Renal System Flashcards
Exam 3
Renal system overview
Kidneys receive what percent of cardiac output?
Kidneys receive 21% of cardiac output
Renal system overview
Kidneys process how much blood per minute?
The kidneys process 1.2 L of blood per minute
Renal system overview
The entire blood volume is filtered through what? How many times a day?
The entire blood volume is filtered through the kidneys 340 times a day
Renal Anatomy
Kidneys are made up of what?
Nephron
Renal Anatomy
Nephrons are composed of?
Glomerulus
Bowman’s capsule
Tubular system
Renal Anatomy
Glomerular Filtration Rate (GRF): What is it?
Rate at which filtrate is formed
Renal Anatomy
Glomerular Filtration Rate (GRF): What does it do?
Autoregulation”
Renal Anatomy
Glomerular Filtration Rate (GRF): What do afferent arterioles do?
Afferent arterioles adjust diameter in response to the pressure of blood coming to them.
Renal Anatomy
Glomerular Filtration Rate (GRF):
Afferent arterioles adjust diameter in response to the pressure of blood coming to them.
During hypotension:
the smooth muscles of the afferent arterioles relax, vasodilation occurs, and perfusion increases, thereby maintaining the GFR at its normal rate.
Renal Anatomy
Glomerular Filtration Rate (GRF):
Afferent arterioles adjust diameter in response to the pressure of blood coming to them.
During hypertension:
vasoconstrict to decrease perfusion
Renal Anatomy
Glomerular Filtration Rate (GRF):
In healthy persons, autoregulation maintains homeostasis quite nicely when mean blood pressure falls approximately within a range of what?
In healthy persons, autoregulation maintains homeostasis quite nicely when mean blood pressure falls approximately within a range of 80 to 180 mm Hg
Renal Anatomy
Proximal tubules: What do they do?
80% filtrate returned to bloodstream by reabsorption in the proximal tubule
Renal Anatomy
Proximal tubules: What do they reabsorb?
All the glucose and amino acids
Much of sodium, chloride, hydrogen, and other electrolytes
Renal Anatomy
Proximal tubules: What do they secrete?
The proximal tubule cells also secrete substances (e.g., some drugs, organic acids, and organic bases) into the filtrate.
Hormonal Influence includes
ADH
Renin
Aldosterone
Hormonal Influence:
ADH: Where are osmoreceptors? What are they sensitive to?
Osmoreceptors in hypothalamus sensitive to serum osmolality
Hormonal Influence:
ADH: What would stimulate release of ADH?What does this lead to?
During dehydration, when serum osmolality rises, osmoreceptors in the hypothalamus respond by stimulating the hypothalamus to secrete ADH which increases the permeability of collecting tubule cells to water.
Hormonal Influence:
ADH: During dehydration, when serum osmolality rises, osmoreceptors in the hypothalamus respond by stimulating the hypothalamus to secrete ADH
which increases the permeability of collecting tubule cells to water.
Hormonal Influence
ADH: What does it do?
This permits the reabsorption of water alone (without electrolytes), which in turn decreases the concentration of the ECF.
Hormonal Influence
Renin: What is it secreted by?
Secreted by juxtaglomerular cells
Hormonal Influence
Renin: How does it effect GFR?
Angiotensin II constricts the smooth muscle surrounding the arterioles. This increases blood pressure, which increases the GFR.
Hormonal Influence
Aldosterone: What triggers the release of this? What is it released from?
Triggered by angiotensin II
Adrenal cortex
Hormonal Influence
Aldosterone: What does it do? How?
By increasing sodium reabsorption in distal tubule cells, aldosterone causes an increase in renal water reabsorption.
Hormonal Influence
Aldosterone: By increasing sodium reabsorption in distal tubule cells, aldosterone causes an increase in renal water reabsorption. What does this lead to?
This increases blood pressure and decreases serum osmolality.
Functions of the Renal System include
Renal clearance
Regulation
Fluid balance
Secretion of hormones
Functions of the Renal System:
Renal clearance: What is cleared? How much?
Clearance of metabolic end products
About 60 mL of plasma “cleared” of urea/minute
Functions of the Renal System
Regulation:
Electrolyte concentrations and pH of the extracellular fliud
Functions of the Renal System
Secretion of hormones: Like what?
Calcitrol and erythropoietin
Slide 9/10
Assessing for Excessive Volume include:
Hypertension, pulmonary edema, crackles
Elevated neck veins, liver congestion and enlargement
Heart failure and shortness of breath
Pitting edema of the feet, ankles, hands, and fingers
Periorbital edema, sacral edema, ascites
Assessment of Urine
What are you assessing for?
Assess for color, clarity, and odor
Assessment of Urine
What is normal?
Normal: clear and yellow to straw-colored (pale yellow);
smells of ammonia
Assessment of Urine
What is abnormal? What may indicate infection?
Being cloudy may indicate infection.
Blood in urine (hematuria) may appear bright red or dark brown
Assessment of Urine
Urine Volume:
What causes acute anuria?
Complete bilateral obstruction
Glomerulonephritis
Bilateral vascular occlusion
Laboratory Studies: Urinalysis
What is included?
Urine pH
Urine protein
Urine glucose
Urine ketones
Urinary sediment
Laboratory Studies: Urinalysis
Urine pH: What is the normal range?
Normal range between 5.0 and 6.5
Laboratory Studies: Urinalysis
Urine pH: pH greater than 7.5 (alkaline urine) suggests what?
pH greater than 7.5 (alkaline urine) suggests urinary tract infection.
Laboratory Studies: Urinalysis
Urine pH: pH less than 5.0 may indicate
pH less than 5.0 may indicate kidney compensating serum acidosis.
Laboratory Studies: Urinalysis
Urine protein: normal?
Normal: 0 to trace
Laboratory Studies: Urinalysis
Urine protein: Proteinuria usually indicates?
Proteinuria usually indicates damage to kidneys.
Laboratory Studies: Urinalysis
Urine glucose: What is normal?
Normal: negative
Laboratory Studies: Urinalysis
Urine glucose: glucosuria?
Glycosuria if serum glucose greater than 200 mg/dL
Laboratory Studies: Urinalysis
Urine ketones: normal?
Normal: negative
Laboratory Studies: Urinalysis
Urine ketones: abnormal?
Ketonuria indicates DKA.
Laboratory Studies: Urinalysis
Urinary sediment: refers to what?
Refers to casts, red cells, white cells, epithelial cells, and crystals
Laboratory Studies: Urinalysis
Urinary sediment: Red blood cells
Red blood cells (hematuria)
Laboratory Studies: Urinalysis
Urinary sediment: Red blood cells
What are examples of external sources?
External source (kidney stones, trauma, prostatic disease)
Laboratory Studies: Urinalysis
Urinary sediment: Red blood cells
What can cause rbcs in urine?
Glomerular diseases
Laboratory Studies: Urinalysis
Urinary sediment: Myoglobin
How can it make the urine appear?
Myoglobin in the urine makes the urine appear red; however, when the urine is inspected under the microscope, there is no evidence of RBCs
Laboratory Studies: Urinalysis
Urinary sediment: White blood cells (pyuria)
What does it indicate?
Pyuria usually indicate infection.
Laboratory Studies: Urinalysis
Urinary sediment: Myoglobin
What is it caused by?
Caused by skeletal muscle breakdown
Diagnostic assessment
Labs include:
Urinalysis
pH
Specific Gravity
BUN/Creatine
Diagnostic assessment
Labs include: Abnormal things
Protein
Glucose
Sediment
RBC/WBC
Diagnostic assessment
Labs include: BUN/Creatine
Creatinine amount of blood cleared of creatinine in 1 minute
Diagnostic assessment
Labs include: BUN/Creatine
What is the normal amount?
normal- 0.6-1.2 mg/dL
Diagnostic assessment
Labs include: BUN/Creatine
When would BUN be high?
BUN higher if dehydrated, too much protein intake, or from protein breakdown (i.e crush injuries)
Diagnostic assessment
Labs include: BUN/Creatine
What is normal BUN values?
Normal 8-20 mg/dL
Increased BUN may have other causes
Such as?
Increased protein intake
Increased tissue breakdown
Febrile illnesses
Steroid or tetracycline administration
Reabsorption of blood from the intestine
Dehydration
Shock, heart failure
Increased BUN may have other causes
When are patients symptomatic?
Patients are symptomatic when osmolality is greater than 350 mOsm/kg
Diagnostic Studies
Include?
Radiologic studies
Renal biopsy
Renal angiography
Diagnostic Studies
Renal biopsy: What are contraindications to this?
Contraindications include serious bleeding disorders, severe obesity, and severe hypertension.
Diagnostic Studies
Renal angiography:
Assess renal vasculature with ultrasonography
Dialysis:
All forms of dialysis use the principle of what? To do what?
All forms of dialysis make use of the principles of osmosis and diffusion to remove waste products and excess fluid from the blood.
Dialysis:
What is present in the dialysis circuit?
Semipermeable membrane is in the dialysis circuit between the blood and the dialysate.
Dialysis:
How do dissolved substances move?
Dissolved substances, such as urea and creatinine, diffuse across the membrane from an area of greater concentration (blood) to an area of lesser concentration (dialysate).
Dialysis:
Diasylate: has what?
Dialysate has varying concentrations of dextrose or sodium to produce an osmotic gradient, pulling excess water from the circulatory system.
Access to Circulation:
What are the three most common methods used to access a patient’s circulation?
The three most common methods used to access a patient’s circulation are:
- vascular catheter,
- arteriovenous fistula, and
- synthetic arteriovenous graft.
Access to Circulation:
Venous catheters: How are they? How long are they used?
(larger than other central lines. used for under 3 weeks of dialysis to prevent infection)
Dual-lumen
Access to Circulation:
Venous catheters: Who are they used for?
For acutely ill who need hemodialysis, CVVH: continuous venovenous hemofiltration or
CVVHD: continuous venovenous hemodialysis
Patients who suddenly need hemodialysis or CRRT have a venous catheter,
**Dual-lumen catheters inserted into large central veins are used for patients with acute illness who need hemodialysis, continuous venovenous hemofiltration (CVVH), or continuous venovenous hemofiltration with dialysis (CVVH/D).
Access to Circulation:
Venous catheters: Why else are they used?
Also for temporary use
Dual-lumen venous catheters are also used temporarily for patients on acute dialysis who are critically ill or patients on chronic dialysis who are waiting for a more permanent access (e.g., an arteriovenous fistula or graft) to mature.
Access to Circulation:
Arteriovenous fistulas: How is it made?
To create the arteriovenous fistula, a surgeon anastomoses an artery and a vein, creating a fistula or artificial opening between them. Arterial blood flowing into the venous system results in a marked dilation of the vein
Access to Circulation:
Arteriovenous fistulas: What is the priority of care?
Maintaining blood flow through the fistula is the priority of care.
Access to Circulation:
Arteriovenous fistulas: Most AV fistulas are developed and ready to use when? When should they be placed?
Most arteriovenous fistulas are developed and ready to use 1 to 3 months after surgery and should be placed at least 6 months prior to the anticipated start of hemodialysis.
Access to Circulation:
Synthetic grafts: What is it?
The graft is anastomosed between an artery and a vein and is used in the same manner as an arteriovenous fistula
Access to Circulation:
Synthetic grafts: Why would this be used?
For many patients whose own vessels are not adequate for fistula formation, PTFE grafts are extremely valuable.
In dialysis, why is anticoagulation used?
Blood in the extracorporeal system, such as the dialyzer and blood lines, clots rapidly.
Anticoagulation:
What is the most commonly used one? Why?
Heparin is most commonly used because it is simple to administer, it increases clotting time rapidly, it is monitored easily, and its effect may be reversed with protamine.
Anticoagulation
Specific anticoagulation procedures vary, but the primary goal of all methods is what?
Specific anticoagulation procedures vary, but the primary goal of all methods is to prevent clotting in the dialyzer with the least amount of anticoagulation.
Anticoagulation
What are the two ways it is done?
Systemic anticoagulation
Regional anticoagulation
Anticoagulation
What are the two ways it is done?
Systemic anticoagulation
Regional anticoagulation
Anticoagulation
Systemic anticoagulation
Circuit is primed with heparin (most common) followed by continuous rate by infusion pump.
Anticoagulation
Regional anticoagulation
Infusing the anticoagulant at a constant rate into the dialyzer and simultaneously neutralizing its effects with its antidote before the blood returns to the patient (heparin/protamine sulfate or trisodium citrate/calcium)
Renal Replacement Therapy
What is it considered?
Lifesaving treatment
Renal Replacement Therapy
How is it classified? (What are the different types)
Hemodialysis:
Continuous renal replacement therapy (CRRT)
Peritoneal dialysis
Renal Replacement Therapy
Classification: HD
What occurs?
Diffusion & Ultrafiltration
Renal Replacement Therapy
What are indications?
Fluid overload
Electrolyte imbalances
Acid-base disturbances
May administer transfusions during dialysis
Renal Replacement Therapy
What are indications for hemodialysis?
Hemodialysis is indicated in chronic kidney injury and for complications of acute kidney injury.
These include but are not limited to
uremia,
fluid overload,
acidosis,
hyperkalemia,
and drug overdose.
Ultrafiltration?
This process of fluid moving across a semipermeable membrane in relation to forces created by osmotic and hydrostatic pressures is called ultrafiltration.
Hemodialysis
What is it?
Quick removal of metabolic wastes and excess fluid
Hemodialysis
What is it useful for?
Useful for drug overdoses and poisonings
Hemodialysis
What does it require?
Requires frequent vascular access
Hemodialysis
What is the length of treatment? What does it depend on?
Length of treatment: 2–4h, three or more times per week,
depending on patient acuity and need
Hemodialysis Complications:
Dialysis dysequilibrium
Hypovolemia
Hypotension
Hypertension
Muscle cramps
Dysrhythmias and angina
Hemodialysis Complications:
What must be done to prevent dialysis disequilibrium? What is dialysis disequilibrium?
Uremia must be corrected slowly to prevent dialysis disequilibrium syndrome, which is a set of signs and symptoms ranging from headache, nausea, restlessness, and mild mental impairment to vomiting, confusion, agitation, and seizures.
Hemodialysis Complications:
When is dialysis disequilibrium first seen?
This complication is seen most commonly when patients begin dialysis treatment for the first time.
Hemodialysis Complications:
Why does dialysis disequilibrium occur?
The process is thought to occur as the plasma concentration of solutes, such as urea nitrogen, is lowered too rapidly.
Continuous Renal Replacement Therapy (CRRT)
What are the types?
Continuous venovenous hemofiltration (CVVH)
CVVH with dialysis (CVVH/D)
Continuous Renal Replacement Therapy (CRRT)
What are indications?
Hemodynamic instability
Large amounts of hourly fluids needed
Need more than 3- to 4-hour treatment to correct acute renal failure
Continuous Renal Replacement Therapy (CRRT)
What does it include?
Dual-lumen venous catheter
Continuous Renal Replacement Therapy (CRRT)
How long is it?
Continuous throughout day; may last as many days as needed
Continuous Renal Replacement Therapy (CRRT)
Continuous venovenous hemofiltration (CVVH): CVVH is used when patients primarily…
CVVH is used when patients primarily need excess fluid removed
Continuous Renal Replacement Therapy (CRRT)
CVVH with dialysis (CVVH/D) : CVVH is used when patients primarily need excess fluid removed, whereas CVVH/D is used when…
CVVH is used when patients primarily need excess fluid removed, whereas CVVH/D is used when patients also need waste products removed because of uremia.
Continuous Renal Replacement Therapy (CRRT):
When is it contraindicated? What should be used instead?
CRRT is contraindicated when patients become hemodynamically stable or no longer require continuous therapy; intermittent hemodialysis should be used for these patients.
Physiologic Complications in CVVH/D include:
Hypotension
Hypothermia
Physiologic Complications in CVVH/D include:
Hypotension: What should be done to fix?
May need to increase rate of replacement fluids
May need to decrease amount of removal, give NS bolus, vasopressors, 5% albumin
Physiologic Complications in CVVH/D include:
Hypothermia: What should be done to fix?
Use a blood warmer, warm lines and fluid
Peritoneal Dialysis
However, in peritoneal dialysis, the peritoneum is the semipermeable membrane, and osmosis, rather than the pressure differentials used in hemodialysis, is used to remove fluid.
Peritoneal Dialysis advantages and disadvantages
Advantages:
Less complicated
More readily available
Less training required
Less adverse effects
Patients can manage themselves at home
Peritoneal Dialysis advantages and disadvantages
Disadvantages:
More time is required.
Peritonitis is a potential complications.
Long periods of immobility may result in complications, such as pulmonary congestion and venous stasis.
Peritoneal Dialysis (cont’d)
Complications include:
Incomplete fluid recovery
Leakage around catheter
Blood tinged peritoneal fluid
Peritonitis
Hypotension
Hypertension and fluid overload
Electrolyte imbalance
Pain, immobility, discomfort
Peritoneal Dialysis (cont’d)
Management:
Strict aseptic technique monitor I & o,
weight, vs,
monitor for peritonitis,
prevent complications
Acute Kidney Injury (AKI)
How many people does it occur in?
AKI occurs in up to 10% to 15% of patients who are hospitalized, with a prevalence that can exceed 50% for patients treated in intensive care units (ICUs).
Acute Kidney Injury (AKI)
Patients with AKI are at risk for what?
Patients with AKI at a high risk of CKD
Acute Kidney Injury (AKI)
Hallmarks include:
Azotemia
Serum creatinine
Acute Kidney Injury (AKI)
Hallmarks include: Azotemia
Azotemia: decreased GFR and accumulation of BUN and creatinine
Acute Kidney Injury (AKI)
Hallmarks include: Why is serum creatinine a better marker?
Serum creatinine better marker because relatively unaffected by metabolic factors
Acute Kidney Injury (AKI)
What is used to define AKI/ARF?
Rifle classification
Acute Kidney Injury (AKI)
Rifle classification
Risk-creatinine
Injury-creatinine
Failure-creatinine
L- loss
E- end-stage kidney disease
Acute Kidney Injury (AKI)
Rifle classification: Risk-creatinine
Risk-creatinine increase of 1.5-2 times baseline
Acute Kidney Injury (AKI)
Rifle classification: Injury-creatinine
Injury-creatinine increase of 2-3 times baseline
Acute Kidney Injury (AKI)
Rifle classification: Failure-creatinine
Failure-creatinine increase of 3 or more times baseline
Acute Kidney Injury (AKI)
Rifle classification: L- loss.
L- loss. Persistent ARF for >4 wk
Acute Kidney Injury (AKI)
Rifle classification: E- end-stage kidney disease
E- end-stage kidney disease Persistent ARF for >3 mo
Acute Kidney Injury (AKI)
A rise of what means AKI?
Any rise of greater that 0.3 mg/dL in 48 hours = AKI
Urine Output Patterns
Oliguria
Nonoliguria
Anuria
Urine Output Patterns
Oliguria:
Oliguria (less than 0.5 mL/kg/h for 6 hours or less than 500 mL/d)
Urine Output Patterns
Nonoliguria:
Nonoliguria (greater than 500 mL/d)
Urine Output Patterns
Anuria:
Anuria (less than 50 mL/d)
Causes of AKI
What are the three classifications?
Prerenal
Intrarenal
Postrenal
Causes of AKI
Prerenal- What is it characterized by?
Prerenal- characterized by any event that leads to an acute decrease in effective renal perfusion
Causes of AKI
Prerenal- characterized by any event that leads to an acute decrease in effective renal perfusion
Most commonly, precipitating events include?
Most commonly, precipitating events include hypovolemia and cardiovascular failure;
Causes of AKI
Intrarenal-
characterized by actual damage to the renal parenchyma
Causes of AKI
Intrarenal- characterized by actual damage to the renal parenchyma
Such as:
Glomerular-
Vascular –
Interstitial –
Tubular –
Causes of AKI
Intrarenal- characterized by actual damage to the renal parenchyma
Such as: Glomerular-
poststreptococcal glomerulonephritis,
diseases causing vasculitis (Wegener granulomatosis)
Causes of AKI
Intrarenal- characterized by actual damage to the renal parenchyma
Such as: Vascular-
malignant hypertension
Causes of AKI
Intrarenal- characterized by actual damage to the renal parenchyma
Such as: Interstitial
Interstitial –pyelonephritis
Causes of AKI
Intrarenal- characterized by actual damage to the renal parenchyma
Such as: Tubular
Tubular – Acute tubular necrosis (ATN)
Causes of AKI
Postrenal
Postrenal –Obstruction of urine flow from collecting ducts in kidneys to external urethral orifice
Causes of AKI
Postrenal –Obstruction of urine flow from collecting ducts in kidneys to external urethral orifice
Such as:
Ureteral stones
Blockage- BPH
Tumor
ACUTE KIDNEY INJURY:
Clinical manifestations are related to:
Clinical manifestations related to decreased GFR,
fluid overload,
and impaired clearance of electrolytes
ACUTE KIDNEY INJURY:
Management includes what kind of therapy?
Diuretic therapy and nutritional therapy
ACUTE KIDNEY INJURY:
Management: What may need to be considered?
Dialysis may need to be considered
ACUTE KIDNEY INJURY:
Management includes:
Eliminate cause, prevent complications, and assist recovery
Acute Tubular Necrosis (ATN):
What are the two types:
Ischemic ATN
Toxic ATN
Acute Tubular Necrosis (ATN):
Ischemic ATN: results from what?
Ischemic ATN results from prolonged hypoperfusion.
Acute Tubular Necrosis (ATN):
Ischemic ATN: What is it caused by?
Caused by hemorrhagic hypotension, volume depletion, poor cardiac output, septic shock, pancreatitis, immunosuppression
Acute Tubular Necrosis (ATN):
Toxic ATN: What is it?
Is an aminoglycosides antibiotics, contrast-induced nephropathy
Acute Tubular Necrosis (ATN):
Toxic ATN: What remains intact?
The basement membrane of renal cells usually remains intact.
Acute Tubular Necrosis (ATN):
Toxic ATN: The basement membrane of renal cells usually remains intact.- So what does this mean?
Thus, non oliguria typically occurs more often and the healing process is often more rapid than ischemic ATN
Acute Tubular Necrosis (ATN):
Toxic ATN: What is treatment?
Treatment: aggressive volume expansion (0.9NS), alkalinize urine with sodium bicarbonate
CHRONIC KIDNEY DISEASE
Epidemiology: What is it considered?
Worldwide health problem
CHRONIC KIDNEY DISEASE
Epidemiology: Who are rates higher in?
Rates higher in African Americans and Native Americans
Higher in men than in women
CHRONIC KIDNEY DISEASE
Pathophysiology: What happens to renal function?
Slow, progressive, irreversible deterioration of renal function
CHRONIC KIDNEY DISEASE
What does it result in?
Results in kidney’s inability to eliminate waste products and maintain fluid and electrolyte balances
CHRONIC KIDNEY DISEASE
What does it lead to?
Leads to end-stage renal disease (ESRD)
CHRONIC KIDNEY DISEASE
What are the most common causes?
Most common causes are diabetes and hypertension
CHRONIC KIDNEY DISEASE (cont’d)
Clinical manifestations
Devastating effect on every body system
CHRONIC KIDNEY DISEASE (cont’d)
Management:
Renal replacement therapies
CHRONIC KIDNEY DISEASE (cont’d)
Management: What should be managed?
Manage fluid balance changes
CHRONIC KIDNEY DISEASE (cont’d)
Management: Manage fluid balance changes- how?
Treat hypovolemia
Prevent hypervolemia
CHRONIC KIDNEY DISEASE (cont’d)
Management: Manage what kind of alterations?
Manage acid-base alterations
Manage cardiovascular alterations
Manage pulmonary alterations
Manage gastrointestinal alterations
CHRONIC KIDNEY DISEASE (cont’d)
Management: Manage acid-base alterations
Metabolic acidosis
CHRONIC KIDNEY DISEASE (cont’d)
Management: Manage cardiovascular alterations
Hypertension
Hyperkalemia
CHRONIC KIDNEY DISEASE (cont’d)
Management: Manage pulmonary alterations
Pulmonary edema
CHRONIC KIDNEY DISEASE (cont’d)
Management: What may be necessary?
Renal transplantation
