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Acute Renal Failure
- Sameer Chadha, Shikha Mehta, Medical Student, MAULANA AZAD MEDICAL COLLEGE (14 October 2006)
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How to measure renal function in clinical practice
- Adie Viljoen, Timothy M Reynolds, and and Patrick J Twomey (16 October 2006)
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eGFR should be clearly documented on drug charts
- Gavin Dreyer (17 October 2006)
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Acute Renal Failure managment
- Prasanna Rao-Balakrishna (17 October 2006)
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Intensive care management of acute renal failure
- Jeremy S Bewley (18 October 2006)
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Acute renal failure - a classification based on function
- Sharmistha Saha, Andrew Mackillop, Consultant in Anaesthesia and Intensive Care (23 October 2006)
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Definitions for Renal Failure
- Ian D Nesbitt, Dr Joe F Cosgrove (23 October 2006)
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Which specialist?
- T John Trinder (26 October 2006)
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Sameer Chadha, Medical Student MAULANA AZAD MEDICAL COLLEGE, Shikha Mehta, Medical Student, MAULANA AZAD MEDICAL COLLEGE
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To this well written article we will like to add the following points 1. Causes of Pre Renal Failure can also include pulmonary hypertension,pulmonary embolus, pancreatitis, peritonitis,and some rare causes like hyperviscosity syndrome in multiple myeloma and polycythemia and also in patients on positive pressure mechanical ventilation. 2. Causes of Intrinsic Renal Failure can also include toxemia of pregnanacy, hemolytic uremia syndrome, renal allograft rejection. 3. Causes of Post Renal Failure can also include neurogenic bladder , phimosis, congenital valves. 4. In managing the ARF complicatons in addition to hyperkalemia , acidosis , we also have to correct hyponatremia(restriction of water intake), hyperphosphatemia(restriction of dietary phosphate) , hypocalcemia( calcium gluconate, calcium carbonate) ,hypermagnesemia( disconitue any antacids)and hyperuricemia( allopurinol, forced alkaline diuresis). 5. In investigations we can also calculate Urine Diagnostic Indices like ( Fractional Excretion of Sodium(Na), Urine Na concentration, Urine creatinine to plasma creatinine ratio, Urine speific gravity, Urine osmolality, Renal failure index, Plasma Blood Urea Nitrogen/ creatinine ratio) . They can help differentiate between pre-renal and intrinsic renal failure. 6.Renal Biopsy is indicated when pre-renal and post renal have been excluded and cause of intrinsic renal failure is other then ischemic or nephrotoxic injury. Competing interests: None declared |
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Adie Viljoen, Consultant Chemical Pathologist Lister Hospital, Stevenage, SG1 4UB, UK, Timothy M Reynolds, and and Patrick J Twomey
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Traynor et al (1) are correct in pointing out that approximately 5% of UK patients have National Kidney Foundation-Kidney Disease Outcomes Quality Initiative (NKF-K/DOQI) stages 3-5, however, the number of patients will vary a lot for several reasons. Firstly, the version of the 4-variable Modification of Diet in Renal Disease Study Group (MDRD) equation employed is very important (2). Secondly, the 4-variable MDRD equation is far from ideal for several reasons including the fact that the study contained few patients with NKF-K/DOQI stages 1 and 2 (3) such that a negative bias of 29% has been reported in healthy persons (4) and that mathematical issues also exist regarding the derivation of the equation (5). It is important to realise that the 95% confidence interval for an estimated glomerular filtration rate (eGFR) of 60 ml/min is ±26 ml/min (6) and accordingly, repeat measurement is essential for values <60 ml/min. Finally, while Traynor et al (1) believe that iohexol is a superior radiocontrast agent the MDRD study employed iothalamate as the reference method despite the fact that it is positively biased (3 – 5 ml/min at low levels of GFR and 15 – 25 ml/min in healthy subjects) when compared to inulin which is seen as the gold standard GFR method (7 – 10). These issues will play an important part in determining the renal workload of every UK general practice. References 1.Traynor J, MactierR, Geddes CC and Fox JG. How to measure renal function in clinical practice. BMJ 2006; 33: 733-7. 2.Reynolds TM and Twomey PJ. Implications of method specific creatinine adjustments on GMS chronic kidney disease classification.JCP. In press. 3.Level AS, Bosch JP, Lewis JB, Greene T, Rogers N, Roth D, for the MDRD Study Group. A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Ann Int Med 1999; 130: 461-70 4.Rule AD, Larson TS, Bergstralh EJ, Slezak JM, Jacobsen SJ and Coslo FG. Using serum creatinine to estimate glomerular filtration rate: Accuracy in good health and in chronic kidney disease. Ann Intern Med 2004; 141:929-937. 5.Twomey PJ and Reynolds TM. The MDRD formula is not as well- validated as one would hope for. QJM 2006. In press. 6.Deacon A. Limitations of estimating kidney function in adults using formulae. Ann Clin Biochem 2006; 43:85. 7.Perrone RD, Steinman TI, Beck GJ et al. Utility of radioisotopic filtratration markers in chronic renal insufficiency: Simultaneous comparison of 125I-iothalmate, 169Yb-DTPA, 99mTc-DTPA and inulin. The Modification of Diet in Renal Disease Study. Am J Kidney Dis 1990;16:224 – 235. 8.Odlind B, Hallgren R, Sohtell M and Lindstrom B: Is 125I-iothalmate an ideal marker for glomerular filtration? Kidney Int 1985; 27:9 – 16. 9.Back SE, Krutzen E and Nilsson-Ehle P: Contrast media and glomerular filtration: Dose dependence of clearance for three agents. J Pharma Sci 1988; 48:765 - 767. 10.Petri M, Bockenstedt L, Colman J et al. Serial assessment of glomerular filtration rate in lupus nephropathy. Kidney Int 1988; 34:832 – 839. Competing interests: None declared |
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Gavin Dreyer, Specialist registrar in nephrology North Middlesex University Hospital, N18
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Editor – Hilton’s review of the management of acute renal failure1 highlights the key issue of prevention of this common and costly in-hospital complication particularly since supportive care rather than definitive treatment is the most commonly available therapeutic strategy. I propose that the estimated glomerular filtration rate (eGFR) should be clearly highlighted on all hospital drug charts in the same way that drug allergies are documented. With the advent of the routine reporting of the eGFR there is now an opportunity to highlight those at risk of acute renal failure from an early stage in their admission. High-risk groups include elderly patients, in whom a normal serum creatinine may represent significantly impaired renal function, and patients with established chronic renal failure. Clear documentation of the eGFR would give medical, nursing and pharmacy staff every opportunity to avoid prescribing potentially nephrotoxic drugs to patients with impaired renal function and would also allow correct and prompt dose adjustment of commonly prescribed drugs such as anti-biotics. This would be a cheap and simple method to help reduce the clinical and cost burden of acute renal failure, a condition in which prevention is far easier than cure. Gavin Dreyer 1. Hilton R. Acute renal failure BMJ 2006 333:786-790 (14 October) I declare no conflict of interest. Competing interests: None declared |
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Prasanna Rao-Balakrishna, SpR Diabetes and GIM MRI, Manchester, M13 9WL
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This is an excellently written review addressing a commonly seen problem. It is now increasingly recognised that measures such as administration of Loop diuretics and Dopamine do not improve outcomes and may sometimes cause undesirable side effects. Despite this, management of Acute Renal Failure very often has involved administration of loop diuretics and Dopamine more by way of tradition and desperation rather than based on evidence base. The main focus as outlined in this review should be to optimise fluid balance and hemodynamics while withdrawing offending drugs and treating infections and obstruction if any. It will be now useful to develop nationally acceptable and auditable guidelines. Guidelines when coming from a nationally recognised body will effectively change practise from convention to that based on evidence. Competing interests: None declared |
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Jeremy S Bewley, Consultant in Intensive Care Bristol Royal Infirmary BS2 8HW
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The review by Hilton acknowledges that the immediate care of most patients with acute renal failure in the UK is provided on Intensive care units by Intensivists(1). Despite this there is an insufficient emphasis placed on an effective clinical approach to the intensive care resuscitation of these patients. In particular the article makes no mention of ensuring an adequate renal perfusion pressure in patients who have an elevated intra-abdominal pressure which can often prevent the need for renal replacement therapy. If the intra-abdominal pressure is greater than 20mmHg and associated with organ dysfunction such as oliguria this condition is known as abdominal compartment syndrome (2). If unrecognised or untreated a persistently elevated intra-abdominal pressure can result in acute renal failure. This condition is well recognised by Intensivists with 76% of Intensive Care Units measuring intra-abdominal pressure via the intravesical route(3). If abdominal compartment syndrome is developing acute renal failure can be prevented by continued fluid resuscitation, use of vasopressors and decompression of the abdomen. Improved recognition of this condition both by Surgeons and Physicians would benefit patient care. 1. Hilton R. Acute renal failure. British Medical Journal 333; 786-790 2. Sugrue M. Intra-abdominal pressure : time for clinical practice guidelines. Intensive Care Medicine 2002;28:389-391. 3.Ravishankar N and Hunter J . Measurement of intra-abdominal pressure in intensive care units in the United Kingdom; a national postal questionnaire study. British Journal of Anaesthesia 2005; 94 : 763-766 Competing interests: None declared |
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Sharmistha Saha, SpR Anaesthesia and Intensive Care Medicine North West Deanery, Manchester M8 5RL, Andrew Mackillop, Consultant in Anaesthesia and Intensive Care
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We would like to thank the author for an erudite and insightful review of such an important subject. One of the problems with describing renal impairment in terms of its histopathology is that the exact nature of the histological injury may not be evident for some time. In addition to this, there is genuine debate surrounding the true histopathology of acute tubular necrosis. Therefore, we would like to describe and recommend a classification based on function rather than pathology. The International Consensus Classification of acute renal failure (ARF) has been produced by the Acute Dialysis Quality Initiative group (www.ADQI.net). It is known as the RILFE classification, which is an acronym: (R)isk of renal dysfunction, (I)njury to the kidney, (F)ailure of kidney function, (L)oss of kidney function and (E)nd-stage kidney disease. RIFLE defines three grades of increasing severity of acute kidney disease, based on changes in either serum creatinine (C) or urine output (U) from baseline. It also includes two clinical outcomes: loss and end- stage renal disease. R = C x 1.5 or U < 0.5ml/kg/h for 6h I = C x 2 or U < 0.5ml/kg/h for 12h F = C x 3 or U < 0.3ml/kg/h for 24h or anuria for > 12h L = persistent ARF, needing Renal Replacement Therapy(RRT) for > 4 weeks E = needing RRT for > 3 months A recent publication looked at over 5000 patients in general intensive care unit beds. The study predictably showed that defined by the RIFLE classification, the incidence of acute kidney injury is high (67.2%), and that it is associated with an increased risk of hospital mortality compared with those who never develop acure kidney injury. Over 50% of patients in class R progressed to more severe RIFLE classes, but importantly, those who did not were not at risk of increased hospital mortality. In conclusion, the RIFLE classification is effective and pragmatic. We would therefore ask for its use to be strongly considered. References 1. Wan L, Bellomo R, et al. The pathogenesis of septic acute renal failure. Current Opinion Critical Care 2003;9(6):496-502. 2. Bellomo R, Ronco C, et al. Acute renal failure – definition, outcome measures, animal models, fluid therapy and information technology needs: the Second International Consensus Conference of the Acute Dialysis Quality Initiative (ADQI) Group. Critical Care 2004;8:R204-R212. 3. Hoste E, Clermont G, et al. RIFLE criteria for acute kidney injury are associated with hospital mortality in critically ill patients: a cohort analysis. Critical Care 2006;10:R73. Competing interests: None declared |
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Ian D Nesbitt, Consultant in Anaesthesia & Critical Care Newcastle upon Tyne, Dr Joe F Cosgrove
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We read with interest the clinical review[1] by Dr Hilton regarding acute renal failure (ARF) in particular her references to the frequency of and outcomes from acute renal failure[2,3]. We note that the Acute Dialysis Quality Initiative (ADQI) group’s RIFLE classification is alluded to[3]; however we feel the text would have benefited from a clear description of this now validated classification of ARF as the myriad of definitions using different criteria complicates understanding and comparison of interventions and management strategies. The ADQI group first published this consensus definition of renal failure in 2004[4]. The use of criteria called RIFLE (Risk, Injury, Failure, Loss, End-Stage) classifies changes in creatinine and/ or glomerular filtration rate and urine output. Since its development it has been validated in more than 20,000 patients seen at a large tertiary centre, including 6,000 readmissions[5]. Hospital mortality increased almost linearly through the Risk-Injury-Failure-End stage continuum. It therefore seems appropriate to use the RIFLE criteria as a standard definition for renal failure allowing for improved comparisons of different patient groups around the world, and better assessment of the management approach and therapies that Hilton describes1. References 1. Acute Renal Failure. Hilton R. BMJ. 2006; 333: 786-90. 2. Feest TG, Round A, Hamad S. Incidence of severe acute renal failure in adults: results of a community based study. BMJ 1993; 306: 481 -3. 3. Abosaif NY, Tolba YA, Heap m, Russell J, El Nahas AM. The outcome of acute renal failure in the intensive care unit according to RIFLE: model application, sensitivity and predictiability. Am J Kidney Dis 2005; 46: 1038-48. 4. Acute renal failure – definition, outcome measures, animal models, fluid therapy and information technology needs: the Second International Consensus Conference of the Acute Dialysis Quality Initiative (ADQI) Group. Bellomo R, Ronco C, Kellum JA et al. Critical Care; 2004; 8: R202 -R212. Available online at http://ccforum.com/content/8/4/R204 5. An Assessment of the RIFLE Criteria for acute renal failure in hospitalized patients. Uchino S, Bellomo R, Goldsmith D, et al. Crit Care Med 2006; 34: 1913-17. Competing interests: None declared |
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T John Trinder, Consultant, Anaesthesia & Intensive Care Medicine The Ulster Hospital, Upper Newtownards Road, Dundonald, Belfast BT16 1RH.
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Editor I urge caution in the apparent suggestion in the review by Hilton (1) that nephrology represents the only source of a specialist opinion for the management of acute renal failure (ARF). Different referral patterns/triage options may be more appropriate in some institutions. In Northern Ireland, the importance of this was recognised in the Department of Health (DHSSPSNI) Review of Renal Services (2). The experience of delayed referral of ARF is not unique to nephrologists. As Dr Hilton points out, ARF commonly presents in hospital patients as one of several organ dysfunctions. The appropriate specialists to look after such patients are those whose training and expertise is in the management of multiple organ dysfunction ie intensivists. Dr Hilton recognises the availability of continuous renal replacement equipment in the ICU setting but apparently not the specialists who manage and prescribe the therapy in this setting, and who treat the underlying condition. Referral of all patients with ARF (rather than those with isolated ARF) to a nephrologist, may result in delayed appropriate therapy. In my institution we enjoy collaboration with our sole nephrology colleague in a fashion analogous to our collaboration with respiratory medicine. The fact that we manage the acute episode does not preclude involvement of other specialists at some point subsequently. There is an onus on us to identify promptly patients who are referred inappropriately to us and whom we should not manage eg those presenting with vasculitic aetiology or glomerulonephritis. Perhaps unintentionally, it appears from the review that Dr Hilton does not recognise the converse situation. This is somewhat surprising in that the definitive study which she quotes (but does not reference) demonstrating the lack of value of dopamine in this situation was carried out by intensivists (3). 1. Hilton R. Acute Renal failure. BMJ 2006;333:786-790. (14 October.) 2. http://www.dhsspsni.gov.uk/renal_chpt7_13.pdf 3. Bellomo R, Chapman M, Finfer S, Hickling K, Myburgh J. Lancet 2000;356(9248):2139-43. Competing interests: None declared |
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