Ebook Acute nephrology for the critical care physician (edition): Part 2
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: Ebook Acute nephrology for the critical care physician (edition): Part 2
Ebook Acute nephrology for the critical care physician (edition): Part 2
Part IIDiagnosis of AKIClassical Biochemical WorkUp of the Patient with Suspected AKI8Lui G. Forni and John Prowle8.1IntroductionThe presentation of a Ebook Acute nephrology for the critical care physician (edition): Part 2acute kidney injury (AKI) is dependent on the cause as the patient is often asymptomatic and the AKI is discovered on subsequent investigation. Whilst AKI is defined by temporal changes in serum creatinine concentration as well as urine output these changes provide no information regarding the under Ebook Acute nephrology for the critical care physician (edition): Part 2lying cause of the AKI and where possible a likely cause should be sought [1.2]. The aim of testing renal function is Io approximate the glomerular tiEbook Acute nephrology for the critical care physician (edition): Part 2
llration rate (GFR) which can be viewed as the best global measure of kidney excretory function reflecting the sum of the filtration rates for all funPart IIDiagnosis of AKIClassical Biochemical WorkUp of the Patient with Suspected AKI8Lui G. Forni and John Prowle8.1IntroductionThe presentation of a Ebook Acute nephrology for the critical care physician (edition): Part 2tion within individuals, while the normal values quoted are in the range of 120 (±25) ml/min/1.73 nr of body surface area. GFR tends to decline from a median value at age 20 of 120 ml/min/l .73 nr by 0.5-1 per year of age over 20. Plasma creatinine is excreted from bloodstream predominantly by glome Ebook Acute nephrology for the critical care physician (edition): Part 2rular ultrafiltration and thus as GFR decreases - creatinine will accumulate. However to understand the meaning of baseline creatinine and its acuteL.Ebook Acute nephrology for the critical care physician (edition): Part 2
G. Forni (Ẽ3)Department of Intensive Care Medicine, Royal Surrey County Hospital NHSFoundation Trust. Surrey Perioperative Anaesthesia Critical Care CPart IIDiagnosis of AKIClassical Biochemical WorkUp of the Patient with Suspected AKI8Lui G. Forni and John Prowle8.1IntroductionThe presentation of a Ebook Acute nephrology for the critical care physician (edition): Part 2al Care Unit. The Royal London Hospital. Barts Health NHS Trust.Whitechapel Road. London El IBB. UKDepartment of Renal Medicine and Transplantation. The Royal London Hospital. BartsHealth NHS Trust. Whitechapel Road. London El IBB. UK© Springer International Publishing 201599H.M. Oudemans-van Straat Ebook Acute nephrology for the critical care physician (edition): Part 2en et al. (eds.). Acute Nephrology for the Criticalni.rsr-o in inm/mừ -J -i in noon 4 Õ100L.G. Forni and J. Prowlealterations requires an understandinEbook Acute nephrology for the critical care physician (edition): Part 2
g of the steady state and dynamic kinetics of creatinine generation and excretion. Similarly urine low output can reflect a wellfunctioning kidney in Part IIDiagnosis of AKIClassical Biochemical WorkUp of the Patient with Suspected AKI8Lui G. Forni and John Prowle8.1IntroductionThe presentation of a Ebook Acute nephrology for the critical care physician (edition): Part 2sensus criteria for the diagnosis of AKI is considered in an accompanying chapter, here we consider the basis for the traditional clinical use of these parameters for assessment of renal function in individuals.8.2Biochemical Work Up8.2.1 Creatinine and the Assessment of Renal FunctionCreatinine is Ebook Acute nephrology for the critical care physician (edition): Part 2a spontaneously formed cyclical derivative of creatine degradation in the tissues. Creatine is synthesised in the liver and to a lesser extent the kidEbook Acute nephrology for the critical care physician (edition): Part 2
ney and enters cells through a membrane transporter system whereby it is utilised to replenish ATP stores via phosphocreatine production [3]. SkeletalPart IIDiagnosis of AKIClassical Biochemical WorkUp of the Patient with Suspected AKI8Lui G. Forni and John Prowle8.1IntroductionThe presentation of a Ebook Acute nephrology for the critical care physician (edition): Part 2t is freely filtered in the glomerulus and appears unaltered in the urine with the addition of a small additional contribution from active tubular secretion. As renal excretion is so efficient, extra-renal creatinine excretion is also negligible in most conditions. The basis of use of creatinine for Ebook Acute nephrology for the critical care physician (edition): Part 2 assessment of renal function thus relies on its rate of excretion being approximately proportional to GFR. Consequently creatinine excretion approximEbook Acute nephrology for the critical care physician (edition): Part 2
ates to GFR (rate of plasma filtered into the urine) multiplied by the concentration of creatinine in the plasma. At steady state (constant plasma crePart IIDiagnosis of AKIClassical Biochemical WorkUp of the Patient with Suspected AKI8Lui G. Forni and John Prowle8.1IntroductionThe presentation of a Ebook Acute nephrology for the critical care physician (edition): Part 2x[Creat]p=G-8.1Where [Creatjp is the plasma concentration of creatinine (in pmol/ml) and G the creatinine generation rate in pmol/min.Thus at steady state a lower GFR will be associated with an higher plasma creatinine following the relationship: GFR a l/[Creat]p- so that, assuming a steady Slate ha Ebook Acute nephrology for the critical care physician (edition): Part 2s been achieved and that G is constant, a halving of GFR will be accompanied by a doubling of plasma creatinine. This relationship forms the basis ofEbook Acute nephrology for the critical care physician (edition): Part 2
the use of fold increase in creatinine from baseline to define severity of AKl in consensus definitions based on the original RIFLE criteria as this wPart IIDiagnosis of AKIClassical Biochemical WorkUp of the Patient with Suspected AKI8Lui G. Forni and John Prowle8.1IntroductionThe presentation of a Ebook Acute nephrology for the critical care physician (edition): Part 2ically ill [4. 5], Firstly, use of plasma creatinine as an indirect measure of the GFR is unreliable outside the steady-state, after an acute change in GFR creatinine will rise or fall until achieving a new steady-state where plasma creatinine reflects the new GFR. this process will take a period of Ebook Acute nephrology for the critical care physician (edition): Part 2 time that is8 Classical Biochemical Work Up of the Patient with Suspected AKI101dependent on both the magnitude of change in GFR and the underlying cEbook Acute nephrology for the critical care physician (edition): Part 2
reatinine generation rate. With large falls in GFR many days may pass before steady-state is achieved and until then creatinine will underestimate sevPart IIDiagnosis of AKIClassical Biochemical WorkUp of the Patient with Suspected AKI8Lui G. Forni and John Prowle8.1IntroductionThe presentation of a Ebook Acute nephrology for the critical care physician (edition): Part 2ion (GFR). I'or example, creatinine production will fall if there is a reduction in lean body mass, if there is a fall in the dietary intake of creatine, or in the presence of liver disease |6J. As these are all common scenario’s in the intensive care unit and the degree of renal dysfunction may be Ebook Acute nephrology for the critical care physician (edition): Part 2underestimated in the critically ill if one is solely guided by the creatinine concentration and. similarly, renal recovery after AKI may be significaEbook Acute nephrology for the critical care physician (edition): Part 2
ntly overestimated [7. 8J. Importantly, sepsis is associated with reduced creatinine production which may account for the seemingly slow rise in creatPart IIDiagnosis of AKIClassical Biochemical WorkUp of the Patient with Suspected AKI8Lui G. Forni and John Prowle8.1IntroductionThe presentation of a Ebook Acute nephrology for the critical care physician (edition): Part 2t that assay is cheap, relatively easy and quick.8.2.2Clearance MeasurementsDespite the limitations of plasma creatinine, acutely, direct measurement of GFR is not normally performed. GFR can be estimated through the calculation of the clearance of a molecule such as creatinine that is freely tiller Ebook Acute nephrology for the critical care physician (edition): Part 2ed from the plasma in the glomerulus and excreted unchanged into the urine (Eq. 8.2)Part IIDiagnosis of AKIClassical Biochemical WorkUp of the Patient with Suspected AKI8Lui G. Forni and John Prowle8.1IntroductionThe presentation of aPart IIDiagnosis of AKIClassical Biochemical WorkUp of the Patient with Suspected AKI8Lui G. Forni and John Prowle8.1IntroductionThe presentation of aGọi ngay
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