100%(6)6 out of 6 people found this document helpful
This preview shows page 66 - 69 out of 76 pages.
Page 66of 76RENAL DECOMPENSATIONAcute Renal Failure (ARF)What is acute renal failure (ARF)?Sudden loss of kidney function Altered fluid and electrolytesWhat are the risk factors for ARF?Volume depletion: dehydrationNephrotoxic ABX and other nephrotoxic agentsFrequent bouts or sustained hypotension (kidneys aren’t being perfused)Sepsis, SIRS (decreased BF to kidneys)CV failure, heart failure, MIHow is ARF classified?Prerenal: conditions decrease blood flow to kidneys (anything that prevents BF to kidneys)Intrarenal: conditions affecting internal (parenchymal) structures (swelling, calculi, glomerulonephritis)oAcute tubular necrosis (ATN): Toxin OR Ischemia damagesPostrenal: conditions obstruction urine outflowWHAT ARE CAUSES OF PRERENAL FAILURE?Hypotension/Hypo profusion, dehydration (Usually a volume issue= decreased BF to kidneys)Decreased cardiac output: MI, CHF, dysrythmias, sepsis (need blood and O2 to do work)Renal artery disorder: embolus, or thrombus, stenosis, trauma (kidneys need O2 to work)WHAT ARE CAUSES INTRARENALFAILURE?Vascular diseaseAcute glomerulonephritisAcute tubercular necrosis (ATN)oProlonged ischemiaoNephrotoxins-drug** major causeAcute Tubercular Necrosis (ATN)Ischemic acute tubular necrosis (ATN) results from prolonged hypoperfusion.A sequence of pathophysiological processes results in the sloughing off of necrotic cells that block the tubular lumen. oToxic ATN occurs when a nephrotoxin becomes concentrated in the renal tubular cells and causes necrosis. The necrotic cells slough off and obstruct the tubular lumen, similar to ischemic ATN. oIn toxic ATN, the basement membrane of the renal cells usually remains intact, and the necrotic areas are more localized.Types of ATNoIschemic ATN – continuum of prerenal conditions
Page 67of 76oNephrotoxic ATN – caused by drugs—(aminoglycosides) May not occur for 7-10 daysoPrevention- Dose dependent – lower doseRisk factors: Volume-depletion-hydrate and advanced age
Page 68of 76What is the clinical course of ATN? There are 4 phasesoOnset (initiating) Phase: Find and treat cause, Prevent damageoOliguric or Non-Oliguric Phase (UOP=urinary output)Oliguric = UOP < 400 ml/day (7-14 days) Non-oliguric = UOP > 400 ml/day (5-8 days) oDiuretic Phase – UOP > 4-5,000 ML/day! (1-2 weeks)oRecovery Phase--months – 1 yearContract- Induced Nephropathy (CIN)oBegins w/in 48 hours of receiving,peaks in 3-5 days, returns 3-5 daysNonoliguric, transient, reversibleDiabetics at greatest riskPrevention: AGGRESSIVE HYDRATION before, during, after procedure Postrenal Caused by obstructionBackflow of urine causes congestion of nephron Requires blockage of both kidneysCauses: stricture, tumors, stones, trauma, blood clots, BPH (causes obstruction)Relief of blockage:oPROFOUNDdiuresis (5-8 L/DAY) follows relief of obstruction!