Renal and urinary tract function

 Objectives
o Review anatomy and physiology of renal system
o Discuss mechanisms to maintain homeostasis
o Discuss changes associated with aging and necessary nursing intervention s
o Discuss cultural considerations
o Discuss assessment techniques
 A and P
o Two kidneys
o Each kidney has own tube- ureter
 That drains into bladder
o Abdominal aortic that goes into renal arteries
o Urinary bladder
 Expands and contracts
 In collapsed state until you start to fill it then it will expand
o Urinary meatus
 Internal sphincters to hold till you get to bathroom
o Kidney inside
 Renal cortex- outside
 Renal medulla- inside
 Stones will usually lodge at vesicoureteral junction
o Both ureters meet bladder
o Each kidney in renal capsule
 Like every organ has Layer around it
 Receives 20-25% of total cardiac output 12x an hour is circulating
 Needs to be filtered and excreted
o Within kidney
 Millions of nephrons
o Afferent arterial
 Brings blood into system
 Oxygenated blood at good pressure going into nephron
 Have millions of those
 Straining out filtrate (not urine yet)
 Every time outflow goes through nephrons
 Remove filtrate
o Toxins, water
o Bowmen’s capsule collects this
 Loop of Henle
 Lasix exerts its effect here
 Never gets rid of fluid at loop normally
 Lasix influences that loop
 Excrete 180 L per hour
 In this section reabsorb some of that fluid
 Actually excrete 1.5 L
o Efferent
o Glomerulus
 o Bowman’s capsule
 If damaged
 Output will decrease
o Lasix get rid of salt, potassium
 Watch values
o Excrete BUN
 Watch value
 When body breaks down blood, body has to reabsorb that blood
 BUN will be elevated when blood is being reabsorbed
 When excrete BUN, some can be reabsorbed
 Bruise
o Cannot reabsorb Creatinine
o Bladder anatomy
 Ureters open into bladder
 Urethra
 Opening at bottom
 Urine comes down and should not go back up
 Not just reservoir
 If problem with meatus can go through wall of pelvic above suprapubic
area
 Detrusor muscle
 When put in bladder, meet resistance that is this muscle
 Hold steady and allow to relax then continue to reinsert
 Function of upper urinary tract
o Regulatory function
 FEAR
 Formation of urine
 Electrolyte balance
 Acid base balance
 Renal clearance
o Rid of body waste
o Hormonal function
 REV
 Secrete renin
o Powerful vasoconstrictor
o Make smaller
 Erythropoietin produced to stimulate bone marrow to RBC synthesis
 Vitamin D converted to an active form for calcium reabsorption and the
parathyroid hormones
 Regulatory function: urine formation
o Filtration at glomerulus
 Dump spaghetti into strainer
 Fluid start to accumulate
 About 20% of blood passing through the globe rule (1200 mL/min) is filtered
into nephron
o Absorption into peritubular capillaries
 Then absorb in tubes around
  Substances move from filtrate back into peritubular capillaries or vasa recta
o Reabsoprtion into tubule for excretion in urine
 Reabsorb more here and excrete out what is left
 Substances move from peritubular capillaries or vasa recta into tubular filtrate
o Processes are dependent on osmolarity and osmolarity
o If blood glucose level reaches 220 or higher
 Will spill into urine
 Not normally be sugar in urine
 If sugar in urine, blood sugar was high, but took time to get there so not high
anymore
 Urine formation by glomerular filtration
o About 20% of blood passing through the glomeruli is filtered into nephron
 1200 mL/min
o 180 L/day
o Normal GFR= 120-130 mL/min
 Controlled by BP and blood flow
 As long as maintained at certain amount then will have enough pressure
to work as it should
 BP decrease= less pressure so filtration decrease
 Self regulating mechanism is not effective with BP below 65- 70 mm Hg
systolic = perfusion problem or MAP of less than 65 mm HG
o Map
 Mean arterial pressure
 ((DBP x2) + SBP then /3)* on test
 If too low, not perfuse as should so hurt kidney
 Systolic= top number
 Diastolic= bottom number
 Water, electrolytes, and small particles filtered
 Enters proximal convoluted tubules (PCT) and is known as “tubular
filtrate”
 Urine formation by tubular reabsorption
o Keep normal urine output at 1-3 L /day
o Most water and electrolytes are reabsorbed from filtrate and returned into blood
o 50% of urea in filtrate is reabsorbed – except creatinine
o Reabsorb some of glucose filtered
 Renal threshold for reabsorption= 220 mg/dL
 > 220 mg/dL stays in filtrate
 Present in urine
o Bicarbonate, calcium, and phosphate are reabsorbed
 Maintain acid base balance
o Tubules return all filtered water back into body
 Vasopressin (ADH- anti diuretic hormone) and aldosterone
 More permeable to water with Vasopressin (ADH) and aldosterone
 Increased arteriole constriction
o Alters bp and amount of fluid that exits the glomerular
capillaries
 Aldosterone promotes the reabsorption of Na in the DCT
 o Water reabsorption occurs as result of movement of Na
 Where sodium goes- water goes
 Urine formation by tubular secretion
o Transfer materials from peritubular capillaries to renal tubular lumen
o Secretion of Hydrogen (H+) and NH4+ (ammonia) from blood into tubular fluid that
helps to keep blood pH at its normal level
 Hormonal function
o Renin- powerful vasoconstrictor
 Assist in BP control
 Triggers chain of events
 RAAS pathway
 Renin angiotensin aldosterone system
o In response to low Bp or serum sodium, kicks in to help
compensate for that
 Serum sodium
 Low sodium= low fluid volume
 Not a lot of fluid= BP decreases
 Regulate bp and bring it up
 Liver Releases hormone called antiotensinogen
 Response to that kidney shoots out renin
 Together they react and end up with angiotensin 1
 When angiotensin 1 gets to lungs, they release ACE
 Level where ACE inhibitors work
 When they take ACE inhibitors, stop enzyme
from being released
 ACE causes raise in blood pressure
 Ace and angiotensin 1 together make angiotensin 2
 Angiotensin 2 works on level of kidney and adrenal
glands
 Go to adrenal glands and create aldosterone
 Aldosterone effect in body
o When created, helps BP regulation
 When have aldosterone,
increase reabsorption of
sodium, so increase fluid on
board that also increases BP
o Aldosterone decreases K so watch
levels and provide preventative
measures
 Angiotensin 2 at kidney
o Cause vasoconstriction in arterioles
 Going to increase BP
 More narrow arteries and
vessels= higher Bp goes
o Diagram information
 Stimuli for renin secretion
  Decreased renal perfusion pressure and/or
decreased salt delivery to kidney tubules
o Examples
 Hemorrhage
 Heart failure
 Cirrhosis
 Loop diuretics
 Decreased salt intake
 Angiotensin to liver
 Renin release
 Angiotensin 1
 Renal autoregulation
o Efferent arterioles constrict
o GFR maintained
 Increased blood pressure
o Vasoconstriction
o Increased myocardial contractility
o Prostaglandin release
 Increased circulating volume
o Aldosterone release
o Sodium and water reabsorption
o K excrete
o ADH release
o Prostaglandins
 Regulate glomerular filtration, kidney vascular resistance and renin production
 Increase sodium and water excretion
o Erythropoietin
 Triggers RBC production in bone marrow
o Vit D
 Processing occurs from sunlight and in liver
 Converted to active form in kidney
 Needed to absorb calcium
 Renal clearance
o Renal clearance test
 How well Kidney clear solutes form plasma
o 24 hr urine collection
 Throw away first
 End of time void and put in container
 On ice or in cool place
 Dark place
o Creatine: waste product of skeletal myo breakdown
 Filtered via glomerulus
 Passes through tubules with minimal change
 Excreted in urine
 Creatinine clearance good indicator of GFR (kidney function)
 Test question
o Factors that affect renal clearance
  Speed across filter
 Affected by pressure
 Substance reabsorption along tubules
 Quantity of substances secreted back into tubules
 some med nephrotoxic
 Normal urinary output
o UO (urinary output)/kg decreases as child ages bc kidney becomes more efficient at
concentrating urine
 Infant
 2ml/kg/hr
 Children
 0.5-1 ml/kg/hr
 Adolescents
 40-80 ml/hr
 Adults
 1-3 L/day
 Ureters, urinary bladder, urethra
o Ureters
 Connects the renal pelvis to urinary bladder
o Urinary bladder
 Muscular sac
 Men
 Front of rectum
 Women
 In front of vagina
o Urethra
 Narrow tube to eliminate urine from bladder
 Men 6-8 in
 Women 1-1 ½ in
 Kidney changes associated with aging *
o Reduced ability to filter and excrete
 Smaller with age
 Reduced blood flow
 Nephrons at risk for damage during BP changes
 Number of glomeruli and GFR decreases
 GFR around 65ml/hr
o ½ the rate of young adult
 Risk for fluid overload
 Decline more rapid in DM, HTN, HF
 Greater risk or damage from drugs and contrast dye
o Why hold metformin when going for dye bc both hard on kidney
and could cause renal failure
o Tubule length decreases
 Decrease ability to concentrate urine
 Urgency
 Nocturnal polyuria
o Regulation of sodium, acids, and bicarbonate less effective
 o Risk for dehydration and hypernatremia
 Impairment in thirst mechanism in addition to age related changes
o Decreased bladder capacity
o Reduced ability to retain urine r/t decreased bladder capacity change secondary to
detrusor muscle
o Urinary sphincters become weak
o Women
 Urinary incontinence
 Wreaked myo in pelvic wall = shorten urethra
o Men
 Urinary retention
 Enlarged prostate gland
 Difficulty starting stream
 Nursing interventions with older adult
o Monitor hydration status and snacks provide adequate fluid intake
 Regulation of water balance decreases with age changes secondary to
decreased GFR
o Administer all drugs carefully especially nephrotoxic
 Blood flow reduced
 Decrease blood clearance secondary to decrease GFR
 Some drugs increase urine output
 Anticholinergic drugs promote urinary retention
o Safety with nocturia
 Ensure lighted and clear pathways
 Bedside toilet/urinal
 No fluid intake 2-4 hr before bedtime
 Home teaching
o Urination needs
 Encourage urination at least every 2 hr
 Scheduled urination may avoid overflow incontinence
 Respond to pt urination need ASAP
 May alleviate stress incontinence
o Perineal care in women
 Shortened urethra increase risk for bladder infections
 Cultural considerations
o African Americans greater risk for kidney failure
 Greater age related decreases in GFR than white people
 Excretion of sodium is less effective in hypertensive pt
 20% less blood flow secondary to changes in small vessels and intrarenal
responses to renin
o Education about yearly urinalysis to check for microalbuminuria and evaluating serum
creatinine
 Microalbuminuria
 Small protein in urine
 Dip stick tests
o Indication of clearance and function of kidney
 Pt history assessment
o Pt history
 Age, gender, race, ethnicity
 Nonmodifiable risk factors
 Sudden onset HTN after 50 could indicate HTN
 Men older than 50 with urine pattern changes could indicate prostate disease
 Women have shorter urethras increase risks for cystitis
 Previous kidney and urologic problems
 Chronic problems
 DM
 HTN
 Vessel damage with these diseases
 Chemical exposure
 Illegal drugs
 Recent travels
 Socioeconomic status
 Lack of insurance
 Access to health care
 Lack of transportation
 Education
 Completing antibiotic therapy
 Which meds do not need to be taken together
 Watch self medication due to socioeconomic factors
o Only take BP pill every other day
 Language barriers
o Nutrition history
 Diet including recent changes in diet
 Increase in protein with poor fluid intake could = calculi
 Fluid amount and type
 2L/day recommended to prevent dehydration and cystitis
 Changes in appetite
 Possible buildup of nitrogenous waste product as result of kidney
impairment
o Medication history
 Identify ALL medications as many can cause impaired kidney function
 Gentamicin can cause ACUTE KIDNEY INJURY (AKI)- NEPHROTOXIC
 OTC
o APAP and NSAIDS
 HTN, DM, cardiac, etc
o Family history and genetic risk
o Current health problems
 URI, GI, arthralgia, myalgia can be related to kidney function problems
 Renal colic
 Pain radiating into perineal area, groin, scrotum, or labia
o Occurs when stones are present as they obstruct or are being
passed and the ureter is distended
o Occurs with pallor, diaphoresis, hypotension
o Pain occurs bc of nerve tracts near kidneys and ureters
  Pattern and control of urination and characteristic of urine
 Encourage diary
 Anorexia, NV, myalgia, pruritus, fatigue and lethargy
 Signs of uremia
o Buildup of nitrogenous, waste products in the blood secondary
to kidney impairment
 Commonly used terms
o Anuria
 Total urine output of less than 100 ml in 24 hr
o Azotemia
 Increased blood urea nitrogen and serum creatinine levels suggestive of kidney
impairment but without outward symptoms of kidney failure
o Bruit
 Audible swishing sound produced when volume of blood or diameter of blood
vessel changes
o Dysuria
 Discomfort or pain associated with micturition
o Frequency
 Feeling need to void often, usually voiding small amounts of urine each time
 May void every hour or even more frequently
o Hesitancy
 Difficulty in initiating the flow of urine, even when the bladder has sufficient
urine to initiate a void and the sensation of need to void is present
o Micturition
 Act of voiding
o Nocturia
 Awaken prematurely from sleep bc of need to empty bladder
o Oliguria
 Decreased urine output
 Total urine outpu between 100-400 ml in 24 hr
o Polyuria
 Increased urine output
 Total urine output usually greater than 2000 ml in 24 hr
o Uremia
 Full blown manifestations of kidney failure
 Sometimes referred to as the uremic syndrome
 Especially if cause of the renal failure is unknown
o Urgency
 Sudden onset to feeling of need to void immediately
 May result in incontinence if pt is unable to get to toileting facilities quickly
 Physical assessment
o General appearance
 Skin
 Rashes
 Ecchymosis
 Yellow discoloration
 Pallor
  Dry and scaly skin
o Uremic pruritus
 Edema
 Pedal, pretibial (shin next to bone), sacral (mostly bed bound), and
periorbital (around eyes, fluid volume overload, heart failure- heart not
pump effectively then kidney will not perfuse)
o Lung auscultation
 Determine if fluid is present
 Crackles, wet lung sounds
 Overload
o Weight
 Water weight
 Weigh every day, same time, same way
 Best assessment of fluid retention
o Vital signs
 BP
 Up
 HR
 Bounding with excessive fluid
 Tachycardia and Brady or faintly felt
o LOC, alertness, and cognitive changes
 Deficit= result of waste buildup
 Lethargy bc toxin not excreted out of system
 Kidney, ureters, and bladder physical assessment
o Inspect
 Abdomen and flank area supine and sitting
 observe for symmetry/ discoloration in CVA (costovertebral angle) region
 outline of bladder may be seen with severe distention
o Auscultate
 Over midclavicular line
 Bruit over renal artery= renal artery stenosis
o Palpate
 Ask about tenderness
 Palpate non tender areas first
 Lightly palpating would be harmful if tumor or aneurism is suspected
o Urethra physical assessment
 Inspect
 Meatus and surrounding tissue
o Discharge
 Blood, mucous, pus
o Lesions, rashes on penis, scrotum, labia, or vaginal opening
 Psychosocial assessment
o Fear
o Anger
o Embarrassment
o Anxiety
o Guilt
 o Sadness
 Laboratory diagnostic assessment
o Urine test
 Urinalysis
 1st morning urine best
 Collection methods voided urine
o Clean catch urine
o Catherterized specimen
o 24 hr urine collection
 Urine color
o Can be altered by concentration of urine and drug metabolites
o Colorless to pale (straw)
 Should be this color
 Darker color more concentration
 Can be altered by drugs
o Pink to red
 Medication
 Pyridium
 Beets, blackberries, rhubarb
 Blood
o Blue/green
 Results from dyes
 Reaction of pH of urine with plastic of catheter bag
 Blue bag syndrome
o Orange to amber
 Dehydration
 Liver Problems
 AZO
 Pyridium
o Brown to black
 Macrobid
 Iron supplements
o Specific gravity
 Normal value- 1.010-1.030
 Scale
 Low, well hydrated, lighter urine 1.010
 High, dehydration, darker urine
 Concentration of particles
 Refers to density of urine compared to distilled water
 High
o Dehydration
 Diarrhea
 Vomit
 Sweating
 Low kidney blood flow
 Excess ADH (vasopressin)
 Surgery
  Anesthetic agents
 Certain drugs of SIADH
o Urine osmolality
 High fluid loss = high concentration bc the kidney’s response to save water
 Diet, drugs, and activity can change osmolarity
o Urinalysis
 RBC (hematuria)
 WBC (pyuria infection inflammation)
 Proteinuria
 High
o Stress, infection, glomerular disorders (increased permeability
allows proteins to pass)
 Microalbuminuria
 Albumin in urine could mean early kidney disease especially in DM pt
 Glucose
 Filtered by glomerulus and reabsorbed by proximal tubule of nephron
 When BG rises above 220 mg/dL
o Renal threshold for reabsorption is exceeded and glucose spills
over into urine
 Ketone bodies
 Present when fat is used instead of glucose for energy
 Leukoesterase
 Indication of UTI
 Sediment
o Urine test
 Urine for culture and sensitivity
 Clean catch or catheterized specimen
 Analyzed for numbers and types of organism
 Culture and sensitivity report
o Blood urine test
o Creatinine clearance
 Measure progression of kidney disease (KD) staging
 Measures volume of blood cleared of endogenous creatinine in 1 min
 Approximates GFR
 Sensitive indicator of KD used to follow progression of disease
 Age, gender, height, weight, diet, and activity level influence expected
results
 Drug dosing may need to be decreased
o Collect urine for 24 hr
o Blood drawn at end of urine collection
o Blood test
 Serum creatinine level
 Muscle and protein break down excreted by kidney
 Normal range
o 0.6-1.2 mg/dL
 Higher in men bc of increased muscle mass
 o Older adults have decrease in muscle mass and a decrease rate
of creatinine clearance
 Caution noted
o Iodinated contrast dyes and some drugs with a serum creatinine
of 1.5 mg/dL or greater
 Notify MD if elevated
o BUN
 Measures effectiveness of kidney excretion of urea nitrogen (by product of
protein breakdown in liver) that has been filtered by kidneys from blood
 Not best indicator for kidney function
 Normal range
 7-18 mg/dL
 >60 yo 8-20 mg/dL
o BUN/serum creatinine ratio
 Determines if non kidney related factors are causing increase in BUN
 Blood volume low or CO low the BUN will rise more rapidly then serum
creatinine= ratio high
 Increase in BUN and serum creatinine= kidney dysfunction unrelated to
dehydration or poor perfusion
 Normal range
 6-25
 BUN divided by creatinine
o Blood osmolarity
 Good indicator of hydration status
 Measures concentration of particles in blood and urine
 Normal range blood
 285-295 MOSM/L
 ADH (vasopressin) is released when levels are high so water can be reabsorbed
 Imaging diagnostic assessment
o Kidney, ureter, and bladder x-ray (KUB)
 No preparation
 Supine position
 Measure kidney size and detect obstruction
o Computed tomography/magnetic resonance imaging of kidney
 Measure size, detect obstruction or masses, assess renal flow
 Dye may be used
 May be NPO
 Hold metformin 24 hr before and 48 hr after
 Evaluate kidney function before restarting
 Increase fluid intake to maintain UO at 1-2 mL/kg/hr for 6 hr
 No metal implants with MRI
 Dye contrast allergies
 Hellfish/iodine
o Renal scan/Nuclear
 PIV for radioisotopes (not dye)
 Preferred with allergies to dye or renal insufficiency
 Examines perfusion, function, and structure
  Encourage increase fluid intake to aid in eliminating isotope
o Renal angiography
 Determines renal blood vessel size and abnormality
 Catheter femoral artery with contrast
o Cystography and cystourethrography
 X-ray to determine structure and function of the bladder and urethra
 Catheter inserted to instill contrast dye to visualize lower urinary tract
 Not absorbed in bloodstream
o Not nephrotoxic
o Retrograde procedures
 Examines structural abnormalities or obstruction
 Contrast dye is instilled in bladder or urethra
 Not nephrotoxic
 Common urological procedures
o Cystoscopy and cystourethroscopy
 General or local anesthesia
 NPO/permit
 Examines bladder trauma or urethral damage
 Remove bladder tumors/stones or plant radium seeds in tumor
 Dilate ureters or urethra
 Place stents if necessary
 Resection of enlarged prostate
 Catheter may be in place after procedure
 Pink tinged urine
o Expected finding
 Monitor urine output, possible clots and s/s of infection
o Kidney biopsy- percutaneously
 Preoperative
 NPO 4-6 hr
 Consent
 CBC/PLT/ PT/ Serum urea
o Blood transfusion may be needed before biopsy (anemia)
o Hold anticoagulants
o HTN managed before and after as it affects clotting
o Dialysis for uremia before as it can affect clotting times
 Postoperative
 Monitor dressing, VS, UO, hematuria, HgB/Hct, flank pain (bleeding),
signs of hypovolemic shock
 Bed rest
o Supine position for 2-6 hr
 Pain med as needed
 Resume activity in 24 hr
o Avoid heavy lifting/strenuous activity for 1-2 weeks