another one of this bullshit Flashcards
- Learn the functions of the kidney and physiology of waste excretion
The main function of the kidney is to maintain homeostatic balance with respect to fluids, electrolytes,and organic sol- utes. The normal kidney can perform this function over a wide range of dietary flucruations in sodium, water, and various solutes.This task is accomplished by the continuous filtration of blood and by alterations (secretion and resorp- tion) in this filtered fluid. The kidney receives20o/oof car- diac output, which allows the filtering of approximately 1600L/day of blood. Each kidney consists of approximately 1 million func- tioning units called nephrons (Figure 36-l). The nephron consistsof a glomerulus connected to a series of tubules, which can be broken into functionally different segments: the proximal convoluted tubule, loop of Henle, distal tubule, and collecting duct. Each nephron functions independently in producing a contribution ro rhe final urine, al- though all are under similar control and thus coordinated. Nevertheless,when one segmentof a nephron is destroyed, that complete nephron is no longer functional.
The glomerulus is a spherical mass of capillaries sur- rounded by a membrane, Bowman’scapsule.The function of the glomerulus is production of the large amount of ul- trafilffate, which the following segments of the nephron then modifi’. The ultrafiltrate produced in the glomerulus is very similar in composition to blood. function, the glomerulus blocks blood cells aswell asmol- ecules of molecular weight greater than 6500 daltons such as protein. The production of ultrafiltrate is mainly passive and relies on the perfusion pressure generated by the heart and supplied by the renal artery.
The tubules resorb the vast majority of components that compose the ultrafiltrate. Much of this processis ac- tive andrequiresalargeexpendirureof energyin the form of adenosinetriphosphate (A TP). A unique structure, dif- ferences in permeability between the various segments, and the responseto hormonal control allow the tubule to produce a final urine that can vary widely in concentration of sodium, potassium, and other electrolltes; osmolality; pH; andvolume.
Ultimately the final urine produced is funneled into com- mon collecting tubules and into the renal pelvis. The renal pelvis narrows into a single ureter per kidney, and eachure- ter carries urine into the bladder, where it accumulates be- fore elimination.
- Learn renin-angiotensin system
Renin is an enz)tme that is re- leasedby the kidney and acts as a catalyst in the production of angiotensinII, and one of the actionsof angiotensinII is stimulation of thirst centers. The sensation of thirst is a signal to consume fluids.
- Learn what nephritic syndrome is. Know the rationale for protein recommendations?
a condition resulting from loss of the glomerular barrier to protein; characterized by massive edema,proteinuria, hypoalbuminemia,hypercholesterolemia,hypercoagulability,and abnormal bone metabolism
However, studies have shown that a reduction of protein intake to a slow as 0.8 mgAg/day can decrease proteinuria without adversely affecting serum albumin. T o allow for optimal protein use,5096to 6006of the proteinshouldbe from sources of high biologic value
- Learn the diet therapy for oxalate and uric acid stones and risk of calcium stones.
Uric acid stones
– Restrict dietary purines
– Alkaline ash diet
Calcium: no restriction Oxalate Animal protein Citrate Magnesium Sodium Potassium Vitamins – Vitamin B6 Obesity Fiber and phytate Omega 3 fatty acids Herbal products
- Learn the major foods that are potentially acidic and alkaline
alkaline foods: veggies
acidic: junk food
- What are the nutrient requirements (kcal, protein, sodium, phosphorus, and fluid) for predialysis and dialysis (hemodialysis & CAPD)
Hemodialysis - protein 1.2 per kg energy 35 per kg Phosphorus - less or equal to 17 per kg sodium - 2-3 per day fluid - 750 - 1000 (ml/d)
CAPD protein - 1.2 - 1.5 per kg energy - 30-35 phosphorus - less than 17 sodium 2-4 fluid - 2000
- What are the roles of calcium, phosphorus, Vitamin D and PTH in ESRD and the development of bone disease?
Metabolic bone disease or renal osteodystrophy
– Osteomalacia (bone demineralization)
– Osteitis fibrosa cystica (hyperparathyroidism)
– Metastatic calcification of joints and soft tissues
– Low turnover bone disease restrict dietary phosphate to
<1200 mg/day
Phosphate binders
Calcium supplements
Active vitamin D (calcitriol)
- What are the foods high in phosphorus and potassium?
High potassium High phosphorus Double jeopardy —High potassium and high phosphorus Fruits Vegetables Meat Poultry Fish and seafood Wild game Eggs Dried beans and peas Milk Dairy products Nuts and seeds Chocolate Whole grain products
- Of the following labs: PO4(phosphorus), albumin, Hgb, Hct, cal/phos product, potassium, BUN, TSAT, and ferritin; why would these labs need to be monitored closely? What recommendations would you give when they are high or low? Know the values for albumin, BUN, Calcium, Ca/PO4 product, Ferritin, phosphorus, potassium, and % TSAT for renal patients.
A decreased serum albumin level is predictive of poor survival in ESRD
low hgb means no erthropoetein which means kidney failure
phosphorus/cal - stones, complications
BUN
TSAT:
potassium:High: Ascerain that no other causes.suchas gastrointestinalbleeding, trauma. or medicationsare creating high potassium values.Tell patient to avoid foodswith over250mg/ servingandlimit dailyintake to 2000 mg. Consider lowering poassium in dialysatebath. Recheckblood level next treafinent.
Low: Add one high-potassium food/day,and recheckblood level (give potassium brochure). Consider raising potassiumin dialysatebath if diet changesare not working.
ferritin Low: Iron in food is not well absorbed.Most patientsneed an oral and/or Wiron supplement.Patients should not takeiron at same time as phosphate binders
- What is the recommended lab value for albumin and why is albumin so important to monitor
3.5-5g/dl (bromcresol green)
3-4.5g/dl (bromcresol purple
Serum albumin is a poor indicator of protein status;acute or chronic inflammation limits its specificity in renal failure. A decreasedserum albumin level is predictive of poor sur- vival in ESRD; howeveq the causeof hypoalbuminemia is multifactorial and related to poor nutrition, inflammation, and comorbid disease
- When is a phosphorus binder recommended?
esrd -dialysis
High: Limit milk and milk productsto I servingper day. Remind patient to take phosphate binders as ordered with meals and snack. Noncompliance with binders is the most common cause of high phosphorus.
- Why caloric and protein needs are different for CAPD, compare with hemodialysis?
Patiens who choose PD have higher protein needs (about 1.2 to 1.5 g of protein per kilogram) becauseof greater pro- tein losses.Most people on PD do not have to limit potas-
sium in their diet. Manyneed to add high-potassium foods to keep blood levels from getting too low; a typical intake is 3 to 4 g/dty. Advantages of this form of treaffnent are avoid- ance of large fluctuations in blood chemistry, longer residualPatiens choosing PD have more liberal fluid, sodium, and potassium allowances becausethe therapy is continuous and more of these producs are removed. The loss of so- dium can be as much rc 6 g/day; thus these patients may need higher sodium intakes
- What is the difference between acute and chronic renal failure?
ARF is characterized by a sudden reduction in glomerular filtration rate(GFR),or the amount of filtrate per unit in the nephrons,and an alteration in the ability of the kidney to excrete the daily production of metabolic waste
Chronic renal failure (CRF) is the progressive loss of kidney function. The kidneys attempt to compensate for renal damage by hyperfiltration (excessive straining of the blood) within the remaining functional nephrons (filtering units that consist of a glomerulus and corresponding tubule). Over time, hyperfiltration causes further loss of function
- What is the maximum recommendation % of fluid gain between dialysis treatments?
4 or 5
- Learn strategies in how to curb thirst for dialysis patients.
Sucking on a few ice chips, cold sliced fruit, or sour can- dies; using artificial saliva; or chewing “sports gum” tJrat contains citric acid may help to alleviate the dryness.
