Chapter 45 Nursing Assessment Renal system S. Buckley, RN, MS ( adapted from Mosby pp) Copyright ©...

Chapter 45Chapter 45

Nursing AssessmentNursing AssessmentRenal systemRenal system

S. Buckley, RN, MSS. Buckley, RN, MS

( adapted from Mosby pp)( adapted from Mosby pp)

Copyright © 2007, 2004, 2000, Mosby, Inc., an affiliate of Elsevier Inc. All Rights Reserved.


Nephron

Basic function is to clean or clear blood plasma of unnecessary substances

~ 1million nephrons in each kidney Contains: glomerulus, Bowman’s capsule,

tubules ( proximal, convoluted, loop of Henle, distal convoluted)


Fig. 45-2


Fig. 45-3


Physiology of urine formationPhysiology of urine formation

* Primary function of kidneys: filter blood, * Primary function of kidneys: filter blood, maintain body’s internal homeostasis. maintain body’s internal homeostasis.

* Multistep process of: * Multistep process of: filtration, reabsorption, filtration, reabsorption, secretions, excretion of water, electrolytes and secretions, excretion of water, electrolytes and metabolic waste.metabolic waste.

* Urine formation begins at glomerulus (blood * Urine formation begins at glomerulus (blood filtered)filtered)

* Glomerular filtration rate (GFR)-* Glomerular filtration rate (GFR)-amount of blood amount of blood filtered by the glomeruli in a given time,filtered by the glomeruli in a given time,

normal is ~ 125ml/min.normal is ~ 125ml/min.


The normal kidney can alter its excretion of salt to match loss with

gain.


Structures and FunctionsStructures and Functionsof the Urinary Systemof the Urinary System

Primary function of kidneys: Primary function of kidneys: 1. Regulation of water and ion balance (electrolyte and 1. Regulation of water and ion balance (electrolyte and

acid base balance) acid base balance) 2. Removal of metabolic waste products from the blood 2. Removal of metabolic waste products from the blood

and excretion in urineand excretion in urine3. Removal of foreign chemicals from the blood and 3. Removal of foreign chemicals from the blood and

excretion in urineexcretion in urine4. Secretion of hormones: 4. Secretion of hormones: a.a. Erythropoietin, which controls Erythropoietin, which controls erythrocyteerythrocyte

productionproductionb.b. Renin, which controls formation of angiotensin and Renin, which controls formation of angiotensin and

influences influences blood pressure and sodium balanceblood pressure and sodium balancec.c. 1, 25-dihydroxyvitamin D3, which influences 1, 25-dihydroxyvitamin D3, which influences

calcium balancecalcium balance


Renal processes for sodium and water

Sodium and water freely filter form the glomerular capillaries into Bowman’s space and undergo reabsorption, Normally ~99%

Most reabsorption (2/3) occurs in proximal tubule, water reabsorption is by diffusion and dependent upon sodium reabsorption.

Major influence on the reabsorption of sodium and water in tubules is ADH ( increases reabsorption of sodium and water and therefore decreases urine output

Sodium excreted=sodium filtered-sodium reabsorbed Serum sodium-135-146mEq/L


Renal water regulation

Major change caused by water loss or gain out of proportion to sodium loss or gain is a change in osmolarity of the body fluids.

Change in osmolarity is responded to via osmoreceptors in hypothalamus, controlling ADH secretion.


Thirst and salt appetite

Must replace sodium and water losses by intake

THIRST, drives ingestion of water, stimulated by low extracellular volume and high plasma osmolarity.


Potassium regulation

Most abundant intracellular ion. Only 2% of total body K is in extracellular fluid.

K concentration in extracellular fluid is important for the function of excitable tissues (nerve and muscle). Any increase (or decrease) in extracellular K, changes resting membrane potential of cells (in heart can result in abnormalities of heart rhythm, or arrythmias or weakness).

K in urine=amount ingested minus amount eliminated in feces and sweat.

Deficit or excess controls aldosterone secretion, which determine excretion of K in urine.

Serum potassium-3.5-5.5 mEq/L


Water balance, acid-base balance

Function of: 1. ADH 2. Aldosterone 3. HCO3 and H+ (acid/base balance) 4. ANP


Antidiuretic hormone (ADH)-required for Antidiuretic hormone (ADH)-required for water reabsorption in the kidney , important in water reabsorption in the kidney , important in fluid balance. fluid balance.

makes tubules and collecting ducts makes tubules and collecting ducts permeable to water, allowing water to be permeable to water, allowing water to be reabsorbed into the peritubular capillaries and reabsorbed into the peritubular capillaries and returned to the circulation. returned to the circulation.

Functions in concert with hypothalamus and Functions in concert with hypothalamus and neural input as loop mechanismneural input as loop mechanism

decreases urine outputdecreases urine output


aldosterone

Released from adrenal cortex, acts on distal tubule to cause reabsorption of Na+ and water.

Influenced by blood concentrations of Na+ and K+

In exchange for Na+ reabsorption, potassium ions (K+) are excreted.


Atrial Natriuretic peptide (ANP)

Hormone secreted from cells in R atrium in response to atrial distention due to an increase in plasma volume.

Acts on kidneys to increase Na+ excretion. Inhibits renin, ADH and action of angiotensinII on the

adrenal glands, thus suppresses aldosterone secretion.

ANP causes relaxation of afferent arteriole, thus increasing the GFR

Combined effects of ANP=production of large volume of dilute urine


Renin angiotensin aldosterone system

You tube; Dr. Najeeb, 1-7 short video’s, RAAS/kidney function.

http://www.youtube.com/watch?v=puM5WCvOBdU


Fig. 45-4


Other Kidney functions(continued)

Erythropoietin-stimulates the production of red blood cells (RBCs) in bone marrow

produced and released in response to hypoxia and decreased renal blood flow.

In renal failure, a deficiency of erythropoietin occurs leading to anemia

Vitamin D-hormone obtained in diet and sun.

requires metabolism in liver and kidney to be “activated”, essential for absorption of Ca+ from GI tract.

In renal failure manifestation of problems of altered Ca+ and PO2 balance.


Other Kidney functions

Calcium balance -parathyroid hormone (PTH) is released from parathyroid gland in response to low serum ca+ levels. PTH works by causing increased tubular reabsorption of CA2+ and decreased tubular reabsorption of phosphate ions (PO4 2-)

In renal disease, the effects of PTH may have major effect on bone metabolism.


Other Kidney functions(continued)

Renin-regulates BP, involved in splitting of angiotensin cascade (p. 1138). Angiotensin II stimulates release of aldosterone (causes Na+ and water retention leading to increased ECF volume) Also causes peripheral vasoconstriction. (both increase BP)

Produced and secreted by cells in kidneys, released into blood in response to decreased; renal perfusion, arterial BP, ECF, Na+

Released into blood in response to increased urinary Na+ concentration


Other kidney functions(continued)

Prostaglandins (PGs)- involved in the regulation of cell function and host defenses

PG synthesis occurs in the medullla of the kidney. PGs increase renal blood flow and promote Na+ excretion.

Counteract the vasoconstrictor effect of angiotensin and norepinephrine =decreased systemic vascular resistance= decreased BP.


Acid base regulation

Reabsorbing and conserving bicarbonate (HCO3) and secreting Hydrogen (H+) in response ph of ECF

Distal tubule functions to maintain the ph of ECF within range of 7.35-7.45.

Metabolic response to ph along with respiratory acid/base balance.


Urinary Bladder

Serves as reservoir for urine Bladder muscle-detrusor muscle Normal urine output, ~1500ml/day, varies

with intake of food and water, diurnal pattern. ~250ml of urine in bladder cause moderate

distention and urge to urinate.


Fig. 45-5


Female/Male anatomy


Gerontologic ConsiderationsGerontologic ConsiderationsEffects of Aging on the Urinary SystemEffects of Aging on the Urinary System

20-30% decrease in size with aging, by 70 yrs old, 30-50% of glomeruli have lost function.

Decreased renal blood flow, decreased GFR, alterations in hormone levels (ADH, aldosterone, ANP=decreased urinary concentration, limitations in excretion of water, Na+, K+ and acid).


Benign prostatic hyperplasia(BPH)

Enlargement of prostate Prevalence-50% of men over 50 yrs, 90% of

men over 80 yrs. Symptoms result from urinary obstruction;1. Obstructive symptoms-decrease in caliber and

force of urinary stream, difficulty initiating voiding, intermittency, dribbling

2. Irritative symptoms- (associated with inflammation or infection)- frequency, urgency, dysuria, nocturia, incontinence


BPH(continued)

Complications-urinary retention, UTI; potential sepsis, urinary calculi, hydronephrosis leading to renal failure, pyelonephritis, bladder damage.

Diagnostic-DRE (digital rectal exam), PSA ( prostate-

specific antigen-blood level associated with ca and BPH) Collaborative care-drug therapy, diet,

catheterization, surgery (TURP), laser prostatectomy, stent placement, monitor for infection, hemorrhage, education, emotional support.


Women’s gerontological urinary issues

Urethrovesical unit undergoes loss of elasticity, vascularity and structure, may result in incontinence (stress), irritation, bladder infections, prolapse

Hormonal changes result in decrease in estrogen, mucosal dryness and irritation (cystitis)


Incidence of uti

Most common bacterial infection, not reportable (US) 7 million office visits, 1million ER visits, 100,000

hospitalizations. 1in 3 women will have 1 episode requiring antibiotics

by age 24, ½ of all women in lifetime Increased in pts with; infants, pregnancy, aids, ms,

dm, BPH Catheter associated uti: most common nosocomial,

>1million cases a year. Costs: 1.6 billion.


Conditions impacting voiding

Any disease or trauma that affects function of the brain, spinal cord, nerves that innervate bladder, sphincter or pelvic floor can affect bladder function. These include:

DM, MS, paraplegia, quadriplegia, spinal problems, drugs affecting nerve transmission.


Assessment ofAssessment ofthe Urinary Systemthe Urinary System

Subjective dataSubjective data Important health informationImportant health information

• Past health history-related diseases, Past health history-related diseases, surgeries, include family hx, surgeries, include family hx, occupation/environment, diet, water intake, occupation/environment, diet, water intake, exercise, elimination patternexercise, elimination pattern

• Smoking hx; major factor in risk for bladder Smoking hx; major factor in risk for bladder ca. tumors occur 4x more frequently .ca. tumors occur 4x more frequently .

• MedicationsMedications

• Surgery or other treatmentsSurgery or other treatments


Assessment terms(p.1145)


Assessment ofAssessment ofthe Urinary System (cont’d)the Urinary System (cont’d)

Functional health patternsFunctional health patterns• Health Perception–Health Management PatternHealth Perception–Health Management Pattern

• Nutritional-Metabolic PatternNutritional-Metabolic Pattern

• Elimination PatternElimination Pattern

• Activity-Exercise PatternActivity-Exercise Pattern

• Sleep-Rest PatternSleep-Rest Pattern

• Cognitive-Perceptual PatternCognitive-Perceptual Pattern

• Self-Perception–Self-Concept PatternSelf-Perception–Self-Concept Pattern

• Role-Relationship PatternRole-Relationship Pattern

• Sexuality-Reproductive PatternSexuality-Reproductive Pattern


Assessment ofAssessment ofthe Urinary System (cont’d)the Urinary System (cont’d)

Objective dataObjective data Physical examinationPhysical examination

• InspectionInspection

• PalpationPalpation

• PercussionPercussion

• Auscultation Auscultation


Diagnostic StudiesDiagnostic Studiesof the Urinary Systemof the Urinary System

Urine studies- accuracy of results Urine studies- accuracy of results influenced by: influenced by: proper procedure, pt. proper procedure, pt. cooperation, often require bowel prep (KUB, IVP).cooperation, often require bowel prep (KUB, IVP). Urinalysis; 1Urinalysis; 1stst test done, best obtained in am, test done, best obtained in am, Creatinine clearance- Creatinine clearance- Creatinine: waste product Creatinine: waste product

produced by muscle breakdown, produced by muscle breakdown, most accurate indicator of renal function

Normal value: 85-135 ml/min Serum creatinine: 0.5-1.5mg/dl BUN-10-30gm/dlBUN-10-30gm/dl Urodynamics; Urodynamics; measures urinary tract functionmeasures urinary tract function Specific gravity; 1.003-1.030Specific gravity; 1.003-1.030


Fig. 45-7


Fig. 45-8


Fig. 45-9

Chapter 45 Nursing Assessment Renal system S. Buckley, RN, MS ( adapted from Mosby pp) Copyright ©...

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