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1. Acute Renal Failure Anil Menon
11/27/06
2. Nitrogenous and non-nitrogenous waste products. Cr/BUN. Remember Cr not good indicator of GFR in non-steady state (production/volume distribution). Many definitions.Nitrogenous and non-nitrogenous waste products. Cr/BUN. Remember Cr not good indicator of GFR in non-steady state (production/volume distribution). Many definitions.
3. Relevance Complicates up to 7% of admissions
Mortality when dialysis is required ranges 50%-75% 75% in context of sepsis and critical care. 75% in context of sepsis and critical care.
4. DDX MAP of 70 is when GFR begins to become impaired (autoregulation). Autoregulation is prerenal dilation regulated by prosglandins and NO and post glom constriction by ATII. NSAIS interfere with these. At risk group elderly, CRI, athero. ATN most common, then post op pre renal 25%, then radiocontrast. Post renal 10%.MAP of 70 is when GFR begins to become impaired (autoregulation). Autoregulation is prerenal dilation regulated by prosglandins and NO and post glom constriction by ATII. NSAIS interfere with these. At risk group elderly, CRI, athero. ATN most common, then post op pre renal 25%, then radiocontrast. Post renal 10%.
5. Diagnostic Approach Cr/BUN, UOP, serum cystatin K, IL18
H&P
Meds
Labs
Imaging
6.
7. Acute or Chronic? History
Previous creatinine
Small kidneys on u/s Duration of sxm, nocturia, absence of acute illness, anemia, hyper pho, hypo calDuration of sxm, nocturia, absence of acute illness, anemia, hyper pho, hypo cal
8. Obstruction excluded? History
Complete anuria
Palpable bladder
Renal u/s Previous stones. Sxm. Bladder flow. Complete anuria rare in arf without obsruction. See dilation of pelvis and calyx if not malignancyPrevious stones. Sxm. Bladder flow. Complete anuria rare in arf without obsruction. See dilation of pelvis and calyx if not malignancy
9. Euvolemic? Pulse, JVP/CVP, orthostatic, wgt, I/O
Disproportionate inc in urea:Cr ratio
FENA
Fluid challenge High antiADH leads to urea resorp by tubules. Fena okay without diuretics. Care for pulm edema in oliguric patientsHigh antiADH leads to urea resorp by tubules. Fena okay without diuretics. Care for pulm edema in oliguric patients
10. Evidence of parenchymal dz? Other than ATN H+P (systemic factors)
Urine dipstick and micro
(red cells, red cell casts, eosinophils, prot) Rash, arthralgia, myalgia, abx, nsaids AIN. Red casts nepritis or eos AIN think nephrologistRash, arthralgia, myalgia, abx, nsaids AIN. Red casts nepritis or eos AIN think nephrologist
11. Major vascular occlusion? Athreosclerosis
Renal Assymetry
Groin pain
Complete Anuria
Macro Hematuria Elderly athreo, renovascular in 34% elderly with CHF. Occlusion of normal renal artery groin pain and hematuria. If one goes down because athero then embolism to the remaining is bad. ACE/Diuretics in stenosis or instrumentation. Cholesterol embolism post angiographhy or surgery livedo reticularis, arf, esoin one to four weeks outElderly athreo, renovascular in 34% elderly with CHF. Occlusion of normal renal artery groin pain and hematuria. If one goes down because athero then embolism to the remaining is bad. ACE/Diuretics in stenosis or instrumentation. Cholesterol embolism post angiographhy or surgery livedo reticularis, arf, esoin one to four weeks out
12. Treatment Prevention
Risk factors (age,DM,HTN,Vasc,renal)
Maintain BP and Volume, avoid neprhotox
Measure plasma aminoglycoside
Allopurinol/urine alk in cancer
13. General Correct prerenal/postrenal factors
Optimise CO, RBF
Review meds
Monitor I/O
Nutritional support
Treat infection, bleeding
Start dialysis before uremic
14. No strong evidence Loop diuretic
Dopamine
Natriuretic peptide
Intermittent HD vs Continuous
ILF
Thyroxine Ototoxic in high does, tach/periph gangrene, hypotension, blank, blank, inc mort in critical ptOtotoxic in high does, tach/periph gangrene, hypotension, blank, blank, inc mort in critical pt
15. ATN Sepsis in ICU 35-50%
Prerenal azotemia spectrum with ischemic ATN
Initiation, maintenance, recovery
BUN/Cr normal 10:1
Rapid rise plasma Cr
Muddy brown epi casts
FENa > 2%
Ucr / PCr
Snake bite, crush injury, nephrotoxin, sepsis.
Snake bite, crush injury, nephrotoxin, sepsis.
16. Post Op 18-40% hospital aquired. 1.2% surgery.
Pre-op BP control (Carmaichael J Surgery 2003)
Hydration and prevention
Poor prognosis of ARF when adjusted (Svensson J Vasc Surg 1989)
Nephrology
Prognosis jumps from 4.3 to 67% when adjusted for cormorbitites in cardiac groupPrognosis jumps from 4.3 to 67% when adjusted for cormorbitites in cardiac group
17. Contrast Isotonic crystalloid 1-1.5ml/kg for 3-12 hours pre proc and 6-24 hours post
Mucomyst not consistently useful
Current eval of theophyline, statins, vit c, pg E
CCB, L-arg, fenoldopam, dopamine, ANP not useful
Prophylactic HD no gain
(Stacul 2006 CIN consensus working panel) NS better than 1/2 because the inc sodium reduces renin pathway response. Duration not clear, oral fluids maybe for outpatient. Emergency? Prep for HD with severe renal failure.NS better than 1/2 because the inc sodium reduces renin pathway response. Duration not clear, oral fluids maybe for outpatient. Emergency? Prep for HD with severe renal failure.