crrt in acute kidney injury
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
CRRT IN ACUTE KIDNEY INJURY
Dr Umut Selda BayrakçıYıldırım 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 diseaseThe evolution of associated complicationsPrognosis
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% survived Mean volume excess 33% 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 2001Goldstein 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
Modality Manual PD
Automated PD
İntermittent HD
Continious 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 100HG dialyzer
$50.00 each;
M60 hemofilter set (filter and bloodlines)$160.00 each
Peritoneal dialysate as at left
pediatric bloodlines $11.40 each
Normocarb dialysate concentrate $20.00/3.0L
Cost of dialysis equipment (in U.S. dollars)
Flynn JT, Pediatr Nephrol 2002
WHICH IS THE BEST DIALYSIS MODALITY?
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 ARFPediatrics: 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 marrow transplant %78 intermittent HD 33% PD 21% HF
ARF following repair of congenital heart disease 100% intermittent HD 33% PD 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
316 adults, AKI patients
Mortality: intermittent HD:62.5%
CRRT: 58.1%
Modality of RRT has no impact on the outcome in ICU
Rins RL et al. Nephrol Dial Transplant 2009
Single center, randomized, controlled trial (CONVINT)
252 adult AKI patients
Survival rate: 39.5% IHD
43.9% CVVH
No significant difference regarding mortality, renal outcome measures or survival
Schefold JC et al. Critical Care 2014
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
Goal of dialysis Hemodynamic status modality
Ultrafiltration Normotensivehypotensive
Intermittent HD (w isolated UF)Continuous HF or PD
Urea clearance Normotensivehypotensive
Intermittent HD or PDContinuous HF or PD
Treatment of hperkalemia
Either normotensiveor hypotensive
Intermittent HD
Correction of metabolic acidosis
Normotensivehypotensive
AnyContinuous HF or PD
Treatment of Hyperphosphatemia
Either normotensiveor hypotensive
Any; continuous hemofiltration possibly superior
Suggested modality choice in pediatric ARF
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 trialsCompare normal or less intensive renal support to intensive therapy
RENAL 1124 patients
25 ml/kg/h CVVHDF vs 40 ml/kg/h
N England J Med, 2009
VA/NIH ARF trial network (ATN)
study 1500 patients
20 ml/kg/h CVVHDF/ 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 indialysis 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 2010Ricci 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 MicroalbuminuriaPuts 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