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84 Cards in this Set
- Front
- Back
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What happens in Uremia?
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Bun increases
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why is cardiovascular events significant in Uremia?
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Because pts w/ ESRD have really high rates of death due to cardiovascular events.
more than 50% will die. |
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What Clinical Manifestations happen in Cardiovascular **
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Volume overload, LVH, HTN
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What are Indications For Dialysis?
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Acid-base imbalance: Metabolic acidosis resulting from the accumulation of organic and inorganic acids
Electrolyte imbalance:Hyperkalemia, Hyperphosphotemia Intoxications:Salicylates, lithium, methanol, ethylene glycol, theophylline, phenobarb Overload-fluid:Postoperative fluid gain Uremia:High catabolism of acute renal failure |
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What electrolyte is the most concerning in dialysis?
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K is most concerning (if increased, patients get EKG changes, ventricular fibrillation
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When is dialysis initiated?
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CrCl < 9-14ml/min
Anuria or oliguria |
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What are Subjective symptoms of dialysis?
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Persistent anorexia, nausea, vomiting
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When will diabetic pts intiate dialysis?
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@ 15ml/min
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What are Three basic components: of dialysis?
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Blood-filled compartment
Dialysate-filled compartment Semi-permeable membrane |
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What are two main processes of dialysis?
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Diffusion
Ultrafiltration |
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What is diffusion?
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Movement of solute down a concentration gradient
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What is the diffusion rate dependent on? (4)
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Difference between blood and dialysate
Solute characteristics: the smaller the solute the easier it will cross the semi permeable membrane Dialyzer membrane composition: how big are the pores? Blood and dialysate flow rates: the faster the rates the better diffusion will be |
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What is Convection / ultrafiltration ?
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Movement of water across dialyzer membrane as a result of hydrostatic or osmotic pressure
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What is convection?
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Dissolved solutes are “dragged” across membrane with fluid transport
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What are the three types of dialysis?
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Intermittent Hemodialysis (IHD)
Peritoneal Dialysis (PD) Continuous Renal Replacement Therapy (CRRT) |
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Intermittent Hemodialysis (IHD)
How long is each session? How often is it done? What do the solutes in the blood come in direct contact with? What does it require? |
Efficient form of dialysis
3-5 hour session 3 times per week Solutes in blood come in direct contact with dialyzing membrane (filter) Requires anticoagulation |
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What are the 3 different membranes of dialyzers?
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Conventional/standard:
Small pore size (<500 daltons) limited solute removal eg. Urea, Scr High efficiency Increased surface area increased ability to remove water, urea, Scr and other small molecules High flux Increased pore size increased removal of large molecules (< 40,000 daltons) |
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What are standard dialysates for IHD?
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Dextrose: 100mg.dl
Potassium: 2 meq/L Sodium: 140meq/l Chloride: 116 meq/l Magnesium Sulfate: 1.5meq/l Calcium Gluconate: 2.5 meq/l Sodium Bicarbonate: ~20-30meq/l |
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What does the rate of ultra filtration depend on?
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The rate of ultrafiltration depends upon the porosity of the membrane and the hydrostatic pressure of the blood, which depends upon blood flow. This is very effective in removal of fluid and middle-sized molecules, which are thought to cause uremia
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Who can venous catheters be used in? what is it good for?
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Small children
Diabetics with severe vascular disease Morbidly obese No AV access sites Good for acute dialysis so can be done immediately |
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Goals of Hemodialysis?
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1.Achieve desired/optimal dry weight
Dry weight: target post-dialysis weight at which patient is normotensive and non-edematous 2.Achieve adequate removal of endogenous waste products |
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When pts are first initated on IHD, what happens?
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Very short session ares done first. 1-2 hours at most and are done daily to allow the body to adjust correctly
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What are the 2 methods of Dialysis Adequacy?
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1.Urea reduction ratio (URR) > 65%
2.Kt/V >1.2 k = dialyzer clearance of urea t = duration of dialysis (hrs) V = urea distribution volume of patient (L) |
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What are 3 Causes of Inadequate Dialysis?
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Patient non-adherence
Access stenosis or thrombosis Use of catheters |
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What happens to patients that have high sodium food?
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Even though on dialysis, it still can"t remove a lot of the phosphorus, so a lot of patients will be given phosphorus binders--> tums, phoslo or none Ca binders like sevelmar or renagel. These must be taken with meals.
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What are 3 common complications of IHD?
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1.Hypotension (20-30%)
Nausea & cramping (with acute decrease in BP) especially in elderly and DM patients 2.Muscle cramps (10-20%)-->occur due to low muscle perfusion 3.Pruritis (5%) |
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What are Non-Rx measures for hypotension?
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Trendelenburg position
Decreased UF rate NS bolus 100-200ml Evaluate BP meds |
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What are pharmacologic therapies for hypotension?
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½ hr before dialysis:
Midodrine 2.5 – 10mg Fludrocortisone 0.1mg Albumin 50 to 100 ml infusion |
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What are Non-Rx measures for muscle cramps?
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NS bolus 100- 200ml
Reset dry weight Stretches |
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What are pharmacologic therapies for
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Vitamin E 400 IU qhs
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what are vascular access complications of IHD?
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Catheters > grafts > fistulas
Thrombosis Infection: Mostly due to S. Aureus (often MRSA) Risk factors: Type of access, DM, immunosuppression, h/o bacteremia, S. aureus nasal carriage. |
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What are non RX measures in IHD of access thrombosis?
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Forced NaCl flush
Medical thrombectomy Change catheter |
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What are pharmacologic measures in IHD of access thrombosis?
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Alteplase 2mg/2ml
Retaplase 0.5mg/2ml |
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What are non RX measures in IHD of infxn?
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Obtain blood culture
Change catheter + Culture catheter tip |
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What are pharmacologic measures in IHD of infxn?
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Antibiotics
Gram+ coverage +/- Gram - coverage |
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What are two kinds of PD?
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Continuous Ambulatory PD (CAPD)
4-5 exchanges per day Automated PD (APD) Performed by machine called cycler while patient sleeping |
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What are advantages of PD?
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It can be done at home, there are no traveling restrictions with it either.
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How often is PD performed?
What does it rely on? What dont solutes come in contact with? What do solutes meet more of? Can blood be regulated? What flow doesnt it have? |
Must be performed daily
Relies entirely on passive diffusion Solutes not in direct contact with dialyzing membrane Solutes meet more barriers Blood flow cannot be regulated No countercurrent dialysate flow |
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explain the Peritoneal Dialysis Process?
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1-3L dialysate solution is instilled into peritoneal cavity & left for prescribed time (“dwell time”)
Dialysate fluid is drained out and new bag is instilled (~30 min) Frequency: 2-3L exchanges 4 to 5 times/day Less efficient than IHD as there is no way to regulate dialysate flow or blood flow PD catheter is placed in permanently |
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What are standard dialysates in PD?
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Dextrose: 100md/dl
Potassium: 2meq/L Sodium: 140 meq/l Chloride: 116 meq/L Magnesium Sulfate: 1.5 meq/l Calcium Gluconate: 2.5 meq/l Sodium Bicarbonate |
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PD and HD dialysate only differ how?
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on dextrose content.
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What is an alternative to dextrose? why is it used?
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Icodextrin…as dextrose can be toxic to peritoneal cavityicodextran is not.
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How can Dialysate drugs be delivered?
By doing this, what don't these drugs have to pass through? |
delivered IP. ..Drugs that are delivered IP do not have systemic absorbtion, but can adhere to polyvinil bags therefore must consider adherence of drug.
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how are PD Dialysate Solutions available ?
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Commercially available in 1-3L polyvinyl chloride bags
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PD Dialysate Solutions Contain varying concentrations of what?
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Electrolytes: Na, CL, Ca, Mg, lactate
Dextrose: 1.5%, 2.5%, 3.85%, 4.25% or Icodextrin: 7.5% Additives: insulin, heparin, antibiotics |
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How is PD adequacy assesed?
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1.Kt/V x 7 days > 1.7
2.Contribution of residual renal function CrCl 9-12 ml/min ~Kt/V 0.2-0.4 Important to preserve residual fxn Use ACEI/ARBs Avoid drugs/procedures associated with kidney insult--> AG, NSAIDS |
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Do PD patients have residual renal function?
Do they have to restrict fluid? What is the monitoring of Kt/V? |
PD patient usually have some residual renal function, not as fluid restricted, Kt/v should be monitored over first month, than every 4 months after for possible decrease in residual kidney function.
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What are mechanical complications of PD?
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Mechanical:
Catheter obstruction Excessive catheter motion infection, tissue aggravation Catheter tip impinging on viscera pain |
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What are medical complications of PD?
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1.Diabetes
Increased insulin requirements 2.Fluid overload Edema, CHF, or pulmonary exacerbations and HF 3.Electrolyte abnormalities 4.Malnutrition Albumin and amino acid loss in PD fluid 5.Infection Exit site, tunnel infections or peritonitis |
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Management of PD Complications
Glucose load leads to what complication? What is pharmacologic therapy? |
Exacerbation of diabetes
IP insulin |
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Management of PD Complications
Fluid overload leads to what complication? What is pharmacologic therapy? |
Exacerbation of CHF
Edema Pulmonary congestion Increase Ultrafiltration Diuretics if patient has residual renal fxn (urine output > 100ml/day) |
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Management of PD Complications
Electrolyte abnormalities leads to what complication? What is pharmacologic therapy? |
Hypo and hyper
-calcemia -kalemia Alter dialysate Ca and K content |
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Management of PD Complications
Malnutrition leads to what complication? What is pharmacologic therapy? |
Albumin loss, loss of amino acids, muscle wasting and increase in adipose tissue
Dietary change, TPN, d/c PD |
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What is number 1 reason for PD failure
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Peritonitis
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What are signs and symptoms of peritonitis?
How is it diagnosed? |
1. Cloudy dialysate effluent* (95%)
Lab tests: dialysate WBC > 100/mm3 2.Abdominal pain* or Rebound tenderness* (75-80%) 3. Fever >38 C* or NV--> 25-30% 4. Chills * Diagnosis includes two of these |
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Diagnosis of Peritonitis consists of what bugs?
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Gram positives
Enterococcus S. aureus or S. Epi Gram negatives E. coli, Pseudomonas or Klebsiella Gram negatives usually found around bowel area, may find way to catheter due to lack of hand washing. |
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What is Empiric Antibiotic Dosing of PD based on?
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1. GFR < 15ml/minute
2.Based on residual urine output < 100 ml per day Cefazolin 1 gm per bag daily Ceftazidime 1 gm per bag daily > 100 ml per day Cefazolin 20mg/kg per bag daily Ceftazidime 20mg/kg per bag daily |
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Empiric Antibiotic for PD last how long?
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Treatment duration: IP antibiotics x 14-21 days
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What are Peritonitis Treatment Guidelines? (6)
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Prompt initiation of empiric therapy
IP administration of antibiotics Adjust treatment based on C & S Re-evaluate on day 4 Consider catheter removal in patients with consistent positive cultures If infection is systemic drugs are given IV or PO |
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What are Infectious Complications?
What are sx? What organism is it usually? |
Catheter-related (exits site infection)
Sx: purulent drainage, with or without erythema at catheter exit site Organism: usually S. aureus Risk increased in patients who are nasal carrier of S. aureus |
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What is a major risk factor for infections?
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Nasal carriage of S. aureus is major risk factor
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Nasal carriage of S. aureus is major risk factor
What are Tx of infections? |
ntranasal mupirocin BID x 5 days (every month)
Topical mupirocin daily to exit site Rifampin 300mg po BID x 5 days (every 3 months) Rifampin is not a favored method as the resistance occurs quite quickly. |
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What are additional risk factors of infections?
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Additional risk factors: elderly, diabetics and immunocompromised patients
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PD is favored in the following patients?
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1.Infants, very young children
2.Severe cardiac disease 3.Hemodynamic stability 4.Difficult vascular access 5.Significant residual renal function 6.Desire for greater freedom, autonomy and ability to travel |
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When can is PD contraindicated in pts?
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Unsuitable peritoneum ( adhesions, fibrosis, malignancy)
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Most common reasons for PD failure?
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Peritonitis
Patient burnout |
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What is CRRT?
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is a means of dialyzing critically ill patients without compromising hemodynamic stability
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In CRRT, how are large volumes of fluids infused?
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infused through the hemodialyzer and must be replaced in the form of buffered, electrolyte solutions supplied by the pharmacy
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CRRT
What process is it similar to? How does it run? What is the dosing estimated on? |
Same basic process as IHD with respect to hemofiltration, access and anticoagulation
Runs continuously with rate changes Pharmacy supplies high volumes of dialysate and replacement fluid Drug dosing for estimated ClCr ~ 30ml/min |
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What are advantages of IHD?
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Higher efficiency
-Closer patient monitoring -Low failure rate |
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What are disadvantages of IHD?
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Travel to dialysis clinic
-Cramps, hypotension -Rapid decline in renal function |
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What are advantages of PD?
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Freedom to move around
-Hemodynamic stability - Preserved renal function |
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What are disadvantages of PD?
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Peritonitis
-High failure rate -Catheter malfunction |
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What are advantages of CRRT?
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Highest efficiency
-Hemodynamic stability -Mimics natural physilogy |
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What are disadvantages of CRRT?
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Frequent clotting of filter
-Highly labor intensive -Expensive |
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What are 3 Membrane and Dialysis characteristics in IHD, PD and CRRT?
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1.Rate of blood and dialysate flow
2.Porosity of the hemodialyzer Large or small size pores Number of pores 3.Composition of the hemodialyzer Increased binding of drug molecules or endogenous substances |
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What are drug characteristics in IHD, PD and CRRT?
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Molecular weight Larger molecules less likely to be cleared (> 40 kDa)
Water solubility Lipophilic molecules more likely to bind to the hemodialyzer Protein binding protein bound substances less likely to be cleared Volume of Distribution drugs with higher Vd less likely to be cleared efficiently |
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How is PD and IHD dosed?
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PD and IHD – Dose for clearance < 15 ml/minute
Adjust dose of all renally cleared drugs and administer dose after dialysis (IHD) |
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CRRT is dosed how??
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Dose for clearance 30 ml/minute
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What are 5 drugs and there dosing in HD?
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Acyclovir 5mg/kg q24h after HD
Levofloxacin 250mg q48h after HD Cefazolin 1 gm q 48 after HD Ciprofloxacin 400mg q 24 after HD Metronidazole 500 mg q8h |
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What are 5 drugs and there dosing in CRRT?
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Acyclovir 10mg/kg q24h
Levofloxacin 250mg q24h Cefazolin 2gm q24h Ciprofloxacin 400mg q12h Metronidazole 500 mg q8h |
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What is the dose and
What do you monitor in Gentamicin? |
Gentamicin 1-2 mg/kg based on levels
Peaks and troughs |
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What is the dose and what do you monitor in vanco?
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Vancomycin 20mg/kg based on levels
Troughs only |
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In Monitoring Serum Drug Levels, when do you obtain peaks? How often are troughs taken?
When do you hold and give doses? |
Peaks: Obtain 1 hour after infusion stopped
Troughs: IHD (after IHD), CRRT – daily, PD ~48 hours after loading dose Hold dose until trough desirable Give dose if trough desirable |
