Complications of CVVH
High cost
Technological complexity
Specialized nursing staff usually required
Hypothermia
Membrane bioincompatibility
Acid-base imbalance
Electrolyte imbalance
Removal of drugs and nutrients
Volume depletion
Common in both CVVH
and IHD
Long-term outcomes
Mortality is high
At least 10% of children who survive AKI have evidence of
Hyperfiltration
Hypertension
Microalbuminuria
Puts them at risk of long term progressive loss of kidney function
Long term follow-up is important!
Early intervention with ACE inhibitors, angiotensin receptor
blockers or other renoprotective therapies if necessary
Askenazi DJ et al. Kidney Int 2006
Firdevs Çalkanoğlu