This section covers general management of acute renal failure only. Diagnosis, prevention and specific treatment are not discussed.<\/p>\n
Initial management should comprise:<\/p>\n
Note that there is no evidence that dopamine is of benefit other than through its action as an inotrope – but inotropes may be valuable in heart disease or shock. Loop diuretics may increase urine output in those with less severe degrees of renal failure, but there is no evidence that they improve outcome (requirement for dialysis, or mortality) and some evidence that they can be harmful. Most interventions tested in prevention of ARF after radiographic contrast administration are ineffective or harmful (eg loop diuretics), apart from fluid administration alone (See Radiology).<\/p>\n
Indications for dialysis<\/span><\/em><\/span> are:<\/p>\n Neither age nor comorbid conditions (that might lead you to question longterm RRT) should be considered as automatically disqualifying dialysis for ARF if there is a substantial chance of recovery. BUT:<\/p>\n Peritoneal dialysis<\/span><\/strong> is now rarely used for ARF in the UK, though it can be effective if the patient is not too catabolic and ultrafiltration requirements not too extreme.<\/p>\n Continuous or very slow treatments<\/span><\/strong> (haemofiltration or haemodialysis)<\/p>\n BUT<\/p>\n Patients with ARF need at least as much dialysis, and frequently more (because of catabolism) than patients with ESRF. Therefore Kt\/V or URR should be at least as good. Dialysis usually needs to be more frequent, and daily treatments should be regarded as the norm in the early phase, or if fluid fluxes are substantial (e.g., from feeding).<\/p>\n Disequilibration is a state of clouding of consciousness, confusion and sometimes fits following dialysis. Disequilibration is most likely:<\/p>\n If the risk is significant it is sensible to give a low-clearance (e.g., Kt\/V 0.5, or 30% URR) and low intensity (low blood flow and\/or small dialyser) treatment initally, intermediate the next day, a full treatment (e.g., Kt\/V 1.2, URR 70%) the third day, if figures permit.<\/p>\n A \u2018gentle start\u2019 is inappropriate if fast removal of small molecules is required – e.g., in severe hyperkalaemia or for removal of low molecular weight poisons such as salicylate. CVVH is also inappropriate in these circumstances, except when the toxin is of molecular size better removed by haemofiltration.<\/p>\n First dialysis treatments can and should be less cautious in catabolic patients in whom figures are rising fast.<\/p>\n Haemofiltration, whether contiuous or intermittent, is less efficient at removal of small molecules including toxins. Prolonged haemofiltration commonly leads to phospate depletion, replacement may be required, and it clears some drugs (e.g., vancomycin) faster than haemodialysis.<\/p>\n Detailed calculations of dialysis dose is beyond the scope of this summary, but see the brief description under ‘Haemodialysis<\/a>‘. Note that for haemofiltration, Kt is equal to (or for urea, >90% of) the total volume of fluid exchanged.<\/p>\n For very crude comparison of small molecule clearance by continuous versus intermittent treatments, the following figures are provided. HD figures are for urea clearance by F8 dialyser, ignoring UF.<\/p>\n\n
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Intermittent haemodialysis<\/span><\/strong><\/h5>\n
Preventing disequilibration<\/span><\/strong><\/h5>\n
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Haemofiltration<\/span><\/strong><\/h5>\n
Amount of dialysis<\/span><\/strong><\/h5>\n
Comparisons<\/span><\/strong><\/h5>\n
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\n Modality<\/span><\/strong><\/td>\n Urea clearance<\/span><\/strong><\/td>\n<\/tr>\n \n Normal GFR<\/td>\n 150 l\/day<\/td>\n<\/tr>\n \n Daily intermittent HF<\/td>\n 15-25 l\/day<\/td>\n<\/tr>\n \n Continuous HF at 1 l\/hr<\/td>\n 24 l\/day<\/td>\n<\/tr>\n \n Continuous HF at 2l\/hr<\/td>\n 48 l\/day<\/td>\n<\/tr>\n \n Daily HD x 4hr at QB = 200ml\/min<\/td>\n 46 l\/day<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Dietary Management<\/span><\/strong><\/h5>\n