What s new in kidneys a renal update for Anaesthetists

Transcription

1 What s new in kidneys a renal update for Anaesthetists Thursday 11 th December 2014 Roslyn Simms Clinical Lecturer in Nephrology

2 Renal update What s new/update AKI When to start RRT in AKI? Perioperative management of CKD4+5 Not new but important

3 Update on AKI - background Sudden, sustained decline in renal function, assoc. metabolic/fluid balance disorders Based on: changes in serum Creatinine, urine output, need for dialysis Changing definitions/challenge epidemiology Difficult no consensus (timing? size change?) Acute Renal failure Acute Kidney Injury

4 Update on AKI Definitions (1) International collaboration (ICU/Renal) 2004: Acute Dialysis Quality Initiative est. RIFLE: 3 severities, 2 outcomes (duration)

5 Update on AKI Definitions (2) Response to criticism 2007 AKI Network RIFLE Staging system (recognise small Creat) AKIN (2007) definition Acute Kidney Injury (i) absolute rise Creat >26.5µmol/l (<48hr) (ii) >50% Creat (>1.5 fold from baseline) or (iii) reduced urine output (<0.5ml/kg/h for >6h)

6 Update on AKI Current KDIGO definition Staging system for AKI -KDIGO Stage Serum Creatinine Urine output 1 >26.5µmol/l (48hrs) or fold baseline (1/52) <0.5ml/kg/h >6h 2 by fold baseline <0.5ml/kg/h >12h 3 >3 fold baseline or > 354µmol/l or Start RRT <0.3ml/kg/h >24h or 12hr anuria KDIGO 2012

7 Update on AKI Current definition Staging system for AKI KDIGO - Validated Prospective study - AKI defined? 1,050 patients with MI during 1/52 admission AKI: RIFLE in 14.8% and KDIGO 36.6% RIFLE & KDIGO assoc. mortality (30d, 1yr) AKI defined by KDIGO but missed by RIFLE had increased risk of mortality Current recommended to use KDIGO staging Rodrigues PLOS One 2013

8 Update on AKI Current definition Staging system for AKI KDIGO - Validated Critical care setting Luo et al Crit Care 2014 KDIGO staging (use Creat + UO) improved sensitivity to RIFLE/AKIN to detect AKI Current recommended to use KDIGO staging to define AKI

9 Update on AKI Importance Lives AKI - recognise increased mortality Evidence? Challenged by different definitions, patient populations

10 Update on AKI Importance Lives AKI in 13-18% hospital admissions (esp. elderly) (incidence pmp/yr) (NICE, UK 2013) Incidence AKI RRT 203pmp/yr (UK 2002) 5-20% all ICU admissions episode AKI (E 2002) 10% ICU bed days (UK 2005) 4.9% AKI in ICU receive RRT (E 2002) AKI + MOF 50% (E 1998) AKI + assoc. mortality 22% (UK 2012) AKI mortality ~ 25-30% (NICE, UK 2013) (UK) data, (E) European data

11 Update on AKI Risks Preventable - Independent risk for mortality Comorbidities: bleeding (Plts/uraemic), sepsis (immunodeficient/drugs) cardiovascular risks Costs NHS (2º care) million/yr (UK) Preventable NCEPOD 2009 avoidable AKI

12 NCEPOD Patient Outcomes & Death 2009 Deceased AKI : assoc. deficiencies in care Only 50% received good care Delays in recognition, Failures in prevention Recommendations (2009): All acute admissions risk assess AKI (UEs) Consultant review within 12hrs Undergrad + Postgrad training: detect, prevent, manage AKI request NICE guideline on AKI

13 NICE Guideline: AKI Aug 2013 Detection, Prevention, Management up to RRT Uses KDIGO (or RIFLE/AKIN) definition AKI NOW: Creat > UO DETECT (UEs): acute illness - at risk /freq. UEs Cause: no cause/risk of obstruction U/S 24hr Pyonephrosis U/S 6hr PREVENT: pre-contrast identify at risk pre-surgery, monitor inpatients (EWS), Mx: UTObs nephrostomy/stent 12hrs dx

14 Update on AKI Early Identification NHS England Patient Safety Alert (July 2014) Lab software AKI Stage 1-3 results e-alert KDIGO classification Standardised across England All patients (except RRT/HD units) Recognition AKI

15 When to start RRT for AKI? Femoral or RIJ line! KDIGO 2012

16 Accepted indications to start RRT: Refractory fluid overload Refractory hyperkalemia (K >6.5 mmol/l) or rapidly rising K levels (oligo/anuric) Complications - signs of uraemia, pericarditis, neuropathy, otherwise unexplained mental status Metabolic acidosis (ph <7.1) Certain alcohol and drug intoxications KDIGO additional supportive uses eg Nutrition if oliguric (volume), solute balance (tumour lysis)

17 When to start RRT? Evidence?? KDIGO 2012 No graded evidence Recommend Initiate emergently when lifethreatening change: fluid/electrolytes/acid-base Renal Association 2011 Strong rec. evid. (1B) - AKI est. + unavoidable, before complications - threshold when AKI part of MOF - defer if early signs of recovery Need for RCTs

18 When to start RRT? Previous studies Difference AKI vs CKD AKI RRT is NOT inevitable (Defer may not need?) Koyner et al TRIBE-AKI Consortium JASN 2012 Post cardiac surgery: Stage 1 AKI 12%, 33% need RRT lower Urea (<28) mortality Liu CJASN 2006 (US PICARD ICU patients) Meta-analyses 2008, 2011 Early /Pre-emptive RRT beneficial. Trend although NOT consistent results NO conclusive evidence clinical/survival benefit to early/prophylactic benefit of RRT Challenges: definitions/timing/power detect sig. outcome

19 Timing - when to start RRT in AKI Outcomes Jun 2014 Crit Car Med (ANZICS Random Eval Norm vs Augm Level of RT) Timing onset crrt in ICU with AKI + patient outcomes Observational Outcomes: 28d & 90d all-cause mortality Multicentre 23 ICUs (Australia + NZ) 439 ICU patients (RIFLE-I criteria) Median time start crrt: 17.6hrs (7.1-46hr) 4 gps timing between RIFLE-I and onset crrt: < 7.1hrs, 7.1 to < 17.6hrs, 17.6 to < 46.0hrs, 46.0 hr

20 Timing - when to start RRT in AKI Outcomes (2) No signif. difference/improved survival if start earlier Suggested need larger study - UNDER Powered p=ns Jun 2014 Crit Car Med (ANZICS Random Eval Norm vs Augm Level of RT)

21 Timing of RRT based on Conventional Indications (CI) Vaara 2014 CJASN (Subgroup Finnish AKI study ) Background Lit. Underpowered RCTs/observational studies suggest better outcomes if start RRT pre-emptively/ early Clin. Pract. trad. await conv. indication, BUT often begin b4 Resource intensive, Risk to patients?? Design: multicentre 17 Finnish ICUs, retrospective Patient inclusion: acute/elective postop + ICU stay (>24hrs) Exclusions: ESRF Objective: Evaluate circumstances to initiate RRT for AKI Indications ( 1 conventional or none) for RRT Timings (urgent <12hrs or delayed >12hrs) Also control gp: start RRT no CI vs matched gp NOT start RRT

22 Timing of RRT: Retrospective Design & 90d mortality 1-9= 90d mortality 1* Indep. of confounders 8*

23 Timing of RRT based on Conventional Indications (CI) Vaara 2014 CJASN (Subgroup Finnish AKI study ) Methods: KDIGO to screen for AKI (1-5d post ICU admission) Results: State oliguria most prevalent indication both groups 90d mortality 38.9% 68.2%

24 Timing of RRT based on Conventional Indications (CI) 29.5% 48.5% 38.9% 68.2%

25 Timing of RRT based on Conventional Indications (CI) Logistic regression: 90d mortality still worst classic-delayed *Pre-emptive RRT unlikely to add excess harm but 49.3% *26.9% 34.2% Why difference? 22.5% Pre-emptive RRT could pose a risk? Significance? 49.3% 26.9%

26 Timing of RRT based on Conventional Indications (CI) Acknowledge unmeasured confounders pre-emptive/classic gps possible (sicker patient population?) 90d mortality 29.5% 48.5% Worst 90d mortality in delayed-classic group thus AVOID delaying initiation if conventional indications for RRT

27 Timing of RRT based on Conventional Indications (CI) Interesting study design Propensity score model for pre-emptive RRT (confounders) Limitations - retrospective analyses, small patient numbers, observational, not capture if had CI but not treated RRT (problems data recording) Need further, larger study assess OPTIMAL timing RCT planning: ~56% treated RRT had conventional indications thus not eligible to include (randomise) Currently recommend: KDIGO guideline 2012: Initiate emergently when life-threatening change: fluid/electrolytes/acid-base

28 Modality of RRT for AKI No difference in renal survival/recovery, overall survival with crrt or IHD Prospective multicentre French, 360pts AKI + MOF randomised IHD or CVVHDF. same. Lancet 2006 HemoDiafe. Meta-analyses no difference Use crrt/ihd - local expertise/staffing/equip. EXCEPT? Acute brain injury/liver failure crrt better (cerebral perfusion) 1991 UK Contrib Nephrol

29 Perioperative management of CKD4+5 Establish norms fluid handling, comorbidities Pre-op: HD minimal anticoag/4hrs pre theatre PD - as normal (no day fill) Post-anaesthetic rpt UEs ~4hrs (esp HD) Nutrition low K feeds (watch volume) Drug dosing timing relative to RRT (IHD) If maintenance Pred augment dose (sepsis/ bp) Anaemia targets.

30 Perioperative management of CKD4+5 Continue EPO during acute illness/surgery Anaemia targets.(create, CHOIR 2006 Predialysis, CV events) If on EPO: Aim Hb g/L Adjust EPO dose Hb<105 or >115g/L Watch Hb in Diabetics (TREAT 2009 CVA Hb13) Need adequate iron Transfusion: ideally when on HD/Transplant status?

31 Perioperative management of CKD4+5 HD Anuric? (no catheter) ~1L fluid restrict Dry weight (rel. to duration inpatient/post-op) Monitor access modality - bp AVF loss Avoid access lines side of AVF/subclavian PD Avoid constipation. If peritoneal membrane breached CAN T use. Transplant trough Tac/Cys/Sirol levels, drug interactions

32 Summary AKI: Increased recognition/nice guidelines Future AKI biomarkers to predict prognosis? When to start RRT for AKI Evidence awaited Initiate emergently when life-threatening change: fluid/electrolytes/acid-base (KDIGO 2012) Perioperative management of CKD4+5

33 Thank you

34 Update on AKI Early Identification