1 / 59

Acute renal failure

Acute renal failure. By H P Shum Intensive care unit PYNEH. Introduction. ARF was first recognized in crush injury victims during World War II

mackenzie
Download Presentation

Acute renal failure

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Acute renal failure By H P Shum Intensive care unit PYNEH

  2. Introduction • ARF was first recognized in crush injury victims during World War II • Eric Bywater described a reversible reduction of renal function, characterized by an initial oliguric phase, followed after 1–2 weeks by a diuretic phasethat marked the onset of complete renal recovery BMJ1941: 427–32

  3. Pre-renal ARF ischaracterized by decreased renal perfusion in the absence of injury to the renal parenchyma • Prompt reversal of the haemodynamic insultresults in the rapid restoration of renal function • If renal hypoperfusion sustained, cellular injury occur resulted in ATN • In ATN, renal dysfunction persists evenafter reversing the haemodynamic insult • Support with dialysis may be necessary whilstawaiting the typical recovery that occurs overdays to weeks

  4. ARF - definition • Great variation • Ranged from a slight increased in Cr by 0.5mg/dl (44umol/l) to needs for dialysis • Difficulty to compare the prevalence of ARF between populations • Reasonable definition: acute and sustained increasein Cr concentration of 0.5mg/dl (44mol/L) if thebaseline is less than 2.5mg/dl (221 mol/L), or an increase in Cr concentration of more than 20% if the baseline is more than 2.5mg/dl (221 mol/L)

  5. Epidemiology of acute renal failure: a prospective, multicenter, community-based study. Madrid Acute Renal Failure Study Group Liano F et al. Kidney Int 1996 Sep;50(3):811-8 • Definite of ARF • Cr >177 with N baseline • >=50% Cr in those with CRF (Cr <265) • 13 tertiary care hospitals • 9 months in duration • N=748 cases of ARF 66% total

  6. Hospital-Acquired Renal Insufficiency Nash K et al. Am J Kidney Dis 2002; 39: 930–36 • 4622 admited to medical and surgical ward • Tertiary care hospital • 7.2% with baseline Cr >105umol/l 164

  7. Pre-renal ARF • complicate any disease characterized by either “true hypovolemia”or a reduction in the “effective circulating volume” • Hypovolemia  fall in SBP  activation of SNS and RAAS  decreased renal perfusion  renal flow flow and GFR were maintained by autoregulation • If the hypovolemia cannot be adequately corrected in short time, kidney autoregulation mechanism will fail and renal perfusion and GFR decreased progressively

  8. NSAID in pre renal ARF • In normal situation, PGI2 and PGE2 do not play very significant role in renal haemodynamic regulation • However, it become important for preservation of renal perfusion and GFR during reduced effective circulating volume

  9. Is COX-2 inhibitor less nephrotoxic than nonselective COX inhibitor ? • Effect of Cyclooxygenase-2 Inhibition on Renal Function in ElderlyPersons Receiving a Low-Salt Diet Ann Intern Med. 2000;133:1-9 • Randomized, three period, single dose cross-over study • N =45, placebo vs vioxx vs indocid • Inulin clearance was determinated every 30min after dosing for total 6 hr

  10. Is COX-2 inhibitor less nephrotoxic than nonselective COX inhibitor ? • Celecoxib vs diclofenac and omeprazole in reducing the risk of recurrent ulcer bleeding in patients with arthritis N Engl J Med 2002;347:2104-10 • Aim at learning the effect of celecoxibs 200mg bd vs. diclofenac + losec on GIB in patient with arthritis • Duration 6 mo • N = 287

  11. ACEI and renal impairment • A study of the prevalence of significant increases in serum creatinine following angiotension-converting enzyme inhibitor administration J Hum Hypertens. 2005 May;19(5):389-92 • 20644 pts on ACEI with age >40 • Monitor RFT changes within 6 mo after ACEI initiation • 31 (0.15%) had increased Cr from 105umol/l to >220umol/l 325umol/l

  12. ACEI and renal impairment • Diarrhoea, vomiting and ACE inhibitors:an important cause of acute renal failure Journal of Human Hypertension (2003) 17, 419–423 • 3 cases of ARF, Cr upto 1000umol/l, on ACEI associated with GE symptom • 3 months, retrospective cohort survey of patients admited to medical wards • 0.3% on ACEI with diarrhea developed ARF, Cr upto 290umol/l, all response to fluid challenge 38%

  13. Key points • Pre-renal ARF is a common cause of ARF • Early restoration of haemodynamic can decrease chance of progression to ischemic ATN which takes longer time for full recovery • NSAID and ACEI/ ARB can induce pre-renal ARF especially in those with depleted volume status and impaired RFT • COX II inhibitor is not a renal safe medication

  14. ATN • Causes of ATN have great variation among different populations • Strongly related to environmental and therapeutic exposure The spectrum of acute renal failure in the intensive care unit compared with that seen in other settings Kidney Int Suppl 1998; 66: S16–24

  15. Septicemia related ATN

  16. Ischemic ATN • Two components contribute to decreased GFR • Vascular • Intrarenal vasoconstriction • Vascular congestion within outer medulla • activation of tubuloglomerular feedback • Tubular • Tubular obstruction • Transtubular backleak • Interstitial inflammation

  17. Tubular changes in ATN • ischemic and reperfusion • loss of polarity • loss of brush border • redistribution of integrin and Na/K ATPase • tubular cell death • shedding of viable and non-viable cell • tubular obstruction • further reduction of GFR

  18. ATN

  19. Prevention and Tx of ARF • Medications that affect autoregulation of renal blood flow should be used with care eg NSAID / ACEI / ARB • Avoid use of nephrotoxic agents • Check dosing of potential nephrotoxic drugs eg aminoglycosides, cyclosporin, tacrolimus

  20. Volume expansion • Essential mx of patients with hypovolemia • Crystalloids vs. colloids vs. albumin ??

  21. Patient survival after human albumin administration. A meta-analysis of randomized, controlled trials Ann Intern Med 2001 Aug 7;135(3):149-64 • 55 trials involving surgery or trauma, burns, hypoalbuminemia, high-risk neonates, asciteswere included • Total >2000 pts • No evidence for either improved outcome or increased mortality in patients given albumin

  22. A Comparison of Albumin and Saline for Fluid Resuscitation in the Intensive Care Unit The SAFE Study Investigators. N Engl J Med 2004;350:2247-56 • 6997 pts admitted to ICU need fluid resuscitation • Half given 4% albumin, half with saline

  23. Colloids versus crystalloids for fluid resuscitation in critically ill patients The Cochrane Database of Systematic ReviewsVolume (3), 2005 • To assess the effects on mortality of colloids compared to crystalloids for fluid resuscitation in critically ill patients • Albumin vs. crystalloids: 19 RCT, 7576 pts, pooled RR was 1.01 (95% CI 0.92 to 1.10) • Hydroxyethyl starch vs. crystalloids: 10 RCT, 374 pts, pooled RR was 1.16 (95% CI 0.68 to 1.96) • Modified gelatin vs. crystalloids: 7 RCT, 346 pts, pooled RR was 0.54 (95% CI 0.16 to 1.85) • Dextran vs. crystalloids: 9 RCT, 834 pts, pooled relative risk was RR 1.24 (95% CI 0.94 to 1.65) • no evidence from RCTs that resuscitation with colloids reduces the risk of death, compared to resuscitation with crystalloids, in patients with trauma, burns or following surgery

  24. Key points • For volume expansion • No significant different between use of albumin, colloid and crystalloid • Given the cost of albumin, potential hypersensitivity reaction and risk of virus transmission, crystalloid should in most cases a preferred choice for fluid resuscitation

  25. Aminoglycoside nephrotoxicity • Precise contribution of aminoglycosides to renal failure to difficult to assess in seriously ill pts who had other predispositions to renal failure • Risk factors included: • High dosage • Prolong or repeated courses • Old age • Female sex • Underlying renal impairment • Hypovolemia • Liver impairment • Presence of other nephrotoxic drugs Ann Int Med 1984; 100: 352-7 AJKD, Vol 39, No 5 (May), 2002: pp 930-936

  26. Once versus thrice daily gentamicin in patients with serious infections Prins JM et al. Lancet1993;341: 335–9 N=123 4 mg/kg/d (OD)vs. 1.33 mg/kg 3x/d (MD) Mean duration of tx 7d In conclusion: A once-daily dosing regimen of gentamicin is at least as effective as and is less nephrotoxic than more frequent dosing A meta-analysisof antibiotic therapy, includingaminoglycosides in patients with neutropenicfevers, found no significant differences incure rates or nephrotoxicity with single vsmultiple doses of aminoglycosides Clin Infect Dis1997;24: 810–5

  27. Key points • Use only in absolutely needed condition • Once daily dose of aminoglycosides is as effective as divided dose with less nephrotoxic side effect • Appropriate dosage adjustment needed for those with renal impairment • Beware on concomitant use of other nephrotoxic agents

  28. Radio-contrast induced nephropathy AJKD, Vol 39, No 5 (May), 2002: pp 930-936

  29. Prevention of contrast nephropathy • NAC • Hydration • Iso-osmolar contrast media • Theophylline • Fenoldopam

  30. Prevention of Radiocontrast NephropathyWith N-Acetylcysteine in patients with Chronic Kidney Disease: A Meta-Analysis ofRandomized, Controlled Trials AJKD Vol 43, No 1 (January), 2004: pp 1-9 8 RCT, 885 pts Another 4 RCT in abstract form, 427 pts Age >18 Cr >106umol/l or CrCl < 70ml/min RCN defined as Cr  > 44umol/l or > 25% baseline

  31. Prevention of contrast media-associated nephropathy: randomized comparisonof 2 hydration regimens in 1620 patients undergoingcoronary angioplasty Mueller C et al. Arch Intern Med. 2002;162: 329-336 • N= 1620 • Compare NS vs. half half sol • CN defined as Cr >44umol/l from baseline • Monitor RFT 24-48 hr postop

  32. Prevention of Contrast-Induced Nephropathy With Sodium Bicarbonate: A Randomized Controlled Trial JAMA Volume 291(19), 19 May 2004, p 2328–2334 • prospective, single-center, RCT • 119 pt • receive a 154-mEq/L infusion of either sodium chloride (n = 59) or sodium bicarbonate (n = 60) • CN defined as  Cr >25% baseline in 2 d

  33. Low osmolar contrast media (LOCM, 780 mOsm) vs. iso-osmolar contrast media (IOCM, 290 mOsm)N Engl J Med. 2003;348:491–499 • Prevent nephrotoxicity in High-Risk PatientsUndergoing Angiography • 129 pts, DM with impaired RFT (cr about 132 – 308umol/l) • coronary or aortofemoral angiography • All well hydrated IV NS 1L before procedure • CN defined as Cr >44umol/l

  34. Theophylline for prevention of contrast-induced nephropathy: a systematic review and meta-analysis • Arch Intern Med. 2005 May 23;165(10):1087-93 Adenosine antagonist (adenosine is an important mediator of CN) 9 RCT, 585 pts Overall pooled OR 0.4 favor theophylline use

  35. Fenoldopam (DA-1 receptor agonist) • Induce renal vasodilatation • Increase renal blood flow • Increase urine output American Journal of Therapeutics 12, 127–132 (2005)

  36. The Prevention of Radiocontrast-Agent–Induced Nephropathy by Hemofiltration N Engl J Med 2003;349:1333-40 • 114 pt • all with Cr >177umol/l • CVVH vs. NS 1ml/kg/h • 4-8 hr before cardiac procedure, 18-24hr after after • CN defined as increased Cr >25% baseline

  37. Results: • CN in CVVH:NS gp = 5% : 50% (p<0.001) • needs for subsequent dialysis support in CVVH : NS = 3% : 25% (p<0.001) • In-hospital mortality in CVVH : NS = 2% : 14% (p=0.02) • Cumulative 1-yr mortality in CVVH : NS = 10% : 30% (p=0.01)

  38. Key points • Consider other imaging technique • Hydration is most important • NS is better than half half solution and NaHCO3 may be better than NS but need larger study to provide firm support • NAC/ theophylline/ IOCM is more useful in those with significant risk factors • CVVH may be useful in extremely high risk group

  39. Low dose dopamine • Thought to restore renal blood flow and GFR • But no evidence that it is beneficial

  40. Low-dose dopamine in patients with early renal dysfunction: a placebo-controlled randomised trial. Australian and New Zealand Intensive Care Society (ANZICS) Clinical Trials Group • Lancet. 2000 Dec 23-30;356(9248):2139-43 328 pts admited to ICU low-dose dopamine (2 µg kg-1 min-1) vs. placebo End point: peak serum creatinine concentration

  41. Survival to ICU discharge (108 vs 105 patients; p=0.61) and survival to hospital discharge (92 vs 97 patients; p=0.66) were similar

  42. Loop diuretics in the management of acute renal failure: a prospective, double-blind, placebo-controlled, randomized study • Nephrol Dial Transplant. 1997 Dec;12(12):2592-6 Unless the patient had fluid overload, use of loop diuretic can further exacerbate ATN • 92 pts with ARF • All received renal dose of dopamine and mannitol 3 d before • Randomized to torasemide, frusemide, or placebo • 3mg/kg q6h

  43. Key points • Renal dose of dopamine do not have any role in ARF Mx • Although, use of loop diuretic in ARF can increase u/o, it use is very limited in most of the cases of ARF

More Related