1、When to Start RRT in AKIAlexander Usorov,MD2/24/09New Diagnostic Criteria for AKI Acute Dialysis Quality Initiative Plus several Critical Care Societies Equals Acute Kidney Injury Network or AKIN The fundamental goal is to improve the outcomes for patients who are at risk The first AKIN conference w
2、as held in Amsterdam in September 2005 Focused on the development of uniform standards for definition and classification of AKIRIFLE-AKIDose and Modality VA/NIH trial vs Schiffls trial Ronco Mehta Vinsonneau(Contniuous venouvenous hemodiafiltration vs intermittent HD for ARF in pts with multiorgan d
3、ysfunction syndrome.Lancet 2006)Timing?Less data available Early literature(1950s-1960s)is significant for the concept of prophylactic HD in AKI Introduced by Dr.Paul E Teschan Observational report using prophylactic HD in 15 pts with oliguric ARF from Renal Center of the US Army Surgical Research U
4、nit HD initiated prior to BUN reaching 200 mg/dL or uremic sxs Comparison was done to authors past experience Improvement in mortality,clinical course,uremic sxsContRCTs Conger et al conducted a study on US Naval Hospital Ship USS Sanctuary between April and October of 1970 18 patients with post-tra
5、umatic AKI Intensive HD arm with pre-HD BUN70 and SCr 5 Non-intensive regimen with delaying HD until BUN approached 150 and SCr approached 10 or if clinically indicated Survival-5/8 pts(64%)vs 2/10(20%)pts Major complications(Gram-neg.sepsis,hemorrhage)were less freq in intensive arm Gillum et al ex
6、amined 34 pts at University of Colorado in 1986 Pts were paired and randomly assigned once SCr reached 8 Intensive regimen with pre-HD BUN60 and SCr 5 Less intensive regimen:BUN and SCr reached 100 mg/dL and 9 mg/dL Average time from AKI to HD:5+2 vs 7+3 days Higher mortality in the intensive HD gro
7、up Conventional wisdom In the absence of uremic symptoms,start hemodialysis if BUN is around 100 mg/dL No additional benefit seen with earlier HD initiation nor more intensive HD prescriptionMoving On Further studies focused mostly on the timing of initiation of CRRT Gettings et al published a retro
8、spective analysis of 100 consecutive patients with post traumatic AKI in 1999 Early vs late initiation based on BUN 60 mg/dL at initiation of therapyCont.Early group CRRT initiated on hospital day 10+15 Mean BUN of 43+13 Late group CRRT initiated on HD 19+27 BUN of 94+28 Survival 39%in early vs 20%i
9、n late group Critical points:Non-randomized,retrospective More pts with multisystem organ failure or sepsis in late group More pts oliguric on first day of CRRT in early than late group,leading to suggestion that there was a confounding effect(?physician bias)More Retrospective Studies Elahi et al r
10、eported a series of 64 consecutive patients s/p cardiac surgery at a single UK center between January 2002 and January 2003 In 28 pts,CVVHDF was started once BUN84,SCr2.8,or serum K6,despite medical therapy and regardless of UOP Remaining 36 pts,CVVHDF was initiated when UOP was 100ml over 8 hrs des
11、pite Lasix Similar demographics and baseline clinical characteristics Surgery to renal support time was 2.6+2.2 days vs 0.8+0.2 daysLimitations of the studies All recent studies are retrospective Using BUN as a surrogate measure of AKI duration is problematic Urea generation varies from patient to p
12、atient Volume of distribution of urea in critically ill patients is variable as well Bias by indicationHow about a prospective study of CRRT timing?Bouman et al randomized 106 criticall ill patients with AKI to three groups:Early high-volume CVVHDF(35 pts)Early low-volume CVVHDF(35 pts)Late low-volu
13、me CVVHDF(36 pts)Two early groups txt started within 12 hrs of meeting inclusion criteria:Oliguria x 6 hrs despite hemodynamic optimization Measured cr clearance 112 K6.5 Pulmonary edema present Outcome No significant differences in survival were observed Critical point is that 28-day mortality was
14、only 27%,much lower than in prvsly reported studies of critically ill patients with AKI Small sample size lead to low statistical power Interestingly,6/36 pts in late group never got RRT(2 pts died and 4 pts recovered renal fxn)So When Do We Initiate RRT?Inadequate data available to answer this question Observational data suggests better outcomes are associated with early RRT initiation?If“less sick”patients are included in these early groups Also,most pts with AKI are not treated with RRT
